1822927 - The signature of overridden methods for maplike/setlike should match that of default methods

Status: NEW

(Core :: DOM: Bindings (WebIDL), defect, P3)

Description

[Edgar Chen [:edgar]]

See https://webidl.spec.whatwg.org/#idl-maplike

Note: Read-write maplike interfaces can have operations named "clear", "delete", or "set", which will override the default implementation of those methods (defined in § 3.7.11 Maplike declarations). If such operations are defined, they must match the input and output expectations of each method, defined in their default implementation sections.

And https://webidl.spec.whatwg.org/#es-map-delete

If the interface does declare a delete method, it should similarly map a -0 key to +0, and must return a boolean indicating whether the key was present or not.

WebIDL parser should throw error if signature of overridden methods isn't matched.

Comment 1

[Jan Jaeschke [:jjaschke]]

Maybe noteworthy here (even though more related to bug 1799890): JS world uses methods that start with a lower key (clear(), delete()) while C++ methods (per convention) start with an Upper key (Clear(), Delete()).

This does actually make a difference when it comes to range-based iteration. Things like for(auto& iter: array) {} only work if the class provides begin() and end() iteration methods which start with a lower key.

Comment 2

[Edgar Chen [:edgar]]

(In reply to Edgar Chen [:edgar] from comment #0)

WebIDL parser should throw error if signature of overridden methods isn't matched.

We could address this around https://searchfox.org/mozilla-central/rev/8011b6325f7ce05d228a3cdefd45d74fb98ee7b4/dom/bindings/parser/WebIDL.py#4883-4889. :jjaschke, ni? you in case you are interested.

Comment 3

[Jan Jaeschke [:jjaschke]]

I'll take a look when I find time.