completion: bash: add __git_have_func helper

This makes the code more readable, and also will help when new code
wants to do similar checks.

Signed-off-by: Felipe Contreras <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: felipec

contrib/completion/git-completion.bash

@@ -3358,15 +3358,19 @@ __git_support_parseopt_helper () {
 	esac
 }
 
+__git_have_func () {
+	declare -f $1 >/dev/null 2>/dev/null
+}
+
 __git_complete_command () {
 	local command="$1"
 	local completion_func="_git_${command//-/_}"
-	if ! declare -f $completion_func >/dev/null 2>/dev/null &&
-		declare -f _completion_loader >/dev/null 2>/dev/null
+	if ! __git_have_func $completion_func &&
+		__git_have_func _completion_loader
 	then
 		_completion_loader "git-$command"
 	fi
-	if declare -f $completion_func >/dev/null 2>/dev/null
+	if __git_have_func $completion_func
 	then
 		$completion_func
 		return 0