fix: remove gap if its last element in line (fix flex gap extra spacing when children determine parents main axis size) (#1188)

Summary:
Fixes - https://github.com/facebook/react-native/issues/35553

## Approach
We're using `betweenMainDim` to add [gap between](bbeede82d3/yoga/Yoga.cpp (L2495)) items in main axis. This is resulting in increased [main axis](bbeede82d3/yoga/Yoga.cpp (L2598)) dimension of the container as it gets added even for the last element. One solution is to keep using it and subtract the gap when last element is reached.

## Aside
Mutating this value feels weird, but I think `betweenMainDim` gets initialized for every line so should be fine? I did some manual tests to verify. I tried running tests but I'll have to downgrade the java version. Let me know if anything fails. Thanks! 🙏

Pull Request resolved: https://github.com/facebook/yoga/pull/1188

Test Plan: Added fixtures which previously failed but now pass.

Reviewed By: necolas

Differential Revision: D42078162

Pulled By: NickGerleman

fbshipit-source-id: 0e535618350422e001141a8786a83fc81651afe9

csharp/tests/Facebook.Yoga/YGGapTest.cs

@@ -1597,6 +1597,74 @@ namespace Facebook.Yoga
             Assert.AreEqual(150f, root_child4.LayoutHeight);
         }
 
+        [Test]
+        public void Test_column_gap_determines_parent_width()
+        {
+            YogaConfig config = new YogaConfig();
+
+            YogaNode root = new YogaNode(config);
+            root.FlexDirection = YogaFlexDirection.Row;
+            root.Height = 100;
+            root.ColumnGap = 10;
+
+            YogaNode root_child0 = new YogaNode(config);
+            root_child0.Width = 10;
+            root.Insert(0, root_child0);
+
+            YogaNode root_child1 = new YogaNode(config);
+            root_child1.Width = 20;
+            root.Insert(1, root_child1);
+
+            YogaNode root_child2 = new YogaNode(config);
+            root_child2.Width = 30;
+            root.Insert(2, root_child2);
+            root.StyleDirection = YogaDirection.LTR;
+            root.CalculateLayout();
+
+            Assert.AreEqual(0f, root.LayoutX);
+            Assert.AreEqual(0f, root.LayoutY);
+            Assert.AreEqual(80f, root.LayoutWidth);
+            Assert.AreEqual(100f, root.LayoutHeight);
+
+            Assert.AreEqual(0f, root_child0.LayoutX);
+            Assert.AreEqual(0f, root_child0.LayoutY);
+            Assert.AreEqual(10f, root_child0.LayoutWidth);
+            Assert.AreEqual(100f, root_child0.LayoutHeight);
+
+            Assert.AreEqual(20f, root_child1.LayoutX);
+            Assert.AreEqual(0f, root_child1.LayoutY);
+            Assert.AreEqual(20f, root_child1.LayoutWidth);
+            Assert.AreEqual(100f, root_child1.LayoutHeight);
+
+            Assert.AreEqual(50f, root_child2.LayoutX);
+            Assert.AreEqual(0f, root_child2.LayoutY);
+            Assert.AreEqual(30f, root_child2.LayoutWidth);
+            Assert.AreEqual(100f, root_child2.LayoutHeight);
+
+            root.StyleDirection = YogaDirection.RTL;
+            root.CalculateLayout();
+
+            Assert.AreEqual(0f, root.LayoutX);
+            Assert.AreEqual(0f, root.LayoutY);
+            Assert.AreEqual(80f, root.LayoutWidth);
+            Assert.AreEqual(100f, root.LayoutHeight);
+
+            Assert.AreEqual(70f, root_child0.LayoutX);
+            Assert.AreEqual(0f, root_child0.LayoutY);
+            Assert.AreEqual(10f, root_child0.LayoutWidth);
+            Assert.AreEqual(100f, root_child0.LayoutHeight);
+
+            Assert.AreEqual(40f, root_child1.LayoutX);
+            Assert.AreEqual(0f, root_child1.LayoutY);
+            Assert.AreEqual(20f, root_child1.LayoutWidth);
+            Assert.AreEqual(100f, root_child1.LayoutHeight);
+
+            Assert.AreEqual(0f, root_child2.LayoutX);
+            Assert.AreEqual(0f, root_child2.LayoutY);
+            Assert.AreEqual(30f, root_child2.LayoutWidth);
+            Assert.AreEqual(100f, root_child2.LayoutHeight);
+        }
+
         [Test]
         public void Test_row_gap_align_items_stretch()
         {
@@ -1981,5 +2049,72 @@ namespace Facebook.Yoga
             Assert.AreEqual(0f, root_child2.LayoutHeight);
         }
 
+        [Test]
+        public void Test_row_gap_determines_parent_height()
+        {
+            YogaConfig config = new YogaConfig();
+
+            YogaNode root = new YogaNode(config);
+            root.Width = 100;
+            root.RowGap = 10;
+
+            YogaNode root_child0 = new YogaNode(config);
+            root_child0.Height = 10;
+            root.Insert(0, root_child0);
+
+            YogaNode root_child1 = new YogaNode(config);
+            root_child1.Height = 20;
+            root.Insert(1, root_child1);
+
+            YogaNode root_child2 = new YogaNode(config);
+            root_child2.Height = 30;
+            root.Insert(2, root_child2);
+            root.StyleDirection = YogaDirection.LTR;
+            root.CalculateLayout();
+
+            Assert.AreEqual(0f, root.LayoutX);
+            Assert.AreEqual(0f, root.LayoutY);
+            Assert.AreEqual(100f, root.LayoutWidth);
+            Assert.AreEqual(80f, root.LayoutHeight);
+
+            Assert.AreEqual(0f, root_child0.LayoutX);
+            Assert.AreEqual(0f, root_child0.LayoutY);
+            Assert.AreEqual(100f, root_child0.LayoutWidth);
+            Assert.AreEqual(10f, root_child0.LayoutHeight);
+
+            Assert.AreEqual(0f, root_child1.LayoutX);
+            Assert.AreEqual(20f, root_child1.LayoutY);
+            Assert.AreEqual(100f, root_child1.LayoutWidth);
+            Assert.AreEqual(20f, root_child1.LayoutHeight);
+
+            Assert.AreEqual(0f, root_child2.LayoutX);
+            Assert.AreEqual(50f, root_child2.LayoutY);
+            Assert.AreEqual(100f, root_child2.LayoutWidth);
+            Assert.AreEqual(30f, root_child2.LayoutHeight);
+
+            root.StyleDirection = YogaDirection.RTL;
+            root.CalculateLayout();
+
+            Assert.AreEqual(0f, root.LayoutX);
+            Assert.AreEqual(0f, root.LayoutY);
+            Assert.AreEqual(100f, root.LayoutWidth);
+            Assert.AreEqual(80f, root.LayoutHeight);
+
+            Assert.AreEqual(0f, root_child0.LayoutX);
+            Assert.AreEqual(0f, root_child0.LayoutY);
+            Assert.AreEqual(100f, root_child0.LayoutWidth);
+            Assert.AreEqual(10f, root_child0.LayoutHeight);
+
+            Assert.AreEqual(0f, root_child1.LayoutX);
+            Assert.AreEqual(20f, root_child1.LayoutY);
+            Assert.AreEqual(100f, root_child1.LayoutWidth);
+            Assert.AreEqual(20f, root_child1.LayoutHeight);
+
+            Assert.AreEqual(0f, root_child2.LayoutX);
+            Assert.AreEqual(50f, root_child2.LayoutY);
+            Assert.AreEqual(100f, root_child2.LayoutWidth);
+            Assert.AreEqual(30f, root_child2.LayoutHeight);
+        }
+
     }
 }

gentest/fixtures/YGGapTest.html

@@ -123,6 +123,12 @@
   <div style="min-width: 60px; flex-grow: 1;"></div>
 </div>
 
+<div id="column_gap_determines_parent_width" style="flex-direction: row; height: 100px; align-items: 'stretch'; column-gap: 10px;">
+  <div style="width: 10px;"></div>
+  <div style="width: 20px;"></div>
+  <div style="width: 30px;"></div>
+</div>
+
 <div id="row_gap_align_items_stretch" style="flex-direction: row; flex-wrap: wrap; width: 100px; height: 200px; column-gap: 10px; row-gap: 20px; align-items:stretch; align-content: stretch">
   <div style="width: 20px; "></div>
   <div style="width: 20px;"></div>
@@ -152,3 +158,9 @@
   <div style="width: 60px; margin-block: 10px;"></div>
   <div style="width: 60px; margin-block: 15px;"></div>
 </div>
+
+<div id="row_gap_determines_parent_height" style="flex-direction: column; width: 100px; align-items: 'stretch'; row-gap: 10px;">
+  <div style="height: 10px;"></div>
+  <div style="height: 20px"></div>
+  <div style="height: 30px"></div>
+</div>

java/tests/com/facebook/yoga/YGGapTest.java

@@ -1589,6 +1589,73 @@ public class YGGapTest {
     assertEquals(150f, root_child4.getLayoutHeight(), 0.0f);
   }
 
+  @Test
+  public void test_column_gap_determines_parent_width() {
+    YogaConfig config = YogaConfigFactory.create();
+
+    final YogaNode root = createNode(config);
+    root.setFlexDirection(YogaFlexDirection.ROW);
+    root.setHeight(100f);
+    root.setGap(YogaGutter.COLUMN, 10f);
+
+    final YogaNode root_child0 = createNode(config);
+    root_child0.setWidth(10f);
+    root.addChildAt(root_child0, 0);
+
+    final YogaNode root_child1 = createNode(config);
+    root_child1.setWidth(20f);
+    root.addChildAt(root_child1, 1);
+
+    final YogaNode root_child2 = createNode(config);
+    root_child2.setWidth(30f);
+    root.addChildAt(root_child2, 2);
+    root.setDirection(YogaDirection.LTR);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(80f, root.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(10f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(20f, root_child1.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child1.getLayoutY(), 0.0f);
+    assertEquals(20f, root_child1.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root_child1.getLayoutHeight(), 0.0f);
+
+    assertEquals(50f, root_child2.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child2.getLayoutY(), 0.0f);
+    assertEquals(30f, root_child2.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root_child2.getLayoutHeight(), 0.0f);
+
+    root.setDirection(YogaDirection.RTL);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(80f, root.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(70f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(10f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(40f, root_child1.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child1.getLayoutY(), 0.0f);
+    assertEquals(20f, root_child1.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root_child1.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child2.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child2.getLayoutY(), 0.0f);
+    assertEquals(30f, root_child2.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root_child2.getLayoutHeight(), 0.0f);
+  }
+
   @Test
   public void test_row_gap_align_items_stretch() {
     YogaConfig config = YogaConfigFactory.create();
@@ -1969,6 +2036,72 @@ public class YGGapTest {
     assertEquals(0f, root_child2.getLayoutHeight(), 0.0f);
   }
 
+  @Test
+  public void test_row_gap_determines_parent_height() {
+    YogaConfig config = YogaConfigFactory.create();
+
+    final YogaNode root = createNode(config);
+    root.setWidth(100f);
+    root.setGap(YogaGutter.ROW, 10f);
+
+    final YogaNode root_child0 = createNode(config);
+    root_child0.setHeight(10f);
+    root.addChildAt(root_child0, 0);
+
+    final YogaNode root_child1 = createNode(config);
+    root_child1.setHeight(20f);
+    root.addChildAt(root_child1, 1);
+
+    final YogaNode root_child2 = createNode(config);
+    root_child2.setHeight(30f);
+    root.addChildAt(root_child2, 2);
+    root.setDirection(YogaDirection.LTR);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(100f, root.getLayoutWidth(), 0.0f);
+    assertEquals(80f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(100f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(10f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child1.getLayoutX(), 0.0f);
+    assertEquals(20f, root_child1.getLayoutY(), 0.0f);
+    assertEquals(100f, root_child1.getLayoutWidth(), 0.0f);
+    assertEquals(20f, root_child1.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child2.getLayoutX(), 0.0f);
+    assertEquals(50f, root_child2.getLayoutY(), 0.0f);
+    assertEquals(100f, root_child2.getLayoutWidth(), 0.0f);
+    assertEquals(30f, root_child2.getLayoutHeight(), 0.0f);
+
+    root.setDirection(YogaDirection.RTL);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(100f, root.getLayoutWidth(), 0.0f);
+    assertEquals(80f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(100f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(10f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child1.getLayoutX(), 0.0f);
+    assertEquals(20f, root_child1.getLayoutY(), 0.0f);
+    assertEquals(100f, root_child1.getLayoutWidth(), 0.0f);
+    assertEquals(20f, root_child1.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child2.getLayoutX(), 0.0f);
+    assertEquals(50f, root_child2.getLayoutY(), 0.0f);
+    assertEquals(100f, root_child2.getLayoutWidth(), 0.0f);
+    assertEquals(30f, root_child2.getLayoutHeight(), 0.0f);
+  }
+
   private YogaNode createNode(YogaConfig config) {
     return mNodeFactory.create(config);
   }

javascript/tests/Facebook.Yoga/YGGapTest.js

@@ -1642,6 +1642,77 @@ it("column_gap_wrap_align_stretch", function () {
     config.free();
   }
 });
+it("column_gap_determines_parent_width", function () {
+  var config = Yoga.Config.create();
+
+  try {
+    var root = Yoga.Node.create(config);
+    root.setFlexDirection(Yoga.FLEX_DIRECTION_ROW);
+    root.setHeight(100);
+    root.setGap(Yoga.GUTTER_COLUMN, 10);
+
+    var root_child0 = Yoga.Node.create(config);
+    root_child0.setWidth(10);
+    root.insertChild(root_child0, 0);
+
+    var root_child1 = Yoga.Node.create(config);
+    root_child1.setWidth(20);
+    root.insertChild(root_child1, 1);
+
+    var root_child2 = Yoga.Node.create(config);
+    root_child2.setWidth(30);
+    root.insertChild(root_child2, 2);
+    root.calculateLayout(Yoga.UNDEFINED, Yoga.UNDEFINED, Yoga.DIRECTION_LTR);
+
+    console.assert(0 === root.getComputedLeft(), "0 === root.getComputedLeft() (" + root.getComputedLeft() + ")");
+    console.assert(0 === root.getComputedTop(), "0 === root.getComputedTop() (" + root.getComputedTop() + ")");
+    console.assert(80 === root.getComputedWidth(), "80 === root.getComputedWidth() (" + root.getComputedWidth() + ")");
+    console.assert(100 === root.getComputedHeight(), "100 === root.getComputedHeight() (" + root.getComputedHeight() + ")");
+
+    console.assert(0 === root_child0.getComputedLeft(), "0 === root_child0.getComputedLeft() (" + root_child0.getComputedLeft() + ")");
+    console.assert(0 === root_child0.getComputedTop(), "0 === root_child0.getComputedTop() (" + root_child0.getComputedTop() + ")");
+    console.assert(10 === root_child0.getComputedWidth(), "10 === root_child0.getComputedWidth() (" + root_child0.getComputedWidth() + ")");
+    console.assert(100 === root_child0.getComputedHeight(), "100 === root_child0.getComputedHeight() (" + root_child0.getComputedHeight() + ")");
+
+    console.assert(20 === root_child1.getComputedLeft(), "20 === root_child1.getComputedLeft() (" + root_child1.getComputedLeft() + ")");
+    console.assert(0 === root_child1.getComputedTop(), "0 === root_child1.getComputedTop() (" + root_child1.getComputedTop() + ")");
+    console.assert(20 === root_child1.getComputedWidth(), "20 === root_child1.getComputedWidth() (" + root_child1.getComputedWidth() + ")");
+    console.assert(100 === root_child1.getComputedHeight(), "100 === root_child1.getComputedHeight() (" + root_child1.getComputedHeight() + ")");
+
+    console.assert(50 === root_child2.getComputedLeft(), "50 === root_child2.getComputedLeft() (" + root_child2.getComputedLeft() + ")");
+    console.assert(0 === root_child2.getComputedTop(), "0 === root_child2.getComputedTop() (" + root_child2.getComputedTop() + ")");
+    console.assert(30 === root_child2.getComputedWidth(), "30 === root_child2.getComputedWidth() (" + root_child2.getComputedWidth() + ")");
+    console.assert(100 === root_child2.getComputedHeight(), "100 === root_child2.getComputedHeight() (" + root_child2.getComputedHeight() + ")");
+
+    root.calculateLayout(Yoga.UNDEFINED, Yoga.UNDEFINED, Yoga.DIRECTION_RTL);
+
+    console.assert(0 === root.getComputedLeft(), "0 === root.getComputedLeft() (" + root.getComputedLeft() + ")");
+    console.assert(0 === root.getComputedTop(), "0 === root.getComputedTop() (" + root.getComputedTop() + ")");
+    console.assert(80 === root.getComputedWidth(), "80 === root.getComputedWidth() (" + root.getComputedWidth() + ")");
+    console.assert(100 === root.getComputedHeight(), "100 === root.getComputedHeight() (" + root.getComputedHeight() + ")");
+
+    console.assert(70 === root_child0.getComputedLeft(), "70 === root_child0.getComputedLeft() (" + root_child0.getComputedLeft() + ")");
+    console.assert(0 === root_child0.getComputedTop(), "0 === root_child0.getComputedTop() (" + root_child0.getComputedTop() + ")");
+    console.assert(10 === root_child0.getComputedWidth(), "10 === root_child0.getComputedWidth() (" + root_child0.getComputedWidth() + ")");
+    console.assert(100 === root_child0.getComputedHeight(), "100 === root_child0.getComputedHeight() (" + root_child0.getComputedHeight() + ")");
+
+    console.assert(40 === root_child1.getComputedLeft(), "40 === root_child1.getComputedLeft() (" + root_child1.getComputedLeft() + ")");
+    console.assert(0 === root_child1.getComputedTop(), "0 === root_child1.getComputedTop() (" + root_child1.getComputedTop() + ")");
+    console.assert(20 === root_child1.getComputedWidth(), "20 === root_child1.getComputedWidth() (" + root_child1.getComputedWidth() + ")");
+    console.assert(100 === root_child1.getComputedHeight(), "100 === root_child1.getComputedHeight() (" + root_child1.getComputedHeight() + ")");
+
+    console.assert(0 === root_child2.getComputedLeft(), "0 === root_child2.getComputedLeft() (" + root_child2.getComputedLeft() + ")");
+    console.assert(0 === root_child2.getComputedTop(), "0 === root_child2.getComputedTop() (" + root_child2.getComputedTop() + ")");
+    console.assert(30 === root_child2.getComputedWidth(), "30 === root_child2.getComputedWidth() (" + root_child2.getComputedWidth() + ")");
+    console.assert(100 === root_child2.getComputedHeight(), "100 === root_child2.getComputedHeight() (" + root_child2.getComputedHeight() + ")");
+  } finally {
+    if (typeof root !== "undefined") {
+      root.freeRecursive();
+    }
+
+    config.free();
+  }
+});
 it("row_gap_align_items_stretch", function () {
   var config = Yoga.Config.create();
 
@@ -2038,3 +2109,73 @@ it("row_gap_row_wrap_child_margins", function () {
     config.free();
   }
 });
+it("row_gap_determines_parent_height", function () {
+  var config = Yoga.Config.create();
+
+  try {
+    var root = Yoga.Node.create(config);
+    root.setWidth(100);
+    root.setGap(Yoga.GUTTER_ROW, 10);
+
+    var root_child0 = Yoga.Node.create(config);
+    root_child0.setHeight(10);
+    root.insertChild(root_child0, 0);
+
+    var root_child1 = Yoga.Node.create(config);
+    root_child1.setHeight(20);
+    root.insertChild(root_child1, 1);
+
+    var root_child2 = Yoga.Node.create(config);
+    root_child2.setHeight(30);
+    root.insertChild(root_child2, 2);
+    root.calculateLayout(Yoga.UNDEFINED, Yoga.UNDEFINED, Yoga.DIRECTION_LTR);
+
+    console.assert(0 === root.getComputedLeft(), "0 === root.getComputedLeft() (" + root.getComputedLeft() + ")");
+    console.assert(0 === root.getComputedTop(), "0 === root.getComputedTop() (" + root.getComputedTop() + ")");
+    console.assert(100 === root.getComputedWidth(), "100 === root.getComputedWidth() (" + root.getComputedWidth() + ")");
+    console.assert(80 === root.getComputedHeight(), "80 === root.getComputedHeight() (" + root.getComputedHeight() + ")");
+
+    console.assert(0 === root_child0.getComputedLeft(), "0 === root_child0.getComputedLeft() (" + root_child0.getComputedLeft() + ")");
+    console.assert(0 === root_child0.getComputedTop(), "0 === root_child0.getComputedTop() (" + root_child0.getComputedTop() + ")");
+    console.assert(100 === root_child0.getComputedWidth(), "100 === root_child0.getComputedWidth() (" + root_child0.getComputedWidth() + ")");
+    console.assert(10 === root_child0.getComputedHeight(), "10 === root_child0.getComputedHeight() (" + root_child0.getComputedHeight() + ")");
+
+    console.assert(0 === root_child1.getComputedLeft(), "0 === root_child1.getComputedLeft() (" + root_child1.getComputedLeft() + ")");
+    console.assert(20 === root_child1.getComputedTop(), "20 === root_child1.getComputedTop() (" + root_child1.getComputedTop() + ")");
+    console.assert(100 === root_child1.getComputedWidth(), "100 === root_child1.getComputedWidth() (" + root_child1.getComputedWidth() + ")");
+    console.assert(20 === root_child1.getComputedHeight(), "20 === root_child1.getComputedHeight() (" + root_child1.getComputedHeight() + ")");
+
+    console.assert(0 === root_child2.getComputedLeft(), "0 === root_child2.getComputedLeft() (" + root_child2.getComputedLeft() + ")");
+    console.assert(50 === root_child2.getComputedTop(), "50 === root_child2.getComputedTop() (" + root_child2.getComputedTop() + ")");
+    console.assert(100 === root_child2.getComputedWidth(), "100 === root_child2.getComputedWidth() (" + root_child2.getComputedWidth() + ")");
+    console.assert(30 === root_child2.getComputedHeight(), "30 === root_child2.getComputedHeight() (" + root_child2.getComputedHeight() + ")");
+
+    root.calculateLayout(Yoga.UNDEFINED, Yoga.UNDEFINED, Yoga.DIRECTION_RTL);
+
+    console.assert(0 === root.getComputedLeft(), "0 === root.getComputedLeft() (" + root.getComputedLeft() + ")");
+    console.assert(0 === root.getComputedTop(), "0 === root.getComputedTop() (" + root.getComputedTop() + ")");
+    console.assert(100 === root.getComputedWidth(), "100 === root.getComputedWidth() (" + root.getComputedWidth() + ")");
+    console.assert(80 === root.getComputedHeight(), "80 === root.getComputedHeight() (" + root.getComputedHeight() + ")");
+
+    console.assert(0 === root_child0.getComputedLeft(), "0 === root_child0.getComputedLeft() (" + root_child0.getComputedLeft() + ")");
+    console.assert(0 === root_child0.getComputedTop(), "0 === root_child0.getComputedTop() (" + root_child0.getComputedTop() + ")");
+    console.assert(100 === root_child0.getComputedWidth(), "100 === root_child0.getComputedWidth() (" + root_child0.getComputedWidth() + ")");
+    console.assert(10 === root_child0.getComputedHeight(), "10 === root_child0.getComputedHeight() (" + root_child0.getComputedHeight() + ")");
+
+    console.assert(0 === root_child1.getComputedLeft(), "0 === root_child1.getComputedLeft() (" + root_child1.getComputedLeft() + ")");
+    console.assert(20 === root_child1.getComputedTop(), "20 === root_child1.getComputedTop() (" + root_child1.getComputedTop() + ")");
+    console.assert(100 === root_child1.getComputedWidth(), "100 === root_child1.getComputedWidth() (" + root_child1.getComputedWidth() + ")");
+    console.assert(20 === root_child1.getComputedHeight(), "20 === root_child1.getComputedHeight() (" + root_child1.getComputedHeight() + ")");
+
+    console.assert(0 === root_child2.getComputedLeft(), "0 === root_child2.getComputedLeft() (" + root_child2.getComputedLeft() + ")");
+    console.assert(50 === root_child2.getComputedTop(), "50 === root_child2.getComputedTop() (" + root_child2.getComputedTop() + ")");
+    console.assert(100 === root_child2.getComputedWidth(), "100 === root_child2.getComputedWidth() (" + root_child2.getComputedWidth() + ")");
+    console.assert(30 === root_child2.getComputedHeight(), "30 === root_child2.getComputedHeight() (" + root_child2.getComputedHeight() + ")");
+  } finally {
+    if (typeof root !== "undefined") {
+      root.freeRecursive();
+    }
+
+    config.free();
+  }
+});

tests/YGGapTest.cpp

@@ -1593,6 +1593,74 @@ TEST(YogaTest, column_gap_wrap_align_stretch) {
   YGConfigFree(config);
 }
 
+TEST(YogaTest, column_gap_determines_parent_width) {
+  const YGConfigRef config = YGConfigNew();
+
+  const YGNodeRef root = YGNodeNewWithConfig(config);
+  YGNodeStyleSetFlexDirection(root, YGFlexDirectionRow);
+  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetGap(root, YGGutterColumn, 10);
+
+  const YGNodeRef root_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetWidth(root_child0, 10);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  const YGNodeRef root_child1 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetWidth(root_child1, 20);
+  YGNodeInsertChild(root, root_child1, 1);
+
+  const YGNodeRef root_child2 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetWidth(root_child2, 30);
+  YGNodeInsertChild(root, root_child2, 2);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(80, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(10, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root_child1));
+
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetLeft(root_child2));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child2));
+  ASSERT_FLOAT_EQ(30, YGNodeLayoutGetWidth(root_child2));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root_child2));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(80, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(70, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(10, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(40, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root_child1));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child2));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child2));
+  ASSERT_FLOAT_EQ(30, YGNodeLayoutGetWidth(root_child2));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root_child2));
+
+  YGNodeFreeRecursive(root);
+
+  YGConfigFree(config);
+}
+
 TEST(YogaTest, row_gap_align_items_stretch) {
   const YGConfigRef config = YGConfigNew();
 
@@ -1976,3 +2044,70 @@ TEST(YogaTest, row_gap_row_wrap_child_margins) {
 
   YGConfigFree(config);
 }
+
+TEST(YogaTest, row_gap_determines_parent_height) {
+  const YGConfigRef config = YGConfigNew();
+
+  const YGNodeRef root = YGNodeNewWithConfig(config);
+  YGNodeStyleSetWidth(root, 100);
+  YGNodeStyleSetGap(root, YGGutterRow, 10);
+
+  const YGNodeRef root_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root_child0, 10);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  const YGNodeRef root_child1 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root_child1, 20);
+  YGNodeInsertChild(root, root_child1, 1);
+
+  const YGNodeRef root_child2 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root_child2, 30);
+  YGNodeInsertChild(root, root_child2, 2);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(80, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(10, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetHeight(root_child1));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child2));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetTop(root_child2));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetWidth(root_child2));
+  ASSERT_FLOAT_EQ(30, YGNodeLayoutGetHeight(root_child2));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(80, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(10, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(20, YGNodeLayoutGetHeight(root_child1));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child2));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetTop(root_child2));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetWidth(root_child2));
+  ASSERT_FLOAT_EQ(30, YGNodeLayoutGetHeight(root_child2));
+
+  YGNodeFreeRecursive(root);
+
+  YGConfigFree(config);
+}

yoga/Yoga.cpp

@@ -2540,6 +2540,11 @@ static void YGJustifyMainAxis(
     const YGNodeRef child = node->getChild(i);
     const YGStyle& childStyle = child->getStyle();
     const YGLayout childLayout = child->getLayout();
+    const bool isLastChild = i == collectedFlexItemsValues.endOfLineIndex - 1;
+    // remove the gap if it is the last element of the line
+    if (isLastChild) {
+      betweenMainDim -= gap;
+    }
     if (childStyle.display() == YGDisplayNone) {
       continue;
     }