view tests/test-issue1802.t @ 39473:b6db2e80a9ce

ancestors: actually iterate over ancestors in topological order (issue5979)

This code previously used a dequeue logic, the first ancestors seen were the
first ancestors to be emitted. In branching/merging situations, it can result
in ancestors being yielded before their descendants, breaking the object
contract.

We got affected by this issue while working on the copy tracing code. At about
the same time, Axel Hecht <[e-mail]> reported the issue and provided
the test case used in this changeset. Thanks Axel.

Running `hg perfancestors` does not show a significant difference between the
old and the new version.

#require execbit

Create extension that can disable exec checks:

  $ cat > noexec.py <<EOF
  > from mercurial import extensions, util
  > def setflags(orig, f, l, x):
  >     pass
  > def checkexec(orig, path):
  >     return False
  > def extsetup(ui):
  >     extensions.wrapfunction(util, 'setflags', setflags)
  >     extensions.wrapfunction(util, 'checkexec', checkexec)
  > EOF

  $ hg init unix-repo
  $ cd unix-repo
  $ touch a
  $ hg add a
  $ hg commit -m 'unix: add a'
  $ hg clone . ../win-repo
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ chmod +x a
  $ hg commit -m 'unix: chmod a'
  $ hg manifest -v
  755 * a

  $ cd ../win-repo

  $ touch b
  $ hg add b
  $ hg commit -m 'win: add b'

  $ hg manifest -v
  644   a
  644   b

  $ hg pull
  pulling from $TESTTMP/unix-repo
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files (+1 heads)
  new changesets 2d8bcf2dda39
  (run 'hg heads' to see heads, 'hg merge' to merge)

  $ hg manifest -v -r tip
  755 * a

Simulate a Windows merge:

  $ hg --config extensions.n=$TESTTMP/noexec.py merge --debug
    searching for copies back to rev 1
    unmatched files in local:
     b
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: a03b0deabf2b, local: d6fa54f68ae1+, remote: 2d8bcf2dda39
   a: update permissions -> e
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

Simulate a Windows commit:

  $ hg --config extensions.n=$TESTTMP/noexec.py commit -m 'win: merge'

  $ hg manifest -v
  755 * a
  644   b

  $ cd ..