Series URL repair: owner-typed, gated by the poller's own fetch gate (#151)

backend/internal/store/store_test.go

@@ -2144,3 +2144,38 @@ func TestGetCoverResolvesLegacyURLDerivedAddress(t *testing.T) {
 		t.Fatalf("legacy cover = (%q, %q), want the planted bytes", body, contentType)
 	}
 }
+
+// SetSeriesURL is the one write that lifts the write-once rule of
+// Series.SeriesURL (issue #151): a client PUT naming an existing Series still
+// has its new URL dropped, yet the owner's repair lands where the Upsert
+// would have ignored it.
+func TestSetSeriesURLWritesWhereUpsertIgnores(t *testing.T) {
+	store := newTestStore(t)
+	base := Bookmark{
+		Key: "asura:solo", Site: "asura", SeriesID: "solo",
+		Title: "Solo Leveling", SeriesURL: "https://asurascans.com/comics/solo",
+		UpdatedAt: 1000,
+	}
+	if _, err := store.Upsert(store.OwnerID(), base); err != nil {
+		t.Fatalf("seed: %v", err)
+	}
+
+	// A client PUT naming the existing Series is refused: the row is shared,
+	// so the stored URL stands.
+	base.SeriesURL = "https://evil.example/solo"
+	if got, err := store.Upsert(store.OwnerID(), base); err != nil {
+		t.Fatalf("Upsert: %v", err)
+	} else if got.SeriesURL != "https://asurascans.com/comics/solo" {
+		t.Fatalf("Upsert stored %q, want the original URL untouched", got.SeriesURL)
+	}
+
+	// The owner's repair writes where the Upsert would have ignored it.
+	repair := "https://asurascans.com/comics/solo-renumbered"
+	if err := store.SetSeriesURL("asura", "solo", repair); err != nil {
+		t.Fatalf("SetSeriesURL: %v", err)
+	}
+	sr := readSeries(t, store, "asura", "solo")
+	if sr.SeriesURL != repair {
+		t.Fatalf("stored URL = %q, want %q", sr.SeriesURL, repair)
+	}
+}