hg incoming (after strip / git-cleanup): 'overlayrepo' object has no attribute 'githandler'

Created originally on Bitbucket by muxator

• python: 2.7.14 (from ubuntu bionic repo)
• dulwich: 0.18.5 (from ubuntu bionic repo)
• mercurial: 4.5.3 (built with make deb)
• hg-git: 0.8.11 (b90c69681d2d)

When invoking hg incoming on a repository that had some commit stripped, it seems that hg-git no longer recognizes itself.

hg pull still works.

Test case on a github repository with just 2 commits.

Setup:

~$ hg clone git+https://github.com/rtyley/small-test-repo.git
destination directory: small-test-repo
importing git objects into hg
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved

~$ cd small-test-repo/

At first, hg incoming works as expected.

~/small-test-repo$ hg incoming
comparing with git+https://github.com/rtyley/small-test-repo.git
no changes found

Let's strip the last commit:

~/small-test-repo$ hg strip -r tip
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
saved backup bundle to ~/small-test-repo/.hg/strip-backup/6c1edf335a95-cec39c48-backup.hg

hg incoming does not work (this is not very surprising: we did not call hg git-cleanup)

~/small-test-repo$ hg incoming
comparing with git+https://github.com/rtyley/small-test-repo.git
no changes found

Let's do the compulsory hg git-cleanup:

~/small-test-repo$ hg git-cleanup 
git commit map cleaned

Now hg incoming breaks:

~/small-test-repo$ hg incoming
comparing with git+https://github.com/rtyley/small-test-repo.git
** unknown exception encountered, please report by visiting
** https://mercurial-scm.org/wiki/BugTracker
** Python 2.7.14+ (default, Apr  2 2018, 04:16:25) [GCC 7.3.0]
** Mercurial Distributed SCM (version 4.5.3+4-386aaa01ffa7+20180415)
** Extensions loaded: convert, extdiff, hggit, strip, mq, rebase, shelve, uncommit, show
Traceback (most recent call last):
  File "/usr/bin/hg", line 41, in <module>
    dispatch.run()
  File "/usr/lib/python2.7/dist-packages/mercurial/dispatch.py", line 88, in run
    status = (dispatch(req) or 0) & 255
[...]
  File "/usr/lib/python2.7/dist-packages/hgext/mq.py", line 3583, in mqcommand
    return orig(ui, repo, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/mercurial/util.py", line 1195, in check
    return func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/mercurial/commands.py", line 3183, in incoming
    return hg.incoming(ui, repo, source, opts)
  File "/usr/lib/python2.7/dist-packages/mercurial/hg.py", line 919, in incoming
    return _incoming(display, subreporecurse, ui, repo, source, opts)
  File "/usr/lib/python2.7/dist-packages/mercurial/hg.py", line 889, in _incoming
    displaychlist(other, chlist, displayer)
  File "/usr/lib/python2.7/dist-packages/mercurial/hg.py", line 918, in display
    displayer.show(other[n])
  File "/usr/lib/python2.7/dist-packages/mercurial/cmdutil.py", line 1695, in show
    self._show(ctx, copies, matchfn, hunksfilterfn, props)
  File "/usr/lib/python2.7/dist-packages/mercurial/cmdutil.py", line 2007, in _show
    self.ui.write(templater.stringify(self.t(key, **props)))
  File "/usr/lib/python2.7/dist-packages/mercurial/templatefilters.py", line 372, in stringify
    return "".join([stringify(t) for t in thing if t is not None])
  File "/usr/lib/python2.7/dist-packages/mercurial/util.py", line 1017, in increasingchunks
    for chunk in source:
  File "/usr/lib/python2.7/dist-packages/mercurial/templater.py", line 1281, in _flatten
    for j in _flatten(i):
[...]
  File "/usr/lib/python2.7/dist-packages/mercurial/templater.py", line 1272, in _flatten
    for i in thing:
  File "/usr/lib/python2.7/dist-packages/mercurial/templater.py", line 795, in if_
    test = evalboolean(context, mapping, args[0])
  File "/usr/lib/python2.7/dist-packages/mercurial/templater.py", line 327, in evalboolean
    thing = func(context, mapping, data, default=None)
  File "/usr/lib/python2.7/dist-packages/mercurial/templater.py", line 404, in runsymbol
    return v(**pycompat.strkwargs(props))
  File "/opt/mercurial/hg-git/hggit/__init__.py", line 429, in gitnodekw
    gitnode = repo.githandler.map_git_get(node.hex())
AttributeError: 'overlayrepo' object has no attribute 'githandler'

The key issue seems to be that repo no longer appear to be a "gitified" repository (it has no githandler attribute now).

On the other hand, hg pull works as expected, pulling back in the change we just stripped:

~/small-test-repo$ hg pull
pulling from git+https://github.com/rtyley/small-test-repo.git
importing git objects into hg
(run 'hg update' to get a working copy)