Attach local commit information to DVCS revisions

Summary: When a revision is created, attach relevant information about the local
commits which it came from if applicable. This supports T473, for DCVSes and
DCVS workflows with immutable history where we can't just amend commit messages.
It will also allow us to enrich the web interface.

Test Plan: Will verify this info shows up for this very diff.

Reviewers: fratrik, aran, jungejason, tuomaspelkonen

Reviewed By: fratrik

CC: aran, epriestley, fratrik

Differential Revision: 857

src/repository/api/base/ArcanistRepositoryAPI.php

@@ -157,5 +157,6 @@ abstract class ArcanistRepositoryAPI {
   abstract public function getRawDiffText($path);
   abstract public function getOriginalFileData($path);
   abstract public function getCurrentFileData($path);
+  abstract public function getLocalCommitInformation();
 
 }

src/repository/api/git/ArcanistGitAPI.php

@@ -46,6 +46,35 @@ class ArcanistGitAPI extends ArcanistRepositoryAPI {
     return $this;
   }
 
+  public function getLocalCommitInformation() {
+    list($info) = execx(
+      '(cd %s && git log %s..%s --format=%s --)',
+      $this->getPath(),
+      $this->getRelativeCommit(),
+      'HEAD',
+      '%H%x00%T%x00%P%x00%at%x00%an%x00%s');
+
+    $commits = array();
+
+    $info = trim($info);
+    $info = explode("\n", $info);
+    foreach ($info as $line) {
+      list($commit, $tree, $parents, $time, $author, $title)
+        = explode("\0", $line, 6);
+
+      $commits[] = array(
+        'commit'  => $commit,
+        'tree'    => $tree,
+        'parents' => array_filter(explode(' ', $parents)),
+        'time'    => $time,
+        'author'  => $author,
+        'summary' => $title,
+      );
+    }
+
+    return $commits;
+  }
+
   public function getRelativeCommit() {
     if ($this->relativeCommit === null) {
       list($err) = exec_manual(

src/repository/api/mercurial/ArcanistMercurialAPI.php

@@ -82,6 +82,16 @@ class ArcanistMercurialAPI extends ArcanistRepositoryAPI {
     return $this->relativeCommit;
   }
 
+  public function getLocalCommitInformation() {
+    list($info) = execx(
+      '(cd %s && hg log --rev %s..%s --)',
+      $this->getPath(),
+      $this->getRelativeCommit(),
+      'tip');
+    return $this->parseMercurialLog($info);
+  }
+
+
   public function getBlame($path) {
     list($stdout) = execx(
       '(cd %s && hg blame -u -v -c --rev %s -- %s)',
@@ -284,6 +294,16 @@ class ArcanistMercurialAPI extends ArcanistRepositoryAPI {
             $commit['local'] = $local;
             $commit['rev'] = $rev;
             break;
+          case 'parent':
+            if (empty($commit['parents'])) {
+              $commit['parents'] = array();
+            }
+            list($local, $rev) = explode(':', $value, 2);
+            $commit['parents'][] = array(
+              'local' => $local,
+              'rev'   => $rev,
+            );
+            break;
           default:
             throw new Exception("Unknown Mercurial log field '{$name}'!");
         }

src/repository/api/subversion/ArcanistSubversionAPI.php

@@ -478,4 +478,8 @@ EODIFF;
     return $info['Repository UUID'];
   }
 
+  public function getLocalCommitInformation() {
+    return null;
+  }
+
 }

src/workflow/diff/ArcanistDiffWorkflow.php

@@ -339,6 +339,17 @@ EOTEXT
         ));
     }
 
+    $local_info = $repository_api->getLocalCommitInformation();
+    if ($local_info) {
+      $conduit->callMethodSynchronous(
+        'differential.setdiffproperty',
+        array(
+          'diff_id' => $diff_info['diffid'],
+          'name'    => 'local:commits',
+          'data'    => json_encode($local_info),
+        ));
+    }
+
     if ($this->unresolvedTests) {
       $data = array();
       foreach ($this->unresolvedTests as $test) {