Fix processes silently ignoring the CWD when it does not exist, refs #9694

src/Composer/Repository/Vcs/GitDriver.php

@@ -38,6 +38,9 @@ class GitDriver extends VcsDriver
     {
         if (Filesystem::isLocalPath($this->url)) {
             $this->url = preg_replace('{[\\/]\.git/?$}', '', $this->url);
+            if (!is_dir($this->url)) {
+                throw new \RuntimeException('Failed to read package information from '.$this->url.' as the path does not exist');
+            }
             $this->repoDir = $this->url;
             $cacheUrl = realpath($this->url);
         } else {

src/Composer/Util/ProcessExecutor.php

@@ -61,6 +61,10 @@ class ProcessExecutor
             $cwd = realpath(getcwd());
         }
 
+        if (null !== $cwd && !is_dir($cwd)) {
+            throw new \RuntimeException('The given CWD for the process does not exist: '.$cwd);
+        }
+
         $this->captureOutput = func_num_args() > 1;
         $this->errorOutput = null;