Re: [StGIT PATCH] Bash snippet to show branch and patch in bash prompt

[Catalin Marinas <catalin.marinas@arm.com>]

Eran Tromer <git2eran@tromer.org> wrote:
> On 2006-10-30 01:37, Robin Rosenberg wrote:
>> +# include this in your bashrc or copy to /etc/bash_completions.d
>> +
>> +if [ "$PS1" ]; then
>> +    # trap 'PS1="\u@\h [$(stg top)] \w]\$ "' DEBUG
>> +    function stgtag
>> +    {
>> +	br=$(stg branch 2>/dev/null)
>> +	top=$(stg top 2>/dev/null)
>> +	if [[ -n "$br$top" ]];then
>> +	    echo "[$top@$br]"
>> +	    return
>> +	fi
>> +    }
>> +    PS1='\u@\h$(stgtag)\w\$ '
>> +
>> +fi
>
> That's an annoying 430ms delay at every prompt, on my box. Does StGIT do
> something expensive on every invocation?

Well, there are some forks. For every "stg" command, "git-symbolic-ref
HEAD" and "git-rev-parse --git-dir" are invoked to get the name of the
main branch and the .git directory. There is also the delay of
invoking python and loading the command modules in main.py (maybe I
should modify this to import the modules on demand, based on what
command was given).

Since the repository format is stable, you could use something like
this (it should be faster):

git_dir=$(git-rev-parse --git-dir 2> /dev/null)
ref=$(git-symbolic-ref HEAD 2> /dev/null)
br=${ref##*/}
top=$(cat $git_dir/patches/$br/current)

--