subtree: don't have loose code outside of a function

Shove all of the loose code inside of a main() function.

This comes down to personal preference more than anything else.  A
preference that I've developed over years of maintaining large Bash
scripts, but still a mere personal preference.

In this specific case, it's also moving the `set -- -h`, the `git
rev-parse --parseopt`, and the `. git-sh-setup` to be closer to all
the rest of the argument parsing, which is a readability win on its
own, IMO.

"Ignore space change" is probably helpful when viewing this diff.

Signed-off-by: Luke Shumaker <lukeshu@datawire.io>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/subtree/git-subtree.sh

@@ -4,10 +4,7 @@
 #
 # Copyright (C) 2009 Avery Pennarun <apenwarr@gmail.com>
 #
-if test $# -eq 0
-then
-	set -- -h
-fi
+
 OPTS_SPEC="\
 git subtree add   --prefix=<prefix> <commit>
 git subtree add   --prefix=<prefix> <repository> <ref>
@@ -30,12 +27,8 @@ rejoin        merge the new branch back into HEAD
  options for 'add', 'merge', and 'pull'
 squash        merge subtree changes as a single commit
 "
-eval "$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"
 
 PATH=$PATH:$(git --exec-path)
-. git-sh-setup
-
-require_work_tree
 
 quiet=
 branch=
@@ -84,8 +77,17 @@ ensure_single_rev () {
 	fi
 }
 
-while test $# -gt 0
-do
+main () {
+	if test $# -eq 0
+	then
+		set -- -h
+	fi
+	eval "$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"
+	. git-sh-setup
+	require_work_tree
+
+	while test $# -gt 0
+	do
 		opt="$1"
 		shift
 
@@ -150,45 +152,45 @@ do
 			die "Unexpected option: $opt"
 			;;
 		esac
-done
+	done
 
-command="$1"
-shift
+	command="$1"
+	shift
 
-case "$command" in
-add|merge|pull)
+	case "$command" in
+	add|merge|pull)
 		default=
 		;;
-split|push)
+	split|push)
 		default="--default HEAD"
 		;;
-*)
+	*)
 		die "Unknown command '$command'"
 		;;
-esac
+	esac
 
-if test -z "$prefix"
-then
+	if test -z "$prefix"
+	then
 		die "You must provide the --prefix option."
-fi
+	fi
 
-case "$command" in
-add)
+	case "$command" in
+	add)
 		test -e "$prefix" &&
 			die "prefix '$prefix' already exists."
 		;;
-*)
+	*)
 		test -e "$prefix" ||
 			die "'$prefix' does not exist; use 'git subtree add'"
 		;;
-esac
+	esac
 
-dir="$(dirname "$prefix/.")"
+	dir="$(dirname "$prefix/.")"
 
-if test "$command" != "pull" &&
+	if test "$command" != "pull" &&
 			test "$command" != "add" &&
 			test "$command" != "push"
-then
+	then
 		revs=$(git rev-parse $default --revs-only "$@") || exit $?
 		dirs=$(git rev-parse --no-revs --no-flags "$@") || exit $?
 		ensure_single_rev $revs
@@ -196,14 +198,17 @@ then
 		then
 			die "Error: Use --prefix instead of bare filenames."
 		fi
-fi
+	fi
 
-debug "command: {$command}"
-debug "quiet: {$quiet}"
-debug "revs: {$revs}"
-debug "dir: {$dir}"
-debug "opts: {$*}"
-debug
+	debug "command: {$command}"
+	debug "quiet: {$quiet}"
+	debug "revs: {$revs}"
+	debug "dir: {$dir}"
+	debug "opts: {$*}"
+	debug
+
+	"cmd_$command" "$@"
+}
 
 cache_setup () {
 	cachedir="$GIT_DIR/subtree-cache/$$"
@@ -898,4 +903,4 @@ cmd_push () {
 	fi
 }
 
-"cmd_$command" "$@"
+main "$@"