contrib/subtree: stop using -o to test for number of args

Functions in git-subtree.sh all assert that they are being passed the
correct number of arguments. In cases where we accept a variable number
of arguments we assert this via a single call to `test` with `-o`, which
is discouraged by our coding guidelines.

Convert these cases to stop doing so. This requires us to decompose
assertions of the style `assert test $# = 2 -o $# = 3` into two calls
because we have no easy way to logically chain statements passed to the
assert function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/subtree/git-subtree.sh

@@ -373,7 +373,8 @@ try_remove_previous () {
 
 # Usage: process_subtree_split_trailer SPLIT_HASH MAIN_HASH [REPOSITORY]
 process_subtree_split_trailer () {
-	assert test $# = 2 -o $# = 3
+	assert test $# -ge 2
+	assert test $# -le 3
 	b="$1"
 	sq="$2"
 	repository=""
@@ -402,7 +403,8 @@ process_subtree_split_trailer () {
 
 # Usage: find_latest_squash DIR [REPOSITORY]
 find_latest_squash () {
-	assert test $# = 1 -o $# = 2
+	assert test $# -ge 1
+	assert test $# -le 2
 	dir="$1"
 	repository=""
 	if test "$#" = 2
@@ -455,7 +457,8 @@ find_latest_squash () {
 
 # Usage: find_existing_splits DIR REV [REPOSITORY]
 find_existing_splits () {
-	assert test $# = 2 -o $# = 3
+	assert test $# -ge 2
+	assert test $# -le 3
 	debug "Looking for prior splits..."
 	local indent=$(($indent + 1))
 
@@ -916,7 +919,7 @@ cmd_split () {
 	if test $# -eq 0
 	then
 		rev=$(git rev-parse HEAD)
-	elif test $# -eq 1 -o $# -eq 2
+	elif test $# -eq 1 || test $# -eq 2
 	then
 		rev=$(git rev-parse -q --verify "$1^{commit}") ||
 			die "fatal: '$1' does not refer to a commit"
@@ -1006,8 +1009,11 @@ cmd_split () {
 
 # Usage: cmd_merge REV [REPOSITORY]
 cmd_merge () {
-	test $# -eq 1 -o $# -eq 2 ||
+	if test $# -lt 1 || test $# -gt 2
+	then
 		die "fatal: you must provide exactly one revision, and optionally a repository. Got: '$*'"
+	fi
+
 	rev=$(git rev-parse -q --verify "$1^{commit}") ||
 		die "fatal: '$1' does not refer to a commit"
 	repository=""