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