git-commit-vandalism/contrib
Florian Gamböck 085e2ee0e6 completion: load completion file for external subcommand
Adding external subcommands to Git is as easy as to put an executable
file git-foo into PATH. Packaging such subcommands for a Linux
distribution can be achieved by unpacking the executable into /usr/bin
of the user's system. Adding system-wide completion scripts for new
subcommands, however, can be a bit tricky.

Since bash-completion started to use dynamical loading of completion
scripts since v1.90 (preview of v2.0), it is no longer sufficient to
drop a completion script of a subcommand into the standard completions
path, /usr/share/bash-completion/completions, since this script will not
be loaded if called as a git subcommand.

For example, look at https://bugs.gentoo.org/544722. To give a short
summary: The popular git-flow subcommand provides a completion script,
which gets installed as /usr/share/bash-completion/completions/git-flow.

If you now type into a Bash shell:

    git flow <TAB>

You will not get any completions, because bash-completion only loads
completions for git and git has no idea that git-flow is defined in
another file. You have to load this script manually or trigger the
dynamic loader with:

    git-flow <TAB> # Please notice the dash instead of whitespace

This will not complete anything either, because it only defines a Bash
function, without generating completions. But now the correct completion
script has been loaded and the first command can use the completions.

So, the goal is now to teach the git completion script to consider the
possibility of external completion scripts for subcommands, but of
course without breaking current workflows.

I think the easiest method is to use a function that was defined by
bash-completion v1.90, namely _completion_loader. It will take care of
loading the correct script if present. Afterwards, the git completion
script behaves as usual.

_completion_loader was introduced in commit 20c05b43 of bash-completion
(https://github.com/scop/bash-completion.git) back in 2011, so it should
be available in even older LTS distributions. This function searches for
external completion scripts not only in the default path
/usr/share/bash-completion/completions, but also in the user's home
directory via $XDG_DATA_HOME and in a user specified directory via
$BASH_COMPLETION_USER_DIR.

The only "drawback" (if it even can be called as such) is, that if
_completion_loader does not find a completion script, it automatically
registers a minimal function for basic path completion. In practice,
however, this will not matter, because in this case the given command is
a git command in its dashed form, e.g. 'git-diff-index', and those have
been deprecated for a long time.

This way we can leverage bash-completion's dynamic loading for git
subcommands and make it easier for developers to distribute custom
completion scripts.

Signed-off-by: Florian Gamböck <mail@floga.de>
Acked-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-05-07 23:24:45 +09:00
..
buildsystems mark Windows build scripts executable 2013-11-25 15:01:22 -08:00
coccinelle Merge branch 'rs/cocci-strbuf-addf-to-addstr' 2018-02-15 14:55:44 -08:00
completion completion: load completion file for external subcommand 2018-05-07 23:24:45 +09:00
contacts git-contacts: also recognise "Reported-by:" 2017-07-27 09:42:55 -07:00
credential Merge branch 'tz/fsf-address-update' into maint 2017-11-21 14:05:32 +09:00
diff-highlight diff-highlight: add clean target to Makefile 2017-09-06 12:56:26 +09:00
emacs Replace Free Software Foundation address in license notices 2017-11-09 13:21:21 +09:00
examples Merge branch 'ab/perl-fixes' 2018-03-15 15:00:46 -07:00
fast-import Replace Free Software Foundation address in license notices 2017-11-09 13:21:21 +09:00
git-jump git-jump: give contact instructions in the README 2017-11-21 11:01:02 +09:00
git-shell-commands
hg-to-git Replace Free Software Foundation address in license notices 2017-11-09 13:21:21 +09:00
hooks hooks/pre-auto-gc-battery: allow gc to run on non-laptops 2018-02-28 14:24:46 -08:00
long-running-filter docs: warn about possible '=' in clean/smudge filter process values 2016-12-06 11:29:52 -08:00
mw-to-git Merge branch 'ab/mediawiki-namespace' 2017-11-15 12:14:32 +09:00
persistent-https docs/config: mention protocol implications of url.insteadOf 2017-06-01 10:07:10 +09:00
remote-helpers contrib: git-remote-{bzr,hg} placeholders don't need Python 2017-03-03 11:09:34 -08:00
stats
subtree Merge branch 'sg/subtree-signed-commits' 2018-03-08 12:36:25 -08:00
svn-fe contrib/svn-fe: fix Makefile 2014-08-28 15:41:28 -07:00
thunderbird-patch-inline contrib/thunderbird-patch-inline/appp.sh: use the $( ... ) construct for command substitution 2015-12-27 15:33:13 -08:00
update-unicode update_unicode.sh: remove the plane filter 2016-12-14 09:48:07 -08:00
workdir git-new-workdir: mark script as LF-only 2017-05-10 13:32:50 +09:00
convert-grafts-to-replace-refs.sh contrib: add convert-grafts-to-replace-refs.sh 2014-07-21 12:05:53 -07:00
git-resurrect.sh Merge branch 'jc/bs-t-is-not-a-tab-for-sed' 2017-04-16 23:29:29 -07:00
README
remotes2config.sh
rerere-train.sh contrib/rerere-train: optionally overwrite existing resolutions 2017-07-26 13:38:48 -07:00

Contributed Software

Although these pieces are available as part of the official git
source tree, they are in somewhat different status.  The
intention is to keep interesting tools around git here, maybe
even experimental ones, to give users an easier access to them,
and to give tools wider exposure, so that they can be improved
faster.

I am not expecting to touch these myself that much.  As far as
my day-to-day operation is concerned, these subdirectories are
owned by their respective primary authors.  I am willing to help
if users of these components and the contrib/ subtree "owners"
have technical/design issues to resolve, but the initiative to
fix and/or enhance things _must_ be on the side of the subtree
owners.  IOW, I won't be actively looking for bugs and rooms for
enhancements in them as the git maintainer -- I may only do so
just as one of the users when I want to scratch my own itch.  If
you have patches to things in contrib/ area, the patch should be
first sent to the primary author, and then the primary author
should ack and forward it to me (git pull request is nicer).
This is the same way as how I have been treating gitk, and to a
lesser degree various foreign SCM interfaces, so you know the
drill.

I expect that things that start their life in the contrib/ area
to graduate out of contrib/ once they mature, either by becoming
projects on their own, or moving to the toplevel directory.  On
the other hand, I expect I'll be proposing removal of disused
and inactive ones from time to time.

If you have new things to add to this area, please first propose
it on the git mailing list, and after a list discussion proves
there are some general interests (it does not have to be a
list-wide consensus for a tool targeted to a relatively narrow
audience -- for example I do not work with projects whose
upstream is svn, so I have no use for git-svn myself, but it is
of general interest for people who need to interoperate with SVN
repositories in a way git-svn works better than git-svnimport),
submit a patch to create a subdirectory of contrib/ and put your
stuff there.

-jc