1921780 - Add some assertions for exception handling

Status: RESOLVED FIXED

(Core :: JavaScript Engine, task)

Description

[Jan de Mooij [:jandem]]

In bug 1921215 I added a cx->hadUncatchableException() flag. We can also use this to assert that if a JSNative (or scripted function execution) returns false, we're either throwing an exception or have reported an uncatchable exception. This helps catch some JSAPI footguns: see bug 552007 and bug 1408013.

Longer-term we should track uncatchable exceptions using the ExceptionStatus enum because it's more precise, but this is a step in that direction.

Initially I'll probably only enable this for the JS shell, but if that's green we can see what happens in the browser.

Comment 1

[Jan de Mooij [:jandem]]

Attachment: Bug 1921780 - Improve exception handling assertions in the JS shell. r?arai!

If a JSNative or script execution returns false, we now assert we have a pending exception
or at some point an uncatchable exception was reported. Bug 1921215 added the hadUncatchableException_
flag to JSContext.

For now enable this only in the JS shell. If that's green we can try enabling it everywhere.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/de8b96102f94
Improve exception handling assertions in the JS shell. r=arai

Comment 3

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/de8b96102f94