From d24fa203f5532f96d798f4b54622e136d93192ad Mon Sep 17 00:00:00 2001
From: robobun <117481402+robobun@users.noreply.github.com>
Date: Wed, 28 Oct 2026 20:24:49 +0000
Subject: [PATCH 1/3] test: run 5 rounds of the reload()/Bun.build() race test
 on a debug build

A round is 4 builds of 80 entry points. A debug build takes about 0.4 s
for one such build, a release build about 0.02 s. The 40 rounds took 58
to 85 s on a debug build, and the test has a timeout of 60 s.

A debug build now runs 5 rounds (11 to 17 s). A release build still runs
40. With the entries_mutex snapshot of the route loader removed, the
5-round fixture ends in an ASAN heap-use-after-free in 26 of 26 runs.
---
 test/js/bun/util/filesystem_router.test.ts | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/test/js/bun/util/filesystem_router.test.ts b/test/js/bun/util/filesystem_router.test.ts
index 8886fb09657b..70e47198dbe7 100644
--- a/test/js/bun/util/filesystem_router.test.ts
+++ b/test/js/bun/util/filesystem_router.test.ts
@@ -2,7 +2,17 @@ import { FileSystemRouter } from "bun";
 import { heapStats } from "bun:jsc";
 import { expect, it } from "bun:test";
 import fs, { mkdirSync, rmSync } from "fs";
-import { bunEnv, bunExe, isASAN, isMacOS, isWindows, normalizeBunSnapshot, tempDir, tmpdirSync } from "harness";
+import {
+  bunEnv,
+  bunExe,
+  isASAN,
+  isDebug,
+  isMacOS,
+  isWindows,
+  normalizeBunSnapshot,
+  tempDir,
+  tmpdirSync,
+} from "harness";
 import path, { dirname } from "path";
 
 function createTree(basedir: string, paths: string[]) {
@@ -1023,6 +1033,11 @@ it("reload() while Bun.build() resolves the same directory", async () => {
   // runs on the bundler thread) share the process-global directory-entry cache.
   // Run in a subprocess so a crash is observable as a signal instead of taking
   // down the test runner.
+  //
+  // A round is 4 builds, and a debug build takes about 0.4 s for each (a release
+  // build 0.02 s). ASAN, the default there, fails on the first read of a freed
+  // listing, so a debug build needs few rounds.
+  const rounds = isDebug ? 5 : 40;
   const files: Record<string, string> = {
     "fixture.ts": /* ts */ `
       import path from "path";
@@ -1044,7 +1059,7 @@ it("reload() while Bun.build() resolves the same directory", async () => {
       await Bun.build({ entrypoints, target: "bun", throw: false });
       let matches = 0;
       let buildsOk = true;
-      for (let round = 0; round < 40; round++) {
+      for (let round = 0; round < ${rounds}; round++) {
         const builds = Array.from({ length: 4 }, () =>
           Bun.build({ entrypoints, target: "bun", throw: false }),
         );
@@ -1078,7 +1093,7 @@ it("reload() while Bun.build() resolves the same directory", async () => {
     stderr: normalizeBunSnapshot(stderr, String(dir)),
     exitCode,
     signalCode: proc.signalCode,
-  }).toEqual({ stdout: "matches 2000 builds-ok true", stderr: "", exitCode: 0, signalCode: null });
+  }).toEqual({ stdout: `matches ${rounds * 50} builds-ok true`, stderr: "", exitCode: 0, signalCode: null });
 }, 60_000);
 
 it("loads routes from a directory already cached by Bun.build()", async () => {

From 72567f0b07b047aaa67dc9b8ca106f0b3b263d98 Mon Sep 17 00:00:00 2001
From: robobun <117481402+robobun@users.noreply.github.com>
Date: Wed, 28 Oct 2026 21:11:21 +0000
Subject: [PATCH 2/3] test: keep 40 rounds on a debug build without ASAN

The 5 rounds rest on ASAN, which fails on the first read of a freed
listing. A debug build without ASAN has no such check, so it keeps the
40 rounds that every other build runs.
---
 test/js/bun/util/filesystem_router.test.ts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/test/js/bun/util/filesystem_router.test.ts b/test/js/bun/util/filesystem_router.test.ts
index 70e47198dbe7..5712d49071d2 100644
--- a/test/js/bun/util/filesystem_router.test.ts
+++ b/test/js/bun/util/filesystem_router.test.ts
@@ -1034,10 +1034,10 @@ it("reload() while Bun.build() resolves the same directory", async () => {
   // Run in a subprocess so a crash is observable as a signal instead of taking
   // down the test runner.
   //
-  // A round is 4 builds, and a debug build takes about 0.4 s for each (a release
-  // build 0.02 s). ASAN, the default there, fails on the first read of a freed
-  // listing, so a debug build needs few rounds.
-  const rounds = isDebug ? 5 : 40;
+  // A round is 4 builds, and a debug build with ASAN takes about 0.4 s for each
+  // (a release build 0.02 s). ASAN fails on the first read of a freed listing,
+  // so that build needs few rounds.
+  const rounds = isDebug && isASAN ? 5 : 40;
   const files: Record<string, string> = {
     "fixture.ts": /* ts */ `
       import path from "path";

From 94d8d1d4c4eaacbea7416660d3ce36ac4735da43 Mon Sep 17 00:00:00 2001
From: robobun <117481402+robobun@users.noreply.github.com>
Date: Thu, 29 Oct 2026 02:44:17 +0000
Subject: [PATCH 3/3] ci: retrigger