[PATCH 4/5] git-mergetool--lib.sh: add error message for unknown tool variant

["Philippe Blain via GitGitGadget" <gitgitgadget@gmail.com>]

From: Philippe Blain <levraiphilippeblain@gmail.com>

In setup_tool, we check if the given tool is a known variant of a tool,
and quietly return with an error if not. This leads to the following
invocation quietly failing:

	git mergetool --tool=vimdiff4

Add an error message before returning in this case.

Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
---
 git-mergetool--lib.sh | 1 +
 1 file changed, 1 insertion(+)

diff --git a/git-mergetool--lib.sh b/git-mergetool--lib.sh
index f4786afc63f..9a00fabba27 100644
--- a/git-mergetool--lib.sh
+++ b/git-mergetool--lib.sh
@@ -263,6 +263,7 @@ setup_tool () {
 
 	if ! list_tool_variants | grep -q "^$tool$"
 	then
+		echo "error: unknown ${tool%[0-9]} variant '$tool'" >&2
 		return 1
 	fi
 
-- 
gitgitgadget