Index: .arcconfig
===================================================================
--- .arcconfig
+++ .arcconfig
@@ -1,5 +1,5 @@
 {
   "phabricator.uri" : "https://code.wildfiregames.com/",
   "repository.callsign" : "P",
-  "load": ["build/arclint/pyrolint"]
+  "load": ["build/arclint/pyrolint", "build/arcpatch/ci-patch"]
 }
Index: build/arcpatch/ci-patch/__phutil_library_init__.php
===================================================================
--- /dev/null
+++ build/arcpatch/ci-patch/__phutil_library_init__.php
@@ -0,0 +1,3 @@
+<?php
+
+phutil_register_library('ci-patch', __FILE__);
Index: build/arcpatch/ci-patch/__phutil_library_map__.php
===================================================================
--- /dev/null
+++ build/arcpatch/ci-patch/__phutil_library_map__.php
@@ -0,0 +1,18 @@
+<?php
+
+/**
+ * This file is automatically generated. Use 'arc liberate' to rebuild it.
+ *
+ * @generated
+ * @phutil-library-version 2
+ */
+phutil_register_library_map(array(
+  '__library_version__' => 2,
+  'class' => array(
+    'CIPatchWorkflow' => 'src/CIPatchWorkflow.php',
+  ),
+  'function' => array(),
+  'xmap' => array(
+    'CIPatchWorkflow' => 'ArcanistWorkflow',
+  ),
+));
Index: build/arcpatch/ci-patch/src/CIPatchWorkflow.php
===================================================================
--- /dev/null
+++ build/arcpatch/ci-patch/src/CIPatchWorkflow.php
@@ -0,0 +1,372 @@
+<?php
+
+/**
+ * This extension assumes that the current working copy is an unmodified
+ * master/trunk HEAD.
+ */
+final class CIPatchWorkflow extends ArcanistWorkflow {
+
+  // Arguments to pass to a child ArcanistPatchWorkflow
+  const PATCH_ARGUMENTS = array(
+      "--force",
+      "--nobranch",
+      "--nocommit",
+      "--skip-dependencies",
+  );
+
+  private $source;
+  private $sourceParam;
+
+  public function getWorkflowName() {
+    return 'ci-patch';
+  }
+
+  public function getCommandSynopses() {
+    return phutil_console_format(<<<EOTEXT
+      **ci-patch** __D12345__
+      **ci-patch** __--revision__ __revision_id__
+      **ci-patch** __--diff__ __diff_id__
+EOTEXT
+      );
+  }
+
+  public function getCommandHelp() {
+    return phutil_console_format(<<<EOTEXT
+          Supports: git, svn, hg
+          Apply the changes in a Differential revision - or a specific
+          diff attached to a revision - and its active dependencies to
+          the working copy.
+EOTEXT
+      );
+  }
+
+  public function getArguments() {
+    return array(
+      'revision' => array(
+        'param' => 'revision_id',
+        'paramtype' => 'complete',
+        'help' => pht(
+          "Apply changes from a Differential revision, using the most recent ".
+          "diff that has been attached to it. You can run '%s' as a shorthand.",
+          'arc patch D12345'),
+      ),
+      'diff' => array(
+        'param' => 'diff_id',
+        'help' => pht(
+          'Apply changes from a specific Differential diff. The diff must be '.
+          'attached to a revision.'),
+      ),
+      'allow-abandoned' => array(
+        'help' => pht(
+          'Allow specifying an abandoned revision (or diff from an abandoned '.
+          'revision).'),
+      ),
+      'allow-abandoned-dependencies' => array(
+        'help' => pht('Apply any abandoned dependencies found.'),
+      ),
+      'allow-untracked' => array(
+        'help' => pht('Skip checks for untracked files in the working copy.'),
+      ),
+      '*' => 'name',
+    );
+  }
+
+  // Certain error message texts depend on whether it's a revision
+  // or a diff being processed.
+  private function getErrorMessage($source, $reason) {
+    return array(
+      ArcanistPatchWorkflow::SOURCE_REVISION => array(
+        'is_closed' => pht(
+          "This revision has been closed, and is likely already merged ".
+          "into the source tree."),
+        'is_abandoned_fatal' => pht(
+          "This revision has been abandoned. If you really want to apply it, ".
+          "pass '%s'.",
+          '--allow-abandoned'),
+        'is_abandoned_continuing' => pht(
+          "This revision has been abandoned."),
+      ),
+      ArcanistPatchWorkflow::SOURCE_DIFF => array(
+        'is_closed' => pht(
+          "The revision this diff is attached to is closed. Any changes ".
+          "contained within are likely already merged into the source tree."),
+        'is_abandoned_fatal' => pht(
+          "The revision this diff is attached to has been abandoned. If you ".
+          "really want to apply this diff, pass '%s'.",
+          '--allow-abandoned'),
+        'is_abandoned_continuing' => pht(
+          "The revision this diff is attached to has been abandoned."),
+      ),
+    )[$source][$reason];
+  }
+
+  public function requiresAuthentication() {
+    return true;
+  }
+
+  public function requiresConduit() {
+    return true;
+  }
+
+  public function requiresRepositoryAPI() {
+    return true;
+  }
+
+  public function requiresWorkingCopy() {
+    return true;
+  }
+
+  public function run() {
+    $this->requireCleanWorkingCopy();
+
+    $source = $this->source;
+    $param = $this->sourceParam;
+    $argument = "";
+    $revisionID = null;
+    switch ($source) {
+      case ArcanistPatchWorkflow::SOURCE_REVISION:
+        $bundle = $this->loadRevisionBundleFromConduit(
+          $this->getConduit(),
+          $param);
+        $argument = '--revision=' . $param;
+        $revisionID = $param;
+        break;
+      case ArcanistPatchWorkflow::SOURCE_DIFF:
+        $bundle = $this->loadDiffBundleFromConduit(
+          $this->getConduit(),
+          $param);
+        $argument = '--diff=' . $param;
+        $revisionID = $bundle->getRevisionID();
+        if (!$revisionID) {
+          $this->throwError(
+            pht('This diff is not attached to a revision!'));
+        }
+        break;
+    }
+
+    // Check that the revision (or the diff that the revision is attached to) is still active.
+    $result = $this->getConduit()->callMethodSynchronous(
+      'differential.query',
+      array(
+        'ids' => array($revisionID),
+      ));
+    if ($result[0]['status'] == ArcanistDifferentialRevisionStatus::CLOSED) {
+      $this->throwError($this->getErrorMessage($source, 'is_closed'));
+    } else if ($result[0]['status'] == ArcanistDifferentialRevisionStatus::ABANDONED) {
+      if ($this->getArgument('allow-abandoned')) {
+        $this->printWarning($this->getErrorMessage($source, 'is_abandoned_continuing'));
+      } else {
+        $this->throwError($this->getErrorMessage($source, 'is_abandoned_fatal'));
+      }
+    }
+
+    $this->updateWorkingCopy();
+    $this->applyDependencies($bundle);
+
+    $this->printInfo(pht('Applying %s %s.', $source, $param));
+    $childWorkflow = $this->buildChildWorkflow(
+      'patch',
+      array_merge(
+        self::PATCH_ARGUMENTS,
+        array($argument)
+      ));
+    $errorCode = $childWorkflow->run();
+
+    // We expect the child workflow to display a suitable message if something
+    // has gone wrong.
+    if (!$errorCode) {
+      echo phutil_console_format(
+        "<bg:green>** %s **</bg>\n",
+        pht('DONE'));
+    }
+    return $errorCode;
+  }
+
+  private function applyDependencies(ArcanistBundle $bundle) {
+    $this->printInfo(pht('Detecting dependencies...'), false);
+    $graph = $this->buildDependencyGraph($bundle);
+    if (!$graph) {
+      echo pht(' none found.')."\n";
+      return;
+    }
+    echo "\n";
+
+    $revisionID = $bundle->getRevisionID();
+    $start_phid = $graph->getStartPHID();
+    $cycle_phids = $graph->detectCycles($start_phid);
+    if ($cycle_phids) {
+      $phids = array_keys($graph->getNodes());
+      $this->printWarning(
+        pht('The dependencies for this patch are cyclic. Applying '.
+            'them might not be successful.'));
+    } else {
+      $phids = $graph->getNodesInTopologicalOrder();
+      $phids = array_reverse($phids);
+    }
+
+    $dep_on_revs = $this->getConduit()->callMethodSynchronous(
+      'differential.query',
+      array(
+        'phids' => $phids,
+      ));
+    $revs = array();
+    foreach ($dep_on_revs as $dep_on_rev) {
+      // Skip the revision we've requested the dependencies of
+      if ($dep_on_rev['id'] == $revisionID)
+        continue;
+
+      // Conditionally skip dependencies that are abandoned
+      if ($dep_on_rev['status'] == ArcanistDifferentialRevisionStatus::ABANDONED) {
+        $this->printWarning(
+          pht('Dependency %s has been abandoned.',
+              'D'.$dep_on_rev['id']));
+        if (!$this->getArgument('allow-abandoned')) {
+          continue;
+        }
+      }
+
+      // Skip dependencies that are closed
+      if ($dep_on_rev['status'] == ArcanistDifferentialRevisionStatus::CLOSED) {
+        continue;
+      }
+
+      $revs[$dep_on_rev['phid']] = 'D'.$dep_on_rev['id'];
+    }
+
+    if (!count($revs)) {
+      $this->printInfo(pht('No active dependencies found.'));
+      return;
+    }
+    $this->printInfo(pht('Found %s active dependencies.', count($revs)));
+
+    // Retain the topological sort order from earlier
+    $revs = array_select_keys($revs, $phids);
+
+    foreach ($revs as $phid => $id) {
+      $this->printInfo(pht('Applying dependancy: %s.', $id));
+      $childWorkflow = $this->buildChildWorkflow(
+        'patch',
+        array_merge(
+          self::PATCH_ARGUMENTS,
+          array('--revision=' . $id)
+        ));
+      $errorCode = $childWorkflow->run();
+
+      // We expect the child workflow to display a suitable message if something
+      // has gone wrong.
+      if ($errorCode) {
+        exit($errorCode);
+      }
+    }
+  }
+
+  private function printInfo($msg, $newline=true) {
+    $format = "<bg:blue>** %s **</bg> %s";
+    if ($newline)
+      $format .= "\n";
+    echo phutil_console_format(
+      $format,
+      pht('INFO'),
+      $msg);
+  }
+
+  private function printWarning($msg) {
+    echo phutil_console_format(
+      "<bg:yellow>** %s **</bg> %s\n",
+      pht('WARNING'),
+      $msg);
+  }
+
+  private function throwError($msg) {
+    echo phutil_console_format(
+      "<bg:red>** %s **</bg> %s\n",
+      pht('ERROR'),
+      $msg);
+    exit(1);
+  }
+
+  private function updateWorkingCopy() {
+    $this->printInfo(pht('Updating working copy...'));
+    $this->getRepositoryAPI()->updateWorkingCopy();
+  }
+
+  protected function didParseArguments() {
+    $arguments = array(
+      'revision' => ArcanistPatchWorkflow::SOURCE_REVISION,
+      'diff' => ArcanistPatchWorkflow::SOURCE_DIFF,
+      'name' => ArcanistPatchWorkflow::SOURCE_REVISION,
+    );
+
+    $sources = array();
+    foreach ($arguments as $key => $source_type) {
+      $value = $this->getArgument($key);
+      if (!$value) {
+        continue;
+      }
+
+      switch ($key) {
+        case 'revision':
+          $value = $this->normalizeRevisionID($value);
+          break;
+        case 'name':
+          if (count($value) > 1) {
+            throw new ArcanistUsageException(
+              pht('Specify at most one revision name.'));
+          }
+          $value = $this->normalizeRevisionID(head($value));
+          break;
+      }
+
+      $sources[] = array(
+        $source_type,
+        $value,
+      );
+    }
+
+    if (!$sources) {
+      throw new ArcanistUsageException(
+        pht(
+          'You must specify changes to apply to the working copy with '.
+          '"D12345", "--revision", or "--diff".'));
+    }
+
+    if (count($sources) > 1) {
+      throw new ArcanistUsageException(
+        pht(
+          'Options "D12345", "--revision", and "--diff" are mutually '.
+          'exclusive. Choose exactly one patch source.'));
+    }
+
+    $source = head($sources);
+
+    $this->source = $source[0];
+    $this->sourceParam = $source[1];
+  }
+
+  private function buildDependencyGraph(ArcanistBundle $bundle) {
+    $graph = null;
+    $revision_id = $bundle->getRevisionID();
+    if ($revision_id) {
+      $revisions = $this->getConduit()->callMethodSynchronous(
+        'differential.query',
+        array(
+          'ids' => array($revision_id),
+        ));
+      if ($revisions) {
+        $revision = head($revisions);
+        $rev_auxiliary = idx($revision, 'auxiliary', array());
+        $phids = idx($rev_auxiliary, 'phabricator:depends-on', array());
+        if ($phids) {
+          $revision_phid = $revision['phid'];
+          $graph = id(new ArcanistDifferentialDependencyGraph())
+            ->setConduit($this->getConduit())
+            ->setRepositoryAPI($this->getRepositoryAPI())
+            ->setStartPHID($revision_phid)
+            ->addNodes(array($revision_phid => $phids))
+            ->loadGraph();
+        }
+      }
+    }
+    return $graph;
+  }
+}
Index: build/jenkins/pipelines/docker-custom.Jenkinsfile
===================================================================
--- build/jenkins/pipelines/docker-custom.Jenkinsfile
+++ build/jenkins/pipelines/docker-custom.Jenkinsfile
@@ -40,7 +40,7 @@
 			}
 			steps {
 				ws("/zpool0/custom") {
-					sh "arc patch --diff ${params.DIFF_ID} --force"
+					sh "arc ci-patch --diff ${params.DIFF_ID}"
 				}
 			}
 		}
Index: build/jenkins/pipelines/docker-differential.Jenkinsfile
===================================================================
--- build/jenkins/pipelines/docker-differential.Jenkinsfile
+++ build/jenkins/pipelines/docker-differential.Jenkinsfile
@@ -27,7 +27,7 @@
 		stage("Patch: ${compiler}") {
 			try {
 				ws("/zpool0/${compiler}") {
-					sh "arc patch --diff ${params.DIFF_ID} --force"
+					sh "arc ci-patch --diff ${params.DIFF_ID}"
 				}
 			} catch(e) {
 				sh "sudo zfs rollback zpool0/${compiler}@latest"
@@ -121,7 +121,7 @@
 	stages {
 		stage("Patch") {
 			steps {
-				sh "arc patch --diff ${params.DIFF_ID} --force"
+				sh "arc ci-patch --diff ${params.DIFF_ID}"
 				script { parallel patchesMap }
 			}
 		}
Index: build/jenkins/pipelines/macos-differential.Jenkinsfile
===================================================================
--- build/jenkins/pipelines/macos-differential.Jenkinsfile
+++ build/jenkins/pipelines/macos-differential.Jenkinsfile
@@ -49,11 +49,11 @@
 			steps {
 				script {
 					try {
-						sh "arc patch --diff ${params.DIFF_ID} --force"
+						sh "arc ci-patch --diff ${params.DIFF_ID}"
 					} catch (e) {
 						sh "svn revert -R ."
 						sh "svn st | cut -c 9- | xargs rm -rf"
-						sh "arc patch --diff ${params.DIFF_ID} --force"
+						sh "arc ci-patch --diff ${params.DIFF_ID}"
 					}
 				}
 			}
Index: build/jenkins/pipelines/vs2015-differential.Jenkinsfile
===================================================================
--- build/jenkins/pipelines/vs2015-differential.Jenkinsfile
+++ build/jenkins/pipelines/vs2015-differential.Jenkinsfile
@@ -51,11 +51,11 @@
 			steps {
 				script {
 					try {
-					 bat "arc patch --diff ${params.DIFF_ID} --force"
+					 bat "arc ci-patch --diff ${params.DIFF_ID}"
 					} catch (e) {
 						bat 'svn revert -R .'
 						bat 'powershell.exe "svn st --no-ignore | %% {$_.substring(8)} | del -r" '
-						bat "arc patch --diff ${params.DIFF_ID} --force"
+						bat "arc ci-patch --diff ${params.DIFF_ID}"
 					}
 				}
 			}