fix

apps/api/internal/processing/category_test.go

@@ -133,6 +133,9 @@ func TestFilterCategoryIfInvalid(t *testing.T) {
 	if out.Category != "" {
 		t.Fatalf("invalid unique_id kept: %q", out.Category)
 	}
+	if src, _ := out.FieldSources["category"].(string); src != "cleared_invalid" {
+		t.Fatalf("field_sources.category=%v want cleared_invalid", out.FieldSources["category"])
+	}
 	out.Category = "50"
 	filterCategoryIfInvalid(&out, nil)
 	if out.Category != "50" {
@@ -179,6 +182,76 @@ func TestCoerceCategoryToCompanyUniqueID_nameToUID(t *testing.T) {
 	if out.Category != "" {
 		t.Fatalf("unknown should clear: %q", out.Category)
 	}
+	if src, _ := out.FieldSources["category"].(string); src != "cleared_invalid" {
+		t.Fatalf("field_sources.category=%v want cleared_invalid", out.FieldSources["category"])
+	}
+}
+
+// Product titles (and nested category.name copies of the title) must never land
+// in Category — only taxonomy unique_ids (+ display names from categories).
+func TestRunSteps_productTitleNeverBecomesCategory(t *testing.T) {
+	t.Parallel()
+	const productTitle = "Bosch Serie 6 WAU28PH0BY 9kg White Washing Machine"
+	names := map[string]string{"50": "Pralni stroji", "28": "TV mounts"}
+	e := &Engine{Vector: NoopVectorCategorizer{}}
+
+	out, err := e.RunSteps(context.Background(), "co", ProductInput{
+		GTIN: "4242005191234",
+		Name: productTitle,
+		Mapped: map[string]any{
+			"name": productTitle,
+			"category": map[string]any{
+				"name": productTitle, // feed pollution: product title as category.name
+			},
+		},
+		CategoryNamesByUID: names,
+	}, "normalize_only", nil, StepPolicy{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if out.Category == productTitle || strings.EqualFold(out.Category, productTitle) {
+		t.Fatalf("Category must not be product title: %q", out.Category)
+	}
+	if out.CategoryName == productTitle || strings.EqualFold(out.CategoryName, productTitle) {
+		t.Fatalf("CategoryName must not be product title: %q", out.CategoryName)
+	}
+	if cat := categoryDisplayLabel(out); cat == productTitle || strings.EqualFold(cat, productTitle) {
+		t.Fatalf("categoryDisplayLabel leaked product title: %q", cat)
+	}
+	if out.Category != "" {
+		t.Fatalf("Category=%q want empty (unresolved product-title token scrubbed)", out.Category)
+	}
+
+	// Plain string category == product title must also be scrubbed.
+	out2, err := e.RunSteps(context.Background(), "co", ProductInput{
+		GTIN: "4242005191235",
+		Name: productTitle,
+		Mapped: map[string]any{
+			"name":     productTitle,
+			"category": productTitle,
+		},
+		CategoryNamesByUID: names,
+	}, "normalize_only", nil, StepPolicy{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if out2.Category != "" {
+		t.Fatalf("plain title-as-category kept: %q", out2.Category)
+	}
+
+	// Real taxonomy display name still coerces via processOne helpers.
+	out3 := StepResult{Category: "Pralni stroji", Name: productTitle, ProcessedName: productTitle}
+	valid := map[string]struct{}{"50": {}, "28": {}}
+	coerceCategoryToCompanyUniqueID(&out3, names, valid)
+	filterCategoryIfInvalid(&out3, valid)
+	scrubCategoryPollution(&out3, names, valid)
+	syncCategoryName(&out3, names)
+	if out3.Category != "50" {
+		t.Fatalf("taxonomy name coerce: Category=%q want 50", out3.Category)
+	}
+	if out3.CategoryName != "Pralni stroji" {
+		t.Fatalf("CategoryName=%q want Pralni stroji", out3.CategoryName)
+	}
 }
 
 func TestResolveCompanyCategoryUniqueID_usedByV1Projection(t *testing.T) {