1611173 - Remove support for non-nsISupports XPIDL interfaces

Status: RESOLVED FIXED

(Core :: XPConnect, task, P3)

Description

[Andrew McCreight [:mccr8]]

In the new world of static XPCOM interfaces, I think we can get rid of nsXPConnect::IsISupportsDescendant(). There are only two uses of it.

For the first, we'd have to make sure that builtinclass is set for any interface that isn't an nsISupports. Hopefully that's already the case?

For the second, we'd have to make sure that the method count for any non-nsISupports descendant is 0. As before, hopefully this is implied by builtinclass.

So, maybe this is just a matter of confirming that the behavior is reasonable and then deleting the methods.

Comment 1

[Andrew McCreight [:mccr8]]

The Rust IDL bindings generator asserts that non-nsISupports interfaces have no attributes or methods, which means the second condition above already holds. It does feel a bit weird to enforce it there and not in xpidl.py.

It looks like we can actually enforce an even stronger invariant, though: we seem to have no non-nsISupports XPIDL interfaces! I wonder when the last one of those went away. (It was supported because you could define an XPIDL interface that only had constants, and you were allowed to use the constants but nothing else.)

Comment 2

[Andrew McCreight [:mccr8]]

I'd guess that Boris's de-COM work on DOM nodes took care of at least some of these non-nsISupports XPIDL interfaces. I recall there being a lot of constants in some of those interfaces.

Comment 3

[Andrew McCreight [:mccr8]]

Attachment: Bug 1611173 - Remove support for non-nsISupports XPIDL interfaces.

It used to be that some XPIDL interfaces were allowed to be non-nsISupports,
and were only used to hold a bunch of constants. It appears that we've now
had enough de-COM work happen that there are no longer any, so we can remove
support for this.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/64c8ab5ec067
Remove support for non-nsISupports XPIDL interfaces. r=nika

Comment 5

[Cristian Brindusan [:cbrindusan]]

Backed out changeset 64c8ab5ec067 (Bug 1611173) for linting failure at xpidl.py.
https://hg.mozilla.org/integration/autoland/rev/d359f8f956fa149503c82bb0d94de0de6d1bc3cc

Push with failures:
https://treeherder.mozilla.org/#/jobs?repo=autoland&resultStatus=pending%2Crunning%2Csuccess%2Ctestfailed%2Cbusted%2Cexception&revision=64c8ab5ec067fbbb1b5429c5fad9d7efa0766d44&selectedJob=286419053

Failure log:
https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=286419053&repo=autoland&lineNumber=323

Comment 6

[Cristian Brindusan [:cbrindusan]]

There are also some Linux asan bustages on runtests.py :
https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=286419033&repo=autoland&lineNumber=56104

Comment 7

[Andrew McCreight [:mccr8]]

I fixed the lint error, but I didn't see the second message before I queued the landing. So it may need to get re-backed out...

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/27bd6308aff7
Remove support for non-nsISupports XPIDL interfaces. r=nika

Comment 9

[Pulsebot]

Backout by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4387ba4db209
Backed out changeset 27bd6308aff7 for build bustages at runtests.py. CLOSED TREE

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/f706b0ac9227
Remove support for non-nsISupports XPIDL interfaces. r=nika

Comment 11

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/f706b0ac9227