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.
adding a
# missing arg
hg cat: invalid arguments
hg cat [OPTION]... FILE...
output the current or given revision of files
Print the specified files as they were at the given revision.
If no revision is given, the parent of the working directory is used,
or tip if no revision is checked out.
Output may be to a file, in which case the name of the file is
given using a format string. The formatting rules are the same as
for the export command, with the following additions:
%s basename of file being printed
%d dirname of file being printed, or '.' if in repo root
%p root-relative path name of file being printed
options:
-o --output print output to file with formatted name
-r --rev print the given revision
-I --include include names matching the given patterns
-X --exclude exclude names matching the given patterns
use "hg -v help cat" to show global options
% [defaults]
a
a
% no repo
abort: There is no Mercurial repository here (.hg not found)!