diff --git a/enums.py b/enums.py
index 2c53672a2e..ceef4deed3 100755
--- a/enums.py
+++ b/enums.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env fbpython
 # Copyright (c) Meta Platforms, Inc. and affiliates.
 #
 # This source code is licensed under the MIT license found in the
@@ -66,6 +66,9 @@
     "ExperimentalFeature": [
         # Mimic web flex-basis behavior (experiment may be broken)
         "WebFlexBasis",
+        # Fix flex basis computation to not apply FitContent constraint in the
+        # main axis for non-measure container nodes
+        "FixFlexBasisFitContent",
     ],
     "Gutter": ["Column", "Row", "All"],
     "GridTrackType": ["Auto", "Points", "Percent", "Fr", "Minmax"],
diff --git a/gentest/fixtures/YGFlexBasisFitContentTest.html b/gentest/fixtures/YGFlexBasisFitContentTest.html
new file mode 100644
index 0000000000..a9176e4ce6
--- /dev/null
+++ b/gentest/fixtures/YGFlexBasisFitContentTest.html
@@ -0,0 +1,68 @@
+<!-- Container child with content overflowing definite column parent.
+     Flex basis uses content size regardless of ExperimentalFeature state,
+     because FitContent and MaxContent produce the same result for containers. -->
+<div id="container_child_overflows_definite_parent_column"
+     style="width: 200px; height: 300px;">
+  <div>
+    <div style="height: 500px; width: 50px;"></div>
+  </div>
+</div>
+
+<!-- Row variant: container child overflows definite row parent. -->
+<div id="container_child_overflows_definite_parent_row"
+     style="width: 300px; height: 200px; flex-direction: row;">
+  <div>
+    <div style="width: 500px; height: 50px;"></div>
+  </div>
+</div>
+
+<!-- Container child content fits within parent bounds.
+     Same behavior with and without feature (no capping needed). -->
+<div id="container_child_within_bounds_column"
+     style="width: 200px; height: 300px;">
+  <div>
+    <div style="height: 100px; width: 50px;"></div>
+  </div>
+</div>
+
+<!-- Multiple container children, both overflowing definite column parent. -->
+<div id="multiple_container_children_overflow_column"
+     style="width: 200px; height: 300px;">
+  <div>
+    <div style="height: 400px;"></div>
+  </div>
+  <div>
+    <div style="height: 500px;"></div>
+  </div>
+</div>
+
+<!-- Scroll container: children always use MaxContent in main axis.
+     Same behavior with and without feature. -->
+<div id="scroll_container_column"
+     style="width: 200px; height: 300px; overflow: scroll;">
+  <div>
+    <div style="height: 500px;"></div>
+  </div>
+</div>
+
+<!-- Mix of explicit-height child and overflowing container child. -->
+<div id="explicit_and_container_children_column"
+     style="width: 200px; height: 300px;">
+  <div style="height: 100px;"></div>
+  <div>
+    <div style="height: 500px;"></div>
+  </div>
+</div>
+
+<!-- Items with flex-basis inside a scroll container's auto-height
+     content container. With FixFlexBasisFitContent, flex-basis is
+     respected even when the content container's main axis size is
+     indefinite (NaN). Without the feature, flex-basis would be ignored. -->
+<div id="flex_basis_in_scroll_content_container"
+     data-experiments="FixFlexBasisFitContent"
+     style="width: 200px; height: 300px; overflow: scroll;">
+  <div>
+    <div style="flex-basis: 200px;"></div>
+    <div style="flex-basis: 300px;"></div>
+  </div>
+</div>
diff --git a/java/com/facebook/yoga/YogaExperimentalFeature.java b/java/com/facebook/yoga/YogaExperimentalFeature.java
index 3fabbb9172..32e643439e 100644
--- a/java/com/facebook/yoga/YogaExperimentalFeature.java
+++ b/java/com/facebook/yoga/YogaExperimentalFeature.java
@@ -10,7 +10,8 @@
 package com.facebook.yoga;
 
 public enum YogaExperimentalFeature {
-  WEB_FLEX_BASIS(0);
+  WEB_FLEX_BASIS(0),
+  FIX_FLEX_BASIS_FIT_CONTENT(1);
 
   private final int mIntValue;
 
@@ -25,6 +26,7 @@ public int intValue() {
   public static YogaExperimentalFeature fromInt(int value) {
     switch (value) {
       case 0: return WEB_FLEX_BASIS;
+      case 1: return FIX_FLEX_BASIS_FIT_CONTENT;
       default: throw new IllegalArgumentException("Unknown enum value: " + value);
     }
   }
diff --git a/java/tests/generated/com/facebook/yoga/YGFlexBasisFitContentTest.java b/java/tests/generated/com/facebook/yoga/YGFlexBasisFitContentTest.java
new file mode 100644
index 0000000000..3941362bb5
--- /dev/null
+++ b/java/tests/generated/com/facebook/yoga/YGFlexBasisFitContentTest.java
@@ -0,0 +1,459 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @generated SignedSource<<43053b7b4f9b08ef644e0bb63c44e78f>>
+ * generated by gentest/src/GentestDriver.ts from gentest/fixtures/YGFlexBasisFitContentTest.html
+ */
+
+package com.facebook.yoga;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Ignore;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import com.facebook.yoga.utils.TestUtils;
+
+@RunWith(Parameterized.class)
+public class YGFlexBasisFitContentTest {
+  @Parameterized.Parameters(name = "{0}")
+  public static Iterable<TestParametrization.NodeFactory> nodeFactories() {
+    return TestParametrization.nodeFactories();
+  }
+
+  @Parameterized.Parameter public TestParametrization.NodeFactory mNodeFactory;
+
+  @Test
+  public void test_container_child_overflows_definite_parent_column() {
+    YogaConfig config = YogaConfigFactory.create();
+
+    final YogaNode root = createNode(config);
+    root.setPositionType(YogaPositionType.ABSOLUTE);
+    root.setWidth(200f);
+    root.setHeight(300f);
+
+    final YogaNode root_child0 = createNode(config);
+    root.addChildAt(root_child0, 0);
+
+    final YogaNode root_child0_child0 = createNode(config);
+    root_child0_child0.setHeight(500f);
+    root_child0_child0.setWidth(50f);
+    root_child0.addChildAt(root_child0_child0, 0);
+    root.setDirection(YogaDirection.LTR);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0_child0.getLayoutY(), 0.0f);
+    assertEquals(50f, root_child0_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child0_child0.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(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(150f, root_child0_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0_child0.getLayoutY(), 0.0f);
+    assertEquals(50f, root_child0_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child0_child0.getLayoutHeight(), 0.0f);
+  }
+
+  @Test
+  public void test_container_child_overflows_definite_parent_row() {
+    YogaConfig config = YogaConfigFactory.create();
+
+    final YogaNode root = createNode(config);
+    root.setPositionType(YogaPositionType.ABSOLUTE);
+    root.setWidth(300f);
+    root.setHeight(200f);
+    root.setFlexDirection(YogaFlexDirection.ROW);
+
+    final YogaNode root_child0 = createNode(config);
+    root.addChildAt(root_child0, 0);
+
+    final YogaNode root_child0_child0 = createNode(config);
+    root_child0_child0.setWidth(500f);
+    root_child0_child0.setHeight(50f);
+    root_child0.addChildAt(root_child0_child0, 0);
+    root.setDirection(YogaDirection.LTR);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(300f, root.getLayoutWidth(), 0.0f);
+    assertEquals(200f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(500f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0_child0.getLayoutY(), 0.0f);
+    assertEquals(500f, root_child0_child0.getLayoutWidth(), 0.0f);
+    assertEquals(50f, root_child0_child0.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(300f, root.getLayoutWidth(), 0.0f);
+    assertEquals(200f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(-200f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(500f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0_child0.getLayoutY(), 0.0f);
+    assertEquals(500f, root_child0_child0.getLayoutWidth(), 0.0f);
+    assertEquals(50f, root_child0_child0.getLayoutHeight(), 0.0f);
+  }
+
+  @Test
+  public void test_container_child_within_bounds_column() {
+    YogaConfig config = YogaConfigFactory.create();
+
+    final YogaNode root = createNode(config);
+    root.setPositionType(YogaPositionType.ABSOLUTE);
+    root.setWidth(200f);
+    root.setHeight(300f);
+
+    final YogaNode root_child0 = createNode(config);
+    root.addChildAt(root_child0, 0);
+
+    final YogaNode root_child0_child0 = createNode(config);
+    root_child0_child0.setHeight(100f);
+    root_child0_child0.setWidth(50f);
+    root_child0.addChildAt(root_child0_child0, 0);
+    root.setDirection(YogaDirection.LTR);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0_child0.getLayoutY(), 0.0f);
+    assertEquals(50f, root_child0_child0.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root_child0_child0.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(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(150f, root_child0_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0_child0.getLayoutY(), 0.0f);
+    assertEquals(50f, root_child0_child0.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root_child0_child0.getLayoutHeight(), 0.0f);
+  }
+
+  @Test
+  public void test_multiple_container_children_overflow_column() {
+    YogaConfig config = YogaConfigFactory.create();
+
+    final YogaNode root = createNode(config);
+    root.setPositionType(YogaPositionType.ABSOLUTE);
+    root.setWidth(200f);
+    root.setHeight(300f);
+
+    final YogaNode root_child0 = createNode(config);
+    root.addChildAt(root_child0, 0);
+
+    final YogaNode root_child0_child0 = createNode(config);
+    root_child0_child0.setHeight(400f);
+    root_child0.addChildAt(root_child0_child0, 0);
+
+    final YogaNode root_child1 = createNode(config);
+    root.addChildAt(root_child1, 1);
+
+    final YogaNode root_child1_child0 = createNode(config);
+    root_child1_child0.setHeight(500f);
+    root_child1.addChildAt(root_child1_child0, 0);
+    root.setDirection(YogaDirection.LTR);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(400f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0_child0.getLayoutWidth(), 0.0f);
+    assertEquals(400f, root_child0_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child1.getLayoutX(), 0.0f);
+    assertEquals(400f, root_child1.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child1.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child1.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child1_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child1_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child1_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child1_child0.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(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(400f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0_child0.getLayoutWidth(), 0.0f);
+    assertEquals(400f, root_child0_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child1.getLayoutX(), 0.0f);
+    assertEquals(400f, root_child1.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child1.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child1.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child1_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child1_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child1_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child1_child0.getLayoutHeight(), 0.0f);
+  }
+
+  @Test
+  public void test_scroll_container_column() {
+    YogaConfig config = YogaConfigFactory.create();
+
+    final YogaNode root = createNode(config);
+    root.setPositionType(YogaPositionType.ABSOLUTE);
+    root.setWidth(200f);
+    root.setHeight(300f);
+    root.setOverflow(YogaOverflow.SCROLL);
+
+    final YogaNode root_child0 = createNode(config);
+    root.addChildAt(root_child0, 0);
+
+    final YogaNode root_child0_child0 = createNode(config);
+    root_child0_child0.setHeight(500f);
+    root_child0.addChildAt(root_child0_child0, 0);
+    root.setDirection(YogaDirection.LTR);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child0_child0.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(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child0_child0.getLayoutHeight(), 0.0f);
+  }
+
+  @Test
+  public void test_explicit_and_container_children_column() {
+    YogaConfig config = YogaConfigFactory.create();
+
+    final YogaNode root = createNode(config);
+    root.setPositionType(YogaPositionType.ABSOLUTE);
+    root.setWidth(200f);
+    root.setHeight(300f);
+
+    final YogaNode root_child0 = createNode(config);
+    root_child0.setHeight(100f);
+    root.addChildAt(root_child0, 0);
+
+    final YogaNode root_child1 = createNode(config);
+    root.addChildAt(root_child1, 1);
+
+    final YogaNode root_child1_child0 = createNode(config);
+    root_child1_child0.setHeight(500f);
+    root_child1.addChildAt(root_child1_child0, 0);
+    root.setDirection(YogaDirection.LTR);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child1.getLayoutX(), 0.0f);
+    assertEquals(100f, root_child1.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child1.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child1.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child1_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child1_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child1_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child1_child0.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(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(100f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child1.getLayoutX(), 0.0f);
+    assertEquals(100f, root_child1.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child1.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child1.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child1_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child1_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child1_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child1_child0.getLayoutHeight(), 0.0f);
+  }
+
+  @Test
+  public void test_flex_basis_in_scroll_content_container() {
+    YogaConfig config = YogaConfigFactory.create();
+    config.setExperimentalFeatureEnabled(YogaExperimentalFeature.FIX_FLEX_BASIS_FIT_CONTENT, true);
+
+    final YogaNode root = createNode(config);
+    root.setPositionType(YogaPositionType.ABSOLUTE);
+    root.setWidth(200f);
+    root.setHeight(300f);
+    root.setOverflow(YogaOverflow.SCROLL);
+
+    final YogaNode root_child0 = createNode(config);
+    root.addChildAt(root_child0, 0);
+
+    final YogaNode root_child0_child0 = createNode(config);
+    root_child0_child0.setFlexBasis(200f);
+    root_child0.addChildAt(root_child0_child0, 0);
+
+    final YogaNode root_child0_child1 = createNode(config);
+    root_child0_child1.setFlexBasis(300f);
+    root_child0.addChildAt(root_child0_child1, 1);
+    root.setDirection(YogaDirection.LTR);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0_child0.getLayoutWidth(), 0.0f);
+    assertEquals(200f, root_child0_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0_child1.getLayoutX(), 0.0f);
+    assertEquals(200f, root_child0_child1.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0_child1.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root_child0_child1.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(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(500f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0_child0.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0_child0.getLayoutWidth(), 0.0f);
+    assertEquals(200f, root_child0_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child0_child1.getLayoutX(), 0.0f);
+    assertEquals(200f, root_child0_child1.getLayoutY(), 0.0f);
+    assertEquals(200f, root_child0_child1.getLayoutWidth(), 0.0f);
+    assertEquals(300f, root_child0_child1.getLayoutHeight(), 0.0f);
+  }
+
+  private YogaNode createNode(YogaConfig config) {
+    return mNodeFactory.create(config);
+  }
+}
diff --git a/javascript/src/generated/YGEnums.ts b/javascript/src/generated/YGEnums.ts
index f50aa88a73..17878ab0bb 100644
--- a/javascript/src/generated/YGEnums.ts
+++ b/javascript/src/generated/YGEnums.ts
@@ -67,6 +67,7 @@ export enum Errata {
 
 export enum ExperimentalFeature {
   WebFlexBasis = 0,
+  FixFlexBasisFitContent = 1,
 }
 
 export enum FlexDirection {
@@ -190,6 +191,7 @@ const constants = {
   ERRATA_ALL: Errata.All,
   ERRATA_CLASSIC: Errata.Classic,
   EXPERIMENTAL_FEATURE_WEB_FLEX_BASIS: ExperimentalFeature.WebFlexBasis,
+  EXPERIMENTAL_FEATURE_FIX_FLEX_BASIS_FIT_CONTENT: ExperimentalFeature.FixFlexBasisFitContent,
   FLEX_DIRECTION_COLUMN: FlexDirection.Column,
   FLEX_DIRECTION_COLUMN_REVERSE: FlexDirection.ColumnReverse,
   FLEX_DIRECTION_ROW: FlexDirection.Row,
diff --git a/javascript/tests/generated/YGFlexBasisFitContentTest.test.ts b/javascript/tests/generated/YGFlexBasisFitContentTest.test.ts
new file mode 100644
index 0000000000..1e5f8c7c44
--- /dev/null
+++ b/javascript/tests/generated/YGFlexBasisFitContentTest.test.ts
@@ -0,0 +1,429 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @generated SignedSource<<a5ae431c62a1c98a30b94c0f12a803de>>
+ * generated by gentest/src/GentestDriver.ts from gentest/fixtures/YGFlexBasisFitContentTest.html
+ */
+
+import { instrinsicSizeMeasureFunc } from '../tools/utils.ts'
+import Yoga from 'yoga-layout';
+import {
+  Align,
+  BoxSizing,
+  Direction,
+  Display,
+  Edge,
+  Errata,
+  ExperimentalFeature,
+  FlexDirection,
+  Gutter,
+  Justify,
+  MeasureMode,
+  Overflow,
+  PositionType,
+  Unit,
+  Wrap,
+} from 'yoga-layout';
+
+test('container_child_overflows_definite_parent_column', () => {
+  const config = Yoga.Config.create();
+
+  const root = Yoga.Node.create(config);
+  root.setPositionType(PositionType.Absolute);
+  root.setWidth(200);
+  root.setHeight(300);
+
+  const root_child0 = Yoga.Node.create(config);
+  root.insertChild(root_child0, 0);
+
+  const root_child0_child0 = Yoga.Node.create(config);
+  root_child0_child0.setHeight(500);
+  root_child0_child0.setWidth(50);
+  root_child0.insertChild(root_child0_child0, 0);
+  root.calculateLayout(undefined, undefined, Direction.LTR);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(200);
+  expect(root.getComputedHeight()).toBe(300);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(200);
+  expect(root_child0.getComputedHeight()).toBe(500);
+
+  expect(root_child0_child0.getComputedLeft()).toBe(0);
+  expect(root_child0_child0.getComputedTop()).toBe(0);
+  expect(root_child0_child0.getComputedWidth()).toBe(50);
+  expect(root_child0_child0.getComputedHeight()).toBe(500);
+
+  root.calculateLayout(undefined, undefined, Direction.RTL);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(200);
+  expect(root.getComputedHeight()).toBe(300);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(200);
+  expect(root_child0.getComputedHeight()).toBe(500);
+
+  expect(root_child0_child0.getComputedLeft()).toBe(150);
+  expect(root_child0_child0.getComputedTop()).toBe(0);
+  expect(root_child0_child0.getComputedWidth()).toBe(50);
+  expect(root_child0_child0.getComputedHeight()).toBe(500);
+});
+test('container_child_overflows_definite_parent_row', () => {
+  const config = Yoga.Config.create();
+
+  const root = Yoga.Node.create(config);
+  root.setPositionType(PositionType.Absolute);
+  root.setWidth(300);
+  root.setHeight(200);
+  root.setFlexDirection(FlexDirection.Row);
+
+  const root_child0 = Yoga.Node.create(config);
+  root.insertChild(root_child0, 0);
+
+  const root_child0_child0 = Yoga.Node.create(config);
+  root_child0_child0.setWidth(500);
+  root_child0_child0.setHeight(50);
+  root_child0.insertChild(root_child0_child0, 0);
+  root.calculateLayout(undefined, undefined, Direction.LTR);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(300);
+  expect(root.getComputedHeight()).toBe(200);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(500);
+  expect(root_child0.getComputedHeight()).toBe(200);
+
+  expect(root_child0_child0.getComputedLeft()).toBe(0);
+  expect(root_child0_child0.getComputedTop()).toBe(0);
+  expect(root_child0_child0.getComputedWidth()).toBe(500);
+  expect(root_child0_child0.getComputedHeight()).toBe(50);
+
+  root.calculateLayout(undefined, undefined, Direction.RTL);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(300);
+  expect(root.getComputedHeight()).toBe(200);
+
+  expect(root_child0.getComputedLeft()).toBe(-200);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(500);
+  expect(root_child0.getComputedHeight()).toBe(200);
+
+  expect(root_child0_child0.getComputedLeft()).toBe(0);
+  expect(root_child0_child0.getComputedTop()).toBe(0);
+  expect(root_child0_child0.getComputedWidth()).toBe(500);
+  expect(root_child0_child0.getComputedHeight()).toBe(50);
+});
+test('container_child_within_bounds_column', () => {
+  const config = Yoga.Config.create();
+
+  const root = Yoga.Node.create(config);
+  root.setPositionType(PositionType.Absolute);
+  root.setWidth(200);
+  root.setHeight(300);
+
+  const root_child0 = Yoga.Node.create(config);
+  root.insertChild(root_child0, 0);
+
+  const root_child0_child0 = Yoga.Node.create(config);
+  root_child0_child0.setHeight(100);
+  root_child0_child0.setWidth(50);
+  root_child0.insertChild(root_child0_child0, 0);
+  root.calculateLayout(undefined, undefined, Direction.LTR);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(200);
+  expect(root.getComputedHeight()).toBe(300);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(200);
+  expect(root_child0.getComputedHeight()).toBe(100);
+
+  expect(root_child0_child0.getComputedLeft()).toBe(0);
+  expect(root_child0_child0.getComputedTop()).toBe(0);
+  expect(root_child0_child0.getComputedWidth()).toBe(50);
+  expect(root_child0_child0.getComputedHeight()).toBe(100);
+
+  root.calculateLayout(undefined, undefined, Direction.RTL);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(200);
+  expect(root.getComputedHeight()).toBe(300);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(200);
+  expect(root_child0.getComputedHeight()).toBe(100);
+
+  expect(root_child0_child0.getComputedLeft()).toBe(150);
+  expect(root_child0_child0.getComputedTop()).toBe(0);
+  expect(root_child0_child0.getComputedWidth()).toBe(50);
+  expect(root_child0_child0.getComputedHeight()).toBe(100);
+});
+test('multiple_container_children_overflow_column', () => {
+  const config = Yoga.Config.create();
+
+  const root = Yoga.Node.create(config);
+  root.setPositionType(PositionType.Absolute);
+  root.setWidth(200);
+  root.setHeight(300);
+
+  const root_child0 = Yoga.Node.create(config);
+  root.insertChild(root_child0, 0);
+
+  const root_child0_child0 = Yoga.Node.create(config);
+  root_child0_child0.setHeight(400);
+  root_child0.insertChild(root_child0_child0, 0);
+
+  const root_child1 = Yoga.Node.create(config);
+  root.insertChild(root_child1, 1);
+
+  const root_child1_child0 = Yoga.Node.create(config);
+  root_child1_child0.setHeight(500);
+  root_child1.insertChild(root_child1_child0, 0);
+  root.calculateLayout(undefined, undefined, Direction.LTR);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(200);
+  expect(root.getComputedHeight()).toBe(300);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(200);
+  expect(root_child0.getComputedHeight()).toBe(400);
+
+  expect(root_child0_child0.getComputedLeft()).toBe(0);
+  expect(root_child0_child0.getComputedTop()).toBe(0);
+  expect(root_child0_child0.getComputedWidth()).toBe(200);
+  expect(root_child0_child0.getComputedHeight()).toBe(400);
+
+  expect(root_child1.getComputedLeft()).toBe(0);
+  expect(root_child1.getComputedTop()).toBe(400);
+  expect(root_child1.getComputedWidth()).toBe(200);
+  expect(root_child1.getComputedHeight()).toBe(500);
+
+  expect(root_child1_child0.getComputedLeft()).toBe(0);
+  expect(root_child1_child0.getComputedTop()).toBe(0);
+  expect(root_child1_child0.getComputedWidth()).toBe(200);
+  expect(root_child1_child0.getComputedHeight()).toBe(500);
+
+  root.calculateLayout(undefined, undefined, Direction.RTL);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(200);
+  expect(root.getComputedHeight()).toBe(300);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(200);
+  expect(root_child0.getComputedHeight()).toBe(400);
+
+  expect(root_child0_child0.getComputedLeft()).toBe(0);
+  expect(root_child0_child0.getComputedTop()).toBe(0);
+  expect(root_child0_child0.getComputedWidth()).toBe(200);
+  expect(root_child0_child0.getComputedHeight()).toBe(400);
+
+  expect(root_child1.getComputedLeft()).toBe(0);
+  expect(root_child1.getComputedTop()).toBe(400);
+  expect(root_child1.getComputedWidth()).toBe(200);
+  expect(root_child1.getComputedHeight()).toBe(500);
+
+  expect(root_child1_child0.getComputedLeft()).toBe(0);
+  expect(root_child1_child0.getComputedTop()).toBe(0);
+  expect(root_child1_child0.getComputedWidth()).toBe(200);
+  expect(root_child1_child0.getComputedHeight()).toBe(500);
+});
+test('scroll_container_column', () => {
+  const config = Yoga.Config.create();
+
+  const root = Yoga.Node.create(config);
+  root.setPositionType(PositionType.Absolute);
+  root.setWidth(200);
+  root.setHeight(300);
+  root.setOverflow(Overflow.Scroll);
+
+  const root_child0 = Yoga.Node.create(config);
+  root.insertChild(root_child0, 0);
+
+  const root_child0_child0 = Yoga.Node.create(config);
+  root_child0_child0.setHeight(500);
+  root_child0.insertChild(root_child0_child0, 0);
+  root.calculateLayout(undefined, undefined, Direction.LTR);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(200);
+  expect(root.getComputedHeight()).toBe(300);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(200);
+  expect(root_child0.getComputedHeight()).toBe(500);
+
+  expect(root_child0_child0.getComputedLeft()).toBe(0);
+  expect(root_child0_child0.getComputedTop()).toBe(0);
+  expect(root_child0_child0.getComputedWidth()).toBe(200);
+  expect(root_child0_child0.getComputedHeight()).toBe(500);
+
+  root.calculateLayout(undefined, undefined, Direction.RTL);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(200);
+  expect(root.getComputedHeight()).toBe(300);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(200);
+  expect(root_child0.getComputedHeight()).toBe(500);
+
+  expect(root_child0_child0.getComputedLeft()).toBe(0);
+  expect(root_child0_child0.getComputedTop()).toBe(0);
+  expect(root_child0_child0.getComputedWidth()).toBe(200);
+  expect(root_child0_child0.getComputedHeight()).toBe(500);
+});
+test('explicit_and_container_children_column', () => {
+  const config = Yoga.Config.create();
+
+  const root = Yoga.Node.create(config);
+  root.setPositionType(PositionType.Absolute);
+  root.setWidth(200);
+  root.setHeight(300);
+
+  const root_child0 = Yoga.Node.create(config);
+  root_child0.setHeight(100);
+  root.insertChild(root_child0, 0);
+
+  const root_child1 = Yoga.Node.create(config);
+  root.insertChild(root_child1, 1);
+
+  const root_child1_child0 = Yoga.Node.create(config);
+  root_child1_child0.setHeight(500);
+  root_child1.insertChild(root_child1_child0, 0);
+  root.calculateLayout(undefined, undefined, Direction.LTR);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(200);
+  expect(root.getComputedHeight()).toBe(300);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(200);
+  expect(root_child0.getComputedHeight()).toBe(100);
+
+  expect(root_child1.getComputedLeft()).toBe(0);
+  expect(root_child1.getComputedTop()).toBe(100);
+  expect(root_child1.getComputedWidth()).toBe(200);
+  expect(root_child1.getComputedHeight()).toBe(500);
+
+  expect(root_child1_child0.getComputedLeft()).toBe(0);
+  expect(root_child1_child0.getComputedTop()).toBe(0);
+  expect(root_child1_child0.getComputedWidth()).toBe(200);
+  expect(root_child1_child0.getComputedHeight()).toBe(500);
+
+  root.calculateLayout(undefined, undefined, Direction.RTL);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(200);
+  expect(root.getComputedHeight()).toBe(300);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(200);
+  expect(root_child0.getComputedHeight()).toBe(100);
+
+  expect(root_child1.getComputedLeft()).toBe(0);
+  expect(root_child1.getComputedTop()).toBe(100);
+  expect(root_child1.getComputedWidth()).toBe(200);
+  expect(root_child1.getComputedHeight()).toBe(500);
+
+  expect(root_child1_child0.getComputedLeft()).toBe(0);
+  expect(root_child1_child0.getComputedTop()).toBe(0);
+  expect(root_child1_child0.getComputedWidth()).toBe(200);
+  expect(root_child1_child0.getComputedHeight()).toBe(500);
+});
+test('flex_basis_in_scroll_content_container', () => {
+  const config = Yoga.Config.create();
+
+  config.setExperimentalFeatureEnabled(ExperimentalFeature.FixFlexBasisFitContent, true);
+
+  const root = Yoga.Node.create(config);
+  root.setPositionType(PositionType.Absolute);
+  root.setWidth(200);
+  root.setHeight(300);
+  root.setOverflow(Overflow.Scroll);
+
+  const root_child0 = Yoga.Node.create(config);
+  root.insertChild(root_child0, 0);
+
+  const root_child0_child0 = Yoga.Node.create(config);
+  root_child0_child0.setFlexBasis(200);
+  root_child0.insertChild(root_child0_child0, 0);
+
+  const root_child0_child1 = Yoga.Node.create(config);
+  root_child0_child1.setFlexBasis(300);
+  root_child0.insertChild(root_child0_child1, 1);
+  root.calculateLayout(undefined, undefined, Direction.LTR);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(200);
+  expect(root.getComputedHeight()).toBe(300);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(200);
+  expect(root_child0.getComputedHeight()).toBe(500);
+
+  expect(root_child0_child0.getComputedLeft()).toBe(0);
+  expect(root_child0_child0.getComputedTop()).toBe(0);
+  expect(root_child0_child0.getComputedWidth()).toBe(200);
+  expect(root_child0_child0.getComputedHeight()).toBe(200);
+
+  expect(root_child0_child1.getComputedLeft()).toBe(0);
+  expect(root_child0_child1.getComputedTop()).toBe(200);
+  expect(root_child0_child1.getComputedWidth()).toBe(200);
+  expect(root_child0_child1.getComputedHeight()).toBe(300);
+
+  root.calculateLayout(undefined, undefined, Direction.RTL);
+
+  expect(root.getComputedLeft()).toBe(0);
+  expect(root.getComputedTop()).toBe(0);
+  expect(root.getComputedWidth()).toBe(200);
+  expect(root.getComputedHeight()).toBe(300);
+
+  expect(root_child0.getComputedLeft()).toBe(0);
+  expect(root_child0.getComputedTop()).toBe(0);
+  expect(root_child0.getComputedWidth()).toBe(200);
+  expect(root_child0.getComputedHeight()).toBe(500);
+
+  expect(root_child0_child0.getComputedLeft()).toBe(0);
+  expect(root_child0_child0.getComputedTop()).toBe(0);
+  expect(root_child0_child0.getComputedWidth()).toBe(200);
+  expect(root_child0_child0.getComputedHeight()).toBe(200);
+
+  expect(root_child0_child1.getComputedLeft()).toBe(0);
+  expect(root_child0_child1.getComputedTop()).toBe(200);
+  expect(root_child0_child1.getComputedWidth()).toBe(200);
+  expect(root_child0_child1.getComputedHeight()).toBe(300);
+});
diff --git a/tests/YGFlexBasisFitContentTest.cpp b/tests/YGFlexBasisFitContentTest.cpp
new file mode 100644
index 0000000000..7ce7873497
--- /dev/null
+++ b/tests/YGFlexBasisFitContentTest.cpp
@@ -0,0 +1,241 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <gtest/gtest.h>
+#include <yoga/Yoga.h>
+#include <algorithm>
+
+static YGSize measureTextLike(
+    YGNodeConstRef /*node*/,
+    float width,
+    YGMeasureMode widthMode,
+    float /*height*/,
+    YGMeasureMode /*heightMode*/) {
+  float measuredWidth = 200.0f;
+  if (widthMode == YGMeasureModeAtMost) {
+    measuredWidth = std::min(measuredWidth, width);
+  }
+  return YGSize{.width = measuredWidth, .height = 20.0f};
+}
+
+class YGFlexBasisFitContentTest : public testing::TestWithParam<bool> {
+ protected:
+  void SetUp() override {
+    config_ = YGConfigNew();
+    YGConfigSetExperimentalFeatureEnabled(
+        config_, YGExperimentalFeatureFixFlexBasisFitContent, GetParam());
+  }
+
+  void TearDown() override {
+    if (root_ != nullptr) {
+      YGNodeFreeRecursive(root_);
+    }
+    YGConfigFree(config_);
+  }
+
+  YGConfigRef config_ = nullptr;
+  YGNodeRef root_ = nullptr;
+};
+
+// Auto-height container with a percentage-height child produces the same
+// layout regardless of feature state, because Check 3 preserves percentage
+// resolution when availableInnerHeight is NaN.
+TEST_P(YGFlexBasisFitContentTest, percentage_height_converges) {
+  root_ = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetHeight(root_, 300);
+  YGNodeStyleSetWidth(root_, 100);
+
+  YGNodeRef container = YGNodeNewWithConfig(config_);
+  YGNodeInsertChild(root_, container, 0);
+
+  YGNodeRef child = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetHeightPercent(child, 50);
+  YGNodeInsertChild(container, child, 0);
+
+  YGNodeCalculateLayout(root_, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(75, YGNodeLayoutGetHeight(child));
+  ASSERT_FLOAT_EQ(150, YGNodeLayoutGetHeight(container));
+}
+
+// Two auto-height containers with percentage children and flexGrow:1 produce
+// the same layout regardless of feature state.
+TEST_P(YGFlexBasisFitContentTest, percentage_with_flex_grow_converges) {
+  root_ = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetHeight(root_, 400);
+  YGNodeStyleSetWidth(root_, 100);
+
+  YGNodeRef containerA = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetFlexGrow(containerA, 1);
+  YGNodeInsertChild(root_, containerA, 0);
+
+  YGNodeRef childA = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetHeightPercent(childA, 25);
+  YGNodeInsertChild(containerA, childA, 0);
+
+  YGNodeRef containerB = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetFlexGrow(containerB, 1);
+  YGNodeInsertChild(root_, containerB, 1);
+
+  YGNodeRef childB = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetHeightPercent(childB, 50);
+  YGNodeInsertChild(containerB, childB, 0);
+
+  YGNodeCalculateLayout(root_, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(150, YGNodeLayoutGetHeight(containerA));
+  ASSERT_FLOAT_EQ(250, YGNodeLayoutGetHeight(containerB));
+}
+
+// Auto-height container with flexShrink and a percentage child causing
+// overflow produces the same layout regardless of feature state.
+TEST_P(YGFlexBasisFitContentTest, flex_shrink_overflow_converges) {
+  root_ = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetHeight(root_, 200);
+  YGNodeStyleSetWidth(root_, 100);
+
+  YGNodeRef container = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetFlexShrink(container, 1);
+  YGNodeInsertChild(root_, container, 0);
+
+  YGNodeRef child = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetHeightPercent(child, 100);
+  YGNodeInsertChild(container, child, 0);
+
+  YGNodeRef fixed = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetHeight(fixed, 150);
+  YGNodeInsertChild(root_, fixed, 1);
+
+  YGNodeCalculateLayout(root_, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetHeight(container));
+  ASSERT_FLOAT_EQ(150, YGNodeLayoutGetHeight(fixed));
+}
+
+// In a scroll container (column), changing a sibling's height does not cause
+// re-measurement of unaffected subtrees when the feature is enabled.
+TEST_P(YGFlexBasisFitContentTest, scroll_avoids_remeasure) {
+  static uint32_t measureCount = 0;
+  auto measureFunc = [](YGNodeConstRef /*node*/,
+                        float /*width*/,
+                        YGMeasureMode /*widthMode*/,
+                        float /*height*/,
+                        YGMeasureMode /*heightMode*/) {
+    measureCount++;
+    return YGSize{.width = 50.0f, .height = 50.0f};
+  };
+
+  measureCount = 0;
+
+  root_ = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetOverflow(root_, YGOverflowScroll);
+  YGNodeStyleSetWidth(root_, 100);
+  YGNodeStyleSetHeight(root_, 500);
+
+  YGNodeRef sibling = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetHeight(sibling, 100);
+  YGNodeInsertChild(root_, sibling, 0);
+
+  YGNodeRef wrapper = YGNodeNewWithConfig(config_);
+  YGNodeInsertChild(root_, wrapper, 1);
+
+  YGNodeRef inner = YGNodeNewWithConfig(config_);
+  YGNodeInsertChild(wrapper, inner, 0);
+
+  YGNodeRef leaf = YGNodeNewWithConfig(config_);
+  YGNodeSetMeasureFunc(leaf, measureFunc);
+  YGNodeInsertChild(inner, leaf, 0);
+
+  YGNodeCalculateLayout(root_, YGUndefined, YGUndefined, YGDirectionLTR);
+  uint32_t firstPassCount = measureCount;
+
+  YGNodeStyleSetHeight(sibling, 200);
+  YGNodeCalculateLayout(root_, YGUndefined, YGUndefined, YGDirectionLTR);
+  uint32_t secondPassCount = measureCount - firstPassCount;
+
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetHeight(leaf));
+
+  EXPECT_EQ(0, secondPassCount);
+}
+
+// Row direction is unaffected by the optimization. Width FitContent is always
+// preserved to support text wrapping through container nodes.
+TEST_P(YGFlexBasisFitContentTest, row_direction_unchanged) {
+  root_ = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetWidth(root_, 100);
+  YGNodeStyleSetHeight(root_, 100);
+
+  YGNodeRef container = YGNodeNewWithConfig(config_);
+  YGNodeInsertChild(root_, container, 0);
+
+  YGNodeRef text = YGNodeNewWithConfig(config_);
+  YGNodeSetMeasureFunc(text, measureTextLike);
+  YGNodeInsertChild(container, text, 0);
+
+  YGNodeCalculateLayout(root_, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetWidth(text));
+}
+
+// Scroll container in row direction: width FitContent is skipped for the
+// main axis (row) in scroll containers, matching legacy behavior.
+TEST_P(YGFlexBasisFitContentTest, row_scroll_skips_width) {
+  root_ = YGNodeNewWithConfig(config_);
+  YGNodeStyleSetFlexDirection(root_, YGFlexDirectionRow);
+  YGNodeStyleSetOverflow(root_, YGOverflowScroll);
+  YGNodeStyleSetWidth(root_, 100);
+  YGNodeStyleSetHeight(root_, 100);
+
+  YGNodeRef text = YGNodeNewWithConfig(config_);
+  YGNodeSetMeasureFunc(text, measureTextLike);
+  YGNodeInsertChild(root_, text, 0);
+
+  YGNodeCalculateLayout(root_, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(text));
+}
+
+INSTANTIATE_TEST_SUITE_P(
+    YogaTest,
+    YGFlexBasisFitContentTest,
+    testing::Values(false, true));
+
+// Feature toggle invalidates layout cache.
+TEST(YogaTest, flex_basis_fit_content_feature_change_invalidates_cache) {
+  YGConfigRef config = YGConfigNew();
+  YGConfigSetExperimentalFeatureEnabled(
+      config, YGExperimentalFeatureFixFlexBasisFitContent, false);
+
+  YGNodeRef root = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root, 300);
+  YGNodeStyleSetWidth(root, 100);
+
+  YGNodeRef container = YGNodeNewWithConfig(config);
+  YGNodeStyleSetFlexGrow(container, 1);
+  YGNodeInsertChild(root, container, 0);
+
+  YGNodeRef child = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeightPercent(child, 50);
+  YGNodeInsertChild(container, child, 0);
+
+  YGNodeRef fixed = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(fixed, 100);
+  YGNodeInsertChild(root, fixed, 1);
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+  float heightBefore = YGNodeLayoutGetHeight(container);
+
+  YGConfigSetExperimentalFeatureEnabled(
+      config, YGExperimentalFeatureFixFlexBasisFitContent, true);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+  float heightAfter = YGNodeLayoutGetHeight(container);
+
+  ASSERT_FLOAT_EQ(heightBefore, heightAfter);
+
+  YGNodeFreeRecursive(root);
+  YGConfigFree(config);
+}
diff --git a/tests/generated/YGFlexBasisFitContentTest.cpp b/tests/generated/YGFlexBasisFitContentTest.cpp
new file mode 100644
index 0000000000..b1dea09665
--- /dev/null
+++ b/tests/generated/YGFlexBasisFitContentTest.cpp
@@ -0,0 +1,447 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * clang-format off
+ * @generated SignedSource<<a42a4541e0d8b8808aedb4abd62c617b>>
+ * generated by gentest/src/GentestDriver.ts from gentest/fixtures/YGFlexBasisFitContentTest.html
+ */
+
+#include <gtest/gtest.h>
+#include <yoga/Yoga.h>
+#include "../util/TestUtil.h"
+
+TEST(YogaTest, container_child_overflows_definite_parent_column) {
+  YGConfigRef config = YGConfigNew();
+
+  YGNodeRef root = YGNodeNewWithConfig(config);
+  YGNodeStyleSetPositionType(root, YGPositionTypeAbsolute);
+  YGNodeStyleSetWidth(root, 200);
+  YGNodeStyleSetHeight(root, 300);
+
+  YGNodeRef root_child0 = YGNodeNewWithConfig(config);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  YGNodeRef root_child0_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root_child0_child0, 500);
+  YGNodeStyleSetWidth(root_child0_child0, 50);
+  YGNodeInsertChild(root_child0, root_child0_child0, 0);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetWidth(root_child0_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child0_child0));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(150, YGNodeLayoutGetLeft(root_child0_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetWidth(root_child0_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child0_child0));
+
+  YGNodeFreeRecursive(root);
+
+  YGConfigFree(config);
+}
+
+TEST(YogaTest, container_child_overflows_definite_parent_row) {
+  YGConfigRef config = YGConfigNew();
+
+  YGNodeRef root = YGNodeNewWithConfig(config);
+  YGNodeStyleSetPositionType(root, YGPositionTypeAbsolute);
+  YGNodeStyleSetWidth(root, 300);
+  YGNodeStyleSetHeight(root, 200);
+  YGNodeStyleSetFlexDirection(root, YGFlexDirectionRow);
+
+  YGNodeRef root_child0 = YGNodeNewWithConfig(config);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  YGNodeRef root_child0_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetWidth(root_child0_child0, 500);
+  YGNodeStyleSetHeight(root_child0_child0, 50);
+  YGNodeInsertChild(root_child0, root_child0_child0, 0);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetWidth(root_child0_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetHeight(root_child0_child0));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(-200, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetWidth(root_child0_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetHeight(root_child0_child0));
+
+  YGNodeFreeRecursive(root);
+
+  YGConfigFree(config);
+}
+
+TEST(YogaTest, container_child_within_bounds_column) {
+  YGConfigRef config = YGConfigNew();
+
+  YGNodeRef root = YGNodeNewWithConfig(config);
+  YGNodeStyleSetPositionType(root, YGPositionTypeAbsolute);
+  YGNodeStyleSetWidth(root, 200);
+  YGNodeStyleSetHeight(root, 300);
+
+  YGNodeRef root_child0 = YGNodeNewWithConfig(config);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  YGNodeRef root_child0_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root_child0_child0, 100);
+  YGNodeStyleSetWidth(root_child0_child0, 50);
+  YGNodeInsertChild(root_child0, root_child0_child0, 0);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetWidth(root_child0_child0));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root_child0_child0));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(150, YGNodeLayoutGetLeft(root_child0_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetWidth(root_child0_child0));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root_child0_child0));
+
+  YGNodeFreeRecursive(root);
+
+  YGConfigFree(config);
+}
+
+TEST(YogaTest, multiple_container_children_overflow_column) {
+  YGConfigRef config = YGConfigNew();
+
+  YGNodeRef root = YGNodeNewWithConfig(config);
+  YGNodeStyleSetPositionType(root, YGPositionTypeAbsolute);
+  YGNodeStyleSetWidth(root, 200);
+  YGNodeStyleSetHeight(root, 300);
+
+  YGNodeRef root_child0 = YGNodeNewWithConfig(config);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  YGNodeRef root_child0_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root_child0_child0, 400);
+  YGNodeInsertChild(root_child0, root_child0_child0, 0);
+
+  YGNodeRef root_child1 = YGNodeNewWithConfig(config);
+  YGNodeInsertChild(root, root_child1, 1);
+
+  YGNodeRef root_child1_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root_child1_child0, 500);
+  YGNodeInsertChild(root_child1, root_child1_child0, 0);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(400, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0_child0));
+  ASSERT_FLOAT_EQ(400, YGNodeLayoutGetHeight(root_child0_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(400, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child1));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child1_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child1_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child1_child0));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(400, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0_child0));
+  ASSERT_FLOAT_EQ(400, YGNodeLayoutGetHeight(root_child0_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(400, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child1));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child1_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child1_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child1_child0));
+
+  YGNodeFreeRecursive(root);
+
+  YGConfigFree(config);
+}
+
+TEST(YogaTest, scroll_container_column) {
+  YGConfigRef config = YGConfigNew();
+
+  YGNodeRef root = YGNodeNewWithConfig(config);
+  YGNodeStyleSetPositionType(root, YGPositionTypeAbsolute);
+  YGNodeStyleSetWidth(root, 200);
+  YGNodeStyleSetHeight(root, 300);
+  YGNodeStyleSetOverflow(root, YGOverflowScroll);
+
+  YGNodeRef root_child0 = YGNodeNewWithConfig(config);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  YGNodeRef root_child0_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root_child0_child0, 500);
+  YGNodeInsertChild(root_child0, root_child0_child0, 0);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child0_child0));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child0_child0));
+
+  YGNodeFreeRecursive(root);
+
+  YGConfigFree(config);
+}
+
+TEST(YogaTest, explicit_and_container_children_column) {
+  YGConfigRef config = YGConfigNew();
+
+  YGNodeRef root = YGNodeNewWithConfig(config);
+  YGNodeStyleSetPositionType(root, YGPositionTypeAbsolute);
+  YGNodeStyleSetWidth(root, 200);
+  YGNodeStyleSetHeight(root, 300);
+
+  YGNodeRef root_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root_child0, 100);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  YGNodeRef root_child1 = YGNodeNewWithConfig(config);
+  YGNodeInsertChild(root, root_child1, 1);
+
+  YGNodeRef root_child1_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetHeight(root_child1_child0, 500);
+  YGNodeInsertChild(root_child1, root_child1_child0, 0);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child1));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child1_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child1_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child1_child0));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child1));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child1_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child1_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child1_child0));
+
+  YGNodeFreeRecursive(root);
+
+  YGConfigFree(config);
+}
+
+TEST(YogaTest, flex_basis_in_scroll_content_container) {
+  YGConfigRef config = YGConfigNew();
+  YGConfigSetExperimentalFeatureEnabled(config, YGExperimentalFeatureFixFlexBasisFitContent, true);
+
+  YGNodeRef root = YGNodeNewWithConfig(config);
+  YGNodeStyleSetPositionType(root, YGPositionTypeAbsolute);
+  YGNodeStyleSetWidth(root, 200);
+  YGNodeStyleSetHeight(root, 300);
+  YGNodeStyleSetOverflow(root, YGOverflowScroll);
+
+  YGNodeRef root_child0 = YGNodeNewWithConfig(config);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  YGNodeRef root_child0_child0 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetFlexBasis(root_child0_child0, 200);
+  YGNodeInsertChild(root_child0, root_child0_child0, 0);
+
+  YGNodeRef root_child0_child1 = YGNodeNewWithConfig(config);
+  YGNodeStyleSetFlexBasis(root_child0_child1, 300);
+  YGNodeInsertChild(root_child0, root_child0_child1, 1);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetHeight(root_child0_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0_child1));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetTop(root_child0_child1));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0_child1));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root_child0_child1));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(500, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0_child0));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetHeight(root_child0_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child0_child1));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetTop(root_child0_child1));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root_child0_child1));
+  ASSERT_FLOAT_EQ(300, YGNodeLayoutGetHeight(root_child0_child1));
+
+  YGNodeFreeRecursive(root);
+
+  YGConfigFree(config);
+}
diff --git a/yoga/YGEnums.cpp b/yoga/YGEnums.cpp
index 9fc4a83a82..538b0b0847 100644
--- a/yoga/YGEnums.cpp
+++ b/yoga/YGEnums.cpp
@@ -129,6 +129,8 @@ const char* YGExperimentalFeatureToString(const YGExperimentalFeature value) {
   switch (value) {
     case YGExperimentalFeatureWebFlexBasis:
       return "web-flex-basis";
+    case YGExperimentalFeatureFixFlexBasisFitContent:
+      return "fix-flex-basis-fit-content";
   }
   return "unknown";
 }
diff --git a/yoga/YGEnums.h b/yoga/YGEnums.h
index 1b69f09318..aa0b1d4350 100644
--- a/yoga/YGEnums.h
+++ b/yoga/YGEnums.h
@@ -73,7 +73,8 @@ YG_DEFINE_ENUM_FLAG_OPERATORS(YGErrata)
 
 YG_ENUM_DECL(
     YGExperimentalFeature,
-    YGExperimentalFeatureWebFlexBasis)
+    YGExperimentalFeatureWebFlexBasis,
+    YGExperimentalFeatureFixFlexBasisFitContent)
 
 YG_ENUM_DECL(
     YGFlexDirection,
diff --git a/yoga/algorithm/CalculateLayout.cpp b/yoga/algorithm/CalculateLayout.cpp
index 0a7224cc0b..d25435071b 100644
--- a/yoga/algorithm/CalculateLayout.cpp
+++ b/yoga/algorithm/CalculateLayout.cpp
@@ -94,7 +94,18 @@ static void computeFlexBasisForChild(
   const bool isColumnStyleDimDefined =
       child->hasDefiniteLength(Dimension::Height, ownerHeight);
 
-  if (resolvedFlexBasis.isDefined() && yoga::isDefined(mainAxisSize)) {
+  const bool fixFlexBasisFitContent =
+      node->getConfig()->isExperimentalFeatureEnabled(
+          ExperimentalFeature::FixFlexBasisFitContent);
+
+  bool useResolvedFlexBasis =
+      resolvedFlexBasis.isDefined() && yoga::isDefined(mainAxisSize);
+  if (fixFlexBasisFitContent && resolvedFlexBasis.isDefined() &&
+      resolvedFlexBasis.unwrap() > 0) {
+    useResolvedFlexBasis = true;
+  }
+
+  if (useResolvedFlexBasis) {
     if (child->getLayout().computedFlexBasis.isUndefined() ||
         (child->getConfig()->isExperimentalFeatureEnabled(
              ExperimentalFeature::WebFlexBasis) &&
@@ -164,12 +175,27 @@ static void computeFlexBasisForChild(
       }
     }
 
-    if ((isMainAxisRow && node->style().overflow() == Overflow::Scroll) ||
-        node->style().overflow() != Overflow::Scroll) {
-      if (yoga::isUndefined(childHeight) && yoga::isDefined(height)) {
-        childHeight = height;
-        childHeightSizingMode = SizingMode::FitContent;
-      }
+    // For height in the main axis (column direction): when the
+    // FixFlexBasisFitContent feature is enabled, skip FitContent for
+    // non-measure container children. This makes the flex basis independent
+    // of the parent's content-determined height, preventing unnecessary
+    // re-measurement cascades when a sibling changes size in a ScrollView.
+    //
+    // We only optimize the height (column) axis because text wrapping depends
+    // on width constraints propagating through container nodes. Removing
+    // FitContent from the width axis would cause text inside nested
+    // containers to stop wrapping.
+    bool applyHeightFitContent =
+        isMainAxisRow || node->style().overflow() != Overflow::Scroll;
+    if (fixFlexBasisFitContent) {
+      applyHeightFitContent = isMainAxisRow ||
+          (child->hasMeasureFunc() &&
+           node->style().overflow() != Overflow::Scroll);
+    }
+    if (applyHeightFitContent && yoga::isUndefined(childHeight) &&
+        yoga::isDefined(height)) {
+      childHeight = height;
+      childHeightSizingMode = SizingMode::FitContent;
     }
 
     const auto& childStyle = child->style();
@@ -537,6 +563,8 @@ static float computeFlexBasisForChildren(
     yoga::Node* const node,
     const float availableInnerWidth,
     const float availableInnerHeight,
+    const float ownerWidth,
+    const float ownerHeight,
     SizingMode widthSizingMode,
     SizingMode heightSizingMode,
     Direction direction,
@@ -598,8 +626,8 @@ static float computeFlexBasisForChildren(
           availableInnerWidth,
           widthSizingMode,
           availableInnerHeight,
-          availableInnerWidth,
-          availableInnerHeight,
+          ownerWidth,
+          ownerHeight,
           heightSizingMode,
           direction,
           layoutMarkerData,
@@ -1429,12 +1457,53 @@ static void calculateLayoutImpl(
 
   // STEP 3: DETERMINE FLEX BASIS FOR EACH ITEM
 
+  // When this node is measured with MaxContent (FixFlexBasisFitContent
+  // behavior), availableInnerHeight is NaN.
+  // To preserve percentage resolution for descendants, derive a definite
+  // owner-size from the parent-provided ownerHeight.
+  float ownerWidthForChildren = availableInnerWidth;
+  float ownerHeightForChildren = availableInnerHeight;
+
+  if (node->getConfig()->isExperimentalFeatureEnabled(
+          ExperimentalFeature::FixFlexBasisFitContent)) {
+    const auto* owner = node->getOwner();
+    const bool isChildOfScrollContainer =
+        owner != nullptr && owner->style().overflow() == Overflow::Scroll;
+
+    if (!isChildOfScrollContainer) {
+      if (yoga::isUndefined(ownerWidthForChildren) &&
+          yoga::isDefined(ownerWidth)) {
+        ownerWidthForChildren = calculateAvailableInnerDimension(
+            node,
+            direction,
+            Dimension::Width,
+            ownerWidth - marginAxisRow,
+            paddingAndBorderAxisRow,
+            ownerWidth,
+            ownerWidth);
+      }
+      if (yoga::isUndefined(ownerHeightForChildren) &&
+          yoga::isDefined(ownerHeight)) {
+        ownerHeightForChildren = calculateAvailableInnerDimension(
+            node,
+            direction,
+            Dimension::Height,
+            ownerHeight - marginAxisColumn,
+            paddingAndBorderAxisColumn,
+            ownerHeight,
+            ownerWidth);
+      }
+    }
+  }
+
   // Computed basis + margins + gap
   float totalMainDim = 0;
   totalMainDim += computeFlexBasisForChildren(
       node,
       availableInnerWidth,
       availableInnerHeight,
+      ownerWidthForChildren,
+      ownerHeightForChildren,
       widthSizingMode,
       heightSizingMode,
       direction,
diff --git a/yoga/enums/ExperimentalFeature.h b/yoga/enums/ExperimentalFeature.h
index bbbf9cda43..7e6c5eb8b6 100644
--- a/yoga/enums/ExperimentalFeature.h
+++ b/yoga/enums/ExperimentalFeature.h
@@ -17,11 +17,12 @@ namespace facebook::yoga {
 
 enum class ExperimentalFeature : uint8_t {
   WebFlexBasis = YGExperimentalFeatureWebFlexBasis,
+  FixFlexBasisFitContent = YGExperimentalFeatureFixFlexBasisFitContent,
 };
 
 template <>
 constexpr int32_t ordinalCount<ExperimentalFeature>() {
-  return 1;
+  return 2;
 }
 
 constexpr ExperimentalFeature scopedEnum(YGExperimentalFeature unscoped) {