view tests/test-issue2137.t @ 45375:8c466bcb0879

revert: remove dangerous `parents` argument from `cmdutil.revert()`

As we found out the hard way (thanks to spectral@ for figuring it
out!), `cmdutil.revert()`'s `parents` argument must be
`repo.dirstate.parents()` or things may go wrong. We had an extension
that passed in the target commit as the first parent. The `hg split`
command from the evolve extension seems to have made the same mistake,
but I haven't looked carefully.

The problem is that `cmdutil._performrevert()` calls
`dirstate.normal()` on reverted files if the commit to revert to
equals the first parent. So if you pass in `ctx=foo` and
`parents=(foo.node(), nullid)`, then `dirstate.normal()` will be
called for the revert files, even though they might not be clean in
the working copy.

There doesn't seem to be any reason, other than a tiny performance
benefit, to passing the `parents` around instead of looking them up
again in `cmdutil._performrevert()`, so that's what this patch does.

Differential Revision: https://phab.mercurial-scm.org/D8925

https://bz.mercurial-scm.org/2137

Setup:

create a little extension that has 3 side-effects:
1) ensure changelog data is not inlined
2) make revlog to use lazyparser
3) test that repo.lookup() works
1 and 2 are preconditions for the bug; 3 is the bug.

  $ cat > commitwrapper.py <<EOF
  > from mercurial import extensions, node, revlog
  > 
  > def reposetup(ui, repo):
  >     class wraprepo(repo.__class__):
  >         def commit(self, *args, **kwargs):
  >             result = super(wraprepo, self).commit(*args, **kwargs)
  >             tip1 = node.short(repo.changelog.tip())
  >             tip2 = node.short(repo.lookup(tip1))
  >             assert tip1 == tip2
  >             ui.write(b'new tip: %s\n' % tip1)
  >             return result
  >     repo.__class__ = wraprepo
  > 
  > def extsetup(ui):
  >     revlog._maxinline = 8             # split out 00changelog.d early
  >     revlog._prereadsize = 8           # use revlog.lazyparser
  > EOF

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > commitwrapper = `pwd`/commitwrapper.py
  > EOF

  $ hg init repo1
  $ cd repo1
  $ echo a > a
  $ hg commit -A -m'add a with a long commit message to make the changelog a bit bigger'
  adding a
  new tip: 553596fad57b

Test that new changesets are visible to repo.lookup():

  $ echo a >> a
  $ hg commit -m'one more commit to demonstrate the bug'
  new tip: 799ae3599e0e

  $ hg tip
  changeset:   1:799ae3599e0e
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     one more commit to demonstrate the bug
  

  $ cd ..