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
cat >findbranch.py <<EOF
import re, sys
head_re = re.compile('^#(?:(?:\\s+([A-Za-z][A-Za-z0-9_]*)(?:\\s.*)?)|(?:\\s*))$')
for line in sys.stdin:
hmatch = head_re.match(line)
if not hmatch:
sys.exit(1)
if hmatch.group(1) == 'Branch':
sys.exit(0)
sys.exit(1)
EOF
hg init a
cd a
echo "Rev 1" >rev
hg add rev
hg commit -m "No branch."
hg branch abranch
echo "Rev 2" >rev
hg commit -m "With branch."
if hg export 0 | python ../findbranch.py; then
echo "Export of default branch revision has Branch header" 1>&2
exit 1
fi
if hg export 1 | python ../findbranch.py; then
: # Do nothing
else
echo "Export of branch revision is missing Branch header" 1>&2
exit 1
fi
# Make sure import still works with branch information in patches.
cd ..
hg init b
cd b
hg -R ../a export 0 | hg import -
hg -R ../a export 1 | hg import -
cd ..
rm -rf b
hg init b
cd b
hg -R ../a export 0 | hg import --exact -
hg -R ../a export 1 | hg import --exact -