diff --git a/src/lint/engine/ArcanistLintEngine.php b/src/lint/engine/ArcanistLintEngine.php
index 9025b839..fd5816eb 100644
--- a/src/lint/engine/ArcanistLintEngine.php
+++ b/src/lint/engine/ArcanistLintEngine.php
@@ -1,409 +1,416 @@
 <?php
 
 /**
  * Manages lint execution. When you run 'arc lint' or 'arc diff', Arcanist
  * checks your .arcconfig to see if you have specified a lint engine in the
  * key "lint.engine". The engine must extend this class. For example:
  *
  *  lang=js
  *  {
  *    // ...
  *    "lint.engine" : "ExampleLintEngine",
  *    // ...
  *  }
  *
  * The lint engine is given a list of paths (generally, the paths that you
  * modified in your change) and determines which linters to run on them. The
  * linters themselves are responsible for actually analyzing file text and
  * finding warnings and errors. For example, if the modified paths include some
  * JS files and some Python files, you might want to run JSLint on the JS files
  * and PyLint on the Python files.
  *
  * You can also run multiple linters on a single file. For instance, you might
  * run one linter on all text files to make sure they don't have trailing
  * whitespace, or enforce tab vs space rules, or make sure there are enough
  * curse words in them.
  *
  * Because lint engines are pretty custom to the rules of a project, you will
  * generally need to build your own. Fortunately, it's pretty easy (and you
  * can use the prebuilt //linters//, you just need to write a little glue code
  * to tell Arcanist which linters to run). For a simple example of how to build
  * a lint engine, see @{class:ExampleLintEngine}.
  *
  * You can test an engine like this:
  *
  *   arc lint --engine ExampleLintEngine --lintall some_file.py
  *
  * ...which will show you all the lint issues raised in the file.
  *
  * See @{article@phabricator:Arcanist User Guide: Customizing Lint, Unit Tests
  * and Workflows} for more information about configuring lint engines.
  *
  * @group lint
  * @stable
  */
 abstract class ArcanistLintEngine {
 
   protected $workingCopy;
   protected $paths = array();
   protected $fileData = array();
 
   protected $charToLine = array();
   protected $lineToFirstChar = array();
   private $cachedResults;
   private $cacheVersion;
   private $results = array();
   private $minimumSeverity = ArcanistLintSeverity::SEVERITY_DISABLED;
 
   private $changedLines = array();
   private $commitHookMode = false;
   private $hookAPI;
 
   private $enableAsyncLint = false;
   private $postponedLinters = array();
 
   public function __construct() {
 
   }
 
   public function setWorkingCopy(ArcanistWorkingCopyIdentity $working_copy) {
     $this->workingCopy = $working_copy;
     return $this;
   }
 
   public function getWorkingCopy() {
     return $this->workingCopy;
   }
 
   public function setPaths($paths) {
     $this->paths = $paths;
     return $this;
   }
 
   public function getPaths() {
     return $this->paths;
   }
 
   public function setPathChangedLines($path, $changed) {
     if ($changed === null) {
       $this->changedLines[$path] = null;
     } else {
       $this->changedLines[$path] = array_fill_keys($changed, true);
     }
     return $this;
   }
 
   public function getPathChangedLines($path) {
     return idx($this->changedLines, $path);
   }
 
   public function setFileData($data) {
     $this->fileData = $data + $this->fileData;
     return $this;
   }
 
   public function setCommitHookMode($mode) {
     $this->commitHookMode = $mode;
     return $this;
   }
 
   public function setHookAPI(ArcanistHookAPI $hook_api) {
     $this->hookAPI  = $hook_api;
     return $this;
   }
 
   public function getHookAPI() {
     return $this->hookAPI;
   }
 
   public function setEnableAsyncLint($enable_async_lint) {
     $this->enableAsyncLint = $enable_async_lint;
     return $this;
   }
 
   public function getEnableAsyncLint() {
     return $this->enableAsyncLint;
   }
 
   public function loadData($path) {
     if (!isset($this->fileData[$path])) {
       if ($this->getCommitHookMode()) {
         $this->fileData[$path] = $this->getHookAPI()
           ->getCurrentFileData($path);
       } else {
         $disk_path = $this->getFilePathOnDisk($path);
         $this->fileData[$path] = Filesystem::readFile($disk_path);
       }
     }
     return $this->fileData[$path];
   }
 
   public function pathExists($path) {
     if ($this->getCommitHookMode()) {
       $file_data = $this->loadData($path);
       return ($file_data !== null);
     } else {
       $disk_path = $this->getFilePathOnDisk($path);
       return Filesystem::pathExists($disk_path);
     }
   }
 
   public function getFilePathOnDisk($path) {
     return Filesystem::resolvePath(
       $path,
       $this->getWorkingCopy()->getProjectRoot());
   }
 
   public function setMinimumSeverity($severity) {
     $this->minimumSeverity = $severity;
     return $this;
   }
 
   public function getCommitHookMode() {
     return $this->commitHookMode;
   }
 
   public function run() {
     $linters = $this->buildLinters();
 
     if (!$linters) {
       throw new ArcanistNoEffectException("No linters to run.");
     }
 
     $have_paths = false;
     foreach ($linters as $linter) {
       if ($linter->getPaths()) {
         $have_paths = true;
         break;
       }
     }
 
     if (!$have_paths) {
       throw new ArcanistNoEffectException("No paths are lintable.");
     }
 
     $versions = array($this->getCacheVersion());
     foreach ($linters as $linter) {
       $versions[] = get_class($linter).':'.$linter->getCacheVersion();
     }
     $this->cacheVersion = crc32(implode("\n", $versions));
 
-    $linters_paths = array();
-    foreach ($linters as $linter_name => $linter) {
-      $linter->setEngine($this);
-      if (!$linter->canRun()) {
-        continue;
-      }
-      $paths = $linter->getPaths();
-
-      $cache_granularity = $linter->getCacheGranularity();
-
-      foreach ($paths as $key => $path) {
-        // Make sure each path has a result generated, even if it is empty
-        // (i.e., the file has no lint messages).
-        $result = $this->getResultForPath($path);
-        if (isset($this->cachedResults[$path][$this->cacheVersion])) {
-          if ($cache_granularity == ArcanistLinter::GRANULARITY_FILE) {
-            unset($paths[$key]);
-          }
-        }
-      }
-      $paths = array_values($paths);
-      $linters_paths[$linter_name] = $paths;
-
-      if ($paths) {
-        $linter->willLintPaths($paths);
-      }
-    }
-
     $stopped = array();
     $exceptions = array();
     foreach ($linters as $linter_name => $linter) {
       try {
-        foreach ($linters_paths[$linter_name] as $path) {
-          if (isset($stopped[$path])) {
-            continue;
-          }
-          $linter->willLintPath($path);
-          $linter->lintPath($path);
-          if ($linter->didStopAllLinters()) {
-            $stopped[$path] = true;
-          }
+        $linter->setEngine($this);
+        if (!$linter->canRun()) {
+          continue;
         }
+        $paths = $linter->getPaths();
+
+        $cache_granularity = $linter->getCacheGranularity();
 
-        $minimum = $this->minimumSeverity;
-        foreach ($linter->getLintMessages() as $message) {
-          if (!ArcanistLintSeverity::isAtLeastAsSevere($message, $minimum)) {
-            continue;
+        foreach ($paths as $key => $path) {
+          // Make sure each path has a result generated, even if it is empty
+          // (i.e., the file has no lint messages).
+          $result = $this->getResultForPath($path);
+          if (isset($stopped[$path])) {
+            unset($paths[$key]);
           }
-          if (!$this->isRelevantMessage($message)) {
-            continue;
+          if (isset($this->cachedResults[$path][$this->cacheVersion])) {
+            if ($cache_granularity == ArcanistLinter::GRANULARITY_FILE) {
+              unset($paths[$key]);
+            }
           }
-          if ($cache_granularity != ArcanistLinter::GRANULARITY_FILE) {
-            $message->setUncacheable(true);
+        }
+        $paths = array_values($paths);
+
+        if ($paths) {
+          $linter->willLintPaths($paths);
+          foreach ($paths as $path) {
+            $linter->willLintPath($path);
+            $linter->lintPath($path);
+            if ($linter->didStopAllLinters()) {
+              $stopped[$path] = true;
+            }
           }
-          $result = $this->getResultForPath($message->getPath());
-          $result->addMessage($message);
         }
+
       } catch (Exception $ex) {
         if (!is_string($linter_name)) {
           $linter_name = get_class($linter);
         }
         $exceptions[$linter_name] = $ex;
       }
     }
 
+    $this->didRunLinters($linters);
+
+    foreach ($linters as $linter) {
+      $minimum = $this->minimumSeverity;
+      foreach ($linter->getLintMessages() as $message) {
+        if (!ArcanistLintSeverity::isAtLeastAsSevere($message, $minimum)) {
+          continue;
+        }
+        if (!$this->isRelevantMessage($message)) {
+          continue;
+        }
+        if ($cache_granularity != ArcanistLinter::GRANULARITY_FILE) {
+          $message->setUncacheable(true);
+        }
+        $result = $this->getResultForPath($message->getPath());
+        $result->addMessage($message);
+      }
+    }
+
     if ($this->cachedResults) {
       foreach ($this->cachedResults as $path => $messages) {
         foreach (idx($messages, $this->cacheVersion, array()) as $message) {
           $this->getResultForPath($path)->addMessage(
             ArcanistLintMessage::newFromDictionary($message));
         }
       }
     }
 
     foreach ($this->results as $path => $result) {
       $disk_path = $this->getFilePathOnDisk($path);
       $result->setFilePathOnDisk($disk_path);
       if (isset($this->fileData[$path])) {
         $result->setData($this->fileData[$path]);
       } else if ($disk_path && Filesystem::pathExists($disk_path)) {
         // TODO: this may cause us to, e.g., load a large binary when we only
         // raised an error about its filename. We could refine this by looking
         // through the lint messages and doing this load only if any of them
         // have original/replacement text or something like that.
         try {
           $this->fileData[$path] = Filesystem::readFile($disk_path);
           $result->setData($this->fileData[$path]);
         } catch (FilesystemException $ex) {
           // Ignore this, it's noncritical that we access this data and it
           // might be unreadable or a directory or whatever else for plenty
           // of legitimate reasons.
         }
       }
     }
 
     if ($exceptions) {
       throw new PhutilAggregateException('Some linters failed:', $exceptions);
     }
 
     return $this->results;
   }
 
   /**
    * @param dict<string path, dict<int version, list<dict message>>>
    * @return this
    */
   public function setCachedResults(array $results) {
     $this->cachedResults = $results;
     return $this;
   }
 
   public function getResults() {
     return $this->results;
   }
 
   abstract protected function buildLinters();
 
+  protected function didRunLinters(array $linters) {
+    assert_instances_of($linters, 'ArcanistLinter');
+    foreach ($linters as $linter) {
+      $linter->didRunLinters();
+    }
+  }
+
   private function isRelevantMessage(ArcanistLintMessage $message) {
     // When a user runs "arc lint", we default to raising only warnings on
     // lines they have changed (errors are still raised anywhere in the
     // file). The list of $changed lines may be null, to indicate that the
     // path is a directory or a binary file so we should not exclude
     // warnings.
 
     if (!$this->changedLines || $message->isError()) {
       return true;
     }
 
     $locations = $message->getOtherLocations();
     $locations[] = $message->toDictionary();
 
     foreach ($locations as $location) {
       $path = idx($location, 'path', $message->getPath());
 
       if (!array_key_exists($path, $this->changedLines)) {
         continue;
       }
 
       $changed = $this->getPathChangedLines($path);
 
       if ($changed === null || !$location['line']) {
         return true;
       }
 
       $last_line = $location['line'];
       if (isset($location['original'])) {
         $last_line += substr_count($location['original'], "\n");
       }
 
       for ($l = $location['line']; $l <= $last_line; $l++) {
         if (!empty($changed[$l])) {
           return true;
         }
       }
     }
 
     return false;
   }
 
   protected function getResultForPath($path) {
     if (empty($this->results[$path])) {
       $result = new ArcanistLintResult();
       $result->setPath($path);
       $result->setCacheVersion($this->cacheVersion);
       $this->results[$path] = $result;
     }
     return $this->results[$path];
   }
 
   public function getLineAndCharFromOffset($path, $offset) {
     if (!isset($this->charToLine[$path])) {
       $char_to_line = array();
       $line_to_first_char = array();
 
       $lines = explode("\n", $this->loadData($path));
       $line_number = 0;
       $line_start = 0;
       foreach ($lines as $line) {
         $len = strlen($line) + 1; // Account for "\n".
         $line_to_first_char[] = $line_start;
         $line_start += $len;
         for ($ii = 0; $ii < $len; $ii++) {
           $char_to_line[] = $line_number;
         }
         $line_number++;
       }
       $this->charToLine[$path] = $char_to_line;
       $this->lineToFirstChar[$path] = $line_to_first_char;
     }
 
     $line = $this->charToLine[$path][$offset];
     $char = $offset - $this->lineToFirstChar[$path][$line];
 
     return array($line, $char);
   }
 
   public function getPostponedLinters() {
     return $this->postponedLinters;
   }
 
   public function setPostponedLinters(array $linters) {
     $this->postponedLinters = $linters;
     return $this;
   }
 
   protected function getCacheVersion() {
     return 0;
   }
 
   protected function getPEP8WithTextOptions() {
     // E101 is subset of TXT2 (Tab Literal).
     // E501 is same as TXT3 (Line Too Long).
     // W291 is same as TXT6 (Trailing Whitespace).
     // W292 is same as TXT4 (File Does Not End in Newline).
     // W293 is same as TXT6 (Trailing Whitespace).
     return '--ignore=E101,E501,W291,W292,W293';
   }
 
 }
diff --git a/src/lint/linter/ArcanistLinter.php b/src/lint/linter/ArcanistLinter.php
index eb2b9d9d..776dded8 100644
--- a/src/lint/linter/ArcanistLinter.php
+++ b/src/lint/linter/ArcanistLinter.php
@@ -1,221 +1,225 @@
 <?php
 
 /**
  * Implements lint rules, like syntax checks for a specific language.
  *
  * @group linter
  * @stable
  */
 abstract class ArcanistLinter {
 
   const GRANULARITY_FILE = 1;
   const GRANULARITY_DIRECTORY = 2;
   const GRANULARITY_REPOSITORY = 3;
   const GRANULARITY_GLOBAL = 4;
 
   protected $paths  = array();
   protected $data   = array();
   protected $engine;
   protected $activePath;
   protected $messages = array();
 
   protected $stopAllLinters = false;
 
   private $customSeverityMap = array();
   private $config = array();
 
   public function setCustomSeverityMap(array $map) {
     $this->customSeverityMap = $map;
     return $this;
   }
 
   public function setConfig(array $config) {
     $this->config = $config;
     return $this;
   }
 
   protected function getConfig($key, $default = null) {
     return idx($this->config, $key, $default);
   }
 
   public function getActivePath() {
     return $this->activePath;
   }
 
   public function stopAllLinters() {
     $this->stopAllLinters = true;
     return $this;
   }
 
   public function didStopAllLinters() {
     return $this->stopAllLinters;
   }
 
   public function addPath($path) {
     $this->paths[$path] = $path;
     return $this;
   }
 
   public function setPaths(array $paths) {
     $this->paths = $paths;
     return $this;
   }
 
   public function getPaths() {
     return array_values($this->paths);
   }
 
   public function addData($path, $data) {
     $this->data[$path] = $data;
     return $this;
   }
 
   protected function getData($path) {
     if (!array_key_exists($path, $this->data)) {
       $this->data[$path] = $this->getEngine()->loadData($path);
     }
     return $this->data[$path];
   }
 
   public function setEngine(ArcanistLintEngine $engine) {
     $this->engine = $engine;
     return $this;
   }
 
   protected function getEngine() {
     return $this->engine;
   }
 
   public function getCacheVersion() {
     return 0;
   }
 
   public function getLintMessageFullCode($short_code) {
     return $this->getLinterName().$short_code;
   }
 
   public function getLintMessageSeverity($code) {
     $map = $this->customSeverityMap;
     if (isset($map[$code])) {
       return $map[$code];
     }
 
     $map = $this->getLintSeverityMap();
     if (isset($map[$code])) {
       return $map[$code];
     }
 
     return ArcanistLintSeverity::SEVERITY_ERROR;
   }
 
   public function isMessageEnabled($code) {
     return ($this->getLintMessageSeverity($code) !==
             ArcanistLintSeverity::SEVERITY_DISABLED);
   }
 
   public function getLintMessageName($code) {
     $map = $this->getLintNameMap();
     if (isset($map[$code])) {
       return $map[$code];
     }
     return "Unknown lint message!";
   }
 
   protected function addLintMessage(ArcanistLintMessage $message) {
     if (!$this->getEngine()->getCommitHookMode()) {
       $root = $this->getEngine()->getWorkingCopy()->getProjectRoot();
       $path = Filesystem::resolvePath($message->getPath(), $root);
       $message->setPath(Filesystem::readablePath($path, $root));
     }
     $this->messages[] = $message;
     return $message;
   }
 
   public function getLintMessages() {
     return $this->messages;
   }
 
   protected function newLintAtLine($line, $char, $code, $desc) {
     return id(new ArcanistLintMessage())
       ->setPath($this->getActivePath())
       ->setLine($line)
       ->setChar($char)
       ->setCode($this->getLintMessageFullCode($code))
       ->setSeverity($this->getLintMessageSeverity($code))
       ->setName($this->getLintMessageName($code))
       ->setDescription($desc);
   }
 
   protected function raiseLintAtLine(
     $line,
     $char,
     $code,
     $desc,
     $original = null,
     $replacement = null) {
 
     $message = $this->newLintAtLine($line, $char, $code, $desc)
       ->setOriginalText($original)
       ->setReplacementText($replacement);
 
     return $this->addLintMessage($message);
   }
 
   protected function raiseLintAtPath(
     $code,
     $desc) {
 
     return $this->raiseLintAtLine(null, null, $code, $desc, null, null);
   }
 
   protected function raiseLintAtOffset(
     $offset,
     $code,
     $desc,
     $original = null,
     $replacement = null) {
 
     $path = $this->getActivePath();
     $engine = $this->getEngine();
     if ($offset === null) {
       $line = null;
       $char = null;
     } else {
       list($line, $char) = $engine->getLineAndCharFromOffset($path, $offset);
     }
 
     return $this->raiseLintAtLine(
       $line + 1,
       $char + 1,
       $code,
       $desc,
       $original,
       $replacement);
   }
 
   public function willLintPath($path) {
     $this->stopAllLinters = false;
     $this->activePath = $path;
   }
 
   public function canRun() {
     return true;
   }
 
   abstract public function willLintPaths(array $paths);
   abstract public function lintPath($path);
   abstract public function getLinterName();
 
+  public function didRunLinters() {
+    // This is a hook.
+  }
+
   public function getLintSeverityMap() {
     return array();
   }
 
   public function getLintNameMap() {
     return array();
   }
 
   public function getCacheGranularity() {
     return self::GRANULARITY_FILE;
   }
 
 }