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 foo > a
hg add a
hg commit -m "1" -d "1000000 0"
echo bar > b
hg add b
hg remove a
echo "%%% should show a removed and b added"
hg status
echo "reverting..."
hg revert --all
echo "%%% should show b unknown and a back to normal"
hg status
rm b
hg co -C 0
echo foo-a > a
hg commit -m "2a" -d "1000000 0"
hg co -C 0
echo foo-b > a
hg commit -m "2b" -d "1000000 0"
HGMERGE=true hg merge 1
echo "%%% should show foo-b"
cat a
echo bar > b
hg add b
rm a
hg remove a
echo "%%% should show a removed and b added"
hg status
echo "%%% revert should fail"
hg revert --all
echo "%%% revert should be ok now"
hg revert -r2 --all
echo "%%% should show b unknown and a marked modified (merged)"
hg status
echo "%%% should show foo-b"
cat a