1438015 - _findSafeGetterValues doesn't make much sense for Promise-returning attributes

Status: RESOLVED DUPLICATE of bug 1477765

(DevTools :: Debugger, enhancement)

Description

[Boris Zbarsky [:bzbarsky]]

When I added a Promise-typed attribute on Document, devtools/shared/webconsole/test/test_object_actor_native_getters_lenient_this.html failed.  This was because aResponse.safeGetterValues contains the name of that attribute.  And that happens because _findSafeGetterValues over in object.js doesn't really make sense, afaict.  It's trying to filter out some attributes somewhere, but the filtering it does wouldn't work for Promise-returning attributes, which would return a rejected Promise where this code expects an exception.

Comment 1

[Boris Zbarsky [:bzbarsky]]

I am hacking around this bug in devtools/shared/webconsole/test/test_object_actor_native_getters_lenient_this.html for now.

Comment 2

[Jason Laster [:jlast]]

_findSafeGetterValues is known to be fragile https://searchfox.org/mozilla-central/source/devtools/server/actors/object.js#354.


CC :jimb what do you think we should do?

Comment 3

[Boris Zbarsky [:bzbarsky]]

Jim and I had a long conversation about this on IRC, fwiw; I was assuming he would follow up here.

He recommended changing _findSafeGetterValues to treat an already-rejected return value promise just like a thrown exception is treated.

Comment 4

[Brian Grinstead [:bgrins]]

(In reply to Boris Zbarsky [:bz] (no decent commit message means r-) from comment #3)
> He recommended changing _findSafeGetterValues to treat an already-rejected
> return value promise just like a thrown exception is treated.

I'm making this change in Bug 1477765.