Function TestExecutorHandlerErrorPreservesStderr

pkg/hooks/handler_test.go:173–204

TestExecutorHandlerErrorPreservesStderr pins the contract that when a handler returns an error, the diagnostic stderr it captured before failing survives all the way to [Result.Stderr]. aggregate routes that field into the user-visible PreToolUse fail-closed message; if runHook ever drops it on the

(t *testing.T)

// HandlerResult-embedding refactor) PreToolUse denials would lose
// their explanatory text.
func TestExecutorHandlerErrorPreservesStderr(t *testing.T) {
	t.Parallel()

	const customType HookType = "errors-with-stderr"
	const diagnostic = "BOOM: subprocess crashed at line 42"

	registry := NewRegistry()
	registry.Register(customType, func(_ HandlerEnv, _ Hook) (Handler, error) {
		return handlerFunc(func(context.Context, []byte) (HandlerResult, error) {
			// Mirrors what commandHandler does on a spawn failure: it
			// captured stderr, then surfaces an exec-level error.
			return HandlerResult{Stderr: diagnostic, ExitCode: -1}, errors.New("spawn failed")
		}), nil
	})

	config := &Config{
		PreToolUse: []MatcherConfig{
			{Matcher: "*", Hooks: []Hook{{Type: customType, Timeout: 5}}},
		},
	}

	exec := NewExecutorWithRegistry(config, t.TempDir(), nil, registry)
	result, err := exec.Dispatch(t.Context(), EventPreToolUse, &Input{
		SessionID: "s", ToolName: "shell", ToolUseID: "t",
	})
	require.NoError(t, err)

	assert.False(t, result.Allowed)
	assert.Equal(t, -1, result.ExitCode)
	assert.Equal(t, diagnostic, result.Stderr,
		"handler-captured stderr must survive the err != nil normalization in runHook")
}

// handlerFunc adapts a function value into a [Handler] for terse tests.
type handlerFunc func(context.Context, []byte) (HandlerResult, error)