Carry optional prompt labels through results

internal/configuration/prompts_test.go

@@ -131,11 +131,112 @@ func TestLoadRejectsMalformedStaticSyntaxAndCapturesOptionalVersion(t *testing.T
 		t.Fatal(err)
 	}
 	definition, inspection, err := state.prompt("example")
-	if err != nil || definition.Version != "release label" || inspection.PromptVersion != "release label" {
+	if err != nil || definition.Version == nil || *definition.Version != "release label" ||
+		inspection.PromptVersion == nil || *inspection.PromptVersion != "release label" {
 		t.Fatalf("optional version metadata was not retained: definition=%+v inspection=%+v err=%v", definition, inspection, err)
 	}
 }
 
+func TestPromptVersionLabelPresenceAndOwnership(t *testing.T) {
+	tests := []struct {
+		name        string
+		version     any
+		include     bool
+		wantPresent bool
+		wantValue   string
+	}{
+		{name: "absent"},
+		{name: "null", include: true},
+		{name: "empty", version: "", include: true, wantPresent: true},
+		{name: "exact text", version: " Release/v1 ", include: true, wantPresent: true, wantValue: " Release/v1 "},
+	}
+
+	hashes := make(map[string]string, len(tests))
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			definition := map[string]any{
+				"messages": []any{map[string]any{"role": "user", "content": "hello"}},
+				"output":   map[string]any{"format": "text", "validation_mode": "basic"},
+			}
+			if test.include {
+				definition["version"] = test.version
+			}
+			state, err := load(mapping("prompt version label", map[string]any{
+				"prompts": map[string]any{"example": definition},
+			}), nil)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			captured, inspection, err := state.prompt("example")
+			if err != nil {
+				t.Fatal(err)
+			}
+			identities, err := state.ListPrompts(context.Background())
+			if err != nil || len(identities) != 1 {
+				t.Fatalf("list prompt labels: %#v, %v", identities, err)
+			}
+			check := func(name string, value *string) {
+				t.Helper()
+				if !test.wantPresent {
+					if value != nil {
+						t.Errorf("%s label = %q, want absent", name, *value)
+					}
+					return
+				}
+				if value == nil || *value != test.wantValue {
+					t.Errorf("%s label = %v, want %q", name, value, test.wantValue)
+				}
+			}
+			check("definition", captured.Version)
+			check("inspection", inspection.PromptVersion)
+			check("listing", identities[0].Version)
+			if captured.Version != nil && (captured.Version == inspection.PromptVersion || captured.Version == identities[0].Version || inspection.PromptVersion == identities[0].Version) {
+				t.Fatal("returned prompt labels share mutable pointers")
+			}
+			hashes[test.name] = inspection.PromptHash
+
+			if captured.Version != nil {
+				*captured.Version = "mutated definition"
+			}
+			if inspection.PromptVersion != nil {
+				*inspection.PromptVersion = "mutated inspection"
+			}
+			if identities[0].Version != nil {
+				*identities[0].Version = "mutated listing"
+			}
+			again, againInspection, err := state.prompt("example")
+			if err != nil {
+				t.Fatal(err)
+			}
+			check("captured definition after mutation", again.Version)
+			check("captured inspection after mutation", againInspection.PromptVersion)
+		})
+	}
+	if hashes["absent"] == hashes["empty"] {
+		t.Fatal("absent and declared-empty labels produced the same definition hash")
+	}
+}
+
+func TestPromptVersionNullClearsInheritedLabel(t *testing.T) {
+	prompt := map[string]any{
+		"version":  "base-label",
+		"messages": []any{map[string]any{"role": "user", "content": "hello"}},
+		"output":   map[string]any{"format": "text", "validation_mode": "basic"},
+	}
+	state, err := load(
+		mapping("clear inherited label", map[string]any{"prompts": map[string]any{"example": map[string]any{"version": nil}}}),
+		[]configkit.Underlay{{Inputs: []configkit.Input{mapping("base prompt", map[string]any{"prompts": map[string]any{"example": prompt}})}}},
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	definition, inspection, err := state.prompt("example")
+	if err != nil || definition.Version != nil || inspection.PromptVersion != nil {
+		t.Fatalf("null overlay retained inherited label: definition=%+v inspection=%+v err=%v", definition, inspection, err)
+	}
+}
+
 func TestPromptInspectionLookupMatchesSnapshotSelectionAndOwnsInputs(t *testing.T) {
 	makePrompt := func(content string) map[string]any {
 		return map[string]any{
@@ -169,7 +270,8 @@ func TestPromptInspectionLookupMatchesSnapshotSelectionAndOwnsInputs(t *testing.
 		if err != nil {
 			t.Fatalf("snapshot prompt ID: %v", err)
 		}
-		if inspection.PromptID != definition.ID || inspection.PromptVersion != definition.Version ||
+		if inspection.PromptID != definition.ID || inspection.PromptVersion == nil || definition.Version == nil ||
+			*inspection.PromptVersion != *definition.Version ||
 			inspection.PromptHash != hash || inspection.DefaultProfileID != "partial" ||
 			len(inspection.Inputs) != 1 || inspection.Inputs[0].Name != "document" ||
 			inspection.Inputs[0].ContentType != "text/plain" || inspection.Inputs[0].Description != "source document" {