From 06f86c8b2fb0a2d40460d31647899497bfd78fc9 Mon Sep 17 00:00:00 2001
From: liyuqian <liyuqian@google.com>
Date: Mon, 13 May 2019 14:36:09 -0700
Subject: [PATCH] Reland matrix check (#32521)

This relands flutter/flutter#31701 with missing const added

This reverts commit 549b412656bb4db80920de56a09912e079fdd2a2.
---
 packages/flutter/lib/src/rendering/layer.dart     |  3 ++-
 packages/flutter/lib/src/rendering/proxy_box.dart |  4 +++-
 .../flutter/test/rendering/proxy_box_test.dart    | 15 +++++++++++----
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/packages/flutter/lib/src/rendering/layer.dart b/packages/flutter/lib/src/rendering/layer.dart
index 5ad0e2e7fca..315c51db1f1 100644
--- a/packages/flutter/lib/src/rendering/layer.dart
+++ b/packages/flutter/lib/src/rendering/layer.dart
@@ -1228,7 +1228,8 @@ class TransformLayer extends OffsetLayer {
   /// The [transform] and [offset] properties must be non-null before the
   /// compositing phase of the pipeline.
   TransformLayer({ Matrix4 transform, Offset offset = Offset.zero })
-    : _transform = transform,
+    : assert(transform.storage.every((double value) => value.isFinite)),
+      _transform = transform,
       super(offset: offset);
 
   /// The matrix to apply.
diff --git a/packages/flutter/lib/src/rendering/proxy_box.dart b/packages/flutter/lib/src/rendering/proxy_box.dart
index 434d6233250..d529bf1fddd 100644
--- a/packages/flutter/lib/src/rendering/proxy_box.dart
+++ b/packages/flutter/lib/src/rendering/proxy_box.dart
@@ -2280,9 +2280,11 @@ class RenderFittedBox extends RenderProxyBox {
       final Rect sourceRect = _resolvedAlignment.inscribe(sizes.source, Offset.zero & childSize);
       final Rect destinationRect = _resolvedAlignment.inscribe(sizes.destination, Offset.zero & size);
       _hasVisualOverflow = sourceRect.width < childSize.width || sourceRect.height < childSize.height;
+      assert(scaleX.isFinite && scaleY.isFinite);
       _transform = Matrix4.translationValues(destinationRect.left, destinationRect.top, 0.0)
         ..scale(scaleX, scaleY, 1.0)
         ..translate(-sourceRect.left, -sourceRect.top);
+      assert(_transform.storage.every((double value) => value.isFinite));
     }
   }
 
@@ -2296,7 +2298,7 @@ class RenderFittedBox extends RenderProxyBox {
 
   @override
   void paint(PaintingContext context, Offset offset) {
-    if (size.isEmpty)
+    if (size.isEmpty || child.size.isEmpty)
       return;
     _updatePaintData();
     if (child != null) {
diff --git a/packages/flutter/test/rendering/proxy_box_test.dart b/packages/flutter/test/rendering/proxy_box_test.dart
index ddba02f8089..81745ff9cfb 100644
--- a/packages/flutter/test/rendering/proxy_box_test.dart
+++ b/packages/flutter/test/rendering/proxy_box_test.dart
@@ -15,11 +15,12 @@ import '../flutter_test_alternative.dart';
 import 'rendering_tester.dart';
 
 void main() {
-  test('RenderFittedBox paint', () {
+  test('RenderFittedBox does not paint with empty sizes', () {
     bool painted;
-    RenderFittedBox makeFittedBox() {
+    RenderFittedBox makeFittedBox(Size size) {
       return RenderFittedBox(
         child: RenderCustomPaint(
+          preferredSize: size,
           painter: TestCallbackPainter(onPaint: () {
             painted = true;
           }),
@@ -27,13 +28,19 @@ void main() {
       );
     }
 
+    // The RenderFittedBox paints if both its size and its child's size are nonempty.
     painted = false;
-    layout(makeFittedBox(), phase: EnginePhase.paint);
+    layout(makeFittedBox(const Size(1, 1)), phase: EnginePhase.paint);
     expect(painted, equals(true));
 
+    // The RenderFittedBox should not paint if its child is empty-sized.
+    painted = false;
+    layout(makeFittedBox(Size.zero), phase: EnginePhase.paint);
+    expect(painted, equals(false));
+
     // The RenderFittedBox should not paint if it is empty.
     painted = false;
-    layout(makeFittedBox(), constraints: BoxConstraints.tight(Size.zero), phase: EnginePhase.paint);
+    layout(makeFittedBox(const Size(1, 1)), constraints: BoxConstraints.tight(Size.zero), phase: EnginePhase.paint);
     expect(painted, equals(false));
   });