diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh
index b06782bc79..7f767b5c38 100755
--- a/contrib/subtree/git-subtree.sh
+++ b/contrib/subtree/git-subtree.sh
@@ -5,8 +5,12 @@
 # Copyright (C) 2009 Avery Pennarun <apenwarr@gmail.com>
 #
 
-if test -z "$GIT_EXEC_PATH" || test "${PATH#"${GIT_EXEC_PATH}:"}" = "$PATH" || ! test -f "$GIT_EXEC_PATH/git-sh-setup"
+if test -z "$GIT_EXEC_PATH" || ! test -f "$GIT_EXEC_PATH/git-sh-setup" || {
+	test "${PATH#"${GIT_EXEC_PATH}:"}" = "$PATH" &&
+	test ! "$GIT_EXEC_PATH" -ef "${PATH%%:*}" 2>/dev/null
+}
 then
+	basename=${0##*[/\\]}
 	echo >&2 'It looks like either your git installation or your'
 	echo >&2 'git-subtree installation is broken.'
 	echo >&2
@@ -14,10 +18,10 @@ then
 	echo >&2 " - If \`git --exec-path\` does not print the correct path to"
 	echo >&2 "   your git install directory, then set the GIT_EXEC_PATH"
 	echo >&2 "   environment variable to the correct directory."
-	echo >&2 " - Make sure that your \`${0##*/}\` file is either in your"
+	echo >&2 " - Make sure that your \`$basename\` file is either in your"
 	echo >&2 "   PATH or in your git exec path (\`$(git --exec-path)\`)."
-	echo >&2 " - You should run git-subtree as \`git ${0##*/git-}\`,"
-	echo >&2 "   not as \`${0##*/}\`." >&2
+	echo >&2 " - You should run git-subtree as \`git ${basename#git-}\`,"
+	echo >&2 "   not as \`$basename\`." >&2
 	exit 126
 fi