when a node is both stretch and auto, get the result with width and height "null"

[Lizz0y]

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when a node is both cross stretch and margin auto, get the result with width and height "null",i have read the source code and found the following code:

          if (alignItem == YGAlignStretch &&
              YGMarginLeadingValue(child, crossAxis)->unit != YGUnitAuto &&
              YGMarginTrailingValue(child, crossAxis)->unit != YGUnitAuto) {

can someone explain , since the alignItem is already stretch ,auto is meaningless, so why this code exclude the auto ?

[woehrl01]

It excludes auto, as if you have a margin of auto, the node should not stretch. Margin is "stronger" than align-item. Thus the node is the size of its content, but it shouldn't be "null". Could you please provide a testcase where it fails, I'll take a look into it.

[Lizz0y]

i write a node with "text" type ,since text has no width&height,so i set a custom measureFunction as:

 YogaNode root = new YogaNode();
 root.setWidth(500);
 root.setHeight(300);

        YogaNode text = new YogaNode();
        text.setMeasureFunction(new YogaMeasureFunction() {
            @Override
            public long measure(YogaNode node, float width, YogaMeasureMode widthMode, float height, YogaMeasureMode heightMode) {
                return new YogaMeasureOutput().make(50,50);
            }
        });
       text.setMarginAuto(YogaEdge.LEFT);
        root.addChildAt(text, 0);

when i run this code ,find the text node return "null" for both height and width, please find what's wrong with it ,thx

[woehrl01]

It should be a width and height of 50 and left 450 here. I'll reproduce and have a look.

[woehrl01]

thank you for the hint @Lizz0y , I pushed a fix for this in #645

[Lizz0y]

thx @woehrl01 for fix this problem