convert: fix mercurial_sink.putcommit Changeset 4ebc8693ce72 added some code to putcommit to avoid creating a revision that touches no files, but this can break regular conversions from some repositories: - conceptually, since we're converting a repo, we should try to make the new hg repo as similar as possible to the original repo - we should create a new changeset, even if the original revision didn't touch any files (maybe the commit message had some important bit); - even if a "regular" revision that doesn't touch any file may seem weird (and maybe even broken), it's completely legitimate for a merge revision to not touch any file, and, if we just skip it, the converted repo will end up with wrong history and possibly an extra head. As an example, say the crew and main hg repos are sync'ed. Somebody sends an important patch to the mailing list. Matt quickly applies and pushes it. But at the same time somebody also applies it to crew and pushes it. Suppose the commit message ended up being a bit different (say, there was a typo and somebody didn't fix it) or that the date ended up being different (because of different patch-applying scripts): the changeset hashes will be different, but the manifests will be the same. Since both changesets were pushed to public repos, it's hard to recall them. If both are merged, the manifest from the resulting merge revision will have the exact same contents as its parents - i.e. the merge revision really doesn't touch any file at all. To keep the file filtering stuff "working", the generic code was changed to skip empty revisions if we're filtering the repo, fixing a bug in the process (we want parents[0] instead of tip).

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)!