Run validation in the selected module

internal/gotool/gotool_test.go

@@ -301,6 +301,72 @@ func TestPersistentSettingsPreserveCachesAndNativeCTools(t *testing.T) {
 	}
 }
 
+func TestOwnerReusesSettingsUntilInheritedEnvironmentChanges(t *testing.T) {
+	clearGoSettings(t)
+	t.Setenv("GOENV", "off")
+	owner := NewOwner(t.TempDir())
+
+	first, err := owner.Acquire(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	second, err := owner.Acquire(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if first != second {
+		t.Fatal("unchanged Go inputs caused settings discovery to be repeated")
+	}
+
+	cache := filepath.Join(t.TempDir(), "changed-cache")
+	t.Setenv("GOCACHE", cache)
+	if err := owner.Refresh(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	third, err := owner.Acquire(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if third == first || third.settings["GOCACHE"] != cache {
+		t.Fatalf("changed inherited environment kept stale settings: tool=%p GOCACHE=%q", third, third.settings["GOCACHE"])
+	}
+}
+
+func TestOwnerRefreshesWhenPersistentSettingsChange(t *testing.T) {
+	clearGoSettings(t)
+	firstCache := filepath.Join(t.TempDir(), "first-cache")
+	secondCache := filepath.Join(t.TempDir(), "second-cache")
+	settingsFile := filepath.Join(t.TempDir(), "go-env")
+	writeSettings := func(cache string) {
+		t.Helper()
+		if err := os.WriteFile(settingsFile, []byte("GOCACHE="+cache+"\n"), 0o600); err != nil {
+			t.Fatal(err)
+		}
+	}
+	writeSettings(firstCache)
+	t.Setenv("GOENV", settingsFile)
+	owner := NewOwner(t.TempDir())
+
+	first, err := owner.Acquire(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if first.settings["GOCACHE"] != firstCache {
+		t.Fatalf("initial GOCACHE = %q, want %q", first.settings["GOCACHE"], firstCache)
+	}
+	writeSettings(secondCache)
+	if err := owner.Refresh(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	second, err := owner.Acquire(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if second == first || second.settings["GOCACHE"] != secondCache {
+		t.Fatalf("changed persistent settings were not rediscovered: tool=%p GOCACHE=%q", second, second.settings["GOCACHE"])
+	}
+}
+
 func readSettings(t *testing.T, tool *Tool, mode Mode, target Target, names ...string) map[string]string {
 	t.Helper()
 	args := append([]string{"env", "-json"}, names...)