Re: [PATCH] git-completion.bash: always swallow error output of for-each-ref

From: SZEDER Gábor <szeder@ira.uka.de>
Date: Feb 13, 2016, 13:53 UTC
Message-ID: <20160213145333.Horde.ZTzk8ajnzz2uB2UcNeCdPtB@webmail.informatik.kit.edu>
In-Reply-To: <alpine.DEB.2.20.1602131021170.2964@virtualbox>

Quoting Johannes Schindelin <Johannes.Schindelin@gmx.de>:

Show 17 quoted lines

> Hi Gábor,
>
> On Sat, 13 Feb 2016, SZEDER Gábor wrote:
>
>>  $ cur=m ; time __gitcomp_nl "$(__git_refs '' 1)"
>>
>>  real  0m7.641s
>>  user  0m5.888s
>>  sys   0m1.832s
>>
>> Using 'refname:strip=2' for both 'git for-each-ref' in __git_refs():
>>
>>  $ cur=m ; time __gitcomp_nl "$(__git_refs '' 1)"
>>
>>  real  0m2.848s
>>  user  0m2.308s
>>  sys   0m0.596s

I timed this one using a version that already included one from those "few more tricks", so the change from ':short' to ':strip=2' alone doesn't bring quite as much:

   $ cur=m ; time __gitcomp_nl "$(__git_refs '' 1)"

   real  0m3.645s
   user  0m3.140s
   sys   0m0.588s

Show 9 quoted lines

>> Quick'n'dirty PoC using 'refname:strip', '**' globbing and a few more
>> tricks to let 'git for-each-ref' do the filtering instead of the
>> shell loop behind __gitcomp_nl():
>>
>>  $ cur=m ; time IFS=$'\n' COMPREPLY=( $(__git_refs_PoC '' 1) )
>>
>>  real  0m0.247s
>>  user  0m0.208s
>>  sys   0m0.032s

And this one now looks like:

   $ cur=m ; time __gitcomp_direct "$(__git_refs_PoC '' 1)"

The timing results are the same.

> May I have that patch, please? ;-)

It's early days, and when I say proof of concept I mean it :) For now it only works for refs from the local repository, and only when the ref to be completed is on its own on the command line (i.e. not for 'git log master..<TAB>' or 'commit --fixup=<TAB>'), and the trailing space is hardcoded, and ... though, arguably, that already covers the majority of the cases. I only switched 'git checkout' to use this optimized version, because that was the worst offender.

So I won't send patches to the list just now, but you or anyone interested can take a peek at:

   https://github.com/szeder/git.git completion-PoC-refs-speedup

Maybe even run some numbers on Windows?

Gábor