setenv(GIT_DIR_ENVIRONMENT, absolute_path(get_git_dir()), 1);
setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(get_git_work_tree()), 1);
+ if (use_gui_tool + !!difftool_cmd + !!extcmd > 1)
+ die(_("--gui, --tool and --extcmd are mutually exclusive"));
+
if (use_gui_tool && diff_gui_tool && *diff_gui_tool)
setenv("GIT_DIFF_TOOL", diff_gui_tool, 1);
else if (difftool_cmd) {
test_cmp expect actual
'
+test_expect_success 'difftool --gui, --tool and --extcmd are mutually exclusive' '
+ difftool_test_setup &&
+ test_must_fail git difftool --gui --tool=test-tool &&
+ test_must_fail git difftool --gui --extcmd=cat &&
+ test_must_fail git difftool --tool=test-tool --extcmd=cat &&
+ test_must_fail git difftool --gui --tool=test-tool --extcmd=cat
+'
+
test_done