node:worker_threads low-hanging fruit by 190n · Pull Request #18758 · oven-sh/bun

190n · 2025-04-03T21:11:48Z

What does this PR do?

Fixes some of the easier tests from test/parallel/test-worker-*

Ensure Worker with execArgv: [] receives an empty array for process.execArgv instead of inheriting the parent thread's array (I haven't found this covered in the Node tests yet so I added it to ours)
~~Progress toward Bun crash with Worker #18139 (but not fixed; I may move that to another PR if I get a complete fix in)~~
- Fix crash running Node-API finalizers during VM destruction #18767
Added support for reading the environment variable BUN_DESTRUCT_VM_ON_EXIT=1, which tells Bun to destroy the main thread's JavaScript VM when the process exits. Normally, Worker VMs are the only ones that get destroyed. The intent of this flag is that running a test or program with it will expose bugs that would otherwise only have occurred if the code was running inside a Worker that exited. For instance, the changes from Fix UDPSocket not being closed when VM destructs #18687 were motivated by running a Node UDP test with BUN_DESTRUCT_VM_ON_EXIT=1.
Makes the name of the node:fs/promises FileHandle constructor be FileHandle instead of FileHandle2, and adds a property Symbol(messaging_transfer_symbol) (this is progress towards test-worker-message-port-transfer-fake-js-transferable-internal.js but does not fix it just yet)
Makes postMessage avoid calling a user-overridden Array.prototype[Symbol.iterator]
Makes autoSelectFamilyAttemptTimeoutDefault in node:net unique per-thread. Our code doesn't use this value anywhere, but Node's test harness multiplies the value by a fixed amount before the tests run. This means that if you have a Node test that repeatedly spawns new Workers, each one will greatly increase the global autoSelectFamilyAttemptTimeoutDefault, until eventually a TypeError is thrown because the harness attempts to increase it past the u32 limit.
Makes worker.getHeapSnapshot() error if called on a Worker that isn't running or if the options object is invalid
~~Makes the online event fire right before a Worker starts running its entrypoint instead of right after~~
- node:worker_threads: improve error messages, support environmentData, emit worker event #18768
Ensures the exit event is fired with code 1 instead of 0 on a Worker which throws an uncaught exception
Accept and call a callback function passed to worker.terminate, and emit a deprecation warning if you do so
Makes Symbol arguments passed in the argv and execArgv arrays coerce to Symbol(description) instead of throwing an error
Makes process.argv contain [worker eval] instead of a Blob URL for Workers spawned with eval: true
Adds error if the env option spawning a Worker is not the right type
Adjusts the error message when closing an already-closed MessagePort~~, and makes MessagePort.close accept a callback~~
- node:worker_threads: improve error messages, support environmentData, emit worker event #18768
Fix never freeing the source code for eval: true Workers

TODOs:

calling terminate doesn't fire the exit event (this affects several tests)
find out which tests are wrongly categorized as worker_threads (several of Node's worker tests are just "do XYZ, but in a worker that terminates at some inconvenient time," and many of those tests run into bugs with our implementation of XYZ before they run into any worker bugs)
ensure there are no regressions
possibly fix more tests

How did you verify your code works?

Node tests

…ynchronously

…rowing synchronously" This reverts commit 1448e6a.

…ference to GlobalObject

…HeapSnapshot()

src/bun.js/bindings/napi.h

test/js/node/test/parallel/test-worker-workerdata-sharedarraybuffer.js

Jarred-Sumner · 2025-04-03T21:29:43Z

src/bun_js.zig

                .args = ctx.args,
                .graph = graph_ptr,
                .is_main_thread = true,
+                .destruct_main_thread_on_exit = bun.getenvTruthy("BUN_DESTRUCT_VM_ON_EXIT"),


Suggested change

.destruct_main_thread_on_exit = bun.getenvTruthy("BUN_DESTRUCT_VM_ON_EXIT"),

.destruct_main_thread_on_exit = bun.getRuntimeFeatureFlag("BUN_DESTRUCT_VM_ON_EXIT"),

Jarred-Sumner

Mostly looks good but a few comments

Jarred-Sumner · 2025-04-03T23:28:06Z

src/bun.js/bindings/webcore/MessagePort.cpp

+        auto* globalObject = defaultGlobalObject(lexicalGlobalObject);
+        if (globalObject && callback.isCallable()) {
+            if (auto* process = jsDynamicCast<Bun::Process*>(globalObject->processObject())) {
+                process->queueNextTick(globalObject, AsyncContextFrame::withAsyncContextIfNeeded(globalObject, callback));


Can you check when Node calls this callback? It's unlikely called on process.nextTick

https://github.com/nodejs/node/blob/24e4a5447197c1adaec1538b0d55732e21b11a87/src/node_messaging.cc#L709

https://github.com/nodejs/node/blob/24e4a5447197c1adaec1538b0d55732e21b11a87/src/handle_wrap.cc#L81-L83

They attach it to the message port to be called later. I didn't look very hard into where it gets called from there; I'll undo the change for now and investigate more for a later PR

#18768 is where the fixed version of this will go

)

This reverts commits: - 92a73de Move napiEnvs to ScriptExecutionContext and give napi_env a strong reference to GlobalObject - a0e41dc Add test for #18139 - 806b59c Test napi_add_finalizer in main thread instead of worker - 110f398 Emit online event before Worker entrypoint runs - 6943c56 Accept callback in MessagePort.close These are being moved to new PRs.

Ben Grant added 30 commits March 14, 2025 13:41

Sync already-added tests with Node

e222f8c

Merge branch 'main' into ben/workers

35e2a6c

Sync declarations and definitions of Bun__Process__exit

c434e07

Merge branch 'main' into ben/workers

5ea190b

add TODO for [[noreturn]] issue

985bd5c

Emit Worker construction errors as error events instead of throwing s…

1448e6a

…ynchronously

Revert "Emit Worker construction errors as error events instead of th…

b0628fe

…rowing synchronously" This reverts commit 1448e6a.

Clean up worker options

3724c34

Undo noreturn

eacc092

Merge branch 'main' into ben/workers

c882d75

Clarify sus code

db77d8c

Move napiEnvs to ScriptExecutionContext and give napi_env a strong re…

92a73de

…ference to GlobalObject

Add test for #18139

a0e41dc

Merge branch 'main' into ben/workers

31e778e

Add BUN_DESTRUCT_VM_ON_EXIT

ea40a1d

Skip destructOnExit while JS is running

6382ae9

Test napi_add_finalizer in main thread instead of worker

806b59c

Make BUN_DESTRUCT_VM_ON_EXIT work for bun test

488fc97

Make FileHandle.name "FileHandle" not "FileHandle2"

92d7a44

Add fake kTransfer property to FileHandle

d55018a

Don't call overridden Array.prototype[Symbol.iterator] in postMessage

4e05b19

Give each Worker its own autoSelectFamilyAttemptTimeoutDefault

86c6282

Add basic argument validation and error for non-running Worker to get…

311a8fb

…HeapSnapshot()

Emit online event before Worker entrypoint runs

110f398

Emit exit() event with code 1 when worker has uncaught exception

58c861b

Accept callback (and emit warning) in Worker.terminate()

62ad353

Merge branch 'main' into ben/workers

4364820

Add basic test for execArgv handling

bca0cea

Add TODO

4795935

Merge branch 'main' into ben/workers

7f2837a

Jarred-Sumner reviewed Apr 3, 2025

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Ben Grant and others added 15 commits April 3, 2025 17:02

Delete test-vm-on-exit.cpp

bdd9d0a

Fix leaking source code of {eval:true} workers

7110127

Add leak test

b8a2166

Delete duplicate getVM call

3e67ef8

Use getRuntimeFeatureFlag instead of getenvTruthy

aaa785c

Lazy-initialize FinalizationRegistry

a25c638

Fix build script outside of CI

b4079af

Bump WebKit (#18667)

4afa668

fix(crypto): remove verifyError from DiffieHellman.prototype (#18710

c63b15b

)

build: do not include UBSan RT in bun-zig.o (#18726)

937cfa6

Disable remap and resize in AllocationScope

78abbb6

fix bundling regression with builtin modules (#18735)

db0ee25

Remove usage of JSC.Strong from Subprocess (#18725)

1562b56

Merge branch 'main' into ben/workers

6e69607

This was referenced Apr 4, 2025

Fix crash running Node-API finalizers during VM destruction #18767

Draft

node:worker_threads: improve error messages, support environmentData, emit worker event #18768

Merged

Ben Grant added 3 commits April 3, 2025 18:51

Remove failing test

7aab1cd

Fix test-util-callbackify.js

708e124

Remove test-worker-process-exit-async-module.js

6ec1a05

190n marked this pull request as ready for review April 7, 2025 21:09

Jarred-Sumner merged commit eee5d4f into main Apr 8, 2025
67 of 70 checks passed

Jarred-Sumner deleted the ben/workers branch April 8, 2025 12:29

190n mentioned this pull request Apr 8, 2025

experiment: destroy JSC::VM at exit when running tests in CI #18870

Closed

Telokis mentioned this pull request Jun 17, 2025

SHARE_ENV doesn't work for worker_threads #20451

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node:worker_threads low-hanging fruit#18758

node:worker_threads low-hanging fruit#18758
Jarred-Sumner merged 55 commits intomainfrom
ben/workers

190n commented Apr 3, 2025 •

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	.destruct_main_thread_on_exit = bun.getenvTruthy("BUN_DESTRUCT_VM_ON_EXIT"),
	.destruct_main_thread_on_exit = bun.getRuntimeFeatureFlag("BUN_DESTRUCT_VM_ON_EXIT"),

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190n commented Apr 3, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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190n commented Apr 3, 2025 •

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