lib: refactor transferable AbortSignal

[flakey5]

Took over the pr from @jasnell with his permission. Original pr was #43388 which can be closed now, feedback comments from there were addressed here.

Co-authored-by: James M Snell jasnell@gmail.com

[jasnell]

+1! Btw, so folks know, this is my son. He wanted something to help get started contributing so I recommended that he take over this change.

/Cc @mcollina

[jasnell]

Ok, it looks like there was a change that landed recently that changed AbortController to use a private #signal field instead of the internal kSymbol.... unfortunately that isn't going to work with the new util.transferableAbortController() API since that needs to be able to create the AbortController instance without using the default constructor. /cc @joyeecheung ...

@flakey5 ... the patch below fixes the error here. You'll want to apply this patch locally, add it as a fixup commit (lookup how to use git commit --fixup) and push the additional commit up

diff --git a/lib/internal/abort_controller.js b/lib/internal/abort_controller.js
index 313aee54fe..c5842a6638 100644
--- a/lib/internal/abort_controller.js
+++ b/lib/internal/abort_controller.js
@@ -82,6 +82,7 @@ const kAborted = Symbol('kAborted');
 const kReason = Symbol('kReason');
 const kCloneData = Symbol('kCloneData');
 const kTimeout = Symbol('kTimeout');
+const kSignal = Symbol('kSignal');
 
 function customInspect(self, obj, depth, options) {
   if (depth < 0)
@@ -309,20 +310,23 @@ function abortSignal(signal, reason) {
 }
 
 class AbortController {
-  #signal = createAbortSignal();
+  // We can't use a private symbol here because doing so would prevent
+  // transferableAbortController from being able to set the transferable
+  // signal.
+  [kSignal] = createAbortSignal();
 
   /**
    * @type {AbortSignal}
    */
   get signal() {
-    return this.#signal;
+    return this[kSignal];
   }
 
   /**
    * @param {any} reason
    */
   abort(reason = new DOMException('This operation was aborted', 'AbortError')) {
-    abortSignal(this.#signal, reason);
+    abortSignal(this[kSignal], reason);
   }
 
   [customInspectSymbol](depth, options) {

[mcollina]

lgtm

Adding a benchmark would be nice, but not strictly necessary.

[ShogunPanda]

LGTM!

[ShogunPanda]

Adding a benchmark would be nice, but not strictly necessary.

@mcollina I think that's the first time I've read this from you. XD

[mcollina]

This has been thoroughly identified as a major fetch issue by @RafaelGSS and @devsnek in nodejs/undici#1203 (comment) and nodejs/undici#1203 (comment).

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/45734/

[rluvaton]

+1! Btw, so folks know, this is my son. He wanted something to help get started contributing so I recommended that he take over this change.

Family goals

[targos]

There's a failing test:

=== release test-abortcontroller ===
Path: parallel/test-abortcontroller
Error: --- stderr ---
node:assert:124
  throw new AssertionError(obj);
  ^

AssertionError [ERR_ASSERTION]: Missing expected exception (TypeError).
    at Object.<anonymous> (/home/runner/work/node/node/test/parallel/test-abortcontroller.js:109:5)
    at Module._compile (node:internal/modules/cjs/loader:1120:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1174:10)
    at Module.load (node:internal/modules/cjs/loader:998:32)
    at Module._load (node:internal/modules/cjs/loader:839:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:86:12)
    at node:internal/main/run_main_module:17:47 {
  generatedMessage: false,
  code: 'ERR_ASSERTION',
  actual: undefined,
  expected: { name: 'TypeError' },
  operator: 'throws'
}

Node.js v19.0.0-pre
Command: out/Release/node --no-warnings --expose-gc --expose-internals /home/runner/work/node/node/test/parallel/test-abortcontroller.js

[jasnell]

@flakey5 ... after the github action checks complete here, if they all come up green, go ahead and squash all of the commits here into a single commit. After, I will run this through the regular CI. Assuming that comes up green, we should be good to go to get this landed :-)

[danielleadams]

@flakey5 do you mind creating a backport PR to this for v18.x? This broke tests on the release line. Thank you.

[juanarbol]

@flakey5 do you mind creating a backport PR to this for v18.x? This broke tests on the release line. Thank you.

Same for v16.x

[flakey5]

@flakey5 do you mind creating a backport PR to this for v18.x? This broke tests on the release line. Thank you.

@flakey5 do you mind creating a backport PR to this for v18.x? This broke tests on the release line. Thank you.

Same for v16.x

My bad didn't see either of these. I'll start working on the v18.x backport in a sec

[flakey5]

v18.x backport: #44941