convert: add a mode where mercurial_sink skips empty revisions.
The getchanges function of some converter_source classes can return
some false positives. I.e. they sometimes claim that a file "foo"
was changed in some revision, even though its contents are still the
same.
convert_svn is particularly bad, but I think this can also happen with
convert_cvs and, at least in theory, with mercurial_source.
For regular conversions this is not really a problem - as long as
getfile returns the right contents, we'll get a converted revision
with the right contents. But when we use --filemap, this could lead
to superfluous revisions being converted.
Instead of fixing every converter_source, I decided to change
mercurial_sink to work around this problem.
When --filemap is used, we're interested only in revisions that touch
some specific files. If a revision doesn't change any of these files,
then we're not interested in it (at least for revisions with a single
parent; merges are special).
For mercurial_sink, we abuse this property and rollback a commit if
the manifest text hasn't changed. This avoids duplicating the logic
from localrepo.filecommit to detect unchanged files.
#!/bin/sh
hg init
echo "# revision 0"
echo "unchanged" > unchanged
echo "remove me" > remove
echo "copy me" > copy
echo "move me" > move
for i in 1 2 3 4 5 6 7 8 9; do
echo "merge ok $i" >> zzz1_merge_ok
done
echo "merge bad" > zzz2_merge_bad
hg ci -Am "revision 0" -d "1000000 0"
echo "# revision 1"
hg rm remove
hg mv move moved
hg cp copy copied
echo "added" > added
hg add added
echo "new first line" > zzz1_merge_ok
hg cat zzz1_merge_ok >> zzz1_merge_ok
echo "new last line" >> zzz2_merge_bad
hg ci -m "revision 1" -d "1000000 0"
echo "# local changes to revision 0"
hg co 0
echo "new last line" >> zzz1_merge_ok
echo "another last line" >> zzz2_merge_bad
hg diff --nodates | grep "^[+-][^<>]"
hg st
echo "# local merge with bad merge tool"
HGMERGE=false hg co
hg co 0
hg diff --nodates | grep "^[+-][^<>]"
hg st
echo "# local merge with conflicts"
hg co
hg co 0
hg diff --nodates | grep "^[+-][^<>]"
hg st
echo "# local merge without conflicts"
hg revert zzz2_merge_bad
hg co
hg diff --nodates | grep "^[+-][^<>]"
hg st