1242789 - Allow lambdas capturing raw pointers to refcounted objects *by reference*

Status: RESOLVED FIXED

(Developer Infrastructure :: Source Code Analysis, defect)

Description

[Botond Ballo [:botond]]

In bug 1153304, we introduced a static analysis to prevent lambdas from capturing raw pointers to refcounted objects. 

The idea was to avoid scenarios where the the captured raw pointer outlives the function in which the lambda is created (e.g. because a copy of the lambda is stored somewhere that outlives the function).

:jgilbert pointed out in bug 1201275 comment 4 that this check doesn't have much value in the case where the raw pointer is being captured *by reference*. In such a case, the correctness of the code is already predicated on the lambda not outliving the original raw pointer variable, so forcing that variable to have type RefPtr doesn't add any safety.

I'd like to propose modifying the static analysis to allow this case. Thoughts?

Comment 1

[Nika Layzell [:nika] (ni? for response)]

Attachment: Allow lambdas to capture raw pointers to refcounted objects by reference

Comment 2

[Nika Layzell [:nika] (ni? for response)]

try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=ed8e8c713011

Comment 3

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/8e3441257c01

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/8e3441257c01