Re: [PATCH] git: Pass prefix filter to ls-files even if it matches no files

[Torstein Hegge <hegge@resisty.net>]

On Sun, Mar 17, 2013 at 13:35:25 +0100, Torstein Hegge wrote:
> When a branch or tag name is completed with zsh in a large git repo, the
> completion is slow if the given prefix doesn't match a file or directory in
> the current working directory. Testing with linux.git, which contains release
> tags like v3.9 and a directory virt/:
> 
>   git log v<tab>
> 
> takes about 0.5 seconds, while
> 
>   git log v3<tab>
> 
> takes about 25 seconds.
> 
> (Timed using zsh 4.3.17, on a fairly slow cpu. zsh from git appears to be
> quite a bit faster, but the difference between completing v and v3 is still
> large.)
> 
> The difference between the two is that v<tab> passes the result of v* to git
> ls-files while v3<tab> determines that v3* matches no files, and passes an
> empty prefix to git ls-files. So git ls-files lists all files in the repo
> and passes that on to _multi_parts.
> 
> Making git do the expansion of the * after the prefix lets git ls-files v3*
> return an empty list, making _multi_parts job easier.
> 
> This does not affect the behavior of git log <tab>, but improves the
> performance of partial tag and branch tab-completion in the common case where
> file names and tag/branch names don't overlap.
> ---

No interest in this? Or did I miss something obvious?

>  Completion/Unix/Command/_git |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/Completion/Unix/Command/_git b/Completion/Unix/Command/_git
> index 2b6a369..d736367 100644
> --- a/Completion/Unix/Command/_git
> +++ b/Completion/Unix/Command/_git
> @@ -5339,7 +5339,7 @@ __git_files () {
>    # TODO: --directory should probably be added to $opts when --others is given.
>  
>    local pref=$gitcdup$gitprefix$PREFIX
> -  files=(${(0)"$(_call_program files git ls-files -z --exclude-standard $opts -- ${pref:+$pref\*} 2>/dev/null)"})
> +  files=(${(0)"$(_call_program files git ls-files -z --exclude-standard $opts -- ${pref:+$pref\\\*} 2>/dev/null)"})
>    __git_command_successful $pipestatus || return
>  
>  #  _wanted $tag expl $description _files -g '{'${(j:,:)files}'}' $compadd_opts -
> -- 
> 1.7.10.4
> 
>