When paddingStart is 0, it should override paddingHorizontal (#816)

Summary:
Fixes #815

Imagine a node with this style: `{ paddingHorizontal: 10, paddingStart: 0 }`.

After running layout on this node, we expect its computed `paddingStart` to be `0`. However, it is actually `10`.

Consider the expression `paddingEdgeStart.getValue() > 0.0f` in [`getLeadingPadding`](328ec7dc4d/yoga/YGNode.cpp (L461)). Why is `0` handled like a negative number rather than a positive number? I suspect this should be `>=` so `0` is handled like the positive numbers (this is how `getTrailingPadding` works).

It looks like 3a82d2b1a8 (diff-07b4949bf42749fde386e769ff08a124) changed the operator from `>=` to `>` in `getLeadingPadding`. I suspect it was a mistake. `getTrailingPadding` still uses `>=`.

I manually verified this using the code in #815 and added some unit tests to catch this bug and other similar issues.

Adam Comella
Microsoft Corp.
Pull Request resolved: https://github.com/facebook/yoga/pull/816

Reviewed By: priteshrnandgaonkar

Differential Revision: D10282617

Pulled By: shergin

fbshipit-source-id: 2ab2874ae39d9454308a020a960ace85573fe777
This commit is contained in:
Adam Comella 2018-10-12 15:04:54 -07:00 committed by Facebook Github Bot
parent 10fc548809
commit f90c9b5292

View File

@ -1,5 +1,5 @@
/* /*
* Copyright (c) Facebook, Inc. and its affiliates. * Copyright (c) 2018-present, Facebook, Inc.
* *
* This source code is licensed under the MIT license found in the LICENSE * This source code is licensed under the MIT license found in the LICENSE
* file in the root directory of this source tree. * file in the root directory of this source tree.
@ -458,7 +458,7 @@ YGFloatOptional YGNode::getLeadingPadding(
YGResolveValue(style_.padding[YGEdgeStart], widthSize); YGResolveValue(style_.padding[YGEdgeStart], widthSize);
if (YGFlexDirectionIsRow(axis) && if (YGFlexDirectionIsRow(axis) &&
style_.padding[YGEdgeStart].unit != YGUnitUndefined && style_.padding[YGEdgeStart].unit != YGUnitUndefined &&
!paddingEdgeStart.isUndefined() && paddingEdgeStart.getValue() > 0.0f) { !paddingEdgeStart.isUndefined() && paddingEdgeStart.getValue() >= 0.0f) {
return paddingEdgeStart; return paddingEdgeStart;
} }