view mercurial/help/diffs.txt @ 29196:bf7b8157c483 stable

strip: invalidate phase cache after stripping changeset (issue5235)

When we remove a changeset from the changelog, the phase cache must be
invalidated, otherwise it could refer to changesets that are no longer in the
repo.

To reproduce the failure, I created an extension querying the phase cache after
the strip transaction is over.

To do that, I stripped two commits with a bookmark on one of them to force
another transaction (we open a transaction for moving bookmarks)
after the strip transaction.

Without the fix in this patch, the test leads to a stacktrace showing the issue:
      repair.strip(ui, repo, revs, backup)
    File "/Users/lcharignon/facebook-hg-rpms/hg-crew/mercurial/repair.py", line 205, in strip
      tr.close()
    File "/Users/lcharignon/facebook-hg-rpms/hg-crew/mercurial/transaction.py", line 44, in _active
      return func(self, *args, **kwds)
    File "/Users/lcharignon/facebook-hg-rpms/hg-crew/mercurial/transaction.py", line 490, in close
      self._postclosecallback[cat](self)
    File "$TESTTMP/crashstrip2.py", line 4, in test
      [repo.changelog.node(r) for r in repo.revs("not public()")]
    File "/Users/lcharignon/facebook-hg-rpms/hg-crew/mercurial/changelog.py", line 337, in node
      return super(changelog, self).node(rev)
    File "/Users/lcharignon/facebook-hg-rpms/hg-crew/mercurial/revlog.py", line 377, in node
      return self.index[rev][7]
  IndexError: revlog index out of range

The situation was encountered in inhibit (evolve's repo) where we would crash
following the volatile set invalidation submitted by Augie in
e6f490e328635312ee214a12bc7fd3c7d46bf9ce. Before his patch the issue was masked
as we were not accessing the phasecache after stripping a revision.

This bug uncovered another but in histedit (see explanation in issue5235).
I changed the histedit test accordingly to avoid fixing two things at once.

Mercurial's default format for showing changes between two versions of
a file is compatible with the unified format of GNU diff, which can be
used by GNU patch and many other standard tools.

While this standard format is often enough, it does not encode the
following information:

- executable status and other permission bits
- copy or rename information
- changes in binary files
- creation or deletion of empty files

Mercurial also supports the extended diff format from the git VCS
which addresses these limitations. The git diff format is not produced
by default because a few widespread tools still do not understand this
format.

This means that when generating diffs from a Mercurial repository
(e.g. with :hg:`export`), you should be careful about things like file
copies and renames or other things mentioned above, because when
applying a standard diff to a different repository, this extra
information is lost. Mercurial's internal operations (like push and
pull) are not affected by this, because they use an internal binary
format for communicating changes.

To make Mercurial produce the git extended diff format, use the --git
option available for many commands, or set 'git = True' in the [diff]
section of your configuration file. You do not need to set this option
when importing diffs in this format or using them in the mq extension.