1216747 - nsRuleNode::ComputePositionData caches writing-mode-specific data in the rule tree

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect)

Description

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Bug 1122253 added code that computes an nsStylePosition struct in ways that depend on the writing mode, and then caches that struct in the rule tree.  This causes the cached struct to be used incorrectly.

Comment 1

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: testcase

Comment 2

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: Record dependency on writing mode in nsRuleNode::ComputeStylePosition

Without the patch, both reftests fail; with it, both pass.

Comment 3

[Cameron McCormack (:heycam)]

I wonder if it would be worth trying to add assertions that fire if mWritingMode or mFont.size are used and conditions isn't updated appropriately.  (It would need some trickiness like exposing those values only through methods on style structs, and also returning them as an object that supports conversion to their actual type, so that we could know when their values are actually used, as opposed to just retrieved.)

Comment 4

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/eae93d445958

Comment 5

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

(In reply to Cameron McCormack (:heycam) from comment #3)
> I wonder if it would be worth trying to add assertions that fire if

At first glance, it sounds like more trouble than it's worth.

Comment 6

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/0bcf20224e95

Comment 7

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: Cleanup after test fix

Comment 8

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/eae93d445958
https://hg.mozilla.org/mozilla-central/rev/0bcf20224e95

Comment 9

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/8390018203c4

Comment 10

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/8390018203c4