use FinalizationRegistry to cancel the body if response is collected

[mcollina]

Fixes #2856

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 97.72727% with 1 line in your changes missing coverage. Please review.

Project coverage is 94.17%. Comparing base (ee64eb5) to head (728412f).
Report is 340 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/web/fetch/response.js	94.73%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3199      +/-   ##
==========================================
- Coverage   94.19%   94.17%   -0.03%     
==========================================
  Files          90       90              
  Lines       24493    24550      +57     
==========================================
+ Hits        23071    23119      +48     
- Misses       1422     1431       +9     

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[mcollina]

@KhafraDev I'm getting 8 WPT unexpected failures:

Uncaught exception in "/Users/matteo/Repositories/undici/test/wpt/tests/fetch/api/abort/general.any.js":
AbortError: This operation was aborted
    at new DOMException (node:internal/per_context/domexception:53:5)
    at AbortController.abort (node:internal/abort_controller:392:18)
    at Test.<anonymous> (evalmachine.<anonymous>:339:14)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
================================================================================================
Uncaught exception in "/Users/matteo/Repositories/undici/test/wpt/tests/fetch/api/abort/general.any.js":
AbortError: This operation was aborted
    at new DOMException (node:internal/per_context/domexception:53:5)
    at AbortController.abort (node:internal/abort_controller:392:18)
    at Test.<anonymous> (evalmachine.<anonymous>:228:16)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
================================================================================================
Uncaught exception in "/Users/matteo/Repositories/undici/test/wpt/tests/fetch/api/abort/general.any.js":
AbortError: This operation was aborted
    at new DOMException (node:internal/per_context/domexception:53:5)
    at AbortController.abort (node:internal/abort_controller:392:18)
    at Test.<anonymous> (evalmachine.<anonymous>:228:16)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
================================================================================================
Uncaught exception in "/Users/matteo/Repositories/undici/test/wpt/tests/fetch/api/abort/general.any.js":
AbortError: This operation was aborted
    at new DOMException (node:internal/per_context/domexception:53:5)
    at AbortController.abort (node:internal/abort_controller:392:18)
    at Test.<anonymous> (evalmachine.<anonymous>:248:14)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
================================================================================================
Uncaught exception in "/Users/matteo/Repositories/undici/test/wpt/tests/fetch/api/abort/general.any.js":
AbortError: This operation was aborted
    at new DOMException (node:internal/per_context/domexception:53:5)
    at AbortController.abort (node:internal/abort_controller:392:18)
    at Test.<anonymous> (evalmachine.<anonymous>:228:16)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
================================================================================================
Uncaught exception in "/Users/matteo/Repositories/undici/test/wpt/tests/fetch/api/abort/general.any.js":
AbortError: This operation was aborted
    at new DOMException (node:internal/per_context/domexception:53:5)
    at AbortController.abort (node:internal/abort_controller:392:18)
    at Test.<anonymous> (evalmachine.<anonymous>:228:16)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
================================================================================================
Uncaught exception in "/Users/matteo/Repositories/undici/test/wpt/tests/fetch/api/abort/general.any.js":
AbortError: This operation was aborted
    at new DOMException (node:internal/per_context/domexception:53:5)
    at AbortController.abort (node:internal/abort_controller:392:18)
    at Test.<anonymous> (evalmachine.<anonymous>:228:16)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
================================================================================================
Uncaught exception in "/Users/matteo/Repositories/undici/test/wpt/tests/fetch/api/abort/general.any.js":
AbortError: This operation was aborted
    at new DOMException (node:internal/per_context/domexception:53:5)
    at AbortController.abort (node:internal/abort_controller:392:18)
    at Test.<anonymous> (evalmachine.<anonymous>:376:14)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

I'm not sure how to debug this. Can you help?

[KhafraDev]

Weird test, I don't totally understand what's happening:

import { fetch } from './index.js'
import { createServer } from 'node:http'
import { once } from 'node:events'

process.on('uncaughtException', (e) => console.log('uncaught', e))

const server = createServer((req, res) => {
  setInterval(() => res.write(Buffer.from('hello, world')), 1)
}).listen(0)

await once(server, 'listening')

const ac = new AbortController()

await fetch(`http://localhost:${server.address().port}`, { signal: ac.signal })
ac.abort()

while (true) {
  await fetch(`http://localhost:${server.address().port}`).then(r => r.text())
}

[mcollina]

Found it!

[ronag]

I'm thinking could we do this one level lower? e.g. if the handler or resume is no longer referenced?

[ronag]

Instead of relying on finalization registry + GC. Should we have a setInterval loop that check all references once a second or something?

[metcoder95]

added

This can potentially benefit several use cases where there are side effects of not consuming the body, making the flow easier to reason about

[github-actions]

The backport to v6.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-v6.x v6.x
# Navigate to the new working tree
cd .worktrees/backport-v6.x
# Create a new branch
git switch --create backport-3199-to-v6.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 63b7794af7c282d543a56d13521f9d5e92fa61ae
# Push it to GitHub
git push --set-upstream origin backport-3199-to-v6.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-v6.x

Then, create a pull request where the base branch is v6.x and the compare/head branch is backport-3199-to-v6.x.

[mcollina]

This was already applied in v6.

[giulianovarriale]

Is the statement below still true after the resolution of this issue?

The Fetch Standard allows users to skip consuming the response body by relying on garbage collection to release connection resources. Undici does not do the same. Therefore, it is important to always either consume or cancel the response body.

Source: https://undici.nodejs.org/#/?id=garbage-collection

[mcollina]

Not entirely, as the resources will be eventually garbage collected. However, this might take some time, so consuming the body is still a best practice.