[PATCH] Speedup bash completion loading

From: Kirill Smelkov <kirr@mns.spb.ru>
Date: Oct 5, 2009, 10:03 UTC
Message-ID: <1254737039-10404-1-git-send-email-kirr@mns.spb.ru>

On my slow laptop (P3 700MHz), system-wide bash completions take too much time to load (> 1s), and significant fraction of this time is spent loading git-completion.bash:

    $ time bash -c '. git-completion.bash'  # before this patch

    real    0m0.317s
    user    0m0.250s
    sys     0m0.060s

I've tracked down that the most time is spent warming up merge_strategy, all_command & porcelain_command caches.

Since git is not used in each and every interactive xterm, I think it would be perfectly ok to load completion support with cold caches, and then load needed thing lazily.

As __git_merge_stratiegies(), __git_all_commands() & __git_porcelain_command() already cache their results, we can safely remove associated cache initialization code and be done with it:

    $ time bash -c '. git-completion.bash'  # after this patch

    real    0m0.069s
    user    0m0.050s
    sys     0m0.020s

Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
---
 contrib/completion/git-completion.bash |    3 ---
 1 files changed, 0 insertions(+), 3 deletions(-)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 2c2a0d4..4c09d41 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -340,7 +340,6 @@ __git_merge_strategies ()
 	}'
 }
 __git_merge_strategylist=
-__git_merge_strategylist=$(__git_merge_strategies 2>/dev/null)
 
 __git_complete_file ()
 {
@@ -505,7 +504,6 @@ __git_all_commands ()
 	done
 }
 __git_all_commandlist=
-__git_all_commandlist="$(__git_all_commands 2>/dev/null)"
 
 __git_porcelain_commands ()
 {
@@ -596,7 +594,6 @@ __git_porcelain_commands ()
 	done
 }
 __git_porcelain_commandlist=
-__git_porcelain_commandlist="$(__git_porcelain_commands 2>/dev/null)"
 
 __git_aliases ()
 {

-- 
1.6.5.rc2.17.gdbc1b