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.
6:755d1e0d79e9
5:9ce2ce29723a 3:a3e00c7dbf11 4:bb4475edb621
4:bb4475edb621 1:5d953a1917d1
3:a3e00c7dbf11
2:befc7d89d081
1:5d953a1917d1
0:837088b6e1d9
should work with tag/branch/node/rev
tip^: 5
default^: 5
755d1e0d79e9^: 5
6^: 5
some random lookups
6^^: 3
6^^^: 2
6^^^^: 1
6^^^^^: 0
6^^^^^^: -1
6^1: 5
6^2: abort: unknown revision '6^2'!
6^^2: 4
6^1^2: 4
6^^3: abort: unknown revision '6^^3'!
6~: abort: unknown revision '6~'!
6~1: 5
6~2: 3
6~3: 2
6~4: 1
6~5: 0
6~42: -1
6~1^2: 4
6~1^2~2: 0
with a tag "6^" pointing to rev 1
6^: 1
6^1: 5
6~1: 5
6^^: 3
with a tag "foo^bar" pointing to rev 2
foo^bar: 2
foo^bar^: abort: unknown revision 'foo^bar^'!