[WIP] Add --rebase and --ensure-sync options to pull-request:merge command

src/Command/PullRequest/PullRequestMergeCommand.php

@@ -40,6 +40,8 @@ protected function configure()
             ->addOption('fast-forward', null, InputOption::VALUE_NONE, 'Merge pull-request using fast forward (no merge commit will be created)')
             ->addOption('squash', null, InputOption::VALUE_NONE, 'Squash the PR before merging')
             ->addOption('force-squash', null, InputOption::VALUE_NONE, 'Force squashing the PR, even if there are multiple authors (this will implicitly use --squash)')
+            ->addOption('rebase', null, InputOption::VALUE_NONE, 'Rebase the PR before merging')
+            ->addOption('ensure-sync', null, InputOption::VALUE_NONE, 'Ensure that the pull request history is up to date before merging')
             ->addOption('switch', null, InputOption::VALUE_REQUIRED, 'Switch the base of the pull request before merging')
             ->addOption('pat', null, InputOption::VALUE_REQUIRED, 'Give the PR\'s author a pat on the back after the merge')
             ->setHelp(
@@ -79,6 +81,16 @@ protected function configure()
 
     <info>$ gush %command.name% --fast-forward 12</info>
 
+If you want to perform an automatic rebase against the base branch before merging, the <comment>--rebase</comment> option can be used
+in order to try that operation:
+
+    <info>$ gush %command.name% --rebase 12</info>
+
+A synchronization check against the base branch can be done before the merge, passing the <comment>--ensure-sync</comment> option; so
+if this check fails, the operation will be aborted:
+
+    <info>$ gush %command.name% --ensure-sync 12</info>
+
 After the pull request is merged, you can give a pat on the back to its author using the <comment>--pat</comment>.
 This option accepts the name of any configured pat's name:
 
@@ -173,6 +185,8 @@ protected function execute(InputInterface $input, OutputInterface $output)
             $mergeOperation->setTarget($targetRemote, $targetBranch);
             $mergeOperation->setSource($sourceRemote, $sourceBranch);
             $mergeOperation->squashCommits($squash, $input->getOption('force-squash'));
+            $mergeOperation->guardSync($input->getOption('ensure-sync'));
+            $mergeOperation->rebase($input->getOption('rebase'));
             $mergeOperation->switchBase($input->getOption('switch'));
             $mergeOperation->setMergeMessage($messageCallback);
             $mergeOperation->useFastForward($input->getOption('fast-forward'));

src/Helper/GitHelper.php

@@ -12,6 +12,7 @@
 namespace Gush\Helper;
 
 use Gush\Exception\CannotSquashMultipleAuthors;
+use Gush\Exception\MergeWorkflowException;
 use Gush\Exception\UserException;
 use Gush\Exception\WorkingTreeIsNotReady;
 use Gush\Operation\RemoteMergeOperation;
@@ -342,7 +343,7 @@ public function clearTempBranches()
      */
     public function createRemoteMergeOperation()
     {
-        return new RemoteMergeOperation($this, $this->filesystemHelper);
+        return new RemoteMergeOperation($this, $this->filesystemHelper, $this->processHelper);
     }
 
     /**
@@ -386,7 +387,7 @@ public function mergeBranch($base, $sourceBranch, $commitMessage, $fastForward =
                     'allow_failures' => false,
                 ],
                 [
-                    'line' => ['git', 'commit', '-F', $tmpName],
+                    'line' => ['git', 'commit', '--file', $tmpName],
                     'allow_failures' => false,
                 ],
             ]
@@ -433,7 +434,7 @@ public function mergeBranchWithLog($base, $sourceBranch, $commitMessage, $source
         $tmpName = $this->filesystemHelper->newTempFilename();
         file_put_contents($tmpName, $commitMessage);
 
-        $this->processHelper->runCommand(['git', 'commit', '-F', $tmpName]);
+        $this->processHelper->runCommand(['git', 'commit', '--file', $tmpName]);
 
         return trim($this->processHelper->runCommand('git rev-parse HEAD'));
     }
@@ -443,15 +444,7 @@ public function addNotes($notes, $commitHash, $ref)
         $tmpName = $this->filesystemHelper->newTempFilename();
         file_put_contents($tmpName, $notes);
 
-        $commands = [
-            'git',
-            'notes',
-            '--ref='.$ref,
-            'add',
-            '-F',
-            $tmpName,
-            $commitHash,
-        ];
+        $commands = ['git', 'notes', '--ref', $ref, 'add', '--file', $tmpName, $commitHash];
 
         $this->processHelper->runCommand($commands, true);
     }
@@ -596,21 +589,19 @@ public function squashCommits($base, $branchName, $ignoreMultipleAuthors = false
         // Get commits only in the branch but not in base (in reverse order)
         // we can't use --max-count here because that is applied before the reversing!
         //
-        // using git-log works better then finding the fork-point with git-merge-base
+        // using git-log works better than finding the fork-point with git-merge-base
         // because this protects against edge cases were there is no valid fork-point
 
-        $firstCommitHash = StringUtil::splitLines($this->processHelper->runCommand(
-            [
-                'git',
-                '--no-pager',
-                'log',
-                '--oneline',
-                '--no-color',
-                '--format=%H',
-                '--reverse',
-                $base.'..'.$branchName,
-            ]
-        ))[0];
+        $firstCommitHash = StringUtil::splitLines($this->processHelper->runCommand([
+            'git',
+            '--no-pager',
+            'log',
+            '--oneline',
+            '--no-color',
+            '--format=%H',
+            '--reverse',
+            $base.'..'.$branchName,
+        ]))[0];
 
         // 0=author anything higher then 0 is the full body
         $commitData = StringUtil::splitLines(
@@ -631,13 +622,7 @@ public function squashCommits($base, $branchName, $ignoreMultipleAuthors = false
         $message = implode("\n", $commitData);
 
         $this->reset($base);
-        $this->commit(
-            $message,
-            [
-                'a',
-                '-author' => $author,
-            ]
-        );
+        $this->commit($message, ['all', 'author' => $author]);
     }
 
     public function syncWithRemote($remote, $branchName = null)
@@ -671,17 +656,25 @@ public function commit($message, array $options = [])
 
         foreach ($options as $option => $value) {
             if (is_int($option)) {
-                $params[] = '-'.$value;
+                if (1 === strlen($value)) {
+                    $params[] = '-'.$value;
+                } else {
+                    $params[] = '--'.$value;
+                }
             } else {
-                $params[] = '-'.$option;
+                if (1 === strlen($option)) {
+                    $params[] = '-'.$option;
+                } else {
+                    $params[] = '--'.$option;
+                }
                 $params[] = $value;
             }
         }
 
         $tmpName = $this->filesystemHelper->newTempFilename();
         file_put_contents($tmpName, $message);
 
-        $this->processHelper->runCommand(array_merge(['git', 'commit', '-F', $tmpName], $params));
+        $this->processHelper->runCommand(array_merge(['git', 'commit', '--file', $tmpName], $params));
     }
 
     /**

src/Operation/RemoteMergeOperation.php

@@ -13,11 +13,13 @@
 
 use Gush\Helper\FilesystemHelper;
 use Gush\Helper\GitHelper;
+use Gush\Helper\ProcessHelper;
 
 class RemoteMergeOperation
 {
     private $gitHelper;
     private $filesystemHelper;
+    private $processHelper;
 
     private $sourceBranch;
     private $sourceRemote;
@@ -31,11 +33,14 @@ class RemoteMergeOperation
     private $performed = false;
     private $fastForward = false;
     private $withLog = false;
+    private $rebase = false;
+    private $guardSync = false;
 
-    public function __construct(GitHelper $gitHelper, FilesystemHelper $filesystemHelper)
+    public function __construct(GitHelper $gitHelper, FilesystemHelper $filesystemHelper, ProcessHelper $processHelper)
     {
         $this->gitHelper = $gitHelper;
         $this->filesystemHelper = $filesystemHelper;
+        $this->processHelper = $processHelper;
     }
 
     public function setSource($remote, $branch)
@@ -80,6 +85,8 @@ public function setMergeMessage($message, $withLog = false)
     public function useFastForward($fastForward = true)
     {
         $this->fastForward = (bool) $fastForward;
+
+        return $this;
     }
 
     public function performMerge()
@@ -143,6 +150,20 @@ public function pushToRemote()
         $this->gitHelper->pushToRemote($this->targetRemote, $target);
     }
 
+    public function rebase(bool $rebase = false)
+    {
+        $this->rebase = $rebase;
+
+        return $this;
+    }
+
+    public function guardSync(bool $guardSync = false)
+    {
+        $this->guardSync = $guardSync;
+
+        return $this;
+    }
+
     private function createBaseBranch()
     {
         $targetBranch = null !== $this->switchBase ? $this->switchBase : $this->targetBranch;
@@ -170,6 +191,24 @@ private function createSourceBranch()
             $this->targetBranch = $this->switchBase;
         }
 
+        $currentBaseHeadCommit = $this->processHelper->runCommand(['git', 'rev-parse', $this->targetBase]);
+        $lastKnownCommonCommit = $this->processHelper->runCommand(['git', 'merge-base', '--fork-point', $this->targetBase, $sourceBranch]);
+
+        if ($currentBaseHeadCommit !== $lastKnownCommonCommit) {
+            if ($this->rebase) {
+                try {
+                    $this->processHelper->runCommand(['git', 'pull', '--rebase', $this->targetBase]);
+                } catch (\Exception $e) {
+                    // Error, abort the rebase operation
+                    $this->processHelper->runCommand(['git', 'rebase', '--abort'], true);
+
+                    throw new MergeWorkflowException(sprintf('Git rebase failed while trying to synchronize history against "%s".', $this->targetBase), 0, $e);
+                }
+            } elseif ($this->guardSync) {
+                throw new MergeWorkflowException(sprintf('Failed while trying to perform merge against "%s", history is out of sync.', $this->targetBase));
+            }
+        }
+
         if ($this->squash) {
             $this->gitHelper->squashCommits($this->targetBase, $sourceBranch, $this->forceSquash);
         }

tests/Command/PullRequest/PullRequestMergeCommandTest.php

@@ -455,7 +455,7 @@ protected function getGitConfigHelper($notes = true)
         return $helper;
     }
 
-    private function getLocalGitHelper($message = null, $squash = false, $forceSquash = false, $switch = null, $withComments = true, $fastForward = false)
+    private function getLocalGitHelper($message = null, $squash = false, $forceSquash = false, $switch = null, $withComments = true, $fastForward = false, $guardSync = false, $rebase = false)
     {
         $helper = parent::getGitHelper();
 
@@ -470,6 +470,8 @@ private function getLocalGitHelper($message = null, $squash = false, $forceSquas
             $mergeOperation->setTarget('gushphp', 'base_ref')->shouldBeCalled();
             $mergeOperation->setSource('cordoval', 'head_ref')->shouldBeCalled();
             $mergeOperation->squashCommits($squash, $forceSquash)->shouldBeCalled();
+            $mergeOperation->guardSync($guardSync)->shouldBeCalled();
+            $mergeOperation->rebase($rebase)->shouldBeCalled();
             $mergeOperation->switchBase($switch)->shouldBeCalled();
             $mergeOperation->useFastForward($fastForward)->shouldBeCalled();
             $mergeOperation->setMergeMessage(

tests/Helper/GitHelperTest.php

@@ -176,7 +176,7 @@ public function merges_remote_branch_in_clean_wc()
                     'allow_failures' => false,
                 ],
                 [
-                    'line' => ['git', 'commit', '-F', $tmpName],
+                    'line' => ['git', 'commit', '--file', $tmpName],
                     'allow_failures' => false,
                 ],
             ]