1825434 - Warning Spew on Debug Build: "WARNING: have unconstrained width or height [...]"

Status: RESOLVED FIXED

(Core :: Layout: Positioned, defect)

Description

[David Shin[:dshin]]

Attachment: Mimimum Reproducible Case

"WARNING: have unconstrained width or height; this should only result from very large sizes, not attempts at intrinsic size calculation: 'aPercentBasis != NS_UNCONSTRAINEDSIZE', file /home/dshin/mozilla-unified/layout/base/nsLayoutUtils.h:1566"

Spews due to New Tab being loaded in. Especially spews when the windows is being resized.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: stack from gdb

Comment 2

[Daniel Holbert [:dholbert]]

I can reproduce with dshin's testcase in kinda-old debug builds, e.g. 2022-09-30, launched via:

mozregression -B debug --launch 2022-09-30

So: preexisting issue, which we presumably started to trip over recently via some frontend change (probably a xul-to-flex conversion)

Comment 3

[Daniel Holbert [:dholbert]]

regression range for this happening on new-tab page:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=ee139bb6ad78eeac5480a561eb92fc156907e956&tochange=aa751ccc4abd19b78cf384df2dcf33461aa5fa87
--> bug 1819712. So, the new-tab save-to-pocket icon must be triggering this preexisting issue.

Comment 4

[Daniel Holbert [:dholbert]]

So, the new-tab save-to-pocket icon must be triggering this preexisting issue.

(This makes sense, given the "stp-button" stuff in the reduced testcase)

Comment 5

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Attachment: Mimimum Reproducible Case #2

I reduced dshin's testcase a bit. The warning can be triggered in block layout.

Comment 6

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Attachment: Bug 1825434 - Use containing block's inline-size as percentage basis when computing abspos hypothetical position.

The containing block's block-size (blockContentSize.BSize()) can be
unconstrained if it has position:relative at the time we call the
CalculateBorderPaddingMargin(). That triggers the warning. However, the
percentage margin and padding should resolve against containing block's
inline-size.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4b44c83b4e67
Use containing block's inline-size as percentage basis when computing abspos hypothetical position. r=AlaskanEmily

Comment 8

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/4b44c83b4e67