convert: fix mercurial_sink.putcommit
Changeset
4ebc8693ce72 added some code to putcommit to avoid creating a
revision that touches no files, but this can break regular conversions
from some repositories:
- conceptually, since we're converting a repo, we should try to make
the new hg repo as similar as possible to the original repo - we
should create a new changeset, even if the original revision didn't
touch any files (maybe the commit message had some important bit);
- even if a "regular" revision that doesn't touch any file may seem
weird (and maybe even broken), it's completely legitimate for a merge
revision to not touch any file, and, if we just skip it, the
converted repo will end up with wrong history and possibly an extra
head.
As an example, say the crew and main hg repos are sync'ed. Somebody
sends an important patch to the mailing list. Matt quickly applies
and pushes it. But at the same time somebody also applies it to crew
and pushes it. Suppose the commit message ended up being a bit
different (say, there was a typo and somebody didn't fix it) or that
the date ended up being different (because of different patch-applying
scripts): the changeset hashes will be different, but the manifests
will be the same.
Since both changesets were pushed to public repos, it's hard to recall
them. If both are merged, the manifest from the resulting merge
revision will have the exact same contents as its parents - i.e. the
merge revision really doesn't touch any file at all.
To keep the file filtering stuff "working", the generic code was changed
to skip empty revisions if we're filtering the repo, fixing a bug in the
process (we want parents[0] instead of tip).
#!/bin/sh
HGMERGE=true; export HGMERGE
hg init basic
cd basic
echo '# should complain'
hg backout
hg backout -r 0 0
echo '# basic operation'
echo a > a
hg commit -d '0 0' -A -m a
echo b >> a
hg commit -d '1 0' -m b
hg backout -d '2 0' tip
cat a
echo '# file that was removed is recreated'
cd ..
hg init remove
cd remove
echo content > a
hg commit -d '0 0' -A -m a
hg rm a
hg commit -d '1 0' -m b
hg backout -d '2 0' --merge tip
cat a
echo '# backout of backout is as if nothing happened'
hg backout -d '3 0' --merge tip
cat a 2>/dev/null || echo cat: a: No such file or directory
echo '# backout with merge'
cd ..
hg init merge
cd merge
echo line 1 > a
hg commit -d '0 0' -A -m a
echo line 2 >> a
hg commit -d '1 0' -m b
echo line 3 >> a
hg commit -d '2 0' -m c
hg backout --merge -d '3 0' 1
hg commit -d '4 0' -m d
cat a
echo '# backout should not back out subsequent changesets'
hg init onecs
cd onecs
echo 1 > a
hg commit -d '0 0' -A -m a
echo 2 >> a
hg commit -d '1 0' -m b
echo 1 > b
hg commit -d '2 0' -A -m c
hg backout -d '3 0' 1
hg locate b
cd ..
hg init m
cd m
echo a > a
hg commit -d '0 0' -A -m a
echo b > b
hg commit -d '1 0' -A -m b
echo c > c
hg commit -d '2 0' -A -m b
hg update 1
echo d > d
hg commit -d '3 0' -A -m c
hg merge 2
hg commit -d '4 0' -A -m d
echo '# backout of merge should fail'
hg backout 4
echo '# backout of merge with bad parent should fail'
hg backout --parent 0 4
echo '# backout of non-merge with parent should fail'
hg backout --parent 0 3
echo '# backout with valid parent should be ok'
hg backout -d '5 0' --parent 2 4
hg rollback
hg update -C
hg backout -d '6 0' --parent 3 4
exit 0