1726595 - WebIDL code generation for Promise returning callbacks doesn't handle abrupt completions correctly.

Status: RESOLVED FIXED

(Core :: DOM: Bindings (WebIDL), defect)

Description

[Matthew Gaudet (he/him) [:mgaudet]]

Our Promise-returning callback interfaces (callback Foo = Promise<...>()) don't correctly handle abrupt completions

The WebIDL spec for callback invoke has as Step 15.5 and 15.6 returning a promise rejected with the error; however, it appears that we instead simply return nullptr and note the exception on the return value.

There's only one in-tree consumer of a Promise returning callback: LockGrantedCallback which has a special helper to handle this.

Comment 1

[Matthew Gaudet (he/him) [:mgaudet]]

I spent more than a few hours trying to get something working; alas, every approach I've taken has been thwarted so far. Can share in progress code if there's interest.

Comment 2

[Peter Van der Beken [:peterv]]

Attachment: Bug 1726595 - WebIDL code generation for Promise returning callbacks doesn't handle abrupt completions correctly. r?edgar!

Comment 3

[Peter Van der Beken [:peterv]]

Attachment: Diff of generated binding code

Comment 4

[Peter Van der Beken [:peterv]]

Note that even with this, there are cases where creating the promise for the return value fails. So I think the LockGrantedCallback helper might need to stay.

Comment 5

[Kagami Rosylight [:saschanaz] (they/them) (OOO until 2025-08-18)]

Thanks, I guess I can resolve bug 1726363 as a dupe of this?

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/68364de67158
WebIDL code generation for Promise returning callbacks doesn't handle abrupt completions correctly. r=edgar

Comment 8

[Cristian Tuns]

https://hg.mozilla.org/mozilla-central/rev/68364de67158