Update "arc amend" for Toolsets

Summary: Ref T13490. Moves "arc amend" to Toolsets with modern ref/hardpoint code.

Test Plan: Ran "arc amend --show", "--revision", etc. Hit all the prompts and errors, probably?

Maniphest Tasks: T13490

Differential Revision: https://secure.phabricator.com/D21095

src/__phutil_library_map__.php

@@ -411,6 +411,7 @@ phutil_register_library_map(array(
     'ArcanistRubyLinterTestCase' => 'lint/linter/__tests__/ArcanistRubyLinterTestCase.php',
     'ArcanistRuntime' => 'runtime/ArcanistRuntime.php',
     'ArcanistRuntimeConfigurationSource' => 'config/source/ArcanistRuntimeConfigurationSource.php',
+    'ArcanistRuntimeHardpointQuery' => 'toolset/query/ArcanistRuntimeHardpointQuery.php',
     'ArcanistScalarConfigOption' => 'config/option/ArcanistScalarConfigOption.php',
     'ArcanistScalarHardpoint' => 'hardpoint/ArcanistScalarHardpoint.php',
     'ArcanistScriptAndRegexLinter' => 'lint/linter/ArcanistScriptAndRegexLinter.php',
@@ -507,7 +508,6 @@ phutil_register_library_map(array(
     'ArcanistWorkflow' => 'workflow/ArcanistWorkflow.php',
     'ArcanistWorkflowArgument' => 'toolset/ArcanistWorkflowArgument.php',
     'ArcanistWorkflowGitHardpointQuery' => 'query/ArcanistWorkflowGitHardpointQuery.php',
-    'ArcanistWorkflowHardpointQuery' => 'toolset/query/ArcanistWorkflowHardpointQuery.php',
     'ArcanistWorkflowInformation' => 'toolset/ArcanistWorkflowInformation.php',
     'ArcanistWorkingCopy' => 'workingcopy/ArcanistWorkingCopy.php',
     'ArcanistWorkingCopyCommitHardpointQuery' => 'query/ArcanistWorkingCopyCommitHardpointQuery.php',
@@ -1006,7 +1006,7 @@ phutil_register_library_map(array(
     'ArcanistAliasFunctionXHPASTLinterRuleTestCase' => 'ArcanistXHPASTLinterRuleTestCase',
     'ArcanistAliasWorkflow' => 'ArcanistWorkflow',
     'ArcanistAliasesConfigOption' => 'ArcanistListConfigOption',
-    'ArcanistAmendWorkflow' => 'ArcanistWorkflow',
+    'ArcanistAmendWorkflow' => 'ArcanistArcWorkflow',
     'ArcanistAnoidWorkflow' => 'ArcanistArcWorkflow',
     'ArcanistArcConfigurationEngineExtension' => 'ArcanistConfigurationEngineExtension',
     'ArcanistArcToolset' => 'ArcanistToolset',
@@ -1035,14 +1035,14 @@ phutil_register_library_map(array(
     'ArcanistBraceFormattingXHPASTLinterRuleTestCase' => 'ArcanistXHPASTLinterRuleTestCase',
     'ArcanistBranchRef' => 'ArcanistRef',
     'ArcanistBranchWorkflow' => 'ArcanistFeatureBaseWorkflow',
-    'ArcanistBrowseCommitHardpointQuery' => 'ArcanistWorkflowHardpointQuery',
+    'ArcanistBrowseCommitHardpointQuery' => 'ArcanistRuntimeHardpointQuery',
     'ArcanistBrowseCommitURIHardpointQuery' => 'ArcanistBrowseURIHardpointQuery',
     'ArcanistBrowseObjectNameURIHardpointQuery' => 'ArcanistBrowseURIHardpointQuery',
     'ArcanistBrowsePathURIHardpointQuery' => 'ArcanistBrowseURIHardpointQuery',
     'ArcanistBrowseRef' => 'ArcanistRef',
     'ArcanistBrowseRefInspector' => 'ArcanistRefInspector',
     'ArcanistBrowseRevisionURIHardpointQuery' => 'ArcanistBrowseURIHardpointQuery',
-    'ArcanistBrowseURIHardpointQuery' => 'ArcanistWorkflowHardpointQuery',
+    'ArcanistBrowseURIHardpointQuery' => 'ArcanistRuntimeHardpointQuery',
     'ArcanistBrowseURIRef' => 'ArcanistRef',
     'ArcanistBrowseWorkflow' => 'ArcanistArcWorkflow',
     'ArcanistBuildPlanRef' => 'Phobject',
@@ -1085,7 +1085,7 @@ phutil_register_library_map(array(
     'ArcanistCommitRef' => 'ArcanistRef',
     'ArcanistCommitSymbolRef' => 'ArcanistSymbolRef',
     'ArcanistCommitSymbolRefInspector' => 'ArcanistRefInspector',
-    'ArcanistCommitUpstreamHardpointQuery' => 'ArcanistWorkflowHardpointQuery',
+    'ArcanistCommitUpstreamHardpointQuery' => 'ArcanistRuntimeHardpointQuery',
     'ArcanistCommitWorkflow' => 'ArcanistWorkflow',
     'ArcanistCompilerLintRenderer' => 'ArcanistLintRenderer',
     'ArcanistComposerLinter' => 'ArcanistLinter',
@@ -1298,7 +1298,7 @@ phutil_register_library_map(array(
     'ArcanistMercurialWorkingCopy' => 'ArcanistWorkingCopy',
     'ArcanistMergeConflictLinter' => 'ArcanistLinter',
     'ArcanistMergeConflictLinterTestCase' => 'ArcanistLinterTestCase',
-    'ArcanistMessageRevisionHardpointQuery' => 'ArcanistWorkflowHardpointQuery',
+    'ArcanistMessageRevisionHardpointQuery' => 'ArcanistRuntimeHardpointQuery',
     'ArcanistMissingArgumentTerminatorException' => 'Exception',
     'ArcanistMissingLinterException' => 'Exception',
     'ArcanistModifierOrderingXHPASTLinterRule' => 'ArcanistXHPASTLinterRule',
@@ -1381,13 +1381,13 @@ phutil_register_library_map(array(
     'ArcanistReusedIteratorXHPASTLinterRule' => 'ArcanistXHPASTLinterRule',
     'ArcanistReusedIteratorXHPASTLinterRuleTestCase' => 'ArcanistXHPASTLinterRuleTestCase',
     'ArcanistRevertWorkflow' => 'ArcanistWorkflow',
-    'ArcanistRevisionCommitMessageHardpointQuery' => 'ArcanistWorkflowHardpointQuery',
+    'ArcanistRevisionCommitMessageHardpointQuery' => 'ArcanistRuntimeHardpointQuery',
     'ArcanistRevisionRef' => array(
       'ArcanistRef',
       'ArcanistDisplayRefInterface',
     ),
     'ArcanistRevisionRefSource' => 'Phobject',
-    'ArcanistRevisionSymbolHardpointQuery' => 'ArcanistWorkflowHardpointQuery',
+    'ArcanistRevisionSymbolHardpointQuery' => 'ArcanistRuntimeHardpointQuery',
     'ArcanistRevisionSymbolRef' => 'ArcanistSymbolRef',
     'ArcanistRevisionSymbolRefInspector' => 'ArcanistRefInspector',
     'ArcanistRuboCopLinter' => 'ArcanistExternalLinter',
@@ -1395,6 +1395,7 @@ phutil_register_library_map(array(
     'ArcanistRubyLinter' => 'ArcanistExternalLinter',
     'ArcanistRubyLinterTestCase' => 'ArcanistExternalLinterTestCase',
     'ArcanistRuntimeConfigurationSource' => 'ArcanistDictionaryConfigurationSource',
+    'ArcanistRuntimeHardpointQuery' => 'ArcanistHardpointQuery',
     'ArcanistScalarConfigOption' => 'ArcanistConfigOption',
     'ArcanistScalarHardpoint' => 'ArcanistHardpoint',
     'ArcanistScriptAndRegexLinter' => 'ArcanistLinter',
@@ -1478,7 +1479,7 @@ phutil_register_library_map(array(
       'ArcanistRef',
       'ArcanistDisplayRefInterface',
     ),
-    'ArcanistUserSymbolHardpointQuery' => 'ArcanistWorkflowHardpointQuery',
+    'ArcanistUserSymbolHardpointQuery' => 'ArcanistRuntimeHardpointQuery',
     'ArcanistUserSymbolRef' => 'ArcanistSymbolRef',
     'ArcanistUserSymbolRefInspector' => 'ArcanistRefInspector',
     'ArcanistVariableReferenceSpacingXHPASTLinterRule' => 'ArcanistXHPASTLinterRule',
@@ -1492,11 +1493,10 @@ phutil_register_library_map(array(
     'ArcanistWildConfigOption' => 'ArcanistConfigOption',
     'ArcanistWorkflow' => 'Phobject',
     'ArcanistWorkflowArgument' => 'Phobject',
-    'ArcanistWorkflowGitHardpointQuery' => 'ArcanistWorkflowHardpointQuery',
-    'ArcanistWorkflowHardpointQuery' => 'ArcanistHardpointQuery',
+    'ArcanistWorkflowGitHardpointQuery' => 'ArcanistRuntimeHardpointQuery',
     'ArcanistWorkflowInformation' => 'Phobject',
     'ArcanistWorkingCopy' => 'Phobject',
-    'ArcanistWorkingCopyCommitHardpointQuery' => 'ArcanistWorkflowHardpointQuery',
+    'ArcanistWorkingCopyCommitHardpointQuery' => 'ArcanistRuntimeHardpointQuery',
     'ArcanistWorkingCopyConfigurationSource' => 'ArcanistFilesystemConfigurationSource',
     'ArcanistWorkingCopyIdentity' => 'Phobject',
     'ArcanistWorkingCopyPath' => 'Phobject',

src/browse/query/ArcanistBrowseCommitHardpointQuery.php

@@ -1,7 +1,7 @@
 <?php
 
 final class ArcanistBrowseCommitHardpointQuery
-  extends ArcanistWorkflowHardpointQuery {
+  extends ArcanistRuntimeHardpointQuery {
 
   public function getHardpoints() {
     return array(

src/browse/query/ArcanistBrowseURIHardpointQuery.php

@@ -1,7 +1,7 @@
 <?php
 
 abstract class ArcanistBrowseURIHardpointQuery
-  extends ArcanistWorkflowHardpointQuery {
+  extends ArcanistRuntimeHardpointQuery {
 
   public function getSupportedBrowseType() {
     return $this->getPhobjectClassConstant('BROWSETYPE', 32);

src/query/ArcanistCommitUpstreamHardpointQuery.php

@@ -1,7 +1,7 @@
 <?php
 
 final class ArcanistCommitUpstreamHardpointQuery
-  extends ArcanistWorkflowHardpointQuery {
+  extends ArcanistRuntimeHardpointQuery {
 
   public function getHardpoints() {
     return array(

src/query/ArcanistMessageRevisionHardpointQuery.php

@@ -1,7 +1,7 @@
 <?php
 
 final class ArcanistMessageRevisionHardpointQuery
-  extends ArcanistWorkflowHardpointQuery {
+  extends ArcanistRuntimeHardpointQuery {
 
   public function getHardpoints() {
     return array(

src/query/ArcanistWorkflowGitHardpointQuery.php

@@ -1,7 +1,7 @@
 <?php
 
 abstract class ArcanistWorkflowGitHardpointQuery
-  extends ArcanistWorkflowHardpointQuery {
+  extends ArcanistRuntimeHardpointQuery {
 
   final protected function canLoadHardpoint() {
     $api = $this->getRepositoryAPI();

src/query/ArcanistWorkingCopyCommitHardpointQuery.php

@@ -1,7 +1,7 @@
 <?php
 
 final class ArcanistWorkingCopyCommitHardpointQuery
-  extends ArcanistWorkflowHardpointQuery {
+  extends ArcanistRuntimeHardpointQuery {
 
   public function getHardpoints() {
     return array(

src/ref/revision/ArcanistRevisionCommitMessageHardpointQuery.php

@@ -1,7 +1,7 @@
 <?php
 
 final class ArcanistRevisionCommitMessageHardpointQuery
-  extends ArcanistWorkflowHardpointQuery {
+  extends ArcanistRuntimeHardpointQuery {
 
   public function getHardpoints() {
     return array(

src/ref/revision/ArcanistRevisionRef.php

@@ -79,6 +79,10 @@ final class ArcanistRevisionRef
     return $this->sources;
   }
 
+  public function getCommitMessage() {
+    return $this->getHardpoint(self::HARDPOINT_COMMITMESSAGE);
+  }
+
   public function getDisplayRefObjectName() {
     return $this->getMonogram();
   }

src/ref/revision/ArcanistRevisionSymbolHardpointQuery.php

@@ -1,7 +1,7 @@
 <?php
 
 final class ArcanistRevisionSymbolHardpointQuery
-  extends ArcanistWorkflowHardpointQuery {
+  extends ArcanistRuntimeHardpointQuery {
 
   public function getHardpoints() {
     return array(

src/ref/user/ArcanistUserRef.php

@@ -8,7 +8,7 @@ final class ArcanistUserRef
   private $parameters;
 
   public function getRefDisplayName() {
-    return pht('User "%s"', $this->getUsername());
+    return pht('User "%s"', $this->getMonogram());
   }
 
   public static function newFromConduit(array $parameters) {
@@ -29,6 +29,18 @@ final class ArcanistUserRef
     return self::newFromConduit($parameters);
   }
 
+  public function getID() {
+    return idx($this->parameters, 'id');
+  }
+
+  public function getPHID() {
+    return idx($this->parameters, 'phid');
+  }
+
+  public function getMonogram() {
+    return '@'.$this->getUsername();
+  }
+
   public function getUsername() {
     return idxv($this->parameters, array('fields', 'username'));
   }
@@ -38,7 +50,7 @@ final class ArcanistUserRef
   }
 
   public function getDisplayRefObjectName() {
-    return '@'.$this->getUsername();
+    return $this->getMonogram();
   }
 
   public function getDisplayRefTitle() {

src/ref/user/ArcanistUserSymbolHardpointQuery.php

@@ -1,7 +1,7 @@
 <?php
 
 final class ArcanistUserSymbolHardpointQuery
-  extends ArcanistWorkflowHardpointQuery {
+  extends ArcanistRuntimeHardpointQuery {
 
   public function getHardpoints() {
     return array(

src/repository/api/ArcanistGitAPI.php

@@ -1687,4 +1687,8 @@ final class ArcanistGitAPI extends ArcanistRepositoryAPI {
     return null;
   }
 
+  protected function newCurrentCommitSymbol() {
+    return 'HEAD';
+  }
+
 }

src/repository/api/ArcanistRepositoryAPI.php

@@ -39,6 +39,10 @@ abstract class ArcanistRepositoryAPI extends Phobject {
   private $symbolicBaseCommit;
   private $resolvedBaseCommit;
 
+  private $runtime;
+  private $currentWorkingCopyStateRef = false;
+  private $currentCommitRef = false;
+
   abstract public function getSourceControlSystemName();
 
   public function getDiffLinesOfContext() {
@@ -665,6 +669,64 @@ abstract class ArcanistRepositoryAPI extends Phobject {
     return null;
   }
 
+  final public function newFuture($pattern /* , ... */) {
+    $args = func_get_args();
+    return $this->buildLocalFuture($args)
+      ->setResolveOnError(false);
+  }
+
+  final public function setRuntime(ArcanistRuntime $runtime) {
+    $this->runtime = $runtime;
+    return $this;
+  }
+
+  final public function getRuntime() {
+    return $this->runtime;
+  }
+
+  final protected function getSymbolEngine() {
+    return $this->getRuntime()->getSymbolEngine();
+  }
+
+  final public function getCurrentWorkingCopyStateRef() {
+    if ($this->currentWorkingCopyStateRef === false) {
+      $ref = $this->newCurrentWorkingCopyStateRef();
+      $this->currentWorkingCopyStateRef = $ref;
+    }
+
+    return $this->currentWorkingCopyStateRef;
+  }
+
+  protected function newCurrentWorkingCopyStateRef() {
+    $commit_ref = $this->getCurrentCommitRef();
+
+    if (!$commit_ref) {
+      return null;
+    }
+
+    return id(new ArcanistWorkingCopyStateRef())
+      ->setCommitRef($commit_ref);
+  }
+
+  final public function getCurrentCommitRef() {
+    if ($this->currentCommitRef === false) {
+      $this->currentCommitRef = $this->newCurrentCommitRef();
+    }
+    return $this->currentCommitRef;
+  }
+
+  protected function newCurrentCommitRef() {
+    $symbols = $this->getSymbolEngine();
+
+    $commit_symbol = $this->newCurrentCommitSymbol();
+
+    return $symbols->loadCommitForSymbol($commit_symbol);
+  }
+
+  protected function newCurrentCommitSymbol() {
+    throw new ArcanistCapabilityNotSupportedException($this);
+  }
+
   final public function newCommitRef() {
     return new ArcanistCommitRef();
   }
@@ -672,41 +734,4 @@ abstract class ArcanistRepositoryAPI extends Phobject {
   final public function newBranchRef() {
     return new ArcanistBranchRef();
   }
-
-  final public function getCurrentCommitRef() {
-    $commit_hash = $this->newCurrentCommitHash();
-    return $this->newCommitRef()
-      ->setCommitHash($commit_hash);
-  }
-
-  protected function newCurrentCommitRef() {
-    $commit_hash = $this->newCurrentCommitHash();
-    return $this->newCommitRefForSymbol($commit_hash);
-  }
-
-  protected function newCommitRefForSymbol() {
-    throw new ArcanistCapabilityNotSupportedException($this);
-  }
-
-  protected function newCurrentCommitHash() {
-    throw new ArcanistCapabilityNotSupportedException($this);
-  }
-
-  final public function getCurrentWorkingCopyStateRef() {
-    return $this->newCurrentWorkingCopyStateRef();
-  }
-
-  protected function newCurrentWorkingCopyStateRef() {
-    $commit_ref = $this->getCurrentCommitRef();
-
-    return id(new ArcanistWorkingCopyStateRef())
-      ->setCommitRef($commit_ref);
-  }
-
-  final public function newFuture($pattern /* , ... */) {
-    $args = func_get_args();
-    return $this->buildLocalFuture($args)
-      ->setResolveOnError(false);
-  }
-
 }

src/runtime/ArcanistRuntime.php

@@ -8,6 +8,12 @@ final class ArcanistRuntime {
 
   private $stack = array();
 
+  private $viewer;
+  private $hardpointEngine;
+  private $symbolEngine;
+  private $conduitEngine;
+  private $workingCopy;
+
   public function execute(array $argv) {
 
     try {
@@ -108,6 +114,7 @@ final class ArcanistRuntime {
     $this->workflows = $workflows;
 
     $conduit_engine = $this->newConduitEngine($config);
+    $this->conduitEngine = $conduit_engine;
 
     $phutil_workflows = array();
     foreach ($workflows as $key => $workflow) {
@@ -301,9 +308,14 @@ final class ArcanistRuntime {
       ->setArguments($args);
 
     $working_copy = ArcanistWorkingCopy::newFromWorkingDirectory(getcwd());
-    if ($working_copy) {
+
     $engine->setWorkingCopy($working_copy);
-    }
+
+    $this->workingCopy = $working_copy;
+
+    $working_copy
+      ->getRepositoryAPI()
+      ->setRuntime($this);
 
     return $engine;
   }
@@ -682,6 +694,10 @@ final class ArcanistRuntime {
     return $this->stack;
   }
 
+  public function getCurrentWorkflow() {
+    return last($this->stack);
+  }
+
   private function newConduitEngine(ArcanistConfigurationSourceList $config) {
 
     $conduit_uri = $config->getConfig('phabricator.uri');
@@ -744,4 +760,81 @@ final class ArcanistRuntime {
     return phutil_passthru('%Ls', $effect->getArguments());
   }
 
+  public function getSymbolEngine() {
+    if ($this->symbolEngine === null) {
+      $this->symbolEngine = $this->newSymbolEngine();
+    }
+    return $this->symbolEngine;
+  }
+
+  private function newSymbolEngine() {
+    return id(new ArcanistSymbolEngine())
+      ->setWorkflow($this);
+  }
+
+  public function getHardpointEngine() {
+    if ($this->hardpointEngine === null) {
+      $this->hardpointEngine = $this->newHardpointEngine();
+    }
+    return $this->hardpointEngine;
+  }
+
+  private function newHardpointEngine() {
+    $engine = new ArcanistHardpointEngine();
+
+    $queries = ArcanistRuntimeHardpointQuery::getAllQueries();
+
+    foreach ($queries as $key => $query) {
+      $queries[$key] = id(clone $query)
+        ->setRuntime($this);
+    }
+
+    $engine->setQueries($queries);
+
+    return $engine;
+  }
+
+  public function getViewer() {
+    if (!$this->viewer) {
+      $viewer = $this->getSymbolEngine()
+        ->loadUserForSymbol('viewer()');
+
+      // TODO: Deal with anonymous stuff.
+      if (!$viewer) {
+        throw new Exception(pht('No viewer!'));
+      }
+
+      $this->viewer = $viewer;
+    }
+
+    return $this->viewer;
+  }
+
+  public function loadHardpoints($objects, $requests) {
+    if (!is_array($objects)) {
+      $objects = array($objects);
+    }
+
+    if (!is_array($requests)) {
+      $requests = array($requests);
+    }
+
+    $engine = $this->getHardpointEngine();
+
+    $requests = $engine->requestHardpoints(
+      $objects,
+      $requests);
+
+    // TODO: Wait for only the required requests.
+    $engine->waitForRequests(array());
+  }
+
+  public function getWorkingCopy() {
+    return $this->workingCopy;
+  }
+
+  public function getConduitEngine() {
+    return $this->conduitEngine;
+  }
+
 }

src/toolset/query/ArcanistRuntimeHardpointQuery.php

@@ -1,22 +1,22 @@
 <?php
 
-abstract class ArcanistWorkflowHardpointQuery
+abstract class ArcanistRuntimeHardpointQuery
   extends ArcanistHardpointQuery {
 
-  private $workflow;
+  private $runtime;
   private $canLoadHardpoint;
 
-  final public function setWorkflow(ArcanistWorkflow $workflow) {
-    $this->workflow = $workflow;
+  final public function setRuntime(ArcanistRuntime $runtime) {
+    $this->runtime = $runtime;
     return $this;
   }
 
-  final public function getWorkflow() {
-    return $this->workflow;
+  final public function getRuntime() {
+    return $this->runtime;
   }
 
   final public function getWorkingCopy() {
-    return $this->getWorkflow()->getWorkingCopy();
+    return $this->getRuntime()->getWorkingCopy();
   }
 
   final public function getRepositoryAPI() {
@@ -52,7 +52,7 @@ abstract class ArcanistWorkflowHardpointQuery
   abstract protected function canLoadRef(ArcanistRef $ref);
 
   final public function newConduitSearch($method, $constraints) {
-    $conduit_engine = $this->getWorkflow()
+    $conduit_engine = $this->getRuntime()
       ->getConduitEngine();
 
     $conduit_future = id(new ConduitSearchFuture())
@@ -69,7 +69,7 @@ abstract class ArcanistWorkflowHardpointQuery
   }
 
   final public function newConduit($method, $parameters) {
-    $conduit_engine = $this->getWorkflow()
+    $conduit_engine = $this->getRuntime()
       ->getConduitEngine();
 
     $call_object = $conduit_engine->newCall($method, $parameters);
@@ -84,7 +84,10 @@ abstract class ArcanistWorkflowHardpointQuery
   }
 
   final public function yieldRepositoryRef() {
-    $workflow = $this->getWorkflow();
+    // TODO: This should probably move to Runtime.
+
+    $runtime = $this->getRuntime();
+    $workflow = $runtime->getCurrentWorkflow();
 
     // TODO: This is currently a blocking request, but should yield to the
     // hardpoint engine in the future.

src/workflow/ArcanistAmendWorkflow.php

@@ -1,210 +1,278 @@
 <?php
 
-/**
- * Synchronizes commit messages from Differential.
- */
-final class ArcanistAmendWorkflow extends ArcanistWorkflow {
+final class ArcanistAmendWorkflow
+  extends ArcanistArcWorkflow {
 
   public function getWorkflowName() {
     return 'amend';
   }
 
-  public function getCommandSynopses() {
-    return phutil_console_format(<<<EOTEXT
-      **amend** [--revision __revision_id__] [--show]
+  public function getWorkflowInformation() {
+    $help = pht(<<<EOTEXT
+Amend the working copy, synchronizing the local commit message from
+Differential.
+
+Supported in Mercurial 2.2 and newer.
 EOTEXT
       );
+
+    return $this->newWorkflowInformation()
+      ->setSynopsis(
+        pht('Amend the working copy, synchronizing the local commit message.'))
+      ->addExample('**amend** [options] -- ')
+      ->setHelp($help);
   }
 
-  public function getCommandHelp() {
-    return phutil_console_format(<<<EOTEXT
-          Supports: git, hg
-          Amend the working copy, synchronizing the local commit message from
-          Differential.
-
-          Supported in Mercurial 2.2 and newer.
-EOTEXT
-      );
-  }
-
-  public function requiresWorkingCopy() {
-    return true;
-  }
-
-  public function requiresConduit() {
-    return true;
-  }
-
-  public function requiresAuthentication() {
-    return true;
-  }
-
-  public function requiresRepositoryAPI() {
-    return true;
-  }
-
-  public function getArguments() {
+  public function getWorkflowArguments() {
     return array(
-      'show' => array(
-        'help' => pht(
+      $this->newWorkflowArgument('show')
+        ->setHelp(
+          pht(
             'Show the amended commit message, without modifying the '.
-          'working copy.'),
-      ),
-      'revision' => array(
-        'param' => 'revision_id',
-        'help' => pht(
+            'working copy.')),
+      $this->newWorkflowArgument('revision')
+        ->setParameter('id')
+        ->setHelp(
+          pht(
             'Use the message from a specific revision. If you do not specify '.
             'a revision, arc will guess which revision is in the working '.
-          'copy.'),
-      ),
+            'copy.')),
     );
   }
 
-  public function run() {
+  protected function newPrompts() {
+    return array(
+      $this->newPrompt('arc.amend.unrelated')
+        ->setDescription(
+          pht(
+            'Confirms use of a revision that does not appear to be '.
+            'present in the working copy.')),
+      $this->newPrompt('arc.amend.author')
+        ->setDescription(
+          pht(
+            'Confirms use of a revision that you are not the author '.
+            'of.')),
+      $this->newPrompt('arc.amend.immutable')
+        ->setDescription(
+          pht(
+            'Confirms history mutation in a working copy marked as '.
+            'immutable.')),
+    );
+  }
+
+  public function runWorkflow() {
+    $symbols = $this->getSymbolEngine();
+
     $is_show = $this->getArgument('show');
 
     $repository_api = $this->getRepositoryAPI();
     if (!$is_show) {
-      if (!$repository_api->supportsAmend()) {
-        throw new ArcanistUsageException(
-          pht(
-            "You may only run '%s' in a git or hg ".
-            "(version 2.2 or newer) working copy.",
-            'arc amend'));
+      $this->requireAmendSupport($repository_api);
     }
 
-      if ($this->isHistoryImmutable()) {
-        throw new ArcanistUsageException(
-          pht(
-            'This project is marked as adhering to a conservative history '.
-            'mutability doctrine (having an immutable local history), which '.
-            'precludes amending commit messages.'));
+    $revision_symbol = $this->getArgument('revision');
+
+    // We only care about the local working copy state if we need it to
+    // figure out which revision we're operating on, or we're planning to
+    // mutate it. If the caller is running "arc amend --show --revision X",
+    // the local state does not matter.
+
+    $need_state =
+      ($revision_symbol === null) ||
+      (!$is_show);
+
+    if ($need_state) {
+      $state_ref = $repository_api->getCurrentWorkingCopyStateRef();
+
+      $this->loadHardpoints(
+        $state_ref,
+        ArcanistWorkingCopyStateRef::HARDPOINT_REVISIONREFS);
+
+      $revision_refs = $state_ref->getRevisionRefs();
     }
 
-      if ($repository_api->getUncommittedChanges()) {
-        throw new ArcanistUsageException(
-          pht(
-            'You have uncommitted changes in this branch. Stage and commit '.
-            '(or revert) them before proceeding.'));
-      }
-    }
-
-    $revision_id = null;
-    if ($this->getArgument('revision')) {
-      $revision_id = $this->normalizeRevisionID($this->getArgument('revision'));
-    }
-
-    $repository_api->setBaseCommitArgumentRules('arc:this');
-    $in_working_copy = $repository_api->loadWorkingCopyDifferentialRevisions(
-      $this->getConduit(),
-      array(
-        'status'    => 'status-any',
-      ));
-    $in_working_copy = ipull($in_working_copy, null, 'id');
-
-    if (!$revision_id) {
-      if (count($in_working_copy) == 0) {
-        throw new ArcanistUsageException(
-          pht(
-            "No revision specified with '%s', and no revisions found ".
-            "in the working copy. Use '%s' to specify which revision ".
-            "you want to amend.",
-            '--revision',
-            '--revision <id>'));
-      } else if (count($in_working_copy) > 1) {
-        $message = pht(
-          "More than one revision was found in the working copy:\n%s\n".
-          "Use '%s' to specify which revision you want to amend.",
-          $this->renderRevisionList($in_working_copy),
-          '--revision <id>');
-        throw new ArcanistUsageException($message);
+    if ($revision_symbol === null) {
+      $revision_ref = $this->selectRevisionRef($revision_refs);
     } else {
-        $revision_id = key($in_working_copy);
-        $revision = $in_working_copy[$revision_id];
-        if ($revision['authorPHID'] != $this->getUserPHID()) {
-          $other_author = $this->getConduit()->callMethodSynchronous(
-            'user.query',
-            array(
-              'phids' => array($revision['authorPHID']),
-            ));
-          $other_author = ipull($other_author, 'userName', 'phid');
-          $other_author = $other_author[$revision['authorPHID']];
-          $rev_title = $revision['title'];
-          $ok = phutil_console_confirm(
+      $revision_ref = $symbols->loadRevisionForSymbol($revision_symbol);
+      if (!$revision_ref) {
+        throw new PhutilArgumentUsageException(
           pht(
-              "You are amending the revision '%s' but you are not ".
-              "the author. Amend this revision by %s?",
-              "D{$revision_id}: {$rev_title}",
-              $other_author));
-          if (!$ok) {
-            throw new ArcanistUserAbortException();
+            'Revision "%s" does not exist, or you do not have permission '.
+            'to see it.',
+            $revision_symbol));
       }
     }
-      }
-    }
-
-    $conduit = $this->getConduit();
-    try {
-      $message = $conduit->callMethodSynchronous(
-        'differential.getcommitmessage',
-        array(
-          'revision_id' => $revision_id,
-          'edit'        => false,
-        ));
-    } catch (ConduitClientException $ex) {
-      if (strpos($ex->getMessage(), 'ERR_NOT_FOUND') === false) {
-        throw $ex;
-      } else {
-        throw new ArcanistUsageException(
-          pht("Revision '%s' does not exist.", "D{$revision_id}")
-        );
-      }
-    }
-
-    $revision = $conduit->callMethodSynchronous(
-      'differential.query',
-      array(
-        'ids' => array($revision_id),
-      ));
-    if (empty($revision)) {
-      throw new Exception(
-        pht("Failed to lookup information for '%s'!", "D{$revision_id}"));
-    }
-    $revision = head($revision);
-    $revision_title = $revision['title'];
 
     if (!$is_show) {
-      if ($revision_id && empty($in_working_copy[$revision_id])) {
-        $ok = phutil_console_confirm(
-          pht(
-            "The revision '%s' does not appear to be in the working copy. Are ".
-            "you sure you want to amend HEAD with the commit message for '%s'?",
-            "D{$revision_id}",
-            "D{$revision_id}: {$revision_title}"));
-        if (!$ok) {
-          throw new ArcanistUserAbortException();
-        }
-      }
+      echo tsprintf(
+        "%s\n\n%s\n",
+        pht('Amending commit message to reflect revision:'),
+        $revision_ref->newDisplayRef());
+
+      $this->confirmAmendAuthor($revision_ref);
+      $this->confirmAmendNotFound($revision_ref, $state_ref);
     }
 
+    $this->loadHardpoints(
+      $revision_ref,
+      ArcanistRevisionRef::HARDPOINT_COMMITMESSAGE);
+
+    $message = $revision_ref->getCommitMessage();
+
     if ($is_show) {
-      echo $message."\n";
+      echo tsprintf(
+        "%B\n",
+        $message);
     } else {
-      echo pht(
-        "Amending commit message to reflect revision %s.\n",
-        phutil_console_format(
-          '**D%d: %s**',
-          $revision_id,
-          $revision_title));
-
       $repository_api->amendCommit($message);
     }
 
     return 0;
   }
 
-  public function getSupportedRevisionControlSystems() {
-    return array('git', 'hg');
+  private function requireAmendSupport(ArcanistRepositoryAPI $api) {
+    if (!$api->supportsAmend()) {
+      if ($api instanceof ArcanistMercurialAPI) {
+        throw new PhutilArgumentUsageException(
+          pht(
+            '"arc amend" is only supported under Mercurial 2.2 or newer. '.
+            'Older versions of Mercurial do not support the "--amend" flag '.
+            'to "hg commit ...", which this workflow requires.'));
+      }
+
+      throw new PhutilArgumentUsageException(
+        pht(
+          '"arc amend" must be run from inside a working copy of a '.
+          'repository using a version control system that supports '.
+          'amending commits, like Git or Mercurial.'));
+    }
+
+    if ($this->isHistoryImmutable()) {
+      echo tsprintf(
+        "%!\n\n%W\n",
+        pht('IMMUTABLE WORKING COPY'),
+        pht(
+          'This working copy is configured to have an immutable local '.
+          'history, using the "history.immutable" configuration option. '.
+          'Amending the working copy will mutate local history.'));
+
+      $prompt = pht('Are you sure you want to mutate history?');
+
+      $this->getPrompt('arc.amend.immutable')
+        ->setQuery($prompt)
+        ->execute();
+    }
+
+    return;
+
+    if ($api->getUncommittedChanges()) {
+      // TODO: Make this class of error show the uncommitted changes.
+
+      // TODO: This only needs to check for staged-but-uncommitted changes.
+      // We can safely amend with untracked and unstaged changes.
+
+      throw new PhutilArgumentUsageException(
+        pht(
+          'You have uncommitted changes in this working copy. Commit or '.
+          'revert them before proceeding.'));
+    }
+  }
+
+  private function selectRevisionRef(array $revisions) {
+    if (!$revisions) {
+      throw new PhutilArgumentUsageException(
+        pht(
+          'No revision specified with "--revision", and no revisions found '.
+          'that match the current working copy state. Use "--revision <id>" '.
+          'to specify which revision you want to amend.'));
+    }
+
+     if (count($revisions) > 1) {
+       echo tsprintf(
+         "%!\n%W\n\n%B\n",
+         pht('MULTIPLE REVISIONS IN WORKING COPY'),
+         pht('More than one revision was found in the working copy:'),
+         mpull($revisions, 'newDisplayRef'));
+
+      throw new PhutilArgumentUsageException(
+        pht(
+          'Use "--revision <id>" to specify which revision you want '.
+          'to amend.'));
+    }
+
+    return head($revisions);
+  }
+
+  private function confirmAmendAuthor(ArcanistRevisionRef $revision_ref) {
+    $viewer = $this->getViewer();
+    $viewer_phid = $viewer->getPHID();
+
+    $author_phid = $revision_ref->getAuthorPHID();
+
+    if ($viewer_phid === $author_phid) {
+      return;
+    }
+
+    $symbols = $this->getSymbolEngine();
+    $author_ref = $symbols->loadUserForSymbol($author_phid);
+    if (!$author_ref) {
+      // If we don't have any luck loading the author, skip this warning.
+      return;
+    }
+
+    echo tsprintf(
+      "%!\n\n%W\n\n%s",
+      pht('NOT REVISION AUTHOR'),
+      array(
+        pht(
+          'You are amending the working copy using information from '.
+          'a revision you are not the author of.'),
+        "\n\n",
+        pht(
+          'The author of this revision (%s) is:',
+          $revision_ref->getMonogram()),
+      ),
+      $author_ref->newDisplayRef());
+
+    $prompt = pht(
+      'Amend working copy using revision owned by %s?',
+      $author_ref->getMonogram());
+
+    $this->getPrompt('arc.amend.author')
+      ->setQuery($prompt)
+      ->execute();
+  }
+
+  private function confirmAmendNotFound(
+    ArcanistRevisionRef $revision_ref,
+    ArcanistWorkingCopyStateRef $state_ref) {
+
+    $local_refs = $state_ref->getRevisionRefs();
+    $local_refs = mpull($local_refs, null, 'getPHID');
+
+    $revision_phid = $revision_ref->getPHID();
+    $is_local = isset($local_refs[$revision_phid]);
+
+    if ($is_local) {
+      return;
+    }
+
+    echo tsprintf(
+      "%!\n\n%W\n",
+      pht('UNRELATED REVISION'),
+      pht(
+        'You are amending the working copy using information from '.
+        'a revision that does not appear to be associated with the '.
+        'current state of the working copy.'));
+
+    $prompt = pht(
+      'Amend working copy using unrelated revision %s?',
+      $revision_ref->getMonogram());
+
+    $this->getPrompt('arc.amend.unrelated')
+      ->setQuery($prompt)
+      ->execute();
   }
 
 }

src/workflow/ArcanistWorkflow.php

@@ -76,9 +76,6 @@ abstract class ArcanistWorkflow extends Phobject {
   private $configurationEngine;
   private $configurationSourceList;
 
-  private $viewer;
-  private $hardpointEngine;
-  private $symbolEngine;
   private $promptMap;
 
   final public function setToolset(ArcanistToolset $toolset) {
@@ -2303,45 +2300,7 @@ abstract class ArcanistWorkflow extends Phobject {
   final public function loadHardpoints(
     $objects,
     $requests) {
-
-    if (!is_array($objects)) {
-      $objects = array($objects);
-    }
-
-    if (!is_array($requests)) {
-      $requests = array($requests);
-    }
-
-    $engine = $this->getHardpointEngine();
-
-    $requests = $engine->requestHardpoints(
-      $objects,
-      $requests);
-
-    // TODO: Wait for only the required requests.
-    $engine->waitForRequests(array());
-  }
-
-  private function getHardpointEngine() {
-    if ($this->hardpointEngine === null) {
-      $this->hardpointEngine = $this->newHardpointEngine();
-    }
-    return $this->hardpointEngine;
-  }
-
-  private function newHardpointEngine() {
-    $engine = new ArcanistHardpointEngine();
-
-    $queries = ArcanistWorkflowHardpointQuery::getAllQueries();
-
-    foreach ($queries as $key => $query) {
-      $queries[$key] = id(clone $query)
-        ->setWorkflow($this);
-    }
-
-    $engine->setQueries($queries);
-
-    return $engine;
+    return $this->getRuntime()->loadHardpoints($objects, $requests);
   }
 
   protected function newPrompts() {
@@ -2404,31 +2363,11 @@ abstract class ArcanistWorkflow extends Phobject {
   }
 
   final protected function getSymbolEngine() {
-    if ($this->symbolEngine === null) {
-      $this->symbolEngine = $this->newSymbolEngine();
-    }
-    return $this->symbolEngine;
-  }
-
-  private function newSymbolEngine() {
-    return id(new ArcanistSymbolEngine())
-      ->setWorkflow($this);
+    return $this->getRuntime()->getSymbolEngine();
   }
 
   final protected function getViewer() {
-    if (!$this->viewer) {
-      $viewer = $this->getSymbolEngine()
-        ->loadUserForSymbol('viewer()');
-
-      // TODO: Deal with anonymous stuff.
-      if (!$viewer) {
-        throw new Exception(pht('No viewer!'));
-      }
-
-      $this->viewer = $viewer;
-    }
-
-    return $this->viewer;
+    return $this->getRuntime()->getViewer();
   }
 
 }

src/xsprintf/tsprintf.php

@@ -38,6 +38,23 @@ function xsprintf_terminal($userdata, &$pattern, &$pos, &$value, &$length) {
     case 'R':
       $type = 's';
       break;
+    case 'W':
+      $value = PhutilTerminalString::escapeStringValue($value, true);
+      $value = phutil_console_wrap($value);
+      $type = 's';
+      break;
+    case '!':
+      $value = tsprintf('<bg:yellow>** <!> %s **</bg>', $value);
+      $value = PhutilTerminalString::escapeStringValue($value, false);
+      $type = 's';
+      break;
+    default:
+      throw new Exception(
+        pht(
+          'Unsupported escape sequence "%s" found in pattern: %s',
+          $type,
+          $pattern));
+      break;
   }
 
   $pattern[$pos] = $type;