933087 - WebIDL codegen bug with Maybe<JS:Rooted> causes marionette failures

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Gregor Wagner [:gwagner]]

Running marionette tests on emulator debug builds hits
Assertion failure: *stack == reinterpret_cast<Rooted<void*>*>(this)
https://tbpl.mozilla.org/php/getParsedLog.php?id=29893900&tree=Pine&full=1

The test uses the settings API.

Mrbkap tracked it down to a Maybe<JS::Rooted> bug in the webidl code generator.
The code in question is in SettingsManagerBinding.cpp:
static bool
set(JSContext* cx, JS::Handle<JSObject*> obj, mozilla::dom::SettingsLock* self, const JSJitMethodCallArgs& args)
with:
  Maybe<JS::Rooted<JSObject*> > unwrappedObj;
  JS::Rooted<JSObject*> arg0(cx);

Comment 1

[Boris Zbarsky [:bzbarsky]]

Oy.  Looks like a regression from bug 903772...  Good thing Rooted is a no-op normally!

We just need to fix the ordering here.

Comment 2

[Boris Zbarsky [:bzbarsky]]

Attachment: Make sure we don't violate stack discipline for Rooted, even when playing Maybe<Rooted> games.

Comment 3

[Gregor Wagner [:gwagner]]

I pushed this patch to our project branch that runs debug emulator tests:
https://tbpl.mozilla.org/?tree=Pine&rev=e334e2d64100

Comment 4

[Boris Zbarsky [:bzbarsky]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/9ca072ad958c

Comment 5

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/9ca072ad958c