fix: prevent memory leaks from AbortController closures (#12024)

packages/opencode/test/memory/abort-leak.test.ts

@@ -0,0 +1,136 @@
+import { describe, test, expect } from "bun:test"
+import path from "path"
+import { Instance } from "../../src/project/instance"
+import { WebFetchTool } from "../../src/tool/webfetch"
+
+const projectRoot = path.join(__dirname, "../..")
+
+const ctx = {
+  sessionID: "test",
+  messageID: "",
+  callID: "",
+  agent: "build",
+  abort: new AbortController().signal,
+  messages: [],
+  metadata: () => {},
+  ask: async () => {},
+}
+
+const MB = 1024 * 1024
+const ITERATIONS = 50
+
+const getHeapMB = () => {
+  Bun.gc(true)
+  return process.memoryUsage().heapUsed / MB
+}
+
+describe("memory: abort controller leak", () => {
+  test("webfetch does not leak memory over many invocations", async () => {
+    await Instance.provide({
+      directory: projectRoot,
+      fn: async () => {
+        const tool = await WebFetchTool.init()
+
+        // Warm up
+        await tool.execute({ url: "https://example.com", format: "text" }, ctx).catch(() => {})
+
+        Bun.gc(true)
+        const baseline = getHeapMB()
+
+        // Run many fetches
+        for (let i = 0; i < ITERATIONS; i++) {
+          await tool.execute({ url: "https://example.com", format: "text" }, ctx).catch(() => {})
+        }
+
+        Bun.gc(true)
+        const after = getHeapMB()
+        const growth = after - baseline
+
+        console.log(`Baseline: ${baseline.toFixed(2)} MB`)
+        console.log(`After ${ITERATIONS} fetches: ${after.toFixed(2)} MB`)
+        console.log(`Growth: ${growth.toFixed(2)} MB`)
+
+        // Memory growth should be minimal - less than 1MB per 10 requests
+        // With the old closure pattern, this would grow ~0.5MB per request
+        expect(growth).toBeLessThan(ITERATIONS / 10)
+      },
+    })
+  }, 60000)
+
+  test("compare closure vs bind pattern directly", async () => {
+    const ITERATIONS = 500
+
+    // Test OLD pattern: arrow function closure
+    // Store closures in a map keyed by content to force retention
+    const closureMap = new Map<string, () => void>()
+    const timers: Timer[] = []
+    const controllers: AbortController[] = []
+
+    Bun.gc(true)
+    Bun.sleepSync(100)
+    const baseline = getHeapMB()
+
+    for (let i = 0; i < ITERATIONS; i++) {
+      // Simulate large response body like webfetch would have
+      const content = `${i}:${"x".repeat(50 * 1024)}` // 50KB unique per iteration
+      const controller = new AbortController()
+      controllers.push(controller)
+
+      // OLD pattern - closure captures `content`
+      const handler = () => {
+        // Actually use content so it can't be optimized away
+        if (content.length > 1000000000) controller.abort()
+      }
+      closureMap.set(content, handler)
+      const timeoutId = setTimeout(handler, 30000)
+      timers.push(timeoutId)
+    }
+
+    Bun.gc(true)
+    Bun.sleepSync(100)
+    const after = getHeapMB()
+    const oldGrowth = after - baseline
+
+    console.log(`OLD pattern (closure): ${oldGrowth.toFixed(2)} MB growth (${closureMap.size} closures)`)
+
+    // Cleanup after measuring
+    timers.forEach(clearTimeout)
+    controllers.forEach((c) => c.abort())
+    closureMap.clear()
+
+    // Test NEW pattern: bind
+    Bun.gc(true)
+    Bun.sleepSync(100)
+    const baseline2 = getHeapMB()
+    const handlers2: (() => void)[] = []
+    const timers2: Timer[] = []
+    const controllers2: AbortController[] = []
+
+    for (let i = 0; i < ITERATIONS; i++) {
+      const _content = `${i}:${"x".repeat(50 * 1024)}` // 50KB - won't be captured
+      const controller = new AbortController()
+      controllers2.push(controller)
+
+      // NEW pattern - bind doesn't capture surrounding scope
+      const handler = controller.abort.bind(controller)
+      handlers2.push(handler)
+      const timeoutId = setTimeout(handler, 30000)
+      timers2.push(timeoutId)
+    }
+
+    Bun.gc(true)
+    Bun.sleepSync(100)
+    const after2 = getHeapMB()
+    const newGrowth = after2 - baseline2
+
+    // Cleanup after measuring
+    timers2.forEach(clearTimeout)
+    controllers2.forEach((c) => c.abort())
+    handlers2.length = 0
+
+    console.log(`NEW pattern (bind): ${newGrowth.toFixed(2)} MB growth`)
+    console.log(`Improvement: ${(oldGrowth - newGrowth).toFixed(2)} MB saved`)
+
+    expect(newGrowth).toBeLessThanOrEqual(oldGrowth)
+  })
+})