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 <axel@mozilla.com> 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.
Test for changeset 9fe267f77f56ff127cf7e65dc15dd9de71ce8ceb
(merge correctly when all the files in a directory are moved
but then local changes are added in the same directory)
$ hg init a
$ cd a
$ mkdir -p testdir
$ echo a > testdir/a
$ hg add testdir/a
$ hg commit -m a
$ cd ..
$ hg clone a b
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd a
$ echo alpha > testdir/a
$ hg commit -m remote-change
$ cd ..
$ cd b
$ mkdir testdir/subdir
$ hg mv testdir/a testdir/subdir/a
$ hg commit -m move
$ mkdir newdir
$ echo beta > newdir/beta
$ hg add newdir/beta
$ hg commit -m local-addition
$ hg pull ../a
pulling from ../a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets cc7000b01af9
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg up -C 2
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg merge
merging testdir/subdir/a and testdir/a to testdir/subdir/a
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg stat
M testdir/subdir/a
$ hg diff --nodates
diff -r bc21c9773bfa testdir/subdir/a
--- a/testdir/subdir/a
+++ b/testdir/subdir/a
@@ -1,1 +1,1 @@
-a
+alpha
$ cd ..