diffmanifests: honor user-supplied manifest paths

The current implementation ignores the user-specified paths to
manifests.  if the "repo diffmanifests" is invoked with absolute
file paths for one or both manifests, the command fails with message:

fatal: duplicate path ... in /tmp/manifest-old.xml

Also the current implementation fails to expand the absolute path to
manifest files if "repo diffmanifests" is invoked with relative
paths, i.e "repo diffmanifests manifest-old.xml manifest-new.xml".

fatal: manifest manifest-old.xml not found

This commit fixes the first issue by disabling the local manifest
discovery for diffmanifests command, and the second issue by
expanding paths to manifests within "diffmanifests" sub-command.

Test: repo manifest --revision-as-HEAD -o /tmp/manifest-old.xml
      repo sync
      repo manifest --revision-as-HEAD -o /tmp/manifest-new.xml
      repo diffmanifests /tmp/manifest-old.xml /tmp/manifest-new.xml
Change-Id: Ia125d769bfbea75adb9aba81abbd8c636f2168d4
Signed-off-by: Vasyl Gello <vasek.gello@gmail.com>

manifest_xml.py

@@ -135,6 +135,7 @@ class XmlManifest(object):
     self.globalConfig = GitConfig.ForUser()
     self.localManifestWarning = False
     self.isGitcClient = False
+    self._load_local_manifests = True
 
     self.repoProject = MetaProject(self, 'repo',
       gitdir   = os.path.join(repodir, 'repo/.git'),
@@ -146,15 +147,26 @@ class XmlManifest(object):
 
     self._Unload()
 
-  def Override(self, name):
+  def Override(self, name, load_local_manifests=True):
     """Use a different manifest, just for the current instantiation.
     """
+    path = None
+
+    # Look for a manifest by path in the filesystem (including the cwd).
+    if not load_local_manifests:
+      local_path = os.path.abspath(name)
+      if os.path.isfile(local_path):
+        path = local_path
+
+    # Look for manifests by name from the manifests repo.
+    if path is None:
       path = os.path.join(self.manifestProject.worktree, name)
       if not os.path.isfile(path):
         raise ManifestParseError('manifest %s not found' % name)
 
     old = self.manifestFile
     try:
+      self._load_local_manifests = load_local_manifests
       self.manifestFile = path
       self._Unload()
       self._Load()
@@ -435,16 +447,19 @@ class XmlManifest(object):
       nodes.append(self._ParseManifestXml(self.manifestFile,
                                           self.manifestProject.worktree))
 
+      if self._load_local_manifests:
         local = os.path.join(self.repodir, LOCAL_MANIFEST_NAME)
         if os.path.exists(local):
           if not self.localManifestWarning:
             self.localManifestWarning = True
-          print('warning: %s is deprecated; put local manifests in `%s` instead'
+            print('warning: %s is deprecated; put local manifests '
-                % (LOCAL_MANIFEST_NAME, os.path.join(self.repodir, LOCAL_MANIFESTS_DIR_NAME)),
+                  'in `%s` instead' % (LOCAL_MANIFEST_NAME,
+                  os.path.join(self.repodir, LOCAL_MANIFESTS_DIR_NAME)),
                   file=sys.stderr)
           nodes.append(self._ParseManifestXml(local, self.repodir))
 
-      local_dir = os.path.abspath(os.path.join(self.repodir, LOCAL_MANIFESTS_DIR_NAME))
+        local_dir = os.path.abspath(os.path.join(self.repodir,
+                                    LOCAL_MANIFESTS_DIR_NAME))
         try:
           for local_file in sorted(platform_utils.listdir(local_dir)):
             if local_file.endswith('.xml'):

subcmds/diffmanifests.py

@@ -190,12 +190,12 @@ synced and their revisions won't be found.
       self.printProject = self.printAdded = self.printRemoved = self.printRevision = self.printText
 
     manifest1 = XmlManifest(self.manifest.repodir)
-    manifest1.Override(args[0])
+    manifest1.Override(args[0], load_local_manifests=False)
     if len(args) == 1:
       manifest2 = self.manifest
     else:
       manifest2 = XmlManifest(self.manifest.repodir)
-      manifest2.Override(args[1])
+      manifest2.Override(args[1], load_local_manifests=False)
 
     diff = manifest1.projectsDiff(manifest2)
     if opt.raw: