fix(search): key the in-flight search by actor and record

Two tabs searching two different records (one's own and a shared one)
cancelled each other, because a new search aborted any earlier one by
the same actor. The slot is now held per actor and record.

src/app/api/search/route.ts

@@ -90,7 +90,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
     });
   }
 
-  const slot = beginSearch(actor.id);
+  const slot = beginSearch(actor.id, user.id);
   try {
     const [modules, domainVisible, timezone] = await Promise.all([
       resolveModuleMap(user.id),

src/lib/search/__tests__/in-flight.test.ts

@@ -0,0 +1,26 @@
+import { describe, expect, it } from "vitest";
+
+import { SUPERSEDED, beginSearch, searchesInFlight } from "../in-flight";
+
+describe("beginSearch", () => {
+  it("a newer search of the same record stops the one before it", () => {
+    const first = beginSearch("actor", "record-a");
+    const second = beginSearch("actor", "record-a");
+    expect(first.signal.aborted).toBe(true);
+    expect(first.signal.reason).toBe(SUPERSEDED);
+    expect(second.signal.aborted).toBe(false);
+    first.end();
+    second.end();
+    expect(searchesInFlight()).toBe(0);
+  });
+
+  it("searches of two different records by one actor run side by side", () => {
+    const own = beginSearch("actor", "record-a");
+    const shared = beginSearch("actor", "record-b");
+    expect(own.signal.aborted).toBe(false);
+    expect(shared.signal.aborted).toBe(false);
+    own.end();
+    shared.end();
+    expect(searchesInFlight()).toBe(0);
+  });
+});

src/lib/search/in-flight.ts

@@ -1,12 +1,14 @@
 /**
- * One search in flight per actor.
+ * One search in flight per actor and record.
  *
  * The palette searches once per pause in typing, and the client cancels the
  * previous request when the text changes. A cancelled fetch does not stop the
  * server, though: without this, every keystroke-pause left a search reading
  * and decrypting on the server until its own budget ran out, so a fast typist
- * held several at once. A new search by the same actor aborts the one before
- * it, which stops at its next budget check.
+ * held several at once. A new search by the same actor in the same record
+ * aborts the one before it, which stops at its next budget check. Searches
+ * of two different records (a tab on one's own record, another on a record
+ * shared with them) are two separate palettes and never cancel each other.
  *
  * Per process: on a multi-instance deploy two searches by one actor on two
  * instances both run, each still bounded by its own time budget and by the
@@ -18,20 +20,22 @@ const inFlight = new Map<string, AbortController>();
 export const SUPERSEDED = "search.superseded";
 
 export interface SearchSlot {
-  /** Aborted when the same actor starts a newer search. */
+  /** Aborted when the same actor starts a newer search of the same record. */
   signal: AbortSignal;
   /** Release the slot once the search answered (or failed). */
   end: () => void;
 }
 
-export function beginSearch(actorId: string): SearchSlot {
-  inFlight.get(actorId)?.abort(SUPERSEDED);
+export function beginSearch(actorId: string, recordId: string): SearchSlot {
+  // Ids are cuids, so the separator cannot occur inside either part.
+  const key = `${actorId}:${recordId}`;
+  inFlight.get(key)?.abort(SUPERSEDED);
   const controller = new AbortController();
-  inFlight.set(actorId, controller);
+  inFlight.set(key, controller);
   return {
     signal: controller.signal,
     end: () => {
-      if (inFlight.get(actorId) === controller) inFlight.delete(actorId);
+      if (inFlight.get(key) === controller) inFlight.delete(key);
     },
   };
 }