fix margin auto lead to negativ positioning

gentest/fixtures/YGMarginTest.html

@@ -149,4 +149,14 @@
 <div id="margin_auto_left_stretching_child" style="width: 200px; height: 200px; align-items: center;">
   <div style="flex: 1; margin-left:auto;"></div>
   <div style="width: 50px; height: 50px;"></div>
-</div>
+</div>
+
+<div id="margin_top_auto_overflow_parent" style="flex-direction:column; height: 500px; width: 20px;">
+  <div style="height: 300px;"></div>
+  <div style="margin-top: auto; height: 300px;"></div>
+</div>
+
+<div id="margin_bottom_auto_overflow_parent" style="flex-direction:column; height: 500px; width: 20px;">
+  <div style="height: 300px;"></div>
+  <div style="margin-top: auto; height: 300px;"></div>
+</div>

tests/YGMarginTest.cpp

@@ -4,7 +4,8 @@
  * This source code is licensed under the MIT license found in the LICENSE
  * file in the root directory of this source tree.
  */
-// @Generated by gentest/gentest.rb from gentest/fixtures/YGMarginTest.html
+// @Generated by gentest/gentest.rb from 
+// gentest/fixtures/YGMarginTest.html
 
 #include <gtest/gtest.h>
 #include <yoga/Yoga.h>
@@ -1714,3 +1715,111 @@ TEST(YogaTest, margin_auto_left_stretching_child) {
 
   YGConfigFree(config);
 }
+
+TEST(YogaTest, margin_top_auto_overflow_parent) {
+  const YGConfigRef config = YGConfigNew();
+
+  const YGNodeRef root = YGNodeNewWithConfig(config);
+  YGNodeStyleSetWidth(root, 20);
+  YGNodeStyleSetHeight(root, 500);
+
+  const YGNodeRef root_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root_child0, 300);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  const YGNodeRef root_child1 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetMarginAuto(root_child1, YGEdgeTop);
+  YGNodeStyleSetHeight(root_child1, 300);
+  YGNodeInsertChild(root, root_child1, 1);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root_child1));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root_child1));
+
+  YGNodeFreeRecursive(root);
+
+  YGConfigFree(config);
+}
+
+TEST(YogaTest, margin_bottom_auto_overflow_parent) {
+  const YGConfigRef config = YGConfigNew();
+
+  const YGNodeRef root = YGNodeNewWithConfig(config);
+  YGNodeStyleSetWidth(root, 20);
+  YGNodeStyleSetHeight(root, 500);
+
+  const YGNodeRef root_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root_child0, 300);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  const YGNodeRef root_child1 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetMarginAuto(root_child1, YGEdgeTop);
+  YGNodeStyleSetHeight(root_child1, 300);
+  YGNodeInsertChild(root, root_child1, 1);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root_child1));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root_child1));
+
+  YGNodeFreeRecursive(root);
+
+  YGConfigFree(config);
+}

yoga/Yoga.cpp

@@ -2590,7 +2590,8 @@ static void YGJustifyMainAxis(
       // We need to do that only for relative elements. Absolute elements do not
       // take part in that phase.
       if (childStyle.positionType() == YGPositionTypeRelative) {
-        if (child->marginLeadingValue(mainAxis).unit == YGUnitAuto) {
+        if (child->marginLeadingValue(mainAxis).unit == YGUnitAuto 
+          && collectedFlexItemsValues.remainingFreeSpace > 0.0f) {
           collectedFlexItemsValues.mainDim +=
               collectedFlexItemsValues.remainingFreeSpace /
               numberOfAutoMarginsOnCurrentLine;
@@ -2603,7 +2604,8 @@ static void YGJustifyMainAxis(
               pos[mainAxis]);
         }
 
-        if (child->marginTrailingValue(mainAxis).unit == YGUnitAuto) {
+        if (child->marginTrailingValue(mainAxis).unit == YGUnitAuto
+          && collectedFlexItemsValues.remainingFreeSpace > 0.0f) {
           collectedFlexItemsValues.mainDim +=
               collectedFlexItemsValues.remainingFreeSpace /
               numberOfAutoMarginsOnCurrentLine;