watchlist add: event only if inserted; adr 0015 jetstream/relay accuracy; drop vacuous assert

crates/domain/src/testing/fakes/store_watchlist.rs

@@ -16,15 +16,23 @@ use super::InMemoryStore;
 
 #[async_trait]
 impl WatchlistRepository for InMemoryStore {
-    /// `INSERT OR IGNORE` on UNIQUE(user_id, movie_id): adding twice is a no-op.
+    /// `INSERT OR IGNORE` on UNIQUE(user_id, movie_id): adding twice is a no-op
+    /// and, like the adapter, records events only for the row it inserted.
     async fn add(&self, entry: &WatchlistEntry, events: &[DomainEvent]) -> Result<(), DomainError> {
         let key = (entry.user_id.value(), entry.movie_id.value());
-        self.watchlist
-            .write()
-            .unwrap()
-            .entry(key)
-            .or_insert_with(|| entry.clone());
-        self.record_events(events);
+        let inserted = {
+            let mut entries = self.watchlist.write().unwrap();
+            match entries.entry(key) {
+                std::collections::hash_map::Entry::Vacant(slot) => {
+                    slot.insert(entry.clone());
+                    true
+                }
+                std::collections::hash_map::Entry::Occupied(_) => false,
+            }
+        };
+        if inserted {
+            self.record_events(events);
+        }
         Ok(())
     }