Fix Git failures due to tag ambiguity (issue #3417)

src/Composer/Downloader/GitDownloader.php

@@ -215,7 +215,7 @@ class GitDownloader extends VcsDownloader
      */
     protected function updateToCommit($path, $reference, $branch, $date)
     {
-        $template = 'git checkout %s && git reset --hard %1$s';
+        $template = 'git checkout %s && git reset --hard %1$s --';
         $branch = preg_replace('{(?:^dev-|(?:\.x)?-dev$)}i', '', $branch);
 
         $branches = null;
@@ -247,7 +247,7 @@ class GitDownloader extends VcsDownloader
             if (0 === $this->process->execute($command, $output, $path)
                 || 0 === $this->process->execute($fallbackCommand, $output, $path)
             ) {
-                $command = sprintf('git reset --hard %s', ProcessExecutor::escape($reference));
+                $command = sprintf('git reset --hard %s --', ProcessExecutor::escape($reference));
                 if (0 === $this->process->execute($command, $output, $path)) {
                     return;
                 }

tests/Composer/Test/Downloader/GitDownloaderTest.php

@@ -79,7 +79,7 @@ class GitDownloaderTest extends \PHPUnit_Framework_TestCase
 
         $processExecutor->expects($this->at(3))
             ->method('execute')
-            ->with($this->equalTo($this->winCompat("git reset --hard '1234567890123456789012345678901234567890'")), $this->equalTo(null), $this->equalTo($this->winCompat('composerPath')))
+            ->with($this->equalTo($this->winCompat("git reset --hard '1234567890123456789012345678901234567890' --")), $this->equalTo(null), $this->equalTo($this->winCompat('composerPath')))
             ->will($this->returnValue(0));
 
         $downloader = $this->getDownloaderMock(null, null, $processExecutor);
@@ -134,7 +134,7 @@ class GitDownloaderTest extends \PHPUnit_Framework_TestCase
 
         $processExecutor->expects($this->at(6))
             ->method('execute')
-            ->with($this->equalTo($this->winCompat("git checkout 'ref' && git reset --hard 'ref'")), $this->equalTo(null), $this->equalTo($this->winCompat('composerPath')))
+            ->with($this->equalTo($this->winCompat("git checkout 'ref' && git reset --hard 'ref' --")), $this->equalTo(null), $this->equalTo($this->winCompat('composerPath')))
             ->will($this->returnValue(0));
 
         $downloader = $this->getDownloaderMock(null, new Config(), $processExecutor);
@@ -266,7 +266,7 @@ class GitDownloaderTest extends \PHPUnit_Framework_TestCase
             ->will($this->returnValue(0));
         $processExecutor->expects($this->at(4))
             ->method('execute')
-            ->with($this->equalTo($this->winCompat("git checkout 'ref' && git reset --hard 'ref'")), $this->equalTo(null), $this->equalTo($this->winCompat($tmpDir)))
+            ->with($this->equalTo($this->winCompat("git checkout 'ref' && git reset --hard 'ref' --")), $this->equalTo(null), $this->equalTo($this->winCompat($tmpDir)))
             ->will($this->returnValue(0));
 
         $downloader = $this->getDownloaderMock(null, new Config(), $processExecutor);