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.
<div>
<a class="title" href="{url}rev/#node|short#{sessionvars%urlparameter}"><span class="age">#date|age# ago</span>#desc|strip|firstline|escape#<span class="logtags"> {branches%branchtag}{tags%tagtag}</span></a>
</div>
<div class="title_text">
<div class="log_link">
<a href="{url}rev/#node|short#{sessionvars%urlparameter}">changeset</a><br/>
</div>
<i>#author|obfuscate# [#date|rfc822date#] rev #rev#</i><br/>
</div>
<div class="log_body">
#desc|strip|escape|addbreaks#
<br/>
<br/>
</div>