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.
#header#
<title>#repo|escape#: changeset #node|short#</title>
</head>
<body>
<div class="buttons">
<a href="?cl=#rev#">changelog</a>
<a href="?sl=#rev#">shortlog</a>
<a href="?cmd=tags">tags</a>
<a href="?mf=#node|short#;path=/">manifest</a>
<a href="?cs=#node|short#;style=raw">raw</a>
#archives%archiveentry#
</div>
<h2>changeset: #desc|strip|escape|firstline#</h2>
<table id="changesetEntry">
<tr>
<th class="changeset">changeset #rev#:</th>
<td class="changeset"><a href="?cs=#node|short#">#node|short#</a></td>
</tr>
#parent%changesetparent#
#child%changesetchild#
#changesettag#
<tr>
<th class="author">author:</th>
<td class="author">#author|obfuscate#</td>
</tr>
<tr>
<th class="date">date:</th>
<td class="date">#date|date# (#date|age# ago)</td></tr>
<tr>
<th class="files">files:</th>
<td class="files">#files#</td></tr>
<tr>
<th class="description">description:</th>
<td class="description">#desc|strip|escape|addbreaks#</td>
</tr>
</table>
<div id="changesetDiff">
#diff#
</div>
#footer#