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 {rev}:{node|short}</title>
<link rel="alternate" type="application/atom+xml"
href="{url}atom-log" title="Atom feed for #repo|escape#">
<link rel="alternate" type="application/rss+xml"
href="{url}rss-log" title="RSS feed for #repo|escape#">
</head>
<body>
<div class="page_header">
<a href="http://www.selenic.com/mercurial/" title="Mercurial"><div style="float:right;">Mercurial</div></a><a href="#url#summary{sessionvars%urlparameter}">#repo|escape#</a> / changeset
</div>
<div class="page_nav">
<a href="{url}summary{sessionvars%urlparameter}">summary</a> | <a href="{url}shortlog/#rev#{sessionvars%urlparameter}">shortlog</a> | <a href="{url}log/#rev#{sessionvars%urlparameter}">changelog</a> | <a href="{url}tags{sessionvars%urlparameter}">tags</a> | <a href="{url}file/#node|short#{sessionvars%urlparameter}">manifest</a> | changeset | <a href="{url}raw-rev/#node|short#">raw</a> #archives%archiveentry#<br/>
</div>
<div>
<a class="title" href="{url}raw-rev/#node|short#">#desc|strip|escape|firstline# <span class="logtags">{branches%branchtag}{tags%tagtag}</span></a>
</div>
<div class="title_text">
<table cellspacing="0">
<tr><td>author</td><td>#author|obfuscate#</td></tr>
<tr><td></td><td>#date|date# (#date|age# ago)</td></tr>
<tr><td>changeset {rev}</td><td style="font-family:monospace">{node|short}</td></tr>
#parent%changesetparent#
#child%changesetchild#
</table></div>
<div class="page_body">
#desc|strip|escape|addbreaks#
</div>
<div class="list_head"></div>
<div class="title_text">
<table cellspacing="0">
#files#
</table></div>
<div class="page_body">#diff#</div>
#footer#