completion: add new __git_complete helper

This simplifies the completions, and would make it easier to define
aliases in the future.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/completion/git-completion.bash

@@ -2603,21 +2603,6 @@ _git ()
 {
 	local i c=1 command __git_dir
 
-	if [[ -n ${ZSH_VERSION-} ]]; then
-		emulate -L bash
-		setopt KSH_TYPESET
-
-		# workaround zsh's bug that leaves 'words' as a special
-		# variable in versions < 4.3.12
-		typeset -h words
-
-		# workaround zsh's bug that quotes spaces in the COMPREPLY
-		# array if IFS doesn't contain spaces.
-		typeset -h IFS
-	fi
-
-	local cur words cword prev
-	_get_comp_words_by_ref -n =: cur words cword prev
 	while [ $c -lt $cword ]; do
 		i="${words[c]}"
 		case "$i" in
@@ -2667,22 +2652,6 @@ _git ()
 
 _gitk ()
 {
-	if [[ -n ${ZSH_VERSION-} ]]; then
-		emulate -L bash
-		setopt KSH_TYPESET
-
-		# workaround zsh's bug that leaves 'words' as a special
-		# variable in versions < 4.3.12
-		typeset -h words
-
-		# workaround zsh's bug that quotes spaces in the COMPREPLY
-		# array if IFS doesn't contain spaces.
-		typeset -h IFS
-	fi
-
-	local cur words cword prev
-	_get_comp_words_by_ref -n =: cur words cword prev
-
 	__git_has_doubledash && return
 
 	local g="$(__gitdir)"
@@ -2703,16 +2672,43 @@ _gitk ()
 	__git_complete_revlist
 }
 
-complete -o bashdefault -o default -o nospace -F _git git 2>/dev/null \
-	|| complete -o default -o nospace -F _git git
-complete -o bashdefault -o default -o nospace -F _gitk gitk 2>/dev/null \
-	|| complete -o default -o nospace -F _gitk gitk
+__git_func_wrap ()
+{
+	if [[ -n ${ZSH_VERSION-} ]]; then
+		emulate -L bash
+		setopt KSH_TYPESET
+
+		# workaround zsh's bug that leaves 'words' as a special
+		# variable in versions < 4.3.12
+		typeset -h words
+
+		# workaround zsh's bug that quotes spaces in the COMPREPLY
+		# array if IFS doesn't contain spaces.
+		typeset -h IFS
+	fi
+	local cur words cword prev
+	_get_comp_words_by_ref -n =: cur words cword prev
+	$1
+}
+
+# Setup completion for certain functions defined above by setting common
+# variables and workarounds.
+# This is NOT a public function; use at your own risk.
+__git_complete ()
+{
+	local wrapper="__git_wrap${2}"
+	eval "$wrapper () { __git_func_wrap $2 ; }"
+	complete -o bashdefault -o default -o nospace -F $wrapper $1 2>/dev/null \
+		|| complete -o default -o nospace -F $wrapper $1
+}
+
+__git_complete git _git
+__git_complete gitk _gitk
 
 # The following are necessary only for Cygwin, and only are needed
 # when the user has tab-completed the executable name and consequently
 # included the '.exe' suffix.
 #
 if [ Cygwin = "$(uname -o 2>/dev/null)" ]; then
-complete -o bashdefault -o default -o nospace -F _git git.exe 2>/dev/null \
-	|| complete -o default -o nospace -F _git git.exe
+__git_complete git.exe _git
 fi

t/t9902-completion.sh

@@ -63,7 +63,7 @@ run_completion ()
 	local _cword
 	_words=( $1 )
 	(( _cword = ${#_words[@]} - 1 ))
-	_git && print_comp
+	__git_wrap_git && print_comp
 }
 
 test_completion ()