777519 - nsHTMLReflowState::InitResizeFlags unnecessarily checks for min-height:auto and max-height:auto

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[Daniel Holbert [:dholbert]]

In bug 763689, I'm adding support for the new min-width / min-height: auto keyword. Before that bug's patches, we don't support "auto" for these properties.

However, nsHTMLReflowState::InitResizeFlags currently has this check:
> 533   bool dependsOnCBHeight =
[...]
> 537     (mStylePosition->MinHeightDependsOnContainer() &&
> 538      // FIXME: condition this on not-abspos?
> 539      mStylePosition->mMinHeight.GetUnit() != eStyleUnit_Auto) ||
http://mxr.mozilla.org/mozilla-central/source/layout/generic/nsHTMLReflowState.cpp#533
from this cset:
http://hg.mozilla.org/mozilla-central/rev/fcc2aa4bd451#l6.11

That "mMinHeight.GetUnit() != eStyleUnit_Auto" check is trivially true right now.

Moreover, after bug 763689 lets us have "auto" in computed-style, we explicitly *won't* want the check for 'auto' here. (since the used value of "min-height:auto" is either 0 or the item's intrinsic height -- it never depends on the container's height).

So, I think we want to just drop this line.

Comment 1

[Daniel Holbert [:dholbert]]

(In reply to Daniel Holbert [:dholbert] from comment #0)
> That "mMinHeight.GetUnit() != eStyleUnit_Auto" check is trivially true right
> now.

That's true of the mMaxHeight check in the same chunk of code, too, actually.

max-height doesn't accept "auto", as shown here:
  http://mxr.mozilla.org/mozilla-central/source/layout/style/nsCSSPropList.h#2064

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: fix v1

Comment 3

[Daniel Holbert [:dholbert]]

Attachment: fix v1a

(reposting patch with 8 lines of context, instead of 3, to make it clearer)

Comment 4

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

Comment on attachment 645904 [details] [diff] [review]
fix v1a

r=dbaron

Comment 5

[Daniel Holbert [:dholbert]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/83a4dfef9a7d

Comment 6

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/83a4dfef9a7d