rust-index: using the `hg::index::Index` in ancestors iterator and lazy set
Since there is no Rust implementation for REVLOGV2/CHANGELOGv2, we declare
them to be incompatible with Rust, hence indexes in these formats will use
the implementations from Python `mercurial.ancestor`. If this is an unacceptable
performance hit for current users of these formats, we can later on add Rust
implementations based on the C index for them or implement these formats for
the Rust indexes.
Among the challenges that we had to meet, we wanted to avoid taking the GIL each
time the inner (vcsgraph) iterator has to call the parents function. This would probably
still be acceptable in terms of performance with `AncestorsIterator`, but not with
`LazyAncestors` nor for the upcoming change in `MissingAncestors`.
Hence we enclose the reference to the index in a `PySharedRef`, leading to more
rigourous checking of mutations, which does pass now that there no logically immutable
methods of `hg::index::Index` that take a mutable reference as input.
#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
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 ..