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
echo "[extensions]" >> $HGRCPATH
echo "extdiff=" >> $HGRCPATH
hg init a
cd a
echo a > a
echo b > b
hg add
# should diff cloned directories
hg extdiff -o -r $opt
echo "[extdiff]" >> $HGRCPATH
echo "cmd.falabala=echo" >> $HGRCPATH
echo "opts.falabala=diffing" >> $HGRCPATH
hg falabala
hg help falabala
hg ci -d '0 0' -mtest1
echo b >> a
hg ci -d '1 0' -mtest2
# should diff cloned files directly
hg falabala -r 0:1
# test diff during merge
hg update 0
echo c >> c
hg add c
hg ci -m "new branch" -d '1 0'
hg update -C 1
hg merge tip
# should diff cloned file against wc file
hg falabala > out || echo "diff-like tools yield a non-zero exit code"
# cleanup the output since the wc is a tmp directory
sed 's:\(.* \).*\(\/test-extdiff\):\1[tmp]\2:' out