Introduce arc lint --only-new 1

Test Plan:
  $ arc lint src/workflow/ArcanistLintWorkflow.php
  $ arc lint --only-new 1 src/workflow/ArcanistLintWorkflow.php

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T2038

Differential Revision: https://secure.phabricator.com/D3934

src/lint/ArcanistLintResult.php

@@ -82,7 +82,7 @@ final class ArcanistLintResult {
     return true;
   }
 
-  private function sortAndFilterMessages() {
+  public function sortAndFilterMessages() {
     $messages = $this->messages;
 
     foreach ($messages as $key => $message) {

src/parser/diff/ArcanistDiffChange.php

@@ -190,6 +190,42 @@ final class ArcanistDiffChange {
     return $this->hunks;
   }
 
+  /**
+   * @return array $old => array($new, )
+   */
+  public function buildLineMap() {
+    $line_map = array();
+    $old = 1;
+    $new = 1;
+    foreach ($this->getHunks() as $hunk) {
+      for ($n = $old; $n < $hunk->getOldOffset(); $n++) {
+        $line_map[$n] = array($n + $new - $old);
+      }
+      $old = $hunk->getOldOffset();
+      $new = $hunk->getNewOffset();
+      $olds = array();
+      $news = array();
+      $lines = explode("\n", $hunk->getCorpus());
+      foreach ($lines as $line) {
+        $type = substr($line, 0, 1);
+        if ($type == '-' || $type == ' ') {
+          $olds[] = $old;
+          $old++;
+        }
+        if ($type == '+' || $type == ' ') {
+          $news[] = $new;
+          $new++;
+        }
+        if ($type == ' ' || $type == '') {
+          $line_map += array_fill_keys($olds, $news);
+          $olds = array();
+          $news = array();
+        }
+      }
+    }
+    return $line_map;
+  }
+
   public function convertToBinaryChange() {
     $this->hunks = array();
     $this->setFileType(ArcanistDiffChangeType::FILE_BINARY);

src/workflow/ArcanistBaseWorkflow.php

@@ -985,7 +985,7 @@ abstract class ArcanistBaseWorkflow {
     return array_keys($lines);
   }
 
-  private function getChange($path) {
+  protected function getChange($path) {
     $repository_api = $this->getRepositoryAPI();
 
     if ($repository_api instanceof ArcanistSubversionAPI) {

src/workflow/ArcanistDiffWorkflow.php

@@ -240,6 +240,14 @@ EOTEXT
           "Require excuse for lint advice in addition to lint warnings and ".
           "errors.",
       ),
+      'only-new' => array(
+        'param' => 'bool',
+        'help' =>
+          'Display only lint messages not present in the original code.',
+        'passthru' => array(
+          'lint' => true,
+        ),
+      ),
       'apply-patches' => array(
         'help' =>
           'Apply patches suggested by lint to the working copy without '.

src/workflow/ArcanistLintWorkflow.php

@@ -83,6 +83,11 @@ EOTEXT
           "With 'json', show lint warnings in machine-readable JSON format. ".
           "With 'compiler', show lint warnings in suitable for your editor."
       ),
+      'only-new' => array(
+        'param' => 'bool',
+        'supports' => array('git', 'hg'), // TODO: svn
+        'help' => 'Display only messages not present in the original code.',
+      ),
       'engine' => array(
         'param' => 'classname',
         'help' =>
@@ -129,6 +134,10 @@ EOTEXT
     );
   }
 
+  public function requiresAuthentication() {
+    return (bool)$this->getArgument('only-new');
+  }
+
   public function requiresWorkingCopy() {
     return true;
   }
@@ -228,6 +237,41 @@ EOTEXT
       $engine->setEnableAsyncLint(false);
     }
 
+    if ($this->getArgument('only-new')) {
+      $conduit = $this->getConduit();
+      $api = $this->getRepositoryAPI();
+      $relative_commit = ($rev ? $rev : $api->resolveBaseCommit());
+      $api->setRelativeCommit($relative_commit);
+      $svn_root = id(new PhutilURI($api->getSourceControlPath()))->getPath();
+
+      $all_paths = array();
+      foreach ($paths as $path) {
+        $path = str_replace(DIRECTORY_SEPARATOR, '/', $path);
+        $full_paths = array($path);
+
+        $change = $this->getChange($path);
+        $type = $change->getType();
+        if (ArcanistDiffChangeType::isOldLocationChangeType($type)) {
+          $full_paths = $change->getAwayPaths();
+        } else if (ArcanistDiffChangeType::isNewLocationChangeType($type)) {
+          continue;
+        } else if (ArcanistDiffChangeType::isDeleteChangeType($type)) {
+          continue;
+        }
+
+        foreach ($full_paths as $full_path) {
+          $all_paths[$svn_root.'/'.$full_path] = $path;
+        }
+      }
+
+      $lint_future = $conduit->callMethod('diffusion.getlintmessages', array(
+        'arcanistProject' => $this->getWorkingCopy()->getProjectID(),
+        'branch' => '', // TODO: Tracking branch.
+        'commit' => $api->getRelativeCommit(),
+        'files' => array_keys($all_paths),
+      ));
+    }
+
     $failed = null;
     try {
       $engine->run();
@@ -237,6 +281,65 @@ EOTEXT
 
     $results = $engine->getResults();
 
+    if ($this->getArgument('only-new')) {
+      $total = 0;
+      foreach ($results as $result) {
+        $total += count($result->getMessages());
+      }
+
+      // Don't wait for response with default value of --only-new.
+      $timeout = null;
+      if ($this->getArgument('only-new') === null || !$total) {
+        $timeout = 0;
+      }
+
+      $raw_messages = $lint_future->resolve($timeout);
+      if ($raw_messages && $total) {
+        $old_messages = array();
+        $line_maps = array();
+        foreach ($raw_messages as $message) {
+          $path = $all_paths[$message['path']];
+          $line = $message['line'];
+          $code = $message['code'];
+
+          if (!isset($line_maps[$path])) {
+            $line_maps[$path] = $this->getChange($path)->buildLineMap();
+          }
+
+          $new_lines = idx($line_maps[$path], $line);
+          if (!$new_lines) { // Unmodified lines after last hunk.
+            $last_old = ($line_maps[$path] ? last_key($line_maps[$path]) : 0);
+            $news = array_filter($line_maps[$path]);
+            $last_new = ($news ? last(end($news)) : 0);
+            $new_lines = array($line + $last_new - $last_old);
+          }
+
+          $error = array($code => array(true));
+          foreach ($new_lines as $new) {
+            if (isset($old_messages[$path][$new])) {
+              $old_messages[$path][$new][$code][] = true;
+              break;
+            }
+            $old_messages[$path][$new] = &$error;
+          }
+          unset($error);
+        }
+
+        foreach ($results as $result) {
+          foreach ($result->getMessages() as $message) {
+            $path = str_replace(DIRECTORY_SEPARATOR, '/', $message->getPath());
+            $line = $message->getLine();
+            $code = $message->getCode();
+            if (!empty($old_messages[$path][$line][$code])) {
+              $message->setObsolete(true);
+              array_pop($old_messages[$path][$line][$code]);
+            }
+          }
+          $result->sortAndFilterMessages();
+        }
+      }
+    }
+
     // It'd be nice to just return a single result from the run method above
     // which contains both the lint messages and the postponed linters.
     // However, to maintain compatibility with existing lint subclasses, use