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.
HGMERGE(1)
==========
Matt Mackall <mpm@selenic.com>
v0.1, 27 May 2005
NAME
----
hgmerge - default wrapper to merge files in Mercurial SCM system
SYNOPSIS
--------
'hgmerge' local ancestor remote
DESCRIPTION
-----------
The hgmerge(1) command provides a graphical interface to merge files in the
Mercurial system. It is a simple wrapper around kdiff3, merge(1) and tkdiff(1),
or simply diff(1) and patch(1) depending on what is present on the system.
hgmerge(1) is used by the Mercurial SCM if the environment variable HGMERGE is
not set.
AUTHOR
------
Written by Vincent Danjean <Vincent.Danjean@free.fr>
SEE ALSO
--------
hg(1) - the command line interface to Mercurial SCM
COPYING
-------
Copyright \(C) 2005-2007 Matt Mackall.
Free use of this software is granted under the terms of the GNU General
Public License (GPL).