LookupError, <file> not found in manifest

[anonymous]

Traceback:

Traceback (most recent call last):
  File "/Users/classic/Desktop/tmp/Trac-0.12.2/trac/web/main.py", line 511, in _dispatch_request
    dispatcher.dispatch(req)
  File "/Users/classic/Desktop/tmp/Trac-0.12.2/trac/web/main.py", line 237, in dispatch
    resp = chosen_handler.process_request(req)
  File "/Users/classic/Desktop/tmp/Trac-0.12.2/trac/versioncontrol/web_ui/browser.py", line 390, in process_request
    dir_data = self._render_dir(req, repos, node, rev, order, desc)
  File "/Users/classic/Desktop/tmp/Trac-0.12.2/trac/versioncontrol/web_ui/browser.py", line 549, in _render_dir
    entries = [entry(n) for n in node.get_entries()
  File "/Users/classic/Desktop/tmp/mercurial-plugin/tracext/hg/backend.py", line 1026, in get_entries
    str_entries)
  File "/Users/classic/Desktop/tmp/mercurial-plugin/tracext/hg/backend.py", line 956, in find_dirctx
    dr = max(dr, max_ctx.filectx(f).linkrev())
  File "/Users/classic/Desktop/tmp/lib/python2.7/site-packages/mercurial/context.py", line 177, in filectx
    fileid = self.filenode(path)
  File "/Users/classic/Desktop/tmp/lib/python2.7/site-packages/mercurial/context.py", line 166, in filenode
    return self._fileinfo(path)[0]
  File "/Users/classic/Desktop/tmp/lib/python2.7/site-packages/mercurial/context.py", line 161, in _fileinfo
    _('not found in manifest'))
LookupError: lib/sqlalchemy/databases/postgresql.py@58937c3f4abe: not found in manifest

Error appears in Trac 0.12 with Mercurial plugin r10879.

The error is be observed by linking Trac to the SQLAlchemy repository at ​http://hg.sqlalchemy.org/sqlalchemy/ , however I have a suspicion that the issue may be related to the latest revision being against a named branch that's not the "default". The error occurs when navigating to "lib/sqlalchemy/" as well as "test/perf", and probably others.

The only similar error I could find was #9611, but I don't have the same thing here as my Mercurial is reporting the version correctly:

classics-MacBook-Pro:mercurial-plugin classic$ ../bin/python
Python 2.7.2 (v2.7.2:8527427914a2, Jun 11 2011, 15:22:34) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from mercurial import __version__
>>> __version__.version
'2.0.1'

A patch which seems to resolve the issue, though is probably not the right way to go as it's just silently squashing the error:

tracext/hg/backend.py

@@ -953 +953 @@
                     str_files = str_entries[str_dir]
                     dr = str_dirctxs.get(str_dir, 0)
                     for f in str_files[:k]:
-                        dr = max(dr, max_ctx.filectx(f).linkrev())
+                        try:
+                            dr = max(dr, max_ctx.filectx(f).linkrev())
+                        except LookupError:
+                            pass
                     str_files = str_files[k:]
                     if str_files:
                         str_entries[str_dir] = str_files

This error did not occur in Trac .11 with the older version of the plugin. I tried working backwards through TracMercurial revs but the earliest rev that even works with 0.12 seems to be r10698 which also has the issue.