diff --git a/NEWS.rst b/NEWS.rst
index bd09bfe..5fef40a 100644
--- a/NEWS.rst
+++ b/NEWS.rst
@@ -33,7 +33,7 @@
   matches all jobs).
 
 * Multiple triggers are now supported (currently Gerrit and a simple
-  Timer trigger ar supported).  Your layout.yaml file will need to
+  Timer trigger are supported).  Your layout.yaml file will need to
   change to add the key "gerrit:" inside of the "triggers:" list to
   specify a Gerrit trigger (and facilitate adding other kinds of
   triggers later).  See the sample layout.yaml and Zuul section of the
diff --git a/doc/source/cloner.rst b/doc/source/cloner.rst
index 2ddf0b5..72b0cb9 100644
--- a/doc/source/cloner.rst
+++ b/doc/source/cloner.rst
@@ -61,6 +61,23 @@
 
 .. program-output:: zuul-cloner --help
 
+
+Ref lookup order
+''''''''''''''''
+
+The Zuul cloner will attempt to lookup references in this order:
+
+ 1) Zuul reference for the indicated branch
+ 2) Zuul reference for the master branch
+ 3) The tip of the indicated branch
+ 4) The tip of the master branch
+
+The "indicated branch" is one of the following:
+
+ A) The project-specific override branch (from project_branches arg)
+ B) The user specified branch (from the branch arg)
+ C) ZUUL_BRANCH (from the zuul_branch arg)
+
 Clone order
 -----------
 
diff --git a/doc/source/gating.rst b/doc/source/gating.rst
index 43a5928..fff2924 100644
--- a/doc/source/gating.rst
+++ b/doc/source/gating.rst
@@ -212,19 +212,20 @@
   }
 
 
-Cross projects dependencies
----------------------------
+Cross Project Testing
+---------------------
 
 When your projects are closely coupled together, you want to make sure
 changes entering the gate are going to be tested with the version of
 other projects currently enqueued in the gate (since they will
 eventually be merged and might introduce breaking features).
 
-Such dependencies can be defined in Zuul configuration by registering a job
-in a DependentPipeline of several projects. Whenever a change enters such a
-pipeline, it will create references for the other projects as well.  As an
-example, given a main project ``acme`` and a plugin ``plugin`` you can
-define a job ``acme-tests`` which should be run for both projects:
+Such relationships can be defined in Zuul configuration by registering
+a job in a DependentPipeline of several projects. Whenever a change
+enters such a pipeline, it will create references for the other
+projects as well.  As an example, given a main project ``acme`` and a
+plugin ``plugin`` you can define a job ``acme-tests`` which should be
+run for both projects:
 
 .. code-block:: yaml
 
@@ -280,3 +281,82 @@
 When your job fetches several repositories without changes ahead in the
 queue, they may not have a Z reference in which case you can just check
 out the branch.
+
+
+Cross Repository Dependencies
+-----------------------------
+
+Zuul permits users to specify dependencies across repositories.  Using
+a special header in Git commit messages, Users may specify that a
+change depends on another change in any repository known to Zuul.
+
+Zuul's cross-repository dependencies (CRD) behave like a directed
+acyclic graph (DAG), like git itself, to indicate a one-way dependency
+relationship between changes in different git repositories.  Change A
+may depend on B, but B may not depend on A.
+
+To use them, include "Depends-On: <gerrit-change-id>" in the footer of
+a commit message.  Use the full Change-ID ('I' + 40 characters).
+
+
+Gate Pipeline
+~~~~~~~~~~~~~
+
+When Zuul sees CRD changes, it serializes them in the usual manner when
+enqueuing them into a pipeline.  This means that if change A depends on
+B, then when they are added to the gate pipeline, B will appear first
+and A will follow.  If tests for B fail, both B and A will be removed
+from the pipeline, and it will not be possible for A to merge until B
+does.
+
+Note that if changes with CRD do not share a change queue then Zuul
+is unable to enqueue them together, and the first will be required to
+merge before the second is enqueued.
+
+Check Pipeline
+~~~~~~~~~~~~~~
+
+When changes are enqueued into the check pipeline, all of the related
+dependencies (both normal git-dependencies that come from parent commits
+as well as CRD changes) appear in a dependency graph, as in gate.  This
+means that even in the check pipeline, your change will be tested with
+its dependency.  So changes that were previously unable to be fully
+tested until a related change landed in a different repo may now be
+tested together from the start.
+
+All of the changes are still independent (so you will note that the
+whole pipeline does not share a graph as in gate), but for each change
+tested, all of its dependencies are visually connected to it, and they
+are used to construct the git references that Zuul uses when testing.
+When looking at this graph on the status page, you will note that the
+dependencies show up as grey dots, while the actual change tested shows
+up as red or green.  This is to indicate that the grey changes are only
+there to establish dependencies.  Even if one of the dependencies is
+also being tested, it will show up as a grey dot when used as a
+dependency, but separately and additionally will appear as its own red
+or green dot for its test.
+
+Multiple Changes
+~~~~~~~~~~~~~~~~
+
+A Gerrit change ID may refer to multiple changes (on multiple branches
+of the same project, or even multiple projects).  In these cases, Zuul
+will treat all of the changes with that change ID as dependencies.  So
+if you say that change in project A Depends-On a change ID that has
+changes in two branches of project B, then when testing the change to
+project A, both project B changes will be applied, and when deciding
+whether the project A change can merge, both changes must merge ahead
+of it.
+
+A change may depend on more than one Gerrit change ID as well.  So it
+is possible for a change in project A to depend on a change in project
+B and a change in project C.  Simply add more "Depends-On:" lines to
+the footer.
+
+Cycles
+~~~~~~
+
+If a cycle is created by use of CRD, Zuul will abort its work very
+early.  There will be no message in Gerrit and no changes that are part
+of the cycle will be enqueued into any pipeline.  This is to protect
+Zuul from infinite loops.
diff --git a/doc/source/launchers.rst b/doc/source/launchers.rst
index c799291..0a1e0e7 100644
--- a/doc/source/launchers.rst
+++ b/doc/source/launchers.rst
@@ -66,6 +66,11 @@
 **LOG_PATH**
   zuul also suggests a unique path for logs to the worker. This is
   "BASE_LOG_PATH/pipeline-name/job-name/uuid"
+**ZUUL_VOTING**
+  Whether Zuul considers this job voting or not.  Note that if Zuul is
+  reconfigured during the run, the voting status of a job may change
+  and this value will be out of date.  Values are '1' if voting, '0'
+  otherwise.
 
 Change related parameters
 ~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -78,6 +83,10 @@
   The target branch for the change that triggered this build.
 **ZUUL_CHANGE**
   The Gerrit change ID for the change that triggered this build.
+**ZUUL_CHANGES**
+  A caret character separated list of the changes upon which this build
+  is dependent upon in the form of a colon character separated list
+  consisting of project name, target branch, and revision ref.
 **ZUUL_CHANGE_IDS**
   All of the Gerrit change IDs that are included in this build (useful
   when the DependentPipelineManager combines changes for testing).
diff --git a/doc/source/zuul.rst b/doc/source/zuul.rst
index ea6660a..a3b3b20 100644
--- a/doc/source/zuul.rst
+++ b/doc/source/zuul.rst
@@ -56,6 +56,10 @@
   Whether to start the internal Gearman server (default: False).
   ``start=true``
 
+**listen_address**
+  IP address or domain name on which to listen (default: all addresses).
+  ``listen_address=127.0.0.1``
+
 **log_config**
   Path to log config file for internal Gearman server.
   ``log_config=/etc/zuul/gearman-logging.yaml``
@@ -647,7 +651,7 @@
   Default: ``linear``.
 
 **window-increase-factor**
-  DependentPipelineManagers only. The value to be added or mulitplied
+  DependentPipelineManagers only. The value to be added or multiplied
   against the previous window value to determine the new window after
   successful change merges.
   Default: ``1``.
@@ -936,9 +940,10 @@
 whether a change merges cleanly::
 
   - name: ^.*-merge$
-    failure-message: This change was unable to be automatically merged
-    with the current state of the repository. Please rebase your
-    change and upload a new patchset.
+    failure-message: This change or one of its cross-repo dependencies
+    was unable to be automatically merged with the current state of
+    its repository. Please rebase the change and upload a new
+    patchset.
 
 Projects
 """"""""
@@ -1049,7 +1054,7 @@
       - foobar-extra-special-job
 
 Individual jobs may optionally be added to pipelines (e.g. check,
-gate, et cetera) for a project, in addtion to those provided by
+gate, et cetera) for a project, in addition to those provided by
 templates.
 
 The order of the jobs listed in the project (which only affects the
@@ -1104,13 +1109,11 @@
 If you need to abort Zuul and intend to manually requeue changes for
 jobs which were running in its pipelines, prior to terminating you can
 use the zuul-changes.py tool script to simplify the process. For
-example, this would give you a list of Gerrit commands to reverify or
-recheck changes for the gate and check pipelines respectively::
+example, this would give you a list of zuul-enqueue commands to requeue
+changes for the gate and check pipelines respectively::
 
-  ./tools/zuul-changes.py --review-host=review.openstack.org \
-      http://zuul.openstack.org/ gate 'reverify'
-  ./tools/zuul-changes.py --review-host=review.openstack.org \
-      http://zuul.openstack.org/ check 'recheck'
+  ./tools/zuul-changes.py http://zuul.openstack.org/ gate
+  ./tools/zuul-changes.py http://zuul.openstack.org/ check
 
 If you send a SIGUSR2 to the zuul-server process, or the forked process
 that runs the Gearman daemon, Zuul will dump a stack trace for each
diff --git a/etc/status/.gitignore b/etc/status/.gitignore
index 1ecdbed..218f297 100644
--- a/etc/status/.gitignore
+++ b/etc/status/.gitignore
@@ -1,4 +1 @@
-public_html/jquery.min.js
-public_html/jquery-visibility.js
-public_html/bootstrap
-public_html/jquery.graphite.js
+public_html/lib
diff --git a/etc/status/.jshintignore b/etc/status/.jshintignore
new file mode 100644
index 0000000..218f297
--- /dev/null
+++ b/etc/status/.jshintignore
@@ -0,0 +1 @@
+public_html/lib
diff --git a/etc/status/.jshintrc b/etc/status/.jshintrc
new file mode 100644
index 0000000..15bd571
--- /dev/null
+++ b/etc/status/.jshintrc
@@ -0,0 +1,21 @@
+{
+    "bitwise": true,
+    "eqeqeq": true,
+    "forin": true,
+    "latedef": true,
+    "newcap": true,
+    "noarg": true,
+    "noempty": true,
+    "nonew": true,
+    "undef": true,
+    "unused": true,
+
+    "strict": false,
+    "laxbreak": true,
+    "browser": true,
+
+    "predef": [
+        "jQuery",
+        "zuul"
+    ]
+}
diff --git a/etc/status/fetch-dependencies.sh b/etc/status/fetch-dependencies.sh
index b31d0de..ccaf74c 100755
--- a/etc/status/fetch-dependencies.sh
+++ b/etc/status/fetch-dependencies.sh
@@ -1,21 +1,23 @@
 #!/bin/bash
 BASE_DIR=$(cd $(dirname $0); pwd)
-echo "Destination: $BASE_DIR/public_html"
+DEST_DIR=$BASE_DIR/public_html/lib
+mkdir -p $DEST_DIR
+echo "Destination: $DEST_DIR"
 
 echo "Fetching jquery.min.js..."
-curl -L --silent http://code.jquery.com/jquery.min.js > $BASE_DIR/public_html/jquery.min.js
+curl -L --silent http://code.jquery.com/jquery.min.js > $DEST_DIR/jquery.min.js
 
 echo "Fetching jquery-visibility.min.js..."
-curl -L --silent https://raw.githubusercontent.com/mathiasbynens/jquery-visibility/master/jquery-visibility.js > $BASE_DIR/public_html/jquery-visibility.js
+curl -L --silent https://raw.githubusercontent.com/mathiasbynens/jquery-visibility/master/jquery-visibility.js > $DEST_DIR/jquery-visibility.js
 
 echo "Fetching jquery.graphite.js..."
 curl -L --silent https://github.com/prestontimmons/graphitejs/archive/master.zip > jquery-graphite.zip
-unzip -q -o jquery-graphite.zip -d $BASE_DIR/public_html/
-mv $BASE_DIR/public_html/graphitejs-master/jquery.graphite.js $BASE_DIR/public_html/
-rm -R jquery-graphite.zip $BASE_DIR/public_html/graphitejs-master
+unzip -q -o jquery-graphite.zip -d $DEST_DIR/
+mv $DEST_DIR/graphitejs-master/jquery.graphite.js $DEST_DIR/
+rm -R jquery-graphite.zip $DEST_DIR/graphitejs-master
 
 echo "Fetching bootstrap..."
 curl -L --silent https://github.com/twbs/bootstrap/releases/download/v3.1.1/bootstrap-3.1.1-dist.zip > bootstrap.zip
-unzip -q -o bootstrap.zip -d $BASE_DIR/public_html/
-mv $BASE_DIR/public_html/bootstrap-3.1.1-dist $BASE_DIR/public_html/bootstrap
+unzip -q -o bootstrap.zip -d $DEST_DIR/
+mv $DEST_DIR/bootstrap-3.1.1-dist $DEST_DIR/bootstrap
 rm bootstrap.zip
diff --git a/etc/status/public_html/index.html b/etc/status/public_html/index.html
index 3bd7a12..97025a6 100644
--- a/etc/status/public_html/index.html
+++ b/etc/status/public_html/index.html
@@ -19,16 +19,14 @@
 <html dir="ltr" lang="en">
 <head>
     <title>Zuul Status</title>
-    <link rel="stylesheet" href="bootstrap/css/bootstrap.min.css">
+    <link rel="stylesheet" href="lib/bootstrap/css/bootstrap.min.css">
     <link rel="stylesheet" href="styles/zuul.css" />
 </head>
 <body>
-
     <div id="zuul_container"></div>
-
-    <script src="jquery.min.js"></script>
-    <script src="jquery-visibility.js"></script>
-    <script src="jquery.graphite.js"></script>
+    <script src="lib/jquery.min.js"></script>
+    <script src="lib/jquery-visibility.js"></script>
+    <script src="lib/jquery.graphite.js"></script>
     <script src="jquery.zuul.js"></script>
     <script src="zuul.app.js"></script>
     <script>
diff --git a/etc/status/public_html/jquery.zuul.js b/etc/status/public_html/jquery.zuul.js
index 5e44205..0ca2718 100644
--- a/etc/status/public_html/jquery.zuul.js
+++ b/etc/status/public_html/jquery.zuul.js
@@ -16,9 +16,10 @@
 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 // License for the specific language governing permissions and limitations
 // under the License.
-'use strict';
 
 (function ($) {
+    'use strict';
+
     function set_cookie(name, value) {
         document.cookie = name + '=' + value + '; path=/';
     }
@@ -39,7 +40,7 @@
     }
 
     $.zuul = function(options) {
-        var options = $.extend({
+        options = $.extend({
             'enabled': true,
             'graphite_url': '',
             'source': 'status.json',
@@ -72,7 +73,7 @@
                         hideGrid: true,
                         target: [
                             "color(stats.gauges.zuul.pipeline." + pipeline_name
-                            + ".current_changes, '6b8182')"
+                                + ".current_changes, '6b8182')"
                         ]
                     });
                 }
@@ -288,10 +289,10 @@
                 }
 
                 var $change_progress_row_left = $('<div />')
-                    .addClass('col-xs-3')
+                    .addClass('col-xs-4')
                     .append($change_link);
                 var $change_progress_row_right = $('<div />')
-                    .addClass('col-xs-9')
+                    .addClass('col-xs-8')
                     .append(this.change_total_progress_bar(change));
 
                 var $change_progress_row = $('<div />')
@@ -375,7 +376,7 @@
                 else if (change.live !== true) {
                     // Grey icon
                     icon_name = 'grey.png';
-                    icon_title = 'Dependent change independently tested';
+                    icon_title = 'Dependent change required for testing';
                 }
                 else if (change.failing_reasons &&
                          change.failing_reasons.length > 0) {
@@ -616,7 +617,7 @@
 
         var app = {
             schedule: function (app) {
-                var app = app || this;
+                app = app || this;
                 if (!options.enabled) {
                     setTimeout(function() {app.schedule(app);}, 5000);
                     return;
@@ -642,7 +643,7 @@
                 this.emit('update-start');
                 var app = this;
 
-                var $msg = $(options.msg_id)
+                var $msg = $(options.msg_id);
                 xhr = $.getJSON(options.source)
                     .done(function (data) {
                         if ('message' in data) {
@@ -682,7 +683,10 @@
                                 data.result_event_queue.length : '0'
                         );
                     })
-                    .fail(function (err, jqXHR, errMsg) {
+                    .fail(function (jqXHR, statusText, errMsg) {
+                        if (statusText === 'abort') {
+                            return;
+                        }
                         $msg.text(options.source + ': ' + errMsg)
                             .addClass('alert-danger')
                             .removeClass('zuul-msg-wrap-off')
@@ -701,7 +705,7 @@
                     var newimg = new Image();
                     var parts = url.split('#');
                     newimg.src = parts[0] + '#' + new Date().getTime();
-                    $(newimg).load(function (x) {
+                    $(newimg).load(function () {
                         zuul_sparkline_urls[name] = newimg.src;
                     });
                 });
@@ -897,5 +901,5 @@
             app: app,
             jq: $jq
         };
-    }
+    };
 }(jQuery));
diff --git a/etc/status/public_html/styles/zuul.css b/etc/status/public_html/styles/zuul.css
index e833f4b..44fd737 100644
--- a/etc/status/public_html/styles/zuul.css
+++ b/etc/status/public_html/styles/zuul.css
@@ -16,7 +16,9 @@
 .zuul-change-total-result {
     height: 10px;
     width: 100px;
-    margin: 5px 0 0 0;
+    margin: 0;
+    display: inline-block;
+    vertical-align: middle;
 }
 
 .zuul-spinner,
diff --git a/etc/status/public_html/zuul.app.js b/etc/status/public_html/zuul.app.js
index 6f87a92..6321af8 100644
--- a/etc/status/public_html/zuul.app.js
+++ b/etc/status/public_html/zuul.app.js
@@ -17,9 +17,11 @@
 // License for the specific language governing permissions and limitations
 // under the License.
 
+/*exported zuul_build_dom, zuul_start */
+
 function zuul_build_dom($, container) {
     // Build a default-looking DOM
-    default_layout = '<div class="container">'
+    var default_layout = '<div class="container">'
         + '<h1>Zuul Status</h1>'
         + '<p>Real-time status monitor of Zuul, the pipeline manager between Gerrit and Workers.</p>'
         + '<div class="zuul-container" id="zuul-container">'
@@ -34,11 +36,14 @@
 
     $(function ($) {
         // DOM ready
-        $container = $(container);
+        var $container = $(container);
         $container.html(default_layout);
     });
 }
 
+/**
+ * @return The $.zuul instance
+ */
 function zuul_start($) {
     // Start the zuul app (expects default dom)
 
@@ -94,4 +99,6 @@
             }
         });
     });
-}
\ No newline at end of file
+
+    return zuul;
+}
diff --git a/requirements.txt b/requirements.txt
index f5525b6..c682999 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,7 +11,7 @@
 extras
 statsd>=1.0.0,<3.0
 voluptuous>=0.7
-gear>=0.5.4,<1.0.0
+gear>=0.5.7,<1.0.0
 apscheduler>=2.1.1,<3.0
 PrettyTable>=0.6,<0.8
 babel>=1.0
diff --git a/setup.cfg b/setup.cfg
index a4deb2f..620e1ac 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -5,7 +5,7 @@
     README.rst
 author = OpenStack Infrastructure Team
 author-email = openstack-infra@lists.openstack.org
-home-page = http://ci.openstack.org/
+home-page = http://docs.openstack.org/infra/system-config/
 classifier =
     Intended Audience :: Information Technology
     Intended Audience :: System Administrators
diff --git a/test-requirements.txt b/test-requirements.txt
index c68b2db..4ae3eb3 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -2,6 +2,11 @@
 
 coverage>=3.6
 sphinx>=1.1.2,!=1.2.0,!=1.3b1,<1.3
+# NOTE(tonyb) Pillow isn't directly needed but it's pulled in via
+# Collecting Pillow (from blockdiag>=1.5.0->sphinxcontrib-blockdiag>=0.5.5
+# So cap as per global-requirements until https://launchpad.net/bugs/1501995
+# is properly fixed
+Pillow>=2.4.0,<3.0.0 # MIT
 sphinxcontrib-blockdiag>=0.5.5
 discover
 fixtures>=0.3.14
diff --git a/tests/base.py b/tests/base.py
index becc854..abbdb0a 100755
--- a/tests/base.py
+++ b/tests/base.py
@@ -47,8 +47,9 @@
 import zuul.rpclistener
 import zuul.launcher.gearman
 import zuul.lib.swift
-import zuul.merger.server
 import zuul.merger.client
+import zuul.merger.merger
+import zuul.merger.server
 import zuul.reporter.gerrit
 import zuul.reporter.smtp
 import zuul.trigger.gerrit
@@ -145,7 +146,7 @@
                                                         self.latest_patchset),
                                      'refs/tags/init')
         repo.head.reference = ref
-        repo.head.reset(index=True, working_tree=True)
+        zuul.merger.merger.reset_repo_to_head(repo)
         repo.git.clean('-x', '-f', '-d')
 
         path = os.path.join(self.upstream_root, self.project)
@@ -167,7 +168,7 @@
 
         r = repo.index.commit(msg)
         repo.head.reference = 'master'
-        repo.head.reset(index=True, working_tree=True)
+        zuul.merger.merger.reset_repo_to_head(repo)
         repo.git.clean('-x', '-f', '-d')
         repo.heads['master'].checkout()
         return r
@@ -258,8 +259,8 @@
                  "comment": "This is a comment"}
         return event
 
-    def addApproval(self, category, value, username='jenkins',
-                    granted_on=None):
+    def addApproval(self, category, value, username='reviewer_john',
+                    granted_on=None, message=''):
         if not granted_on:
             granted_on = time.time()
         approval = {
@@ -277,20 +278,20 @@
                 del self.patchsets[-1]['approvals'][i]
         self.patchsets[-1]['approvals'].append(approval)
         event = {'approvals': [approval],
-                 'author': {'email': 'user@example.com',
-                            'name': 'User Name',
-                            'username': 'username'},
+                 'author': {'email': 'author@example.com',
+                            'name': 'Patchset Author',
+                            'username': 'author_phil'},
                  'change': {'branch': self.branch,
                             'id': 'Iaa69c46accf97d0598111724a38250ae76a22c87',
                             'number': str(self.number),
-                            'owner': {'email': 'user@example.com',
-                                      'name': 'User Name',
-                                      'username': 'username'},
+                            'owner': {'email': 'owner@example.com',
+                                      'name': 'Change Owner',
+                                      'username': 'owner_jane'},
                             'project': self.project,
                             'subject': self.subject,
                             'topic': 'master',
                             'url': 'https://hostname/459'},
-                 'comment': '',
+                 'comment': message,
                  'patchSet': self.patchsets[-1],
                  'type': 'comment-added'}
         self.data['submitRecords'] = self.getSubmitRecords()
@@ -380,11 +381,16 @@
 class FakeGerrit(object):
     log = logging.getLogger("zuul.test.FakeGerrit")
 
-    def __init__(self, *args, **kw):
+    def __init__(self, hostname, username, port=29418, keyfile=None,
+                 changes_dbs={}):
+        self.hostname = hostname
+        self.username = username
+        self.port = port
+        self.keyfile = keyfile
         self.event_queue = Queue.Queue()
         self.fixture_dir = os.path.join(FIXTURE_DIR, 'gerrit')
         self.change_number = 0
-        self.changes = {}
+        self.changes = changes_dbs.get(hostname, {})
         self.queries = []
 
     def addFakeChange(self, project, branch, subject, status='NEW'):
@@ -407,7 +413,27 @@
     def review(self, project, changeid, message, action):
         number, ps = changeid.split(',')
         change = self.changes[int(number)]
+
+        # Add the approval back onto the change (ie simulate what gerrit would
+        # do).
+        # Usually when zuul leaves a review it'll create a feedback loop where
+        # zuul's review enters another gerrit event (which is then picked up by
+        # zuul). However, we can't mimic this behaviour (by adding this
+        # approval event into the queue) as it stops jobs from checking what
+        # happens before this event is triggered. If a job needs to see what
+        # happens they can add their own verified event into the queue.
+        # Nevertheless, we can update change with the new review in gerrit.
+
+        for cat in ['CRVW', 'VRFY', 'APRV']:
+            if cat in action:
+                change.addApproval(cat, action[cat], username=self.username)
+
+        if 'label' in action:
+            parts = action['label'].split('=')
+            change.addApproval(parts[0], parts[2], username=self.username)
+
         change.messages.append(message)
+
         if 'submit' in action:
             change.setMerged()
         if message:
@@ -598,6 +624,8 @@
             result = 'RUN_ERROR'
         else:
             data['result'] = result
+            data['node_labels'] = ['bare-necessities']
+            data['node_name'] = 'foo'
             work_fail = False
 
         changes = None
@@ -892,6 +920,7 @@
         self.init_repo("org/conflict-project")
         self.init_repo("org/noop-project")
         self.init_repo("org/experimental-project")
+        self.init_repo("org/no-jobs-project")
 
         self.statsd = FakeStatsd()
         os.environ['STATSD_HOST'] = 'localhost'
@@ -938,7 +967,19 @@
             args = [self.smtp_messages] + list(args)
             return FakeSMTP(*args, **kw)
 
-        zuul.lib.gerrit.Gerrit = FakeGerrit
+        # Set a changes database so multiple FakeGerrit's can report back to
+        # a virtual canonical database given by the configured hostname
+        self.gerrit_changes_dbs = {
+            self.config.get('gerrit', 'server'): {}
+        }
+
+        def FakeGerritFactory(*args, **kw):
+            kw['changes_dbs'] = self.gerrit_changes_dbs
+            return FakeGerrit(*args, **kw)
+
+        self.useFixture(fixtures.MonkeyPatch('zuul.lib.gerrit.Gerrit',
+                                             FakeGerritFactory))
+
         self.useFixture(fixtures.MonkeyPatch('smtplib.SMTP', FakeSMTPFactory))
 
         self.gerrit = FakeGerritTrigger(
@@ -1044,7 +1085,7 @@
         repo.create_tag('init')
 
         repo.head.reference = master
-        repo.head.reset(index=True, working_tree=True)
+        zuul.merger.merger.reset_repo_to_head(repo)
         repo.git.clean('-x', '-f', '-d')
 
         self.create_branch(project, 'mp')
@@ -1063,7 +1104,7 @@
         repo.index.commit('%s commit' % branch)
 
         repo.head.reference = repo.heads['master']
-        repo.head.reset(index=True, working_tree=True)
+        zuul.merger.merger.reset_repo_to_head(repo)
         repo.git.clean('-x', '-f', '-d')
 
     def ref_has_change(self, ref, change):
@@ -1116,6 +1157,12 @@
         while len(self.gearman_server.functions) < count:
             time.sleep(0)
 
+    def orderedRelease(self):
+        # Run one build at a time to ensure non-race order:
+        while len(self.builds):
+            self.release(self.builds[0])
+            self.waitUntilSettled()
+
     def release(self, job):
         if isinstance(job, FakeBuild):
             job.release()
diff --git a/tests/fixtures/layout-live-reconfiguration-add-job.yaml b/tests/fixtures/layout-live-reconfiguration-add-job.yaml
new file mode 100644
index 0000000..e4aea6f
--- /dev/null
+++ b/tests/fixtures/layout-live-reconfiguration-add-job.yaml
@@ -0,0 +1,38 @@
+pipelines:
+  - name: gate
+    manager: DependentPipelineManager
+    failure-message: Build failed.  For information on how to proceed, see http://wiki.example.org/Test_Failures
+    trigger:
+      gerrit:
+        - event: comment-added
+          approval:
+            - approved: 1
+    success:
+      gerrit:
+        verified: 2
+        submit: true
+    failure:
+      gerrit:
+        verified: -2
+    start:
+      gerrit:
+        verified: 0
+    precedence: high
+
+jobs:
+  - name: ^.*-merge$
+    failure-message: Unable to merge change
+    hold-following-changes: true
+  - name: project-testfile
+    files:
+      - '.*-requires'
+
+projects:
+  - name: org/project
+    merge-mode: cherry-pick
+    gate:
+      - project-merge:
+        - project-test1
+        - project-test2
+        - project-test3
+        - project-testfile
diff --git a/tests/fixtures/layout-live-reconfiguration-del-project.yaml b/tests/fixtures/layout-live-reconfiguration-del-project.yaml
new file mode 100644
index 0000000..07ffb2e
--- /dev/null
+++ b/tests/fixtures/layout-live-reconfiguration-del-project.yaml
@@ -0,0 +1,21 @@
+pipelines:
+  - name: check
+    manager: IndependentPipelineManager
+    trigger:
+      gerrit:
+        - event: patchset-created
+    success:
+      gerrit:
+        verified: 1
+    failure:
+      gerrit:
+        verified: -1
+
+projects:
+  - name: org/project
+    merge-mode: cherry-pick
+    check:
+      - project-merge:
+        - project-test1
+        - project-test2
+        - project-testfile
diff --git a/tests/fixtures/layout-live-reconfiguration-failed-job.yaml b/tests/fixtures/layout-live-reconfiguration-failed-job.yaml
new file mode 100644
index 0000000..e811af1
--- /dev/null
+++ b/tests/fixtures/layout-live-reconfiguration-failed-job.yaml
@@ -0,0 +1,25 @@
+pipelines:
+  - name: check
+    manager: IndependentPipelineManager
+    trigger:
+      gerrit:
+        - event: patchset-created
+    success:
+      gerrit:
+        verified: 1
+    failure:
+      gerrit:
+        verified: -1
+
+jobs:
+  - name: ^.*-merge$
+    failure-message: Unable to merge change
+    hold-following-changes: true
+
+projects:
+  - name: org/project
+    merge-mode: cherry-pick
+    check:
+      - project-merge:
+        - project-test2
+        - project-testfile
diff --git a/tests/fixtures/layout-live-reconfiguration-shared-queue.yaml b/tests/fixtures/layout-live-reconfiguration-shared-queue.yaml
new file mode 100644
index 0000000..ad3f666
--- /dev/null
+++ b/tests/fixtures/layout-live-reconfiguration-shared-queue.yaml
@@ -0,0 +1,62 @@
+pipelines:
+  - name: check
+    manager: IndependentPipelineManager
+    trigger:
+      gerrit:
+        - event: patchset-created
+    success:
+      gerrit:
+        verified: 1
+    failure:
+      gerrit:
+        verified: -1
+
+  - name: gate
+    manager: DependentPipelineManager
+    failure-message: Build failed.  For information on how to proceed, see http://wiki.example.org/Test_Failures
+    trigger:
+      gerrit:
+        - event: comment-added
+          approval:
+            - approved: 1
+    success:
+      gerrit:
+        verified: 2
+        submit: true
+    failure:
+      gerrit:
+        verified: -2
+    start:
+      gerrit:
+        verified: 0
+    precedence: high
+
+jobs:
+  - name: ^.*-merge$
+    failure-message: Unable to merge change
+    hold-following-changes: true
+  - name: project1-project2-integration
+    queue-name: integration
+
+projects:
+  - name: org/project1
+    check:
+      - project1-merge:
+        - project1-test1
+        - project1-test2
+    gate:
+      - project1-merge:
+        - project1-test1
+        - project1-test2
+
+  - name: org/project2
+    check:
+      - project2-merge:
+        - project2-test1
+        - project2-test2
+        - project1-project2-integration
+    gate:
+      - project2-merge:
+        - project2-test1
+        - project2-test2
+        - project1-project2-integration
diff --git a/tests/fixtures/layout-no-timer.yaml b/tests/fixtures/layout-no-timer.yaml
index 9436821..ca40d13 100644
--- a/tests/fixtures/layout-no-timer.yaml
+++ b/tests/fixtures/layout-no-timer.yaml
@@ -1,14 +1,28 @@
 pipelines:
+  - name: check
+    manager: IndependentPipelineManager
+    trigger:
+      gerrit:
+        - event: patchset-created
+    success:
+      gerrit:
+        verified: 1
+    failure:
+      gerrit:
+        verified: -1
+
   - name: periodic
     manager: IndependentPipelineManager
     # Trigger is required, set it to one that is a noop
     # during tests that check the timer trigger.
     trigger:
       gerrit:
-        - event: patchset-created
+        - event: ref-updated
 
 projects:
   - name: org/project
+    check:
+      - project-test1
     periodic:
       - project-bitrot-stable-old
       - project-bitrot-stable-older
diff --git a/tests/fixtures/layout.yaml b/tests/fixtures/layout.yaml
index cc4d34c..1d23443 100644
--- a/tests/fixtures/layout.yaml
+++ b/tests/fixtures/layout.yaml
@@ -246,3 +246,7 @@
   - name: org/experimental-project
     experimental:
       - experimental-project-test
+
+  - name: org/no-jobs-project
+    check:
+      - project-testfile
diff --git a/tests/test_merger_repo.py b/tests/test_merger_repo.py
new file mode 100644
index 0000000..454f3cc
--- /dev/null
+++ b/tests/test_merger_repo.py
@@ -0,0 +1,79 @@
+#!/usr/bin/env python
+
+# Copyright 2012 Hewlett-Packard Development Company, L.P.
+# Copyright 2014 Wikimedia Foundation Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import logging
+import os
+
+import git
+
+from zuul.merger.merger import Repo
+from tests.base import ZuulTestCase
+
+logging.basicConfig(level=logging.DEBUG,
+                    format='%(asctime)s %(name)-32s '
+                    '%(levelname)-8s %(message)s')
+
+
+class TestMergerRepo(ZuulTestCase):
+
+    log = logging.getLogger("zuul.test.merger.repo")
+    workspace_root = None
+
+    def setUp(self):
+        super(TestMergerRepo, self).setUp()
+        self.workspace_root = os.path.join(self.test_root, 'workspace')
+
+    def test_ensure_cloned(self):
+        parent_path = os.path.join(self.upstream_root, 'org/project1')
+
+        # Forge a repo having a submodule
+        parent_repo = git.Repo(parent_path)
+        parent_repo.git.submodule('add', os.path.join(
+            self.upstream_root, 'org/project2'), 'subdir')
+        parent_repo.index.commit('Adding project2 as a submodule in subdir')
+        # git 1.7.8 changed .git from being a directory to a file pointing
+        # to the parent repository /.git/modules/*
+        self.assertTrue(os.path.exists(
+            os.path.join(parent_path, 'subdir', '.git')),
+            msg='.git file in submodule should be a file')
+
+        work_repo = Repo(parent_path, self.workspace_root,
+                         'none@example.org', 'User Name')
+        self.assertTrue(
+            os.path.isdir(os.path.join(self.workspace_root, 'subdir')),
+            msg='Cloned repository has a submodule placeholder directory')
+        self.assertFalse(os.path.exists(
+            os.path.join(self.workspace_root, 'subdir', '.git')),
+            msg='Submodule is not initialized')
+
+        sub_repo = Repo(
+            os.path.join(self.upstream_root, 'org/project2'),
+            os.path.join(self.workspace_root, 'subdir'),
+            'none@example.org', 'User Name')
+        self.assertTrue(os.path.exists(
+            os.path.join(self.workspace_root, 'subdir', '.git')),
+            msg='Cloned over the submodule placeholder')
+
+        self.assertEquals(
+            os.path.join(self.upstream_root, 'org/project1'),
+            work_repo.createRepoObject().remotes[0].url,
+            message="Parent clone still point to upstream project1")
+
+        self.assertEquals(
+            os.path.join(self.upstream_root, 'org/project2'),
+            sub_repo.createRepoObject().remotes[0].url,
+            message="Sub repository points to upstream project2")
diff --git a/tests/test_requirements.py b/tests/test_requirements.py
index 120e37e..4316925 100644
--- a/tests/test_requirements.py
+++ b/tests/test_requirements.py
@@ -52,13 +52,14 @@
         self.assertEqual(len(self.history), 0)
 
         # Add a too-old +1, should not be enqueued
-        A.addApproval('VRFY', 1, granted_on=time.time() - 72 * 60 * 60)
+        A.addApproval('VRFY', 1, username='jenkins',
+                      granted_on=time.time() - 72 * 60 * 60)
         self.fake_gerrit.addEvent(comment)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 0)
 
         # Add a recent +1
-        self.fake_gerrit.addEvent(A.addApproval('VRFY', 1))
+        self.fake_gerrit.addEvent(A.addApproval('VRFY', 1, username='jenkins'))
         self.fake_gerrit.addEvent(comment)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 1)
@@ -95,7 +96,8 @@
         self.assertEqual(len(self.history), 0)
 
         # Add an old +1 which should be enqueued
-        A.addApproval('VRFY', 1, granted_on=time.time() - 72 * 60 * 60)
+        A.addApproval('VRFY', 1, username='jenkins',
+                      granted_on=time.time() - 72 * 60 * 60)
         self.fake_gerrit.addEvent(comment)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 1)
@@ -126,7 +128,7 @@
         self.assertEqual(len(self.history), 0)
 
         # Add an approval from Jenkins
-        A.addApproval('VRFY', 1)
+        A.addApproval('VRFY', 1, username='jenkins')
         self.fake_gerrit.addEvent(comment)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 1)
@@ -157,7 +159,7 @@
         self.assertEqual(len(self.history), 0)
 
         # Add an approval from Jenkins
-        A.addApproval('VRFY', 1)
+        A.addApproval('VRFY', 1, username='jenkins')
         self.fake_gerrit.addEvent(comment)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 1)
@@ -188,13 +190,13 @@
         self.assertEqual(len(self.history), 0)
 
         # A -1 from jenkins should not cause it to be enqueued
-        A.addApproval('VRFY', -1)
+        A.addApproval('VRFY', -1, username='jenkins')
         self.fake_gerrit.addEvent(comment)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 0)
 
         # A +1 should allow it to be enqueued
-        A.addApproval('VRFY', 1)
+        A.addApproval('VRFY', 1, username='jenkins')
         self.fake_gerrit.addEvent(comment)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 1)
@@ -225,19 +227,19 @@
         self.assertEqual(len(self.history), 0)
 
         # A -1 from jenkins should not cause it to be enqueued
-        A.addApproval('VRFY', -1)
+        A.addApproval('VRFY', -1, username='jenkins')
         self.fake_gerrit.addEvent(comment)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 0)
 
         # A -2 from jenkins should not cause it to be enqueued
-        A.addApproval('VRFY', -2)
+        A.addApproval('VRFY', -2, username='jenkins')
         self.fake_gerrit.addEvent(comment)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 0)
 
-        # A +1 should allow it to be enqueued
-        A.addApproval('VRFY', 1)
+        # A +1 from jenkins should allow it to be enqueued
+        A.addApproval('VRFY', 1, username='jenkins')
         self.fake_gerrit.addEvent(comment)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 1)
@@ -251,7 +253,7 @@
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 1)
 
-        B.addApproval('VRFY', 2)
+        B.addApproval('VRFY', 2, username='jenkins')
         self.fake_gerrit.addEvent(comment)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 2)
diff --git a/tests/test_scheduler.py b/tests/test_scheduler.py
index 4b2b517..af3e488 100755
--- a/tests/test_scheduler.py
+++ b/tests/test_scheduler.py
@@ -111,6 +111,9 @@
         self.assertReportedStat(
             'zuul.pipeline.gate.org.project.total_changes', value='1|c')
 
+        for build in self.builds:
+            self.assertEqual(build.parameters['ZUUL_VOTING'], '1')
+
     def test_initial_pipeline_gauges(self):
         "Test that each pipeline reported its length on start"
         pipeline_names = self.sched.layout.pipelines.keys()
@@ -1256,6 +1259,9 @@
             self.getJobFromHistory('nonvoting-project-test2').result,
             'FAILURE')
 
+        for build in self.builds:
+            self.assertEqual(build.parameters['ZUUL_VOTING'], '0')
+
     def test_check_queue_success(self):
         "Test successful check queue jobs."
 
@@ -1710,6 +1716,41 @@
         self.assertEqual(A.reported, 0, "Abandoned change should not report")
         self.assertEqual(B.reported, 1, "Change should report")
 
+    def test_abandoned_not_timer(self):
+        "Test that an abandoned change does not cancel timer jobs"
+
+        self.worker.hold_jobs_in_build = True
+
+        # Start timer trigger - also org/project
+        self.config.set('zuul', 'layout_config',
+                        'tests/fixtures/layout-idle.yaml')
+        self.sched.reconfigure(self.config)
+        self.registerJobs()
+        # The pipeline triggers every second, so we should have seen
+        # several by now.
+        time.sleep(5)
+        self.waitUntilSettled()
+        # Stop queuing timer triggered jobs so that the assertions
+        # below don't race against more jobs being queued.
+        self.config.set('zuul', 'layout_config',
+                        'tests/fixtures/layout-no-timer.yaml')
+        self.sched.reconfigure(self.config)
+        self.registerJobs()
+        self.assertEqual(len(self.builds), 2, "Two timer jobs")
+
+        A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A')
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+        self.assertEqual(len(self.builds), 3, "One change plus two timer jobs")
+
+        self.fake_gerrit.addEvent(A.getChangeAbandonedEvent())
+        self.waitUntilSettled()
+
+        self.assertEqual(len(self.builds), 2, "Two timer jobs remain")
+
+        self.worker.release()
+        self.waitUntilSettled()
+
     def test_zuul_url_return(self):
         "Test if ZUUL_URL is returning when zuul_url is set in zuul.conf"
         self.assertTrue(self.sched.config.has_option('merger', 'zuul_url'))
@@ -1843,6 +1884,23 @@
         self.assertEqual(A.data['status'], 'MERGED')
         self.assertEqual(A.reported, 2)
 
+    def test_no_job_project(self):
+        "Test that reports with no jobs don't get sent"
+        A = self.fake_gerrit.addFakeChange('org/no-jobs-project',
+                                           'master', 'A')
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+
+        # Change wasn't reported to
+        self.assertEqual(A.reported, False)
+
+        # Check queue is empty afterwards
+        check_pipeline = self.sched.layout.pipelines['check']
+        items = check_pipeline.getAllItems()
+        self.assertEqual(len(items), 0)
+
+        self.assertEqual(len(self.history), 0)
+
     def test_zuul_refs(self):
         "Test that zuul refs exist and have the right changes"
         self.worker.hold_jobs_in_build = True
@@ -1984,6 +2042,30 @@
         self.assertEqual(self.history[0].name, 'gate-noop')
         self.assertEqual(self.history[0].result, 'SUCCESS')
 
+    def test_file_head(self):
+        # This is a regression test for an observed bug.  A change
+        # with a file named "HEAD" in the root directory of the repo
+        # was processed by a merger.  It then was unable to reset the
+        # repo because of:
+        #   GitCommandError: 'git reset --hard HEAD' returned
+        #       with exit code 128
+        #   stderr: 'fatal: ambiguous argument 'HEAD': both revision
+        #       and filename
+        #   Use '--' to separate filenames from revisions'
+
+        A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A')
+        A.addPatchset(['HEAD'])
+        B = self.fake_gerrit.addFakeChange('org/project', 'master', 'B')
+
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(2))
+        self.waitUntilSettled()
+
+        self.fake_gerrit.addEvent(B.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+
+        self.assertIn('Build succeeded', A.messages[0])
+        self.assertIn('Build succeeded', B.messages[0])
+
     def test_file_jobs(self):
         "Test that file jobs run only when appropriate"
         A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A')
@@ -2089,9 +2171,7 @@
         self.waitUntilSettled()
 
         # Run one build at a time to ensure non-race order:
-        for x in range(6):
-            self.release(self.builds[0])
-            self.waitUntilSettled()
+        self.orderedRelease()
         self.worker.hold_jobs_in_build = False
         self.waitUntilSettled()
 
@@ -2120,7 +2200,10 @@
         self.assertIn('Content-Type', headers)
         self.assertEqual(headers['Content-Type'],
                          'application/json; charset=UTF-8')
+        self.assertIn('Access-Control-Allow-Origin', headers)
+        self.assertIn('Cache-Control', headers)
         self.assertIn('Last-Modified', headers)
+        self.assertIn('Expires', headers)
         data = f.read()
 
         self.worker.hold_jobs_in_build = False
@@ -2188,6 +2271,286 @@
         self.assertEqual(A.data['status'], 'MERGED')
         self.assertEqual(A.reported, 2)
 
+    def test_live_reconfiguration_merge_conflict(self):
+        # A real-world bug: a change in a gate queue has a merge
+        # conflict and a job is added to its project while it's
+        # sitting in the queue.  The job gets added to the change and
+        # enqueued and the change gets stuck.
+        self.worker.registerFunction('build:project-test3')
+        self.worker.hold_jobs_in_build = True
+
+        # This change is fine.  It's here to stop the queue long
+        # enough for the next change to be subject to the
+        # reconfiguration, as well as to provide a conflict for the
+        # next change.  This change will succeed and merge.
+        A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A')
+        A.addPatchset(['conflict'])
+        A.addApproval('CRVW', 2)
+
+        # This change will be in merge conflict.  During the
+        # reconfiguration, we will add a job.  We want to make sure
+        # that doesn't cause it to get stuck.
+        B = self.fake_gerrit.addFakeChange('org/project', 'master', 'B')
+        B.addPatchset(['conflict'])
+        B.addApproval('CRVW', 2)
+
+        self.fake_gerrit.addEvent(A.addApproval('APRV', 1))
+        self.fake_gerrit.addEvent(B.addApproval('APRV', 1))
+
+        self.waitUntilSettled()
+
+        # No jobs have run yet
+        self.assertEqual(A.data['status'], 'NEW')
+        self.assertEqual(A.reported, 1)
+        self.assertEqual(B.data['status'], 'NEW')
+        self.assertEqual(B.reported, 1)
+        self.assertEqual(len(self.history), 0)
+
+        # Add the "project-test3" job.
+        self.config.set('zuul', 'layout_config',
+                        'tests/fixtures/layout-live-'
+                        'reconfiguration-add-job.yaml')
+        self.sched.reconfigure(self.config)
+        self.waitUntilSettled()
+
+        self.worker.hold_jobs_in_build = False
+        self.worker.release()
+        self.waitUntilSettled()
+
+        self.assertEqual(A.data['status'], 'MERGED')
+        self.assertEqual(A.reported, 2)
+        self.assertEqual(B.data['status'], 'NEW')
+        self.assertEqual(B.reported, 2)
+        self.assertEqual(self.getJobFromHistory('project-merge').result,
+                         'SUCCESS')
+        self.assertEqual(self.getJobFromHistory('project-test1').result,
+                         'SUCCESS')
+        self.assertEqual(self.getJobFromHistory('project-test2').result,
+                         'SUCCESS')
+        self.assertEqual(self.getJobFromHistory('project-test3').result,
+                         'SUCCESS')
+        self.assertEqual(len(self.history), 4)
+
+    def test_live_reconfiguration_failed_root(self):
+        # An extrapolation of test_live_reconfiguration_merge_conflict
+        # that tests a job added to a job tree with a failed root does
+        # not run.
+        self.worker.registerFunction('build:project-test3')
+        self.worker.hold_jobs_in_build = True
+
+        # This change is fine.  It's here to stop the queue long
+        # enough for the next change to be subject to the
+        # reconfiguration.  This change will succeed and merge.
+        A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A')
+        A.addPatchset(['conflict'])
+        A.addApproval('CRVW', 2)
+        self.fake_gerrit.addEvent(A.addApproval('APRV', 1))
+        self.waitUntilSettled()
+        self.worker.release('.*-merge')
+        self.waitUntilSettled()
+
+        B = self.fake_gerrit.addFakeChange('org/project', 'master', 'B')
+        self.worker.addFailTest('project-merge', B)
+        B.addApproval('CRVW', 2)
+        self.fake_gerrit.addEvent(B.addApproval('APRV', 1))
+        self.waitUntilSettled()
+
+        self.worker.release('.*-merge')
+        self.waitUntilSettled()
+
+        # Both -merge jobs have run, but no others.
+        self.assertEqual(A.data['status'], 'NEW')
+        self.assertEqual(A.reported, 1)
+        self.assertEqual(B.data['status'], 'NEW')
+        self.assertEqual(B.reported, 1)
+        self.assertEqual(self.history[0].result, 'SUCCESS')
+        self.assertEqual(self.history[0].name, 'project-merge')
+        self.assertEqual(self.history[1].result, 'FAILURE')
+        self.assertEqual(self.history[1].name, 'project-merge')
+        self.assertEqual(len(self.history), 2)
+
+        # Add the "project-test3" job.
+        self.config.set('zuul', 'layout_config',
+                        'tests/fixtures/layout-live-'
+                        'reconfiguration-add-job.yaml')
+        self.sched.reconfigure(self.config)
+        self.waitUntilSettled()
+
+        self.worker.hold_jobs_in_build = False
+        self.worker.release()
+        self.waitUntilSettled()
+
+        self.assertEqual(A.data['status'], 'MERGED')
+        self.assertEqual(A.reported, 2)
+        self.assertEqual(B.data['status'], 'NEW')
+        self.assertEqual(B.reported, 2)
+        self.assertEqual(self.history[0].result, 'SUCCESS')
+        self.assertEqual(self.history[0].name, 'project-merge')
+        self.assertEqual(self.history[1].result, 'FAILURE')
+        self.assertEqual(self.history[1].name, 'project-merge')
+        self.assertEqual(self.history[2].result, 'SUCCESS')
+        self.assertEqual(self.history[3].result, 'SUCCESS')
+        self.assertEqual(self.history[4].result, 'SUCCESS')
+        self.assertEqual(len(self.history), 5)
+
+    def test_live_reconfiguration_failed_job(self):
+        # Test that a change with a removed failing job does not
+        # disrupt reconfiguration.  If a change has a failed job and
+        # that job is removed during a reconfiguration, we observed a
+        # bug where the code to re-set build statuses would run on
+        # that build and raise an exception because the job no longer
+        # existed.
+        self.worker.hold_jobs_in_build = True
+
+        A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A')
+
+        # This change will fail and later be removed by the reconfiguration.
+        self.worker.addFailTest('project-test1', A)
+
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+        self.worker.release('.*-merge')
+        self.waitUntilSettled()
+        self.worker.release('project-test1')
+        self.waitUntilSettled()
+
+        self.assertEqual(A.data['status'], 'NEW')
+        self.assertEqual(A.reported, 0)
+
+        self.assertEqual(self.getJobFromHistory('project-merge').result,
+                         'SUCCESS')
+        self.assertEqual(self.getJobFromHistory('project-test1').result,
+                         'FAILURE')
+        self.assertEqual(len(self.history), 2)
+
+        # Remove the test1 job.
+        self.config.set('zuul', 'layout_config',
+                        'tests/fixtures/layout-live-'
+                        'reconfiguration-failed-job.yaml')
+        self.sched.reconfigure(self.config)
+        self.waitUntilSettled()
+
+        self.worker.hold_jobs_in_build = False
+        self.worker.release()
+        self.waitUntilSettled()
+
+        self.assertEqual(self.getJobFromHistory('project-test2').result,
+                         'SUCCESS')
+        self.assertEqual(self.getJobFromHistory('project-testfile').result,
+                         'SUCCESS')
+        self.assertEqual(len(self.history), 4)
+
+        self.assertEqual(A.data['status'], 'NEW')
+        self.assertEqual(A.reported, 1)
+        self.assertIn('Build succeeded', A.messages[0])
+        # Ensure the removed job was not included in the report.
+        self.assertNotIn('project-test1', A.messages[0])
+
+    def test_live_reconfiguration_shared_queue(self):
+        # Test that a change with a failing job which was removed from
+        # this project but otherwise still exists in the system does
+        # not disrupt reconfiguration.
+
+        self.worker.hold_jobs_in_build = True
+
+        A = self.fake_gerrit.addFakeChange('org/project1', 'master', 'A')
+
+        self.worker.addFailTest('project1-project2-integration', A)
+
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+        self.worker.release('.*-merge')
+        self.waitUntilSettled()
+        self.worker.release('project1-project2-integration')
+        self.waitUntilSettled()
+
+        self.assertEqual(A.data['status'], 'NEW')
+        self.assertEqual(A.reported, 0)
+
+        self.assertEqual(self.getJobFromHistory('project1-merge').result,
+                         'SUCCESS')
+        self.assertEqual(self.getJobFromHistory(
+            'project1-project2-integration').result, 'FAILURE')
+        self.assertEqual(len(self.history), 2)
+
+        # Remove the integration job.
+        self.config.set('zuul', 'layout_config',
+                        'tests/fixtures/layout-live-'
+                        'reconfiguration-shared-queue.yaml')
+        self.sched.reconfigure(self.config)
+        self.waitUntilSettled()
+
+        self.worker.hold_jobs_in_build = False
+        self.worker.release()
+        self.waitUntilSettled()
+
+        self.assertEqual(self.getJobFromHistory('project1-merge').result,
+                         'SUCCESS')
+        self.assertEqual(self.getJobFromHistory('project1-test1').result,
+                         'SUCCESS')
+        self.assertEqual(self.getJobFromHistory('project1-test2').result,
+                         'SUCCESS')
+        self.assertEqual(self.getJobFromHistory(
+            'project1-project2-integration').result, 'FAILURE')
+        self.assertEqual(len(self.history), 4)
+
+        self.assertEqual(A.data['status'], 'NEW')
+        self.assertEqual(A.reported, 1)
+        self.assertIn('Build succeeded', A.messages[0])
+        # Ensure the removed job was not included in the report.
+        self.assertNotIn('project1-project2-integration', A.messages[0])
+
+    def test_live_reconfiguration_del_project(self):
+        # Test project deletion from layout
+        # while changes are enqueued
+
+        self.worker.hold_jobs_in_build = True
+        A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A')
+        B = self.fake_gerrit.addFakeChange('org/project1', 'master', 'B')
+        C = self.fake_gerrit.addFakeChange('org/project1', 'master', 'C')
+
+        # A Depends-On: B
+        A.data['commitMessage'] = '%s\n\nDepends-On: %s\n' % (
+            A.subject, B.data['id'])
+        self.fake_gerrit.addEvent(B.addApproval('APRV', 1))
+
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(1))
+        self.fake_gerrit.addEvent(C.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+        self.worker.release('.*-merge')
+        self.waitUntilSettled()
+        self.assertEqual(len(self.builds), 5)
+
+        # This layout defines only org/project, not org/project1
+        self.config.set('zuul', 'layout_config',
+                        'tests/fixtures/layout-live-'
+                        'reconfiguration-del-project.yaml')
+        self.sched.reconfigure(self.config)
+        self.waitUntilSettled()
+
+        # Builds for C aborted, builds for A succeed,
+        # and have change B applied ahead
+        job_c = self.getJobFromHistory('project1-test1')
+        self.assertEqual(job_c.changes, '3,1')
+        self.assertEqual(job_c.result, 'ABORTED')
+
+        self.worker.hold_jobs_in_build = False
+        self.worker.release()
+        self.waitUntilSettled()
+
+        self.assertEqual(self.getJobFromHistory('project-test1').changes,
+                         '2,1 1,1')
+
+        self.assertEqual(A.data['status'], 'NEW')
+        self.assertEqual(B.data['status'], 'NEW')
+        self.assertEqual(C.data['status'], 'NEW')
+        self.assertEqual(A.reported, 1)
+        self.assertEqual(B.reported, 0)
+        self.assertEqual(C.reported, 0)
+
+        self.assertEqual(len(self.sched.layout.pipelines['check'].queues), 0)
+        self.assertIn('Build succeeded', A.messages[0])
+
     def test_live_reconfiguration_functions(self):
         "Test live reconfiguration with a custom function"
         self.worker.registerFunction('build:node-project-test1:debian')
@@ -2430,7 +2793,7 @@
         self.worker.release('.*')
         self.waitUntilSettled()
 
-    def test_client_enqueue(self):
+    def test_client_enqueue_change(self):
         "Test that the RPC client can enqueue a change"
         A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A')
         A.addApproval('CRVW', 2)
@@ -2453,6 +2816,24 @@
         self.assertEqual(A.reported, 2)
         self.assertEqual(r, True)
 
+    def test_client_enqueue_ref(self):
+        "Test that the RPC client can enqueue a ref"
+
+        client = zuul.rpcclient.RPCClient('127.0.0.1',
+                                          self.gearman_server.port)
+        r = client.enqueue_ref(
+            pipeline='post',
+            project='org/project',
+            trigger='gerrit',
+            ref='master',
+            oldrev='90f173846e3af9154517b88543ffbd1691f31366',
+            newrev='d479a0bfcb34da57a31adb2a595c0cf687812543')
+        self.waitUntilSettled()
+        job_names = [x.name for x in self.history]
+        self.assertEqual(len(self.history), 1)
+        self.assertIn('project-post', job_names)
+        self.assertEqual(r, True)
+
     def test_client_enqueue_negative(self):
         "Test that the RPC client returns errors"
         client = zuul.rpcclient.RPCClient('127.0.0.1',
@@ -2915,9 +3296,10 @@
         self.registerJobs()
 
         self.assertEqual(
-            "Merge Failed.\n\nThis change was unable to be automatically "
-            "merged with the current state of the repository. Please rebase "
-            "your change and upload a new patchset.",
+            "Merge Failed.\n\nThis change or one of its cross-repo "
+            "dependencies was unable to be automatically merged with the "
+            "current state of its repository. Please rebase the change and "
+            "upload a new patchset.",
             self.sched.layout.pipelines['check'].merge_failure_message)
         self.assertEqual(
             "The merge failed! For more information...",
@@ -3343,6 +3725,48 @@
         self.assertEqual(A.data['status'], 'NEW')
         self.assertEqual(B.data['status'], 'NEW')
 
+    def test_crd_gate_unknown(self):
+        "Test unknown projects in dependent pipeline"
+        self.init_repo("org/unknown")
+        A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A')
+        B = self.fake_gerrit.addFakeChange('org/unknown', 'master', 'B')
+        A.addApproval('CRVW', 2)
+        B.addApproval('CRVW', 2)
+
+        # A Depends-On: B
+        A.data['commitMessage'] = '%s\n\nDepends-On: %s\n' % (
+            A.subject, B.data['id'])
+
+        B.addApproval('APRV', 1)
+        self.fake_gerrit.addEvent(A.addApproval('APRV', 1))
+        self.waitUntilSettled()
+
+        # Unknown projects cannot share a queue with any other
+        # since they don't have common jobs with any other (they have no jobs).
+        # Changes which depend on unknown project changes
+        # should not be processed in dependent pipeline
+        self.assertEqual(A.data['status'], 'NEW')
+        self.assertEqual(B.data['status'], 'NEW')
+        self.assertEqual(A.reported, 0)
+        self.assertEqual(B.reported, 0)
+        self.assertEqual(len(self.history), 0)
+
+        # Simulate change B being gated outside this layout
+        self.fake_gerrit.addEvent(B.addApproval('APRV', 1))
+        B.setMerged()
+        self.waitUntilSettled()
+        self.assertEqual(len(self.history), 0)
+
+        # Now that B is merged, A should be able to be enqueued and
+        # merged.
+        self.fake_gerrit.addEvent(A.addApproval('APRV', 1))
+        self.waitUntilSettled()
+
+        self.assertEqual(A.data['status'], 'MERGED')
+        self.assertEqual(A.reported, 2)
+        self.assertEqual(B.data['status'], 'MERGED')
+        self.assertEqual(B.reported, 0)
+
     def test_crd_check(self):
         "Test cross-repo dependencies in independent pipelines"
 
@@ -3387,7 +3811,7 @@
 
     def test_crd_check_git_depends(self):
         "Test single-repo dependencies in independent pipelines"
-        self.gearman_server.hold_jobs_in_queue = True
+        self.gearman_server.hold_jobs_in_build = True
         A = self.fake_gerrit.addFakeChange('org/project1', 'master', 'A')
         B = self.fake_gerrit.addFakeChange('org/project1', 'master', 'B')
 
@@ -3399,8 +3823,8 @@
         self.fake_gerrit.addEvent(B.getPatchsetCreatedEvent(1))
         self.waitUntilSettled()
 
-        self.gearman_server.hold_jobs_in_queue = False
-        self.gearman_server.release()
+        self.orderedRelease()
+        self.gearman_server.hold_jobs_in_build = False
         self.waitUntilSettled()
 
         self.assertEqual(A.data['status'], 'NEW')
@@ -3417,7 +3841,7 @@
 
     def test_crd_check_duplicate(self):
         "Test duplicate check in independent pipelines"
-        self.gearman_server.hold_jobs_in_queue = True
+        self.worker.hold_jobs_in_build = True
         A = self.fake_gerrit.addFakeChange('org/project1', 'master', 'A')
         B = self.fake_gerrit.addFakeChange('org/project1', 'master', 'B')
         check_pipeline = self.sched.layout.pipelines['check']
@@ -3440,13 +3864,9 @@
 
         # Release jobs in order to avoid races with change A jobs
         # finishing before change B jobs.
-        self.gearman_server.release('.*-merge')
-        self.gearman_server.release('project1-.*')
-        self.waitUntilSettled()
-        self.gearman_server.release('.*-merge')
-        self.gearman_server.release('project1-.*')
-        self.waitUntilSettled()
-        self.gearman_server.release()
+        self.orderedRelease()
+        self.worker.hold_jobs_in_build = False
+        self.worker.release()
         self.waitUntilSettled()
 
         self.assertEqual(A.data['status'], 'NEW')
@@ -3461,12 +3881,12 @@
         self.assertIn('Build succeeded', A.messages[0])
         self.assertIn('Build succeeded', B.messages[0])
 
-    def test_crd_check_reconfiguration(self):
+    def _test_crd_check_reconfiguration(self, project1, project2):
         "Test cross-repo dependencies re-enqueued in independent pipelines"
 
         self.gearman_server.hold_jobs_in_queue = True
-        A = self.fake_gerrit.addFakeChange('org/project1', 'master', 'A')
-        B = self.fake_gerrit.addFakeChange('org/project2', 'master', 'B')
+        A = self.fake_gerrit.addFakeChange(project1, 'master', 'A')
+        B = self.fake_gerrit.addFakeChange(project2, 'master', 'B')
 
         # A Depends-On: B
         A.data['commitMessage'] = '%s\n\nDepends-On: %s\n' % (
@@ -3499,6 +3919,17 @@
         self.assertEqual(self.history[0].changes, '2,1 1,1')
         self.assertEqual(len(self.sched.layout.pipelines['check'].queues), 0)
 
+    def test_crd_check_reconfiguration(self):
+        self._test_crd_check_reconfiguration('org/project1', 'org/project2')
+
+    def test_crd_undefined_project(self):
+        """Test that undefined projects in dependencies are handled for
+        independent pipelines"""
+        # It's a hack for fake gerrit,
+        # as it implies repo creation upon the creation of any change
+        self.init_repo("org/unknown")
+        self._test_crd_check_reconfiguration('org/project1', 'org/unknown')
+
     def test_crd_check_ignore_dependencies(self):
         "Test cross-repo dependencies can be ignored"
         self.config.set('zuul', 'layout_config',
diff --git a/tests/test_zuultrigger.py b/tests/test_zuultrigger.py
index 2f0e4f0..0d52fc9 100644
--- a/tests/test_zuultrigger.py
+++ b/tests/test_zuultrigger.py
@@ -107,9 +107,10 @@
         self.assertEqual(E.reported, 0)
         self.assertEqual(
             B.messages[0],
-            "Merge Failed.\n\nThis change was unable to be automatically "
-            "merged with the current state of the repository. Please rebase "
-            "your change and upload a new patchset.")
+            "Merge Failed.\n\nThis change or one of its cross-repo "
+            "dependencies was unable to be automatically merged with the "
+            "current state of its repository. Please rebase the change and "
+            "upload a new patchset.")
 
         self.assertTrue("project:org/project status:open" in
                         self.fake_gerrit.queries)
@@ -133,8 +134,9 @@
         self.assertEqual(E.reported, 1)
         self.assertEqual(
             E.messages[0],
-            "Merge Failed.\n\nThis change was unable to be automatically "
-            "merged with the current state of the repository. Please rebase "
-            "your change and upload a new patchset.")
+            "Merge Failed.\n\nThis change or one of its cross-repo "
+            "dependencies was unable to be automatically merged with the "
+            "current state of its repository. Please rebase the change and "
+            "upload a new patchset.")
         self.assertEqual(self.fake_gerrit.queries[1],
                          "project:org/project status:open")
diff --git a/zuul/cmd/client.py b/zuul/cmd/client.py
index bc2c152..59ac419 100644
--- a/zuul/cmd/client.py
+++ b/zuul/cmd/client.py
@@ -56,6 +56,24 @@
                                  required=True)
         cmd_enqueue.set_defaults(func=self.enqueue)
 
+        cmd_enqueue = subparsers.add_parser('enqueue-ref',
+                                            help='enqueue a ref')
+        cmd_enqueue.add_argument('--trigger', help='trigger name',
+                                 required=True)
+        cmd_enqueue.add_argument('--pipeline', help='pipeline name',
+                                 required=True)
+        cmd_enqueue.add_argument('--project', help='project name',
+                                 required=True)
+        cmd_enqueue.add_argument('--ref', help='ref name',
+                                 required=True)
+        cmd_enqueue.add_argument(
+            '--oldrev', help='old revision',
+            default='0000000000000000000000000000000000000000')
+        cmd_enqueue.add_argument(
+            '--newrev', help='new revision',
+            default='0000000000000000000000000000000000000000')
+        cmd_enqueue.set_defaults(func=self.enqueue_ref)
+
         cmd_promote = subparsers.add_parser('promote',
                                             help='promote one or more changes')
         cmd_promote.add_argument('--pipeline', help='pipeline name',
@@ -82,6 +100,9 @@
         show_running_jobs.set_defaults(func=self.show_running_jobs)
 
         self.args = parser.parse_args()
+        if self.args.func == self.enqueue_ref:
+            if self.args.oldrev == self.args.newrev:
+                parser.error("The old and new revisions must not be the same.")
 
     def setup_logging(self):
         """Client logging does not rely on conf file"""
@@ -112,6 +133,16 @@
                            change=self.args.change)
         return r
 
+    def enqueue_ref(self):
+        client = zuul.rpcclient.RPCClient(self.server, self.port)
+        r = client.enqueue_ref(pipeline=self.args.pipeline,
+                               project=self.args.project,
+                               trigger=self.args.trigger,
+                               ref=self.args.ref,
+                               oldrev=self.args.oldrev,
+                               newrev=self.args.newrev)
+        return r
+
     def promote(self):
         client = zuul.rpcclient.RPCClient(self.server, self.port)
         r = client.promote(pipeline=self.args.pipeline,
@@ -232,6 +263,12 @@
             'number': {
                 'title': 'Number'
             },
+            'node_labels': {
+                'title': 'Node Labels'
+            },
+            'node_name': {
+                'title': 'Node Name'
+            },
             'worker.name': {
                 'title': 'Worker'
             },
@@ -245,7 +282,7 @@
             'worker.fqdn': {
                 'title': 'Worker Domain'
             },
-            'worker.progam': {
+            'worker.program': {
                 'title': 'Worker Program'
             },
             'worker.version': {
diff --git a/zuul/cmd/cloner.py b/zuul/cmd/cloner.py
index d0bb966..e4a0e7b 100755
--- a/zuul/cmd/cloner.py
+++ b/zuul/cmd/cloner.py
@@ -25,10 +25,6 @@
 
 ZUUL_ENV_SUFFIXES = (
     'branch',
-    'change',
-    'patchset',
-    'pipeline',
-    'project',
     'ref',
     'url',
 )
@@ -81,7 +77,7 @@
         )
 
         zuul_env = parser.add_argument_group(
-            'zuul environnement',
+            'zuul environment',
             'Let you override $ZUUL_* environment variables.'
         )
         for zuul_suffix in ZUUL_ENV_SUFFIXES:
@@ -92,15 +88,14 @@
             )
 
         args = parser.parse_args()
+        # Validate ZUUL_* arguments. If ref is provided then URL is required.
+        zuul_args = [zuul_opt for zuul_opt, val in vars(args).items()
+                     if zuul_opt.startswith('zuul') and val is not None]
+        if 'zuul_ref' in zuul_args and 'zuul_url' not in zuul_args:
+            parser.error("Specifying a Zuul ref requires a Zuul url. "
+                         "Define Zuul arguments either via environment "
+                         "variables or using options above.")
 
-        # Validate ZUUL_* arguments
-        zuul_missing = [zuul_opt for zuul_opt, val in vars(args).items()
-                        if zuul_opt.startswith('zuul') and val is None]
-        if zuul_missing:
-            parser.error(("Some Zuul parameters are not set:\n\t%s\n"
-                          "Define them either via environment variables or "
-                          "using options above." %
-                          "\n\t".join(sorted(zuul_missing))))
         self.args = args
 
     def setup_logging(self, color=False, verbose=False):
diff --git a/zuul/cmd/server.py b/zuul/cmd/server.py
index 832eae4..2d99a1f 100755
--- a/zuul/cmd/server.py
+++ b/zuul/cmd/server.py
@@ -62,7 +62,10 @@
         signal.signal(signal.SIGHUP, signal.SIG_IGN)
         self.read_config()
         self.setup_logging('zuul', 'log_config')
-        self.sched.reconfigure(self.config)
+        try:
+            self.sched.reconfigure(self.config)
+        except Exception:
+            self.log.exception("Reconfiguration failed:")
         signal.signal(signal.SIGHUP, self.reconfigure_handler)
 
     def exit_handler(self, signum, frame):
@@ -118,7 +121,12 @@
             import gear
             statsd_host = os.environ.get('STATSD_HOST')
             statsd_port = int(os.environ.get('STATSD_PORT', 8125))
+            if self.config.has_option('gearman_server', 'listen_address'):
+                host = self.config.get('gearman_server', 'listen_address')
+            else:
+                host = None
             gear.Server(4730,
+                        host=host,
                         statsd_host=statsd_host,
                         statsd_port=statsd_port,
                         statsd_prefix='zuul.geard')
diff --git a/zuul/launcher/gearman.py b/zuul/launcher/gearman.py
index 653678a..69fb71b 100644
--- a/zuul/launcher/gearman.py
+++ b/zuul/launcher/gearman.py
@@ -265,16 +265,19 @@
                                                        params))
 
     def launch(self, job, item, pipeline, dependent_items=[]):
-        self.log.info("Launch job %s for change %s with dependent changes %s" %
-                      (job, item.change,
-                       [x.change for x in dependent_items]))
+        uuid = str(uuid4().hex)
+        self.log.info(
+            "Launch job %s (uuid: %s) for change %s with dependent "
+            "changes %s" % (
+                job, uuid, item.change,
+                [x.change for x in dependent_items]))
         dependent_items = dependent_items[:]
         dependent_items.reverse()
-        uuid = str(uuid4().hex)
         params = dict(ZUUL_UUID=uuid,
                       ZUUL_PROJECT=item.change.project.name)
         params['ZUUL_PIPELINE'] = pipeline.name
         params['ZUUL_URL'] = item.current_build_set.zuul_url
+        params['ZUUL_VOTING'] = job.voting and '1' or '0'
         if hasattr(item.change, 'refspec'):
             changes_str = '^'.join(
                 ['%s:%s:%s' % (i.change.project.name, i.change.branch,
@@ -340,8 +343,7 @@
         build.parameters = params
 
         if job.name == 'noop':
-            build.result = 'SUCCESS'
-            self.sched.onBuildCompleted(build)
+            self.sched.onBuildCompleted(build, 'SUCCESS')
             return build
 
         gearman_job = gear.Job(name, json.dumps(params),
@@ -421,16 +423,17 @@
 
         build = self.builds.get(job.unique)
         if build:
+            data = getJobData(job)
+            build.node_labels = data.get('node_labels', [])
+            build.node_name = data.get('node_name')
             if not build.canceled:
                 if result is None:
-                    data = getJobData(job)
                     result = data.get('result')
                 if result is None:
                     build.retry = True
                 self.log.info("Build %s complete, result %s" %
                               (job, result))
-                build.result = result
-                self.sched.onBuildCompleted(build)
+                self.sched.onBuildCompleted(build, result)
             # The test suite expects the build to be removed from the
             # internal dict after it's added to the report queue.
             del self.builds[job.unique]
diff --git a/zuul/lib/cloner.py b/zuul/lib/cloner.py
index 67e238a..0ac7f0f 100644
--- a/zuul/lib/cloner.py
+++ b/zuul/lib/cloner.py
@@ -125,33 +125,47 @@
 
         repo = self.cloneUpstream(project, dest)
 
-        repo.reset()
         # Ensure that we don't have stale remotes around
         repo.prune()
+        # We must reset after pruning because reseting sets HEAD to point
+        # at refs/remotes/origin/master, but `git branch` which prune runs
+        # explodes if HEAD does not point at something in refs/heads.
+        # Later with repo.checkout() we set HEAD to something that
+        # `git branch` is happy with.
+        repo.reset()
 
         indicated_branch = self.branch or self.zuul_branch
         if project in self.project_branches:
             indicated_branch = self.project_branches[project]
 
-        override_zuul_ref = re.sub(self.zuul_branch, indicated_branch,
-                                   self.zuul_ref)
+        if indicated_branch:
+            override_zuul_ref = re.sub(self.zuul_branch, indicated_branch,
+                                       self.zuul_ref)
+        else:
+            override_zuul_ref = None
 
-        if repo.hasBranch(indicated_branch):
-            self.log.debug("upstream repo has branch %s", indicated_branch)
+        if indicated_branch and repo.hasBranch(indicated_branch):
+            self.log.info("upstream repo has branch %s", indicated_branch)
             fallback_branch = indicated_branch
         else:
-            self.log.debug("upstream repo is missing branch %s",
-                           self.branch)
+            self.log.info("upstream repo is missing branch %s",
+                          self.branch)
             # FIXME should be origin HEAD branch which might not be 'master'
             fallback_branch = 'master'
 
-        fallback_zuul_ref = re.sub(self.zuul_branch, fallback_branch,
-                                   self.zuul_ref)
+        if self.zuul_branch:
+            fallback_zuul_ref = re.sub(self.zuul_branch, fallback_branch,
+                                       self.zuul_ref)
+        else:
+            fallback_zuul_ref = None
 
-        if (self.fetchFromZuul(repo, project, override_zuul_ref)
-            or (fallback_zuul_ref != override_zuul_ref and
-                self.fetchFromZuul(repo, project, fallback_zuul_ref))
-            ):
+        # If we have a non empty zuul_ref to use, use it. Otherwise we fall
+        # back to checking out the branch.
+        if ((override_zuul_ref and
+            self.fetchFromZuul(repo, project, override_zuul_ref)) or
+            (fallback_zuul_ref and
+             fallback_zuul_ref != override_zuul_ref and
+            self.fetchFromZuul(repo, project, fallback_zuul_ref))):
             # Work around a bug in GitPython which can not parse FETCH_HEAD
             gitcmd = git.Git(dest)
             fetch_head = gitcmd.rev_parse('FETCH_HEAD')
@@ -160,11 +174,11 @@
                           project, fetch_head)
         else:
             # Checkout branch
-            self.log.debug("Falling back to branch %s", fallback_branch)
+            self.log.info("Falling back to branch %s", fallback_branch)
             try:
-                repo.checkout('remotes/origin/%s' % fallback_branch)
+                commit = repo.checkout('remotes/origin/%s' % fallback_branch)
             except (ValueError, GitCommandError):
                 self.log.exception("Fallback branch not found: %s",
                                    fallback_branch)
-            self.log.info("Prepared %s repo with branch %s",
-                          project, fallback_branch)
+            self.log.info("Prepared %s repo with branch %s at commit %s",
+                          project, fallback_branch, commit)
diff --git a/zuul/lib/gerrit.py b/zuul/lib/gerrit.py
index 6c7906b..90faf40 100644
--- a/zuul/lib/gerrit.py
+++ b/zuul/lib/gerrit.py
@@ -146,7 +146,7 @@
 
     def simpleQuery(self, query):
         def _query_chunk(query):
-            args = '--current-patch-set'
+            args = '--commit-message --current-patch-set'
 
             cmd = 'gerrit query --format json %s %s' % (
                 args, query)
diff --git a/zuul/merger/merger.py b/zuul/merger/merger.py
index 8774f10..1e881bf 100644
--- a/zuul/merger/merger.py
+++ b/zuul/merger/merger.py
@@ -20,6 +20,21 @@
 import zuul.model
 
 
+def reset_repo_to_head(repo):
+    # This lets us reset the repo even if there is a file in the root
+    # directory named 'HEAD'.  Currently, GitPython does not allow us
+    # to instruct it to always include the '--' to disambiguate.  This
+    # should no longer be necessary if this PR merges:
+    #   https://github.com/gitpython-developers/GitPython/pull/319
+    try:
+        repo.git.reset('--hard', 'HEAD', '--')
+    except git.GitCommandError as e:
+        # git nowadays may use 1 as status to indicate there are still unstaged
+        # modifications after the reset
+        if e.status != 1:
+            raise
+
+
 class ZuulReference(git.Reference):
     _common_path_default = "refs/zuul"
     _points_to_commits_only = True
@@ -40,7 +55,7 @@
             self.log.exception("Unable to initialize repo for %s" % remote)
 
     def _ensure_cloned(self):
-        repo_is_cloned = os.path.exists(self.local_path)
+        repo_is_cloned = os.path.exists(os.path.join(self.local_path, '.git'))
         if self._initialized and repo_is_cloned:
             return
         # If the repo does not exist, clone the repo.
@@ -71,9 +86,9 @@
         return repo
 
     def reset(self):
-        repo = self.createRepoObject()
         self.log.debug("Resetting repository %s" % self.local_path)
         self.update()
+        repo = self.createRepoObject()
         origin = repo.remotes.origin
         for ref in origin.refs:
             if ref.remote_head == 'HEAD':
@@ -82,7 +97,7 @@
 
         # Reset to remote HEAD (usually origin/master)
         repo.head.reference = origin.refs['HEAD']
-        repo.head.reset(index=True, working_tree=True)
+        reset_repo_to_head(repo)
         repo.git.clean('-x', '-f', '-d')
 
     def prune(self):
@@ -114,7 +129,8 @@
         repo = self.createRepoObject()
         self.log.debug("Checking out %s" % ref)
         repo.head.reference = ref
-        repo.head.reset(index=True, working_tree=True)
+        reset_repo_to_head(repo)
+        return repo.head.commit
 
     def cherryPick(self, ref):
         repo = self.createRepoObject()
@@ -152,7 +168,7 @@
 
     def createZuulRef(self, ref, commit='HEAD'):
         repo = self.createRepoObject()
-        self.log.debug("CreateZuulRef %s at %s" % (ref, commit))
+        self.log.debug("CreateZuulRef %s at %s on %s" % (ref, commit, repo))
         ref = ZuulReference.create(repo, ref, commit)
         return ref.commit
 
diff --git a/zuul/model.py b/zuul/model.py
index 1c69e75..0c12f88 100644
--- a/zuul/model.py
+++ b/zuul/model.py
@@ -435,9 +435,13 @@
 
 
 class Project(object):
-    def __init__(self, name):
+    def __init__(self, name, foreign=False):
         self.name = name
         self.merge_mode = MERGER_MERGE_RESOLVE
+        # foreign projects are those referenced in dependencies
+        # of layout projects, this should matter
+        # when deciding whether to enqueue their changes
+        self.foreign = foreign
 
     def __str__(self):
         return self.name
@@ -547,6 +551,9 @@
             t = JobTree(job)
             self.job_trees.append(t)
             return t
+        for tree in self.job_trees:
+            if tree.job == job:
+                return tree
 
     def getJobs(self):
         jobs = []
@@ -582,6 +589,8 @@
         self.retry = False
         self.parameters = {}
         self.worker = Worker()
+        self.node_labels = []
+        self.node_name = None
 
     def __repr__(self):
         return ('<Build %s of %s on %s>' %
@@ -739,7 +748,13 @@
         ret['items_behind'] = [i.change._id() for i in self.items_behind]
         ret['failing_reasons'] = self.current_build_set.failing_reasons
         ret['zuul_ref'] = self.current_build_set.ref
-        ret['project'] = changeish.project.name
+        if changeish.project:
+            ret['project'] = changeish.project.name
+        else:
+            # For cross-project dependencies with the depends-on
+            # project not known to zuul, the project is None
+            # Set it to a static value
+            ret['project'] = "Unknown Project"
         ret['enqueue_time'] = int(self.enqueue_time * 1000)
         ret['jobs'] = []
         if hasattr(changeish, 'owner'):
@@ -797,7 +812,9 @@
                 'canceled': build.canceled if build else None,
                 'retry': build.retry if build else None,
                 'number': build.number if build else None,
-                'worker': worker
+                'node_labels': build.node_labels if build else [],
+                'node_name': build.node_name if build else None,
+                'worker': worker,
             })
 
         if self.pipeline.haveAllJobsStarted(self):
@@ -969,7 +986,8 @@
         return None
 
     def equals(self, other):
-        if (self.project == other.project):
+        if (self.project == other.project
+            and other._id() is None):
             return True
         return False
 
diff --git a/zuul/rpcclient.py b/zuul/rpcclient.py
index f43c3b9..609f636 100644
--- a/zuul/rpcclient.py
+++ b/zuul/rpcclient.py
@@ -56,6 +56,16 @@
                 }
         return not self.submitJob('zuul:enqueue', data).failure
 
+    def enqueue_ref(self, pipeline, project, trigger, ref, oldrev, newrev):
+        data = {'pipeline': pipeline,
+                'project': project,
+                'trigger': trigger,
+                'ref': ref,
+                'oldrev': oldrev,
+                'newrev': newrev,
+                }
+        return not self.submitJob('zuul:enqueue_ref', data).failure
+
     def promote(self, pipeline, change_ids):
         data = {'pipeline': pipeline,
                 'change_ids': change_ids,
diff --git a/zuul/rpclistener.py b/zuul/rpclistener.py
index 05b8d03..d54da9f 100644
--- a/zuul/rpclistener.py
+++ b/zuul/rpclistener.py
@@ -48,6 +48,7 @@
 
     def register(self):
         self.worker.registerFunction("zuul:enqueue")
+        self.worker.registerFunction("zuul:enqueue_ref")
         self.worker.registerFunction("zuul:promote")
         self.worker.registerFunction("zuul:get_running_jobs")
 
@@ -83,7 +84,7 @@
             except Exception:
                 self.log.exception("Exception while getting job")
 
-    def handle_enqueue(self, job):
+    def _common_enqueue(self, job):
         args = json.loads(job.arguments)
         event = model.TriggerEvent()
         errors = ''
@@ -106,6 +107,11 @@
         else:
             errors += 'Invalid pipeline: %s\n' % (args['pipeline'],)
 
+        return (args, event, errors, pipeline, project)
+
+    def handle_enqueue(self, job):
+        (args, event, errors, pipeline, project) = self._common_enqueue(job)
+
         if not errors:
             event.change_number, event.patch_number = args['change'].split(',')
             try:
@@ -119,6 +125,20 @@
             self.sched.enqueue(event)
             job.sendWorkComplete()
 
+    def handle_enqueue_ref(self, job):
+        (args, event, errors, pipeline, project) = self._common_enqueue(job)
+
+        if not errors:
+            event.ref = args['ref']
+            event.oldrev = args['oldrev']
+            event.newrev = args['newrev']
+
+        if errors:
+            job.sendWorkException(errors.encode('utf8'))
+        else:
+            self.sched.enqueue(event)
+            job.sendWorkComplete()
+
     def handle_promote(self, job):
         args = json.loads(job.arguments)
         pipeline_name = args['pipeline']
diff --git a/zuul/scheduler.py b/zuul/scheduler.py
index 9fd974d..333117c 100644
--- a/zuul/scheduler.py
+++ b/zuul/scheduler.py
@@ -198,7 +198,7 @@
         self.management_event_queue = Queue.Queue()
         self.layout = model.Layout()
 
-        self.zuul_version = zuul_version.version_info.version_string()
+        self.zuul_version = zuul_version.version_info.release_string()
         self.last_reconfigured = None
 
     def stop(self):
@@ -272,9 +272,10 @@
             pipeline.failure_message = conf_pipeline.get('failure-message',
                                                          "Build failed.")
             pipeline.merge_failure_message = conf_pipeline.get(
-                'merge-failure-message', "Merge Failed.\n\nThis change was "
-                "unable to be automatically merged with the current state of "
-                "the repository. Please rebase your change and upload a new "
+                'merge-failure-message', "Merge Failed.\n\nThis change or one "
+                "of its cross-repo dependencies was unable to be "
+                "automatically merged with the current state of its "
+                "repository. Please rebase the change and upload a new "
                 "patchset.")
             pipeline.success_message = conf_pipeline.get('success-message',
                                                          "Build succeeded.")
@@ -476,10 +477,6 @@
                         config_project.update(
                             {pipeline.name: expanded[pipeline.name] +
                              config_project.get(pipeline.name, [])})
-            # TODO: future enhancement -- handle the case where
-            # duplicate jobs have different children and you want all
-            # of the children to run after a single run of the
-            # parent).
 
             layout.projects[config_project['name']] = project
             mode = config_project.get('merge-mode', 'merge-resolve')
@@ -515,11 +512,15 @@
             name = reporter.name
         self.reporters[name] = reporter
 
-    def getProject(self, name):
+    def getProject(self, name, create_foreign=False):
         self.layout_lock.acquire()
         p = None
         try:
             p = self.layout.projects.get(name)
+            if p is None and create_foreign:
+                self.log.info("Registering foreign project: %s" % name)
+                p = Project(name, foreign=True)
+                self.layout.projects[name] = p
         finally:
             self.layout_lock.release()
         return p
@@ -538,25 +539,52 @@
     def onBuildStarted(self, build):
         self.log.debug("Adding start event for build: %s" % build)
         build.start_time = time.time()
+        try:
+            if statsd and build.pipeline:
+                jobname = build.job.name.replace('.', '_')
+                key = 'zuul.pipeline.%s.job.%s.wait_time' % (
+                    build.pipeline.name, jobname)
+                dt = int((build.start_time - build.launch_time) * 1000)
+                statsd.timing(key, dt)
+                statsd.incr(key)
+        except:
+            self.log.exception("Exception reporting runtime stats")
         event = BuildStartedEvent(build)
         self.result_event_queue.put(event)
         self.wake_event.set()
         self.log.debug("Done adding start event for build: %s" % build)
 
-    def onBuildCompleted(self, build):
-        self.log.debug("Adding complete event for build: %s" % build)
+    def onBuildCompleted(self, build, result):
+        self.log.debug("Adding complete event for build: %s result: %s" % (
+            build, result))
         build.end_time = time.time()
+        # Note, as soon as the result is set, other threads may act
+        # upon this, even though the event hasn't been fully
+        # processed.  Ensure that any other data from the event (eg,
+        # timing) is recorded before setting the result.
+        build.result = result
         try:
             if statsd and build.pipeline:
                 jobname = build.job.name.replace('.', '_')
+                key = 'zuul.pipeline.%s.all_jobs' % build.pipeline.name
+                statsd.incr(key)
+                for label in build.node_labels:
+                    # Jenkins includes the node name in its list of labels, so
+                    # we filter it out here, since that is not statistically
+                    # interesting.
+                    if label == build.node_name:
+                        continue
+                    dt = int((build.start_time - build.launch_time) * 1000)
+                    key = 'zuul.node_type.%s.job.%s.wait_time' % (
+                        label, jobname)
+                    statsd.timing(key, dt)
+                    statsd.incr(key)
                 key = 'zuul.pipeline.%s.job.%s.%s' % (build.pipeline.name,
                                                       jobname, build.result)
                 if build.result in ['SUCCESS', 'FAILURE'] and build.start_time:
                     dt = int((build.end_time - build.start_time) * 1000)
                     statsd.timing(key, dt)
                 statsd.incr(key)
-                key = 'zuul.pipeline.%s.all_jobs' % build.pipeline.name
-                statsd.incr(key)
         except:
             self.log.exception("Exception reporting runtime stats")
         event = BuildCompletedEvent(build)
@@ -677,7 +705,7 @@
                     continue
                 self.log.debug("Re-enqueueing changes for pipeline %s" % name)
                 items_to_remove = []
-                builds_to_remove = []
+                builds_to_cancel = []
                 last_head = None
                 for shared_queue in old_pipeline.queues:
                     for item in shared_queue.queue:
@@ -687,28 +715,30 @@
                         item.items_behind = []
                         item.pipeline = None
                         item.queue = None
-                        project = layout.projects.get(item.change.project.name)
-                        if not project:
-                            self.log.warning("Unable to find project for "
-                                             "change %s while reenqueueing" %
-                                             item.change)
-                            item.change.project = None
-                            items_to_remove.append(item)
-                            continue
-                        item.change.project = project
+                        project_name = item.change.project.name
+                        item.change.project = layout.projects.get(project_name)
+                        if not item.change.project:
+                            self.log.debug("Project %s not defined, "
+                                           "re-instantiating as foreign" %
+                                           project_name)
+                            project = Project(project_name, foreign=True)
+                            layout.projects[project_name] = project
+                            item.change.project = project
+                        item_jobs = new_pipeline.getJobs(item)
                         for build in item.current_build_set.getBuilds():
                             job = layout.jobs.get(build.job.name)
-                            if job:
+                            if job and job in item_jobs:
                                 build.job = job
                             else:
-                                builds_to_remove.append(build)
+                                item.removeBuild(build)
+                                builds_to_cancel.append(build)
                         if not new_pipeline.manager.reEnqueueItem(item,
                                                                   last_head):
                             items_to_remove.append(item)
                 for item in items_to_remove:
                     for build in item.current_build_set.getBuilds():
-                        builds_to_remove.append(build)
-                for build in builds_to_remove:
+                        builds_to_cancel.append(build)
+                for build in builds_to_cancel:
                     self.log.warning(
                         "Canceling build %s during reconfiguration" % (build,))
                     try:
@@ -861,7 +891,7 @@
         self.log.debug("Processing trigger event %s" % event)
         try:
             project = self.layout.projects.get(event.project_name)
-            if not project:
+            if not project or project.foreign:
                 self.log.debug("Project %s not found" % event.project_name)
                 return
 
@@ -1184,6 +1214,18 @@
                 self.log.debug("Re-enqueing change %s in queue %s" %
                                (item.change, change_queue))
                 change_queue.enqueueItem(item)
+
+                # Re-set build results in case any new jobs have been
+                # added to the tree.
+                for build in item.current_build_set.getBuilds():
+                    if build.result:
+                        self.pipeline.setResult(item, build)
+                # Similarly, reset the item state.
+                if item.current_build_set.unable_to_merge:
+                    self.pipeline.setUnableToMerge(item)
+                if item.dequeued_needing_change:
+                    self.pipeline.setDequeuedNeedingChange(item)
+
                 self.reportStats(item)
                 return True
             else:
@@ -1351,6 +1393,7 @@
                                    "for change %s" % (build, item.change))
             build.result = 'CANCELED'
             canceled = True
+        self.updateBuildDescriptions(old_build_set)
         for item_behind in item.items_behind:
             self.log.debug("Canceling jobs for change %s, behind change %s" %
                            (item_behind.change, item.change))
@@ -1358,7 +1401,7 @@
                 canceled = True
         return canceled
 
-    def _processOneItem(self, item, nnfi, ready_ahead):
+    def _processOneItem(self, item, nnfi):
         changed = False
         item_ahead = item.item_ahead
         if item_ahead and (not item_ahead.live):
@@ -1378,7 +1421,7 @@
                     self.reportItem(item)
                 except MergeFailure:
                     pass
-            return (True, nnfi, ready_ahead)
+            return (True, nnfi)
         dep_items = self.getFailingDependentItems(item)
         actionable = change_queue.isActionable(item)
         item.active = actionable
@@ -1405,9 +1448,7 @@
                 if item.current_build_set.unable_to_merge:
                     failing_reasons.append("it has a merge conflict")
                     ready = False
-        if not ready:
-            ready_ahead = False
-        if actionable and ready_ahead and self.launchJobs(item):
+        if actionable and ready and self.launchJobs(item):
             changed = True
         if self.pipeline.didAnyJobFail(item):
             failing_reasons.append("at least one job failed")
@@ -1434,7 +1475,7 @@
         if failing_reasons:
             self.log.debug("%s is a failing item because %s" %
                            (item, failing_reasons))
-        return (changed, nnfi, ready_ahead)
+        return (changed, nnfi)
 
     def processQueue(self):
         # Do whatever needs to be done for each change in the queue
@@ -1443,10 +1484,9 @@
         for queue in self.pipeline.queues:
             queue_changed = False
             nnfi = None  # Nearest non-failing item
-            ready_ahead = True  # All build sets ahead are ready
             for item in queue.queue[:]:
-                item_changed, nnfi, ready_ahhead = self._processOneItem(
-                    item, nnfi, ready_ahead)
+                item_changed, nnfi = self._processOneItem(
+                    item, nnfi)
                 if item_changed:
                     queue_changed = True
                 self.reportStats(item)
@@ -1474,7 +1514,6 @@
 
     def onBuildStarted(self, build):
         self.log.debug("Build %s started" % build)
-        self.updateBuildDescriptions(build.build_set)
         return True
 
     def onBuildCompleted(self, build):
@@ -1484,7 +1523,6 @@
         self.pipeline.setResult(item, build)
         self.log.debug("Item %s status is now:\n %s" %
                        (item, item.formatStatus()))
-        self.updateBuildDescriptions(build.build_set)
         return True
 
     def onMergeCompleted(self, event):
@@ -1529,7 +1567,13 @@
     def _reportItem(self, item):
         self.log.debug("Reporting change %s" % item.change)
         ret = True  # Means error as returned by trigger.report
-        if self.pipeline.didAllJobsSucceed(item):
+        if not self.pipeline.getJobs(item):
+            # We don't send empty reports with +1,
+            # and the same for -1's (merge failures or transient errors)
+            # as they cannot be followed by +1's
+            self.log.debug("No jobs for change %s" % item.change)
+            actions = []
+        elif self.pipeline.didAllJobsSucceed(item):
             self.log.debug("success %s" % (self.pipeline.success_actions))
             actions = self.pipeline.success_actions
             item.setReportedResult('SUCCESS')
@@ -1796,10 +1840,11 @@
         if existing:
             return DynamicChangeQueueContextManager(existing)
         if change.project not in self.pipeline.getProjects():
-            return DynamicChangeQueueContextManager(None)
+            self.pipeline.addProject(change.project)
         change_queue = ChangeQueue(self.pipeline)
         change_queue.addProject(change.project)
         self.pipeline.addQueue(change_queue)
+        self.log.debug("Dynamically created queue %s", change_queue)
         return DynamicChangeQueueContextManager(change_queue)
 
     def enqueueChangesAhead(self, change, quiet, ignore_requirements,
diff --git a/zuul/trigger/gerrit.py b/zuul/trigger/gerrit.py
index a99db4d..05d7581 100644
--- a/zuul/trigger/gerrit.py
+++ b/zuul/trigger/gerrit.py
@@ -94,7 +94,7 @@
                     Can not get account information." % event.type)
             event.account = None
 
-        if event.change_number:
+        if event.change_number and self.sched.getProject(event.project_name):
             # Call _getChange for the side effect of updating the
             # cache.  Note that this modifies Change objects outside
             # the main thread.
@@ -272,7 +272,7 @@
                     return True
                 elif sr['status'] == 'NOT_READY':
                     for label in sr['labels']:
-                        if label['status'] == 'OK':
+                        if label['status'] in ['OK', 'MAY']:
                             continue
                         elif label['status'] in ['NEED', 'REJECT']:
                             # It may be our own rejection, so we ignore
@@ -404,22 +404,27 @@
         if 'project' not in data:
             raise Exception("Change %s,%s not found" % (change.number,
                                                         change.patchset))
-        change.project = self.sched.getProject(data['project'])
+        # If updated changed came as a dependent on
+        # and its project is not defined,
+        # then create a 'foreign' project for it in layout
+        change.project = self.sched.getProject(data['project'],
+                                               create_foreign=bool(history))
         change.branch = data['branch']
         change.url = data['url']
         max_ps = 0
-        change.files = []
+        files = []
         for ps in data['patchSets']:
             if ps['number'] == change.patchset:
                 change.refspec = ps['ref']
                 for f in ps.get('files', []):
-                    change.files.append(f['file'])
+                    files.append(f['file'])
             if int(ps['number']) > int(max_ps):
                 max_ps = ps['number']
         if max_ps == change.patchset:
             change.is_current_patchset = True
         else:
             change.is_current_patchset = False
+        change.files = files
 
         change.is_merged = self._isMerged(change)
         change.approvals = data['currentPatchSet'].get('approvals', [])
@@ -438,7 +443,7 @@
             history = history[:]
         history.append(change.number)
 
-        change.needs_changes = []
+        needs_changes = []
         if 'dependsOn' in data:
             parts = data['dependsOn'][0]['ref'].split('/')
             dep_num, dep_ps = parts[3], parts[4]
@@ -448,8 +453,8 @@
             self.log.debug("Getting git-dependent change %s,%s" %
                            (dep_num, dep_ps))
             dep = self._getChange(dep_num, dep_ps, history=history)
-            if (not dep.is_merged) and dep not in change.needs_changes:
-                change.needs_changes.append(dep)
+            if (not dep.is_merged) and dep not in needs_changes:
+                needs_changes.append(dep)
 
         for record in self._getDependsOnFromCommit(data['commitMessage']):
             dep_num = record['number']
@@ -460,17 +465,18 @@
             self.log.debug("Getting commit-dependent change %s,%s" %
                            (dep_num, dep_ps))
             dep = self._getChange(dep_num, dep_ps, history=history)
-            if (not dep.is_merged) and dep not in change.needs_changes:
-                change.needs_changes.append(dep)
+            if (not dep.is_merged) and dep not in needs_changes:
+                needs_changes.append(dep)
+        change.needs_changes = needs_changes
 
-        change.needed_by_changes = []
+        needed_by_changes = []
         if 'neededBy' in data:
             for needed in data['neededBy']:
                 parts = needed['ref'].split('/')
                 dep_num, dep_ps = parts[3], parts[4]
                 dep = self._getChange(dep_num, dep_ps)
                 if (not dep.is_merged) and dep.is_current_patchset:
-                    change.needed_by_changes.append(dep)
+                    needed_by_changes.append(dep)
 
         for record in self._getNeededByFromCommit(data['id']):
             dep_num = record['number']
@@ -483,7 +489,8 @@
             # change).
             dep = self._getChange(dep_num, dep_ps, refresh=True)
             if (not dep.is_merged) and dep.is_current_patchset:
-                change.needed_by_changes.append(dep)
+                needed_by_changes.append(dep)
+        change.needed_by_changes = needed_by_changes
 
         return change
 
diff --git a/zuul/webapp.py b/zuul/webapp.py
index e289398..44c333b 100644
--- a/zuul/webapp.py
+++ b/zuul/webapp.py
@@ -121,5 +121,10 @@
                 raise webob.exc.HTTPNotFound()
 
         response.headers['Access-Control-Allow-Origin'] = '*'
+
+        response.cache_control.public = True
+        response.cache_control.max_age = self.cache_expiry
         response.last_modified = self.cache_time
-        return response
+        response.expires = self.cache_time + self.cache_expiry
+
+        return response.conditional_response_app