Support detached HEAD in manifest repository

If the manifest repository is on a detached HEAD and we are parsing
an XML formatted manifest we should simply set the branch property
to None, rather than crash with an AttributeError.

Signed-off-by: Shawn O. Pearce <sop@google.com>

editor.py

@@ -76,8 +76,15 @@ least one of these before using this command."""
       os.close(fd)
       fd = None
 
-      if subprocess.Popen(editor + [path]).wait() != 0:
-        raise EditorError()
+      try:
+        rc = subprocess.Popen(editor + [path]).wait()
+      except OSError, e:
+        raise EditorError('editor failed, %s: %s %s'
+          % (str(e), cls._GetEditor(), path))
+      if rc != 0:
+        raise EditorError('editor failed with exit status %d: %s %s'
+          % (rc, cls._GetEditor(), path))
+
       fd2 = open(path)
       try:
         return fd2.read()

error.py

@@ -24,6 +24,11 @@ class ManifestInvalidRevisionError(Exception):
 class EditorError(Exception):
   """Unspecified error from the user's text editor.
   """
+  def __init__(self, reason):
+    self.reason = reason
+
+  def __str__(self):
+    return self.reason
 
 class GitError(Exception):
   """Unspecified internal error from git.

git_config.py

@@ -385,8 +385,11 @@ def _open_ssh(host, port):
 
 def close_ssh():
   for key,p in _ssh_cache.iteritems():
-    os.kill(p.pid, SIGTERM)
-    p.wait()
+    try:
+      os.kill(p.pid, SIGTERM)
+      p.wait()
+    except OSError:
+      pass
   _ssh_cache.clear()
 
   d = _ssh_sock(create=False)

manifest_xml.py

@@ -183,7 +183,7 @@ class XmlManifest(object):
     if not self._loaded:
       m = self.manifestProject
       b = m.GetBranch(m.CurrentBranch).merge
-      if b.startswith(R_HEADS):
+      if b is not None and b.startswith(R_HEADS):
         b = b[len(R_HEADS):]
       self.branch = b