From be1cf9bba833449ff8d668240e1529be552cadc9 Mon Sep 17 00:00:00 2001
From: Virgil <virgil@lethean.io>
Date: Thu, 2 Apr 2026 00:28:29 +0000
Subject: [PATCH] fix(i18n): preserve structured missing-key args

Co-Authored-By: Virgil <virgil@lethean.io>
---
 hooks_test.go | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 service.go    | 41 +++++++++++++++++++++++++++++++++++------
 2 files changed, 84 insertions(+), 6 deletions(-)

diff --git a/hooks_test.go b/hooks_test.go
index 0fa6355..7698abc 100644
--- a/hooks_test.go
+++ b/hooks_test.go
@@ -208,6 +208,55 @@ func TestOnMissingKey_Good(t *testing.T) {
 	assert.Equal(t, "hooks_test.go", filepath.Base(captured.CallerFile))
 }
 
+func TestOnMissingKey_Good_SubjectArgs(t *testing.T) {
+	svc, err := New()
+	require.NoError(t, err)
+	prev := Default()
+	SetDefault(svc)
+	t.Cleanup(func() {
+		SetDefault(prev)
+	})
+	svc.SetMode(ModeCollect)
+
+	var captured MissingKey
+	OnMissingKey(func(m MissingKey) {
+		captured = m
+	})
+
+	_ = T("missing.subject.key", S("file", "config.yaml").Count(3).In("workspace").Formal())
+
+	assert.Equal(t, "missing.subject.key", captured.Key)
+	assert.Equal(t, "config.yaml", captured.Args["Subject"])
+	assert.Equal(t, "file", captured.Args["Noun"])
+	assert.Equal(t, 3, captured.Args["Count"])
+	assert.Equal(t, "workspace", captured.Args["Location"])
+	assert.Equal(t, FormalityFormal, captured.Args["Formality"])
+}
+
+func TestOnMissingKey_Good_TranslationContextArgs(t *testing.T) {
+	svc, err := New()
+	require.NoError(t, err)
+	prev := Default()
+	SetDefault(svc)
+	t.Cleanup(func() {
+		SetDefault(prev)
+	})
+	svc.SetMode(ModeCollect)
+
+	var captured MissingKey
+	OnMissingKey(func(m MissingKey) {
+		captured = m
+	})
+
+	_ = T("missing.context.key", C("navigation").WithGender("feminine").In("workspace").Formal())
+
+	assert.Equal(t, "missing.context.key", captured.Key)
+	assert.Equal(t, "navigation", captured.Args["Context"])
+	assert.Equal(t, "feminine", captured.Args["Gender"])
+	assert.Equal(t, "workspace", captured.Args["Location"])
+	assert.Equal(t, FormalityFormal, captured.Args["Formality"])
+}
+
 func TestDispatchMissingKey_Good_NoHandler(t *testing.T) {
 	// Store nil handler (using correct type)
 	missingKeyHandler.Store(MissingKeyHandler(nil))
diff --git a/service.go b/service.go
index 4618041..8295646 100644
--- a/service.go
+++ b/service.go
@@ -545,12 +545,7 @@ func (s *Service) handleMissingKey(key string, args []any) string {
 	case ModeStrict:
 		panic(core.Sprintf("i18n: missing translation key %q", key))
 	case ModeCollect:
-		var argsMap map[string]any
-		if len(args) > 0 {
-			if m, ok := args[0].(map[string]any); ok {
-				argsMap = m
-			}
-		}
+		argsMap := missingKeyArgs(args)
 		dispatchMissingKey(key, argsMap)
 		return "[" + key + "]"
 	default:
@@ -558,6 +553,40 @@ func (s *Service) handleMissingKey(key string, args []any) string {
 	}
 }
 
+func missingKeyArgs(args []any) map[string]any {
+	if len(args) == 0 {
+		return nil
+	}
+	switch v := args[0].(type) {
+	case map[string]any:
+		return v
+	case *TranslationContext:
+		return missingKeyContextArgs(v)
+	case *Subject:
+		return missingKeySubjectArgs(v)
+	default:
+		return nil
+	}
+}
+
+func missingKeyContextArgs(ctx *TranslationContext) map[string]any {
+	if ctx == nil {
+		return nil
+	}
+	data := templateDataForRendering(ctx)
+	result, _ := data.(map[string]any)
+	return result
+}
+
+func missingKeySubjectArgs(subj *Subject) map[string]any {
+	if subj == nil {
+		return nil
+	}
+	data := templateDataForRendering(subj)
+	result, _ := data.(map[string]any)
+	return result
+}
+
 // Raw translates without i18n.* namespace magic.
 func (s *Service) Raw(messageID string, args ...any) string {
 	s.mu.RLock()