On my slow laptop (P3 600MHz), system-wide bash completions take
too much time to load (> 2s), and a significant fraction of this
time is spent loading git-completion.bash:
$ time bash -c ". ./git-completion.bash" # hot cache, before this patch
real 0m0.509s
user 0m0.310s
sys 0m0.180s
Kirill noticed that most of the time is spent warming up
merge_strategy, all_command & porcelain_command caches.
Since git is not used in each and every interactive xterm, it
seems best to load completion support with cold caches, and then
load each needed thing lazily. This has most of the speed
advantage of pre-generating everything at build time, without the
complication of figuring out at build time what commands will be
available at run time.
The result is that loading completion is significantly faster
now:
$ time bash -c ". ./git-completion.bash" # cold cache, after this patch
real 0m0.171s
user 0m0.060s
sys 0m0.040s
Suggested-by: Kirill Smelkov <kirr@xxxxxxxxxx>
Cc: Shawn O. Pearce <spearce@xxxxxxxxxxx>
Cc: Stephen Boyd <bebarino@xxxxxxxxx>
Cc: Sverre Rabbelier <srabbelier@xxxxxxxxx>
Cc: Junio C Hamano <junio@xxxxxxxxx>
Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
---
Jonathan Nieder wrote:
> Stephen Boyd wrote:
>> Ah ok. I think this proves even more that pregenerating the
>> completion is a bad idea. With dynamic population we don't have
>> these problems and it only takes 250ms more to load on a P3
>> 700Mhz.
>
> Hmm, 250 ms is a lot.
Here’s the real patch. Sorry about that.
Jonathan
contrib/completion/git-completion.bash | 67 +++++++++++++++----------------
1 files changed, 32 insertions(+), 35 deletions(-)
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index e3ddecc..7088ec7 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -21,13 +21,7 @@
# 2) Added the following line to your .bashrc:
# source ~/.git-completion.sh
#
-# 3) You may want to make sure the git executable is available
-# in your PATH before this script is sourced, as some caching
-# is performed while the script loads. If git isn't found
-# at source time then all lookups will be done on demand,
-# which may be slightly slower.
-#
-# 4) Consider changing your PS1 to also show the current branch:
+# 3) Consider changing your PS1 to also show the current branch:
# PS1='[\u@\h \W$(__git_ps1 " (%s)")]\$ '
#
# The argument to __git_ps1 will be displayed only if you
@@ -324,12 +318,8 @@ __git_remotes ()
done
}
-__git_merge_strategies ()
+__git_list_merge_strategies ()
{
- if [ -n "${__git_merge_strategylist-}" ]; then
- echo "$__git_merge_strategylist"
- return
- fi
git merge -s help 2>&1 |
sed -n -e '/[Aa]vailable strategies are: /,/^$/{
s/\.$//
@@ -339,8 +329,11 @@ __git_merge_strategies ()
p
}'
}
-__git_merge_strategylist=
-__git_merge_strategylist=$(__git_merge_strategies 2>/dev/null)
+
+__git_compute_merge_strategies ()
+{
+ : ${__git_merge_strategies=$(__git_list_merge_strategies)}
+}
__git_complete_file ()
{
@@ -474,27 +467,24 @@ __git_complete_remote_or_refspec ()
__git_complete_strategy ()
{
+ __git_compute_merge_strategies
case "${COMP_WORDS[COMP_CWORD-1]}" in
-s|--strategy)
- __gitcomp "$(__git_merge_strategies)"
+ __gitcomp "$__git_merge_strategies"
return 0
esac
local cur="${COMP_WORDS[COMP_CWORD]}"
case "$cur" in
--strategy=*)
- __gitcomp "$(__git_merge_strategies)" "" "${cur##--strategy=}"
+ __gitcomp "$__git_merge_strategies" "" "${cur##--strategy=}"
return 0
;;
esac
return 1
}
-__git_all_commands ()
+__git_list_all_commands ()
{
- if [ -n "${__git_all_commandlist-}" ]; then
- echo "$__git_all_commandlist"
- return
- fi
local i IFS=" "$'\n'
for i in $(git help -a|egrep '^ [a-zA-Z0-9]')
do
@@ -504,17 +494,17 @@ __git_all_commands ()
esac
done
}
-__git_all_commandlist=
-__git_all_commandlist="$(__git_all_commands 2>/dev/null)"
-__git_porcelain_commands ()
+__git_compute_all_commands ()
+{
+ : ${__git_all_commands=$(__git_list_all_commands)}
+}
+
+__git_list_porcelain_commands ()
{
- if [ -n "${__git_porcelain_commandlist-}" ]; then
- echo "$__git_porcelain_commandlist"
- return
- fi
local i IFS=" "$'\n'
- for i in "help" $(__git_all_commands)
+ __git_compute_all_commands
+ for i in "help" $__git_all_commands
do
case $i in
*--*) : helper pattern;;
@@ -595,8 +585,11 @@ __git_porcelain_commands ()
esac
done
}
-__git_porcelain_commandlist=
-__git_porcelain_commandlist="$(__git_porcelain_commands 2>/dev/null)"
+
+__git_compute_porcelain_commands ()
+{
+ : ${__git_porcelain_commands=$(__git_list_porcelain_commands)}
+}
__git_aliases ()
{
@@ -1088,7 +1081,8 @@ _git_help ()
return
;;
esac
- __gitcomp "$(__git_all_commands)
+ __git_compute_all_commands
+ __gitcomp "__git_all_commands
attributes cli core-tutorial cvs-migration
diffcore gitk glossary hooks ignore modules
repository-layout tutorial tutorial-2
@@ -1444,7 +1438,8 @@ _git_config ()
return
;;
pull.twohead|pull.octopus)
- __gitcomp "$(__git_merge_strategies)"
+ __git_compute_merge_strategies
+ __gitcomp "$__git_merge_strategies"
return
;;
color.branch|color.diff|color.interactive|\
@@ -1545,7 +1540,8 @@ _git_config ()
pager.*)
local pfx="${cur%.*}."
cur="${cur#*.}"
- __gitcomp "$(__git_all_commands)" "$pfx" "$cur"
+ __git_compute_all_commands
+ __gitcomp "__git_all_commands" "$pfx" "$cur"
return
;;
remote.*.*)
@@ -2142,7 +2138,8 @@ _git ()
--help
"
;;
- *) __gitcomp "$(__git_porcelain_commands) $(__git_aliases)" ;;
+ *) __git_compute_porcelain_commands
+ __gitcomp "$__git_porcelain_commands $(__git_aliases)" ;;
esac
return
fi
--
1.6.5.2
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