On 2018-04-18 21:51, SZEDER Gábor wrote:
On Tue, Apr 10, 2018 at 10:28 PM, Florian Gamböck <mail@xxxxxxxx>
wrote:
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),
I believe the main bash-completion repository can be found at:
https://github.com/scop/bash-completion.git
This repository still contains the branch 'dynamic-loading'; for the
record it points to 3b029892f6f9db3b7210a7f66d636be3e5ec5fa2.
Two commits on that branch are worth mentioning:
20c05b43 (Load completions in separate files dynamically, get rid of
have()., 2011-10-12)
5baebf81 (Add _xfunc for loading and calling functions on demand,
use it in apt-get, cvsps, rsync, and sshfs., 2011-10-13)
Nice, thanks for the pointers!
(...)
I think the easiest method is to use a function that is defined by
bash-completion v2.0+, namely __load_completion.
This is wrong, __load_completion() was introduced in cad3abfc
(__load_completion: New function, use in _completion_loader and
_xfunc, 2015-07-15), and the first release tag containg it is '2.2'
from 2016-03-03.
Dang, I thought it was introduced at the same time. Sorry for that. I
guess, 2016 is a bit too young to take it for granted then?
The release tags '1.90' and '2.0' are from 2011-11-03 and 2012-06-17,
respectively. This leaves a couple of years long hole where
completions were already loaded dynamically but there was no
__load_completion() function.
Would it be possible to use _xfunc() instead to plug that hole? It
seems the be tricky, because that function not only sources but also
_calls_ the completion function.
But isn't this exactly what we want? Lucky us, we can replace the whole
if-fi block with a simpler:
_xfunc git-$command $completion_func 2>/dev/null && return
If _xfunc is not defined -- as in, bashcomp is not installed / loaded --
then the return will not get called and the original completion will
continue:
declare -f $completion_func >/dev/null 2>/dev/null &&
$completion_func && return
Since this would be redundant, we could define a fall-back for _xfunc
like so:
declare -f _xfunc || _xfunc() {
declare -f $completion_func >/dev/null 2>/dev/null &&
$completion_func && return
}
This way, we retain the "old" behavior and get dynamic loading if
bashcomp is available. The actual call to get the completions would just
be _xfunc like in my first example above.
What do you think?
--
Regards
Florian
