From 47b3530af3a099456e19b313695f40fef294df38 Mon Sep 17 00:00:00 2001
From: Peter Steinberger <steipete@gmail.com>
Date: Wed, 29 Apr 2026 14:01:31 +0100
Subject: [PATCH] fix(discord): prune idle rest route mappings

---
 .../discord/src/internal/rest-scheduler.ts    | 39 ++++++++++++++++++-
 extensions/discord/src/internal/rest.test.ts  |  8 ++--
 2 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/extensions/discord/src/internal/rest-scheduler.ts b/extensions/discord/src/internal/rest-scheduler.ts
index 2bc8c86505f..2ca4d395276 100644
--- a/extensions/discord/src/internal/rest-scheduler.ts
+++ b/extensions/discord/src/internal/rest-scheduler.ts
@@ -89,6 +89,7 @@ export class RestScheduler<TData> {
     return {
       globalRateLimitUntil: this.globalRateLimitUntil,
       activeBuckets: this.buckets.size,
+      routeBucketMappings: this.routeBuckets.size,
       buckets: Array.from(this.buckets.entries()).map(([key, bucket]) => ({
         key,
         active: bucket.active,
@@ -144,6 +145,34 @@ export class RestScheduler<TData> {
     return false;
   }
 
+  private isBucketRateLimited(bucket: BucketState<TData>, now = Date.now()): boolean {
+    return bucket.remaining === 0 && bucket.resetAt > now;
+  }
+
+  private pruneRouteMapping(routeKey: string): void {
+    const bucketKey = this.routeBuckets.get(routeKey);
+    if (!bucketKey) {
+      return;
+    }
+    this.routeBuckets.delete(routeKey);
+    this.buckets.get(bucketKey)?.routeKeys.delete(routeKey);
+  }
+
+  private pruneIdleRouteMappings(
+    bucketKey: string,
+    bucket: BucketState<TData>,
+    now = Date.now(),
+  ): void {
+    if (bucket.active > 0 || bucket.pending.length > 0 || this.isBucketRateLimited(bucket, now)) {
+      return;
+    }
+    for (const routeKey of Array.from(bucket.routeKeys)) {
+      if (this.routeBuckets.get(routeKey) === bucketKey) {
+        this.pruneRouteMapping(routeKey);
+      }
+    }
+  }
+
   private shouldPruneIdleBucket(key: string): boolean {
     const mappedBucketKey = this.routeBuckets.get(key);
     return mappedBucketKey !== key && !this.hasBucketReference(key);
@@ -267,7 +296,15 @@ export class RestScheduler<TData> {
         break;
       }
       if (bucket.pending.length === 0) {
-        if (bucket.active === 0 && this.shouldPruneIdleBucket(key)) {
+        if (bucket.active !== 0) {
+          continue;
+        }
+        if (this.isBucketRateLimited(bucket, now)) {
+          nextDelayMs = Math.min(nextDelayMs, bucket.resetAt - now);
+          continue;
+        }
+        this.pruneIdleRouteMappings(key, bucket, now);
+        if (this.shouldPruneIdleBucket(key)) {
           this.buckets.delete(key);
         }
         continue;
diff --git a/extensions/discord/src/internal/rest.test.ts b/extensions/discord/src/internal/rest.test.ts
index b03db6fe48f..f7373ad73fd 100644
--- a/extensions/discord/src/internal/rest.test.ts
+++ b/extensions/discord/src/internal/rest.test.ts
@@ -83,7 +83,7 @@ describe("RequestClient", () => {
     ]);
   });
 
-  it("prunes idle route buckets after Discord bucket remapping", async () => {
+  it("prunes idle route buckets and mappings after Discord bucket remapping", async () => {
     const client = new RequestClient("test-token", {
       fetch: async () =>
         new Response(JSON.stringify({ id: "first" }), {
@@ -95,8 +95,9 @@ describe("RequestClient", () => {
     await expect(client.get("/channels/c1/messages")).resolves.toEqual({ id: "first" });
 
     const metrics = client.getSchedulerMetrics();
-    expect(metrics.activeBuckets).toBe(1);
-    expect(metrics.buckets.map((bucket) => bucket.key)).toEqual(["channel-messages:channels/c1"]);
+    expect(metrics.activeBuckets).toBe(0);
+    expect(metrics.routeBucketMappings).toBe(0);
+    expect(metrics.buckets).toEqual([]);
   });
 
   it("waits for a learned bucket reset before dispatching the next request", async () => {
@@ -135,6 +136,7 @@ describe("RequestClient", () => {
     const client = new RequestClient("test-token", { fetch: fetchSpy });
 
     await expect(client.get("/channels/c1/messages")).resolves.toEqual({ id: "first" });
+    expect(client.getSchedulerMetrics().routeBucketMappings).toBe(1);
 
     const second = client.get("/channels/c1/messages");
     await Promise.resolve();