Add hg support for arc land

Summary:
Makes arc land support hg repositories. Both bookmarks and named branches can be landed.  For the most part all the arc land options work, but there are a few caveats:

- bookmarks can only be landed on bookmarks
- branches can only be landed on branches
- landing a named branch with --merge creates a commit to close the branch before the merge.
- since mercurial doesn't start with a default master bookmark, landing a bookmark requires specifying --onto or setting arc.land.onto.default

Test Plan:
Tested arc land with all permutations of --merge, --keep-branch on both bookmark branches and named branches.  Also tested --hold, --revision, --onto, --remote.

See https://secure.phabricator.com/P619

Also tested git arc land with --merge and --keep-branch.

Reviewers: dschleimer, sid0, epriestley, bos

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4068

src/repository/api/ArcanistMercurialAPI.php

@@ -39,6 +39,17 @@ final class ArcanistMercurialAPI extends ArcanistRepositoryAPI {
     return $future;
   }
 
+  public function execPassthru($pattern /* , ... */) {
+    $args = func_get_args();
+    if (phutil_is_windows()) {
+      $args[0] = 'set HGPLAIN=1 & hg '.$args[0];
+    } else {
+      $args[0] = 'HGPLAIN=1 hg '.$args[0];
+    }
+
+    return call_user_func_array("phutil_passthru", $args);
+  }
+
   public function getSourceControlSystemName() {
     return 'hg';
   }
@@ -768,17 +779,98 @@ final class ArcanistMercurialAPI extends ArcanistRepositoryAPI {
   }
 
   public function getActiveBookmark() {
+    $bookmarks = $this->getBookmarks();
+    foreach ($bookmarks as $bookmark) {
+      if ($bookmark['is_active']) {
+        return $bookmark['name'];
+      }
+    }
+
+    return null;
+  }
+
+  public function isBookmark($name) {
+    $bookmarks = $this->getBookmarks();
+    foreach ($bookmarks as $bookmark) {
+      if ($bookmark['name'] === $name) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  public function isBranch($name) {
+    $branches = $this->getBranches();
+    foreach ($branches as $branch) {
+      if ($branch['name'] === $name) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  public function getBranches() {
+    $branches = array();
+
+    list($raw_output) = $this->execxLocal('branches');
+    $raw_output = trim($raw_output);
+
+    foreach (explode("\n", $raw_output) as $line) {
+      // example line: default                 0:a5ead76cdf85 (inactive)
+      list($name, $rev_line) = $this->splitBranchOrBookmarkLine($line);
+
+      // strip off the '(inactive)' bit if it exists
+      $rev_parts = explode(' ', $rev_line);
+      $revision = $rev_parts[0];
+
+      $branches[] = array(
+        'name' => $name,
+        'revision' => $revision);
+    }
+
+    return $branches;
+  }
+
+  public function getBookmarks() {
+    $bookmarks = array();
+
     list($raw_output) = $this->execxLocal('bookmarks');
     $raw_output = trim($raw_output);
     if ($raw_output !== 'no bookmarks set') {
       foreach (explode("\n", $raw_output) as $line) {
-        $line = trim($line);
+        // example line:  * mybook               2:6b274d49be97
-        if ('*' === $line[0]) {
+        list($name, $revision) = $this->splitBranchOrBookmarkLine($line);
-          return idx(explode(' ', $line, 3), 1);
+
-        }
+        $is_active = false;
-      }
+        if ('*' === $name[0]) {
-    }
+          $is_active = true;
-    return null;
+          $name = substr($name, 2);
         }
 
+        $bookmarks[] = array(
+          'is_active' => $is_active,
+          'name' => $name,
+          'revision' => $revision);
+      }
+    }
+
+    return $bookmarks;
+  }
+
+  private function splitBranchOrBookmarkLine($line) {
+    // branches and bookmarks are printed in the format:
+    // default                 0:a5ead76cdf85 (inactive)
+    // * mybook               2:6b274d49be97
+    // this code divides the name half from the revision half
+    // it does not parse the * and (inactive) bits
+    $colon_index = strrpos($line, ':');
+    $before_colon = substr($line, 0, $colon_index);
+    $start_rev_index = strrpos($before_colon, ' ');
+    $name = substr($line, 0, $start_rev_index);
+    $rev = substr($line, $start_rev_index);
+
+    return array(trim($name), trim($rev));
+  }
 }

src/workflow/ArcanistLandWorkflow.php

@@ -7,6 +7,7 @@
  */
 final class ArcanistLandWorkflow extends ArcanistBaseWorkflow {
   private $isGit;
+  private $isHg;
 
   private $oldBranch;
   private $branch;
@@ -17,7 +18,7 @@ final class ArcanistLandWorkflow extends ArcanistBaseWorkflow {
   private $keepBranch;
 
   private $revision;
-  private $message;
+  private $messageFile;
 
   public function getWorkflowName() {
     return 'land';
@@ -32,7 +33,7 @@ EOTEXT
 
   public function getCommandHelp() {
     return phutil_console_format(<<<EOTEXT
-          Supports: git
+          Supports: git, hg
 
           Land an accepted change (currently sitting in local feature branch
           __branch__) onto __master__ and push it to the remote. Then, delete
@@ -44,6 +45,8 @@ EOTEXT
           immutable repositories (or when --merge is provided), it will perform
           a --no-ff merge (the branch will always be merged into __master__ with
           a merge commit).
+
+          Under hg, bookmarks can be landed the same way as branches.
 EOTEXT
       );
   }
@@ -68,10 +71,10 @@ EOTEXT
     return array(
       'onto' => array(
         'param' => 'master',
-        'help' => "Land feature branch onto a branch other than ".
+        'help' => "Land feature branch onto a branch other than the default ".
-                  "'master' (default). You can change the default by setting ".
+                  "('master' in git, 'default' in hg). You can change the ".
-                  "'arc.land.onto.default' with `arc set-config` or for the ".
+                  "default by setting 'arc.land.onto.default' with ".
-                  "entire project in .arcconfig.",
+                  "`arc set-config` or for the entire project in .arcconfig.",
       ),
       'hold' => array(
         'help' => "Prepare the change to be pushed, but do not actually ".
@@ -83,12 +86,18 @@ EOTEXT
       ),
       'remote' => array(
         'param' => 'origin',
-        'help' => "Push to a remote other than 'origin' (default).",
+        'help' => "Push to a remote other than the default ('origin' in git).",
       ),
       'merge' => array(
         'help' => 'Perform a --no-ff merge, not a --squash merge. If the '.
                   'project is marked as having an immutable history, this is '.
                   'the default behavior.',
+        'supports' => array(
+          'git',
+        ),
+        'nosupport'   => array(
+          'hg' => 'Use the --squash strategy when landing in mercurial.',
+        ),
       ),
       'squash' => array(
         'help' => 'Perform a --squash merge, not a --no-ff merge. If the '.
@@ -154,14 +163,16 @@ EOTEXT
   private function readArguments() {
     $repository_api = $this->getRepositoryAPI();
     $this->isGit = $repository_api instanceof ArcanistGitAPI;
+    $this->isHg = $repository_api instanceof ArcanistMercurialAPI;
 
-    if (!$this->isGit) {
+    if (!$this->isGit && !$this->isHg) {
-      throw new ArcanistUsageException("'arc land' only supports git.");
+      throw new ArcanistUsageException(
+        "'arc land' only supports git and mercurial.");
     }
 
     $branch = $this->getArgument('branch');
     if (empty($branch)) {
-      $branch = $repository_api->getBranchName();
+      $branch = $this->getBranchOrBookmark();
 
       if ($branch) {
         echo "Landing current branch '{$branch}'.\n";
@@ -174,14 +185,16 @@ EOTEXT
         "Specify exactly one branch to land changes from.");
     }
     $this->branch = head($branch);
+    $this->keepBranch = $this->getArgument('keep-branch');
 
+    $onto_default = $this->isGit ? 'master' : 'default';
     $onto_default = nonempty(
       $this->getWorkingCopy()->getConfigFromAnySource('arc.land.onto.default'),
-      'master');
+      $onto_default);
-
-    $this->remote = $this->getArgument('remote', 'origin');
     $this->onto = $this->getArgument('onto', $onto_default);
-    $this->keepBranch = $this->getArgument('keep-branch');
+
+    $remote_default = $this->isGit ? 'origin' : '';
+    $this->remote = $this->getArgument('remote', $remote_default);
 
     if ($this->getArgument('merge')) {
       $this->useSquash = false;
@@ -191,9 +204,12 @@ EOTEXT
       $this->useSquash = !$this->isHistoryImmutable();
     }
 
+    $this->ontoRemoteBranch = $this->onto;
+    if ($this->isGit) {
       $this->ontoRemoteBranch = $this->remote.'/'.$this->onto;
+    }
 
-    $this->oldBranch = $repository_api->getBranchName();
+    $this->oldBranch = $this->getBranchOrBookmark();
   }
 
   private function validate() {
@@ -211,6 +227,36 @@ EOTEXT
       throw new ArcanistUsageException($message);
     }
 
+    if ($this->isHg) {
+      if ($this->useSquash) {
+        list ($err) = $repository_api->execManualLocal("rebase --help");
+        if ($err) {
+          throw new ArcanistUsageException(
+            "You must enable the rebase extension to use ".
+            "the --squash strategy.");
+        }
+      }
+
+      if ($repository_api->isBookmark($this->branch) &&
+          !$repository_api->isBookmark($this->onto)) {
+        throw new ArcanistUsageException(
+          "Source {$this->branch} is a bookmark but destination ".
+          "{$this->onto} is not a bookmark. When landing a bookmark, ".
+          "the destination must also be a bookmark. Use --onto to specify ".
+          "a bookmark, or set arc.land.onto.default in .arcconfig.");
+      }
+
+      if ($repository_api->isBranch($this->branch) &&
+          !$repository_api->isBranch($this->onto)) {
+        throw new ArcanistUsageException(
+          "Source {$this->branch} is a branch but destination {$this->onto} ".
+          "is not a branch. When landing a branch, the destination must also ".
+          "be a branch. Use --onto to specify a branch, or set ".
+          "arc.land.onto.default in .arcconfig.");
+      }
+    }
+
+    if ($this->isGit) {
       list($err) = $repository_api->execManualLocal(
         'rev-parse --verify %s',
         $this->branch);
@@ -219,6 +265,7 @@ EOTEXT
         throw new ArcanistUsageException(
           "Branch '{$this->branch}' does not exist.");
       }
+    }
 
     $this->requireCleanWorkingCopy();
   }
@@ -290,12 +337,15 @@ EOTEXT
       }
     }
 
-    $this->message = $this->getConduit()->callMethodSynchronous(
+    $message = $this->getConduit()->callMethodSynchronous(
       'differential.getcommitmessage',
       array(
         'revision_id' => $rev_id,
       ));
 
+    $this->messageFile = new TempFile();
+    Filesystem::writeFile($this->messageFile, $message);
+
     echo "Landing revision 'D{$rev_id}: ".
          "{$rev_title}'...\n";
   }
@@ -308,6 +358,8 @@ EOTEXT
       "Switched to branch **%s**. Updating branch...\n",
       $this->onto);
 
+    $local_ahead_of_remote = false;
+    if ($this->isGit) {
       $repository_api->execxLocal('pull --ff-only');
 
       list($out) = $repository_api->execxLocal(
@@ -316,6 +368,54 @@ EOTEXT
         $this->onto,
         $this->onto);
       if (strlen(trim($out))) {
+        $local_ahead_of_remote = true;
+      }
+    } else if ($this->isHg) {
+      // execManual instead of execx because outgoing returns
+      // code 1 when there is nothing outgoing
+      list($err, $out) = $repository_api->execManualLocal(
+        'outgoing -r %s',
+        $this->onto);
+
+      // $err === 0 means something is outgoing
+      if ($err === 0) {
+        $local_ahead_of_remote = true;
+      }
+      else {
+        try {
+          $repository_api->execxLocal('pull -u');
+        } catch (CommandException $ex) {
+          $err = $ex->getError();
+          $stdout = $ex->getStdOut();
+
+          // Copied from: PhabricatorRepositoryPullLocalDaemon.php
+          // NOTE: Between versions 2.1 and 2.1.1, Mercurial changed the
+          // behavior of "hg pull" to return 1 in case of a successful pull
+          // with no changes. This behavior has been reverted, but users who
+          // updated between Feb 1, 2012 and Mar 1, 2012 will have the
+          // erroring version. Do a dumb test against stdout to check for this
+          // possibility.
+          // See: https://github.com/facebook/phabricator/issues/101/
+
+          // NOTE: Mercurial has translated versions, which translate this error
+          // string. In a translated version, the string will be something else,
+          // like "aucun changement trouve". There didn't seem to be an easy way
+          // to handle this (there are hard ways but this is not a common
+          // problem and only creates log spam, not application failures).
+          // Assume English.
+
+          // TODO: Remove this once we're far enough in the future that
+          // deployment of 2.1 is exceedingly rare?
+          if ($err == 1 && preg_match('/no changes found/', $stdout)) {
+            return;
+          } else {
+            throw $ex;
+          }
+        }
+      }
+    }
+
+    if ($local_ahead_of_remote) {
       throw new ArcanistUsageException(
           "Local branch '{$this->onto}' is ahead of remote branch ".
           "'{$this->ontoRemoteBranch}', so landing a feature branch ".
@@ -328,26 +428,67 @@ EOTEXT
     $repository_api = $this->getRepositoryAPI();
 
     chdir($repository_api->getPath());
+    if ($this->isGit) {
       $err = phutil_passthru('git rebase %s', $this->onto);
+    }
+    else if ($this->isHg) {
+      // keep branch here so later we can decide whether to remove it
+      $err = $repository_api->execPassthru(
+        'rebase -d %s --keepbranches',
+        $this->onto);
+    }
 
     if ($err) {
+      $command = $repository_api->getSourceControlSystemName();
       throw new ArcanistUsageException(
-        "'git rebase {$this->onto}' failed. ".
+        "'{$command} rebase {$this->onto}' failed. ".
-        "You can abort with 'git rebase --abort', ".
+        "You can abort with '{$command} rebase --abort', ".
-        "or resolve conflicts and use 'git rebase ".
+        "or resolve conflicts and use '{$command} rebase ".
         "--continue' to continue forward. After resolving the rebase, ".
         "run 'arc land' again.");
     }
+
+    // Now that we've rebased, the merge-base of origin/master and HEAD may
+    // be different. Reparse the relative commit.
+    $repository_api->parseRelativeLocalCommit(array($this->ontoRemoteBranch));
   }
 
   private function squash() {
     $repository_api = $this->getRepositoryAPI();
     $repository_api->execxLocal('checkout %s', $this->onto);
 
+    if ($this->isGit) {
       $repository_api->execxLocal(
         'merge --squash --ff-only %s',
         $this->branch);
     }
+    else if ($this->isHg) {
+      $branch_rev_id = $repository_api->getCanonicalRevisionName($this->branch);
+
+      $repository_api->execxLocal(
+        'rebase --collapse --logfile %s -b %s -d %s %s',
+        $this->messageFile,
+        $this->branch,
+        $this->onto,
+        $this->keepBranch ? '--keep' : '');
+      if ($repository_api->isBookmark($this->branch)) {
+        // a bug in mercurial means bookmarks end up on the revision prior
+        // to the collapse when using --collapse with --keep,
+        // so we manually move them to the correct spots
+        // see: http://bz.selenic.com/show_bug.cgi?id=3716
+        $repository_api->execxLocal(
+          'bookmark -f %s',
+          $this->onto);
+
+        if ($this->keepBranch) {
+          $repository_api->execxLocal(
+            'bookmark -f %s -r %s',
+            $this->branch,
+            $branch_rev_id);
+        }
+      }
+    }
+  }
 
   private function merge() {
     $repository_api = $this->getRepositoryAPI();
@@ -357,6 +498,7 @@ EOTEXT
     $repository_api->execxLocal('checkout %s', $this->onto);
 
     chdir($repository_api->getPath());
+    if ($this->isGit) {
       $err = phutil_passthru(
         'git merge --no-ff --no-commit %s',
         $this->branch);
@@ -368,16 +510,35 @@ EOTEXT
           "the instructions to complete the merge.");
       }
     }
+    else if ($this->isHg) {
+      // HG arc land currently doesn't support --merge.
+      // When merging a bookmark branch to a master branch that
+      // hasn't changed since the fork, mercurial fails to merge.
+      // Instead of only working in some cases, we just disable --merge
+      // until there is a demand for it.
+      // The user should never reach this line, since --merge is
+      // forbidden at the command line argument level.
+      throw new ArcanistUsageException(
+        "--merge is not currently supported for hg repos.");
+    }
+  }
 
   private function push() {
     $repository_api = $this->getRepositoryAPI();
 
-    $tmp_file = new TempFile();
+    if ($this->isGit) {
-    Filesystem::writeFile($tmp_file, $this->message);
-
       $repository_api->execxLocal(
         'commit -F %s',
-      $tmp_file);
+        $this->messageFile);
+    }
+    else if ($this->isHg) {
+      // hg rebase produces a commit earlier as part of rebase
+      if (!$this->useSquash) {
+        $repository_api->execxLocal(
+          'commit --logfile %s',
+          $this->messageFile);
+      }
+    }
 
     if ($this->getArgument('hold')) {
       echo phutil_console_format(
@@ -388,10 +549,18 @@ EOTEXT
 
       chdir($repository_api->getPath());
 
+      if ($this->isGit) {
         $err = phutil_passthru(
           'git push %s %s',
           $this->remote,
           $this->onto);
+      }
+      else if ($this->isHg) {
+        $err = $repository_api->execPassthru(
+          'push --new-branch -r %s %s',
+          $this->onto,
+          $this->remote);
+      }
 
       if ($err) {
         $repo_command = $repository_api->getSourceControlSystemName();
@@ -415,6 +584,7 @@ EOTEXT
     $repository_api = $this->getRepositoryAPI();
 
     echo "Cleaning up feature branch...\n";
+    if ($this->isGit) {
       list($ref) = $repository_api->execxLocal(
         'rev-parse --verify %s',
         $this->branch);
@@ -427,8 +597,19 @@ EOTEXT
       $repository_api->execxLocal(
         'branch -D %s',
         $this->branch);
+    }
+    else if ($this->isHg) {
+      // named branches were closed as part of the earlier commit
+      // so only worry about bookmarks
+      if ($repository_api->isBookmark($this->branch)) {
+        $repository_api->execxLocal(
+        'bookmark -d %s',
+        $this->branch);
+      }
+    }
 
     if ($this->getArgument('delete-remote')) {
+      if ($this->isGit) {
         list($err, $ref) = $repository_api->execManualLocal(
           'rev-parse --verify %s/%s',
           $this->remote,
@@ -450,10 +631,35 @@ EOTEXT
             $this->branch);
         }
       }
+      else if ($this->isHg) {
+        // named branches were closed as part of the earlier commit
+        // so only worry about bookmarks
+        if ($repository_api->isBookmark($this->branch)) {
+          $repository_api->execxLocal(
+            'push -B %s %s',
+            $this->branch,
+            $this->remote);
+        }
+      }
+    }
   }
 
   protected function getSupportedRevisionControlSystems() {
-    return array('git');
+    return array('git', 'hg');
   }
 
+  private function getBranchOrBookmark() {
+    $repository_api = $this->getRepositoryAPI();
+    if ($this->isGit) {
+      $branch = $repository_api->getBranchName();
+    }
+    else if ($this->isHg) {
+      $branch = $repository_api->getActiveBookmark();
+      if (!$branch) {
+        $branch = $repository_api->getBranchName();
+      }
+    }
+
+    return $branch;
+  }
 }