format-patch: inform user that patch-id generation is unstable

diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index bb9a7f4ff91120424e300f4ced821a9217b5e34e..480dd0633fd3e979aecca82784d38642232d44b4 100755 (executable)
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -705,4 +705,14 @@ test_expect_success SYMLINKS 'difftool --dir-diff handles modified symlinks' '
        test_cmp expect actual
 '
 
+test_expect_success 'outside worktree' '
+       echo 1 >1 &&
+       echo 2 >2 &&
+       test_expect_code 1 nongit git \
+               -c diff.tool=echo -c difftool.echo.cmd="echo \$LOCAL \$REMOTE" \
+               difftool --no-prompt --no-index ../1 ../2 >actual &&
+       echo "../1 ../2" >expect &&
+       test_cmp expect actual
+'
+
 test_done