fix: bound issue privacy grant cache

Co-Authored-By: Paperclip <noreply@paperclip.ing>

server/src/__tests__/authorization-service.test.ts

@@ -20,7 +20,14 @@ import {
   getEmbeddedPostgresTestSupport,
   startEmbeddedPostgresTestDatabase,
 } from "./helpers/embedded-postgres.js";
-import { authorizationService, type AuthorizationActor } from "../services/authorization.js";
+import {
+  __clearIssuePrivacyGrantCacheForTests,
+  __getIssuePrivacyGrantCacheSizeForTests,
+  authorizationService,
+  canActorReadIssuePrivacy,
+  ISSUE_PRIVACY_GRANT_CACHE_MAX_ENTRIES,
+  type AuthorizationActor,
+} from "../services/authorization.js";
 import { logger } from "../middleware/logger.js";
 
 const embeddedPostgresSupport = await getEmbeddedPostgresTestSupport();
@@ -2299,4 +2306,28 @@ describeEmbeddedPostgres("authorization service", () => {
       else process.env.PAPERCLIP_ISSUE_PRIVACY_CACHE_TTL_MS = previousTtl;
     }
   });
+
+  it("bounds the private issue grant cache across distinct issues", async () => {
+    __clearIssuePrivacyGrantCacheForTests();
+    try {
+      const actor: AuthorizationActor = { type: "board", userId: randomUUID(), source: "session" };
+      for (let index = 0; index < ISSUE_PRIVACY_GRANT_CACHE_MAX_ENTRIES + 5; index += 1) {
+        const issueId = randomUUID();
+        await expect(canActorReadIssuePrivacy(db, actor, {
+          id: issueId,
+          companyId: randomUUID(),
+          visibility: "private",
+          privacyRootIssueId: issueId,
+          responsibleUserId: null,
+          createdByUserId: null,
+          assigneeUserId: null,
+          assigneeAgentId: null,
+        })).resolves.toBe(false);
+      }
+
+      expect(__getIssuePrivacyGrantCacheSizeForTests()).toBe(ISSUE_PRIVACY_GRANT_CACHE_MAX_ENTRIES);
+    } finally {
+      __clearIssuePrivacyGrantCacheForTests();
+    }
+  });
 });

server/src/services/authorization.ts

@@ -470,8 +470,39 @@ export type IssuePrivacyRow = {
   assigneeAgentId: string | null;
 };
 
+export const ISSUE_PRIVACY_GRANT_CACHE_MAX_ENTRIES = 256;
 const issuePrivacyGrantCache = new Map<string, { expiresAt: number; promise: Promise<boolean> }>();
 
+export function __getIssuePrivacyGrantCacheSizeForTests() {
+  return issuePrivacyGrantCache.size;
+}
+
+export function __clearIssuePrivacyGrantCacheForTests() {
+  issuePrivacyGrantCache.clear();
+}
+
+function pruneExpiredIssuePrivacyGrantCache(now: number) {
+  for (const [key, entry] of issuePrivacyGrantCache) {
+    if (entry.expiresAt <= now) issuePrivacyGrantCache.delete(key);
+  }
+}
+
+function setIssuePrivacyGrantCacheEntry(
+  key: string,
+  entry: { expiresAt: number; promise: Promise<boolean> },
+) {
+  if (issuePrivacyGrantCache.size >= ISSUE_PRIVACY_GRANT_CACHE_MAX_ENTRIES) {
+    pruneExpiredIssuePrivacyGrantCache(Date.now());
+  }
+  issuePrivacyGrantCache.delete(key);
+  issuePrivacyGrantCache.set(key, entry);
+  while (issuePrivacyGrantCache.size > ISSUE_PRIVACY_GRANT_CACHE_MAX_ENTRIES) {
+    const oldestKey = issuePrivacyGrantCache.keys().next().value as string | undefined;
+    if (oldestKey === undefined) return;
+    issuePrivacyGrantCache.delete(oldestKey);
+  }
+}
+
 export function issuePrivacyMode(): "off" | "shadow" | "enforce" {
   const mode = process.env.PAPERCLIP_ISSUE_PRIVACY_MODE?.trim().toLowerCase();
   if (mode === "off" || mode === "enforce") return mode;
@@ -507,7 +538,11 @@ async function actorHasIssuePrivacyGrant(db: Db, actor: AuthorizationActor, issu
   const cacheKey = `${principal.type}:${principal.id}:${issue.id}:${rootId}`;
   const now = Date.now();
   const cached = issuePrivacyGrantCache.get(cacheKey);
-  if (cached && cached.expiresAt > now) return cached.promise;
+  if (cached && cached.expiresAt > now) {
+    setIssuePrivacyGrantCacheEntry(cacheKey, cached);
+    return cached.promise;
+  }
+  if (cached) issuePrivacyGrantCache.delete(cacheKey);
   const promise = db
     .select({ id: issueAccessGrants.id })
     .from(issueAccessGrants)
@@ -519,7 +554,7 @@ async function actorHasIssuePrivacyGrant(db: Db, actor: AuthorizationActor, issu
     ))
     .limit(1)
     .then((rows) => rows.length > 0);
-  issuePrivacyGrantCache.set(cacheKey, { expiresAt: now + issuePrivacyCacheTtlMs(), promise });
+  setIssuePrivacyGrantCacheEntry(cacheKey, { expiresAt: now + issuePrivacyCacheTtlMs(), promise });
   const granted = await promise;
   // Positive authorization decisions must observe revocation on the next read.
   // Keep only negative decisions cached; grant creation paths already tolerate