Merge pull request #2175 from dscho/difftool-no-index

Allow `git difftool --no-index` to run outside of a worktree

Author: dscho

builtin/difftool.c

@@ -723,16 +723,16 @@ int cmd_difftool(int argc, const char **argv, const char *prefix)
 	if (!no_index && !startup_info->have_repository)
 		die(_("difftool requires worktree or --no-index"));
 
+	if (use_gui_tool + !!difftool_cmd + !!extcmd > 1)
+		die(_("--gui, --tool and --extcmd are mutually exclusive"));
+
 	if (!no_index){
 		setup_work_tree();
 		setenv(GIT_DIR_ENVIRONMENT, absolute_path(get_git_dir()), 1);
 		setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(get_git_work_tree()), 1);
 	} else if (dir_diff)
 		die(_("--dir-diff is incompatible with --no-index"));
 
-	if (use_gui_tool + !!difftool_cmd + !!extcmd > 1)
-		die(_("--gui, --tool and --extcmd are mutually exclusive"));
-
 	if (use_gui_tool)
 		setenv("GIT_MERGETOOL_GUI", "true", 1);
 	else if (difftool_cmd) {