Fix error reporting for missing git process

src/Composer/Downloader/GitDownloader.php

@@ -93,19 +93,14 @@ class GitDownloader extends VcsDownloader
                     $this->filesystem->removeDirectory($path);
                 }
             }
-            
-            // failed to checkout, first check git accessibility
-            $output = $this->process->getErrorOutput();
-            if (127 === $this->process->execute('git --version', $handler)) {
-                throw new \RuntimeException('Failed to checkout ' . $url . ' via git, it isn\'t accessible through the console, please check your installation and your PATH env.' . "\n\n" . $this->process->getErrorOutput());
-            }
 
-            throw new \RuntimeException('Failed to checkout ' . $url .' via git, https and http protocols, aborting.' . "\n\n" . $output);
+            // failed to checkout, first check git accessibility
+            $this->throwException('Failed to clone ' . $url .' via git, https and http protocols, aborting.' . "\n\n" . $this->process->getErrorOutput(), $url);
         }
 
         $command = call_user_func($commandCallable, $url);
         if (0 !== $this->process->execute($command, $handler)) {
-            throw new \RuntimeException('Failed to execute ' . $command . "\n\n" . $this->process->getErrorOutput());
+            $this->throwException('Failed to execute ' . $command . "\n\n" . $this->process->getErrorOutput(), $url);
         }
     }
 
@@ -119,6 +114,15 @@ class GitDownloader extends VcsDownloader
         }
     }
 
+    protected function throwException($message, $url)
+    {
+        if (0 !== $this->process->execute('git --version', $ignoredOutput)) {
+            throw new \RuntimeException('Failed to clone '.$url.', git was not found, check that it is installed and in your PATH env.' . "\n\n" . $this->process->getErrorOutput());
+        }
+
+        throw new \RuntimeException($message);
+    }
+
     protected function setPushUrl(PackageInterface $package, $path)
     {
         // set push url for github projects

src/Composer/Repository/Vcs/GitDriver.php

@@ -54,12 +54,12 @@ class GitDriver extends VcsDriver
                 $command = sprintf('git clone --mirror %s %s', escapeshellarg($this->url), escapeshellarg($this->repoDir));
                 if (0 !== $this->process->execute($command, $output)) {
                     $output = $this->process->getErrorOutput();
-            
-                    if (127 === $this->process->execute('git --version', $handler)) {
-                        throw new \RuntimeException('Failed to clone '.$this->url.', git isn\'t accessible through the console, please check your installation and your PATH env.' . "\n\n" . $this->process->getErrorOutput());
+
+                    if (0 !== $this->process->execute('git --version', $ignoredOutput)) {
+                        throw new \RuntimeException('Failed to clone '.$this->url.', git was not found, check that it is installed and in your PATH env.' . "\n\n" . $this->process->getErrorOutput());
                     }
-                    
-                    throw new \RuntimeException('Failed to clone '.$this->url.', could not read packages from it ('.$output.')');
+
+                    throw new \RuntimeException('Failed to clone '.$this->url.', could not read packages from it' . "\n\n" .$output);
                 }
             }
         }

tests/Composer/Test/Downloader/GitDownloaderTest.php

@@ -113,7 +113,7 @@ class GitDownloaderTest extends \PHPUnit_Framework_TestCase
             ->method('getSourceUrl')
             ->will($this->returnValue('https://example.com/composer/composer'));
         $processExecutor = $this->getMock('Composer\Util\ProcessExecutor');
-        $processExecutor->expects($this->once())
+        $processExecutor->expects($this->at(0))
             ->method('execute')
             ->with($this->equalTo($expectedGitCommand))
             ->will($this->returnValue(1));