From 60b868ed1c80a8ab8645d9f27d5165464a581100 Mon Sep 17 00:00:00 2001
From: jonahwilliams <jonahwilliams@google.com>
Date: Sun, 24 Mar 2024 13:26:40 -0700
Subject: [PATCH 1/2] [Impeller] fix unbalanced restores.

---
 impeller/entity/BUILD.gn                 |  1 +
 impeller/entity/entity_pass.cc           |  8 +++-
 impeller/entity/entity_pass_unittests.cc | 52 ++++++++++++++++++++++++
 3 files changed, 59 insertions(+), 2 deletions(-)
 create mode 100644 impeller/entity/entity_pass_unittests.cc

diff --git a/impeller/entity/BUILD.gn b/impeller/entity/BUILD.gn
index b13e8f81526d8..a917b91b781cf 100644
--- a/impeller/entity/BUILD.gn
+++ b/impeller/entity/BUILD.gn
@@ -272,6 +272,7 @@ impeller_component("entity_unittests") {
     "contents/tiled_texture_contents_unittests.cc",
     "contents/vertices_contents_unittests.cc",
     "entity_pass_target_unittests.cc",
+    "entity_pass_unittests.cc",
     "entity_playground.cc",
     "entity_playground.h",
     "entity_unittests.cc",
diff --git a/impeller/entity/entity_pass.cc b/impeller/entity/entity_pass.cc
index 353fccf8cd5f9..b470189a242a9 100644
--- a/impeller/entity/entity_pass.cc
+++ b/impeller/entity/entity_pass.cc
@@ -869,7 +869,9 @@ bool EntityPass::RenderElement(Entity& element_entity,
 
       if constexpr (ContentContext::kEnableStencilThenCover) {
         // Skip all clip restores when stencil-then-cover is enabled.
-        clip_replay_->RecordEntity(element_entity, clip_coverage.type);
+        if (clip_coverage_stack.back().coverage.has_value()) {
+          clip_replay_->RecordEntity(element_entity, clip_coverage.type);
+        }
         return true;
       }
 
@@ -1269,7 +1271,9 @@ void EntityPassClipRecorder::RecordEntity(const Entity& entity,
       rendered_clip_entities_.push_back(entity.Clone());
       break;
     case Contents::ClipCoverage::Type::kRestore:
-      rendered_clip_entities_.pop_back();
+      if (!rendered_clip_entities_.empty()) {
+        rendered_clip_entities_.pop_back();
+      }
       break;
   }
 }
diff --git a/impeller/entity/entity_pass_unittests.cc b/impeller/entity/entity_pass_unittests.cc
new file mode 100644
index 0000000000000..d1f05448e938b
--- /dev/null
+++ b/impeller/entity/entity_pass_unittests.cc
@@ -0,0 +1,52 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "flutter/testing/testing.h"
+#include "gtest/gtest.h"
+#include "impeller/entity/entity_pass.h"
+
+namespace impeller {
+namespace testing {
+
+TEST(EntityPassClipRecorderTest, CanPushAndPopEntities) {
+  EntityPassClipRecorder recorder = EntityPassClipRecorder();
+
+  EXPECT_TRUE(recorder.GetReplayEntities().empty());
+
+  Entity entity;
+  recorder.RecordEntity(entity, Contents::ClipCoverage::Type::kAppend);
+  EXPECT_EQ(recorder.GetReplayEntities().size(), 1u);
+
+  recorder.RecordEntity(entity, Contents::ClipCoverage::Type::kAppend);
+  EXPECT_EQ(recorder.GetReplayEntities().size(), 2u);
+
+  recorder.RecordEntity(entity, Contents::ClipCoverage::Type::kRestore);
+  EXPECT_EQ(recorder.GetReplayEntities().size(), 1u);
+
+  recorder.RecordEntity(entity, Contents::ClipCoverage::Type::kRestore);
+  EXPECT_TRUE(recorder.GetReplayEntities().empty());
+}
+
+TEST(EntityPassClipRecorderTest, CanPopEntitiesSafely) {
+  EntityPassClipRecorder recorder = EntityPassClipRecorder();
+
+  EXPECT_TRUE(recorder.GetReplayEntities().empty());
+
+  Entity entity;
+  recorder.RecordEntity(entity, Contents::ClipCoverage::Type::kRestore);
+  EXPECT_TRUE(recorder.GetReplayEntities().empty());
+}
+
+TEST(EntityPassClipRecorderTest, CanAppendNoChange) {
+  EntityPassClipRecorder recorder = EntityPassClipRecorder();
+
+  EXPECT_TRUE(recorder.GetReplayEntities().empty());
+
+  Entity entity;
+  recorder.RecordEntity(entity, Contents::ClipCoverage::Type::kNoChange);
+  EXPECT_TRUE(recorder.GetReplayEntities().empty());
+}
+
+}  // namespace testing
+}  // namespace impeller

From 7d56494982e807eb1dd134e94bf6fa1c5e41a4e7 Mon Sep 17 00:00:00 2001
From: jonahwilliams <jonahwilliams@google.com>
Date: Mon, 25 Mar 2024 08:56:19 -0700
Subject: [PATCH 2/2] update licenses

---
 ci/licenses_golden/excluded_files | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ci/licenses_golden/excluded_files b/ci/licenses_golden/excluded_files
index e89bbf56616b0..c9c50cea46b57 100644
--- a/ci/licenses_golden/excluded_files
+++ b/ci/licenses_golden/excluded_files
@@ -152,6 +152,7 @@
 ../../../flutter/impeller/entity/contents/tiled_texture_contents_unittests.cc
 ../../../flutter/impeller/entity/contents/vertices_contents_unittests.cc
 ../../../flutter/impeller/entity/entity_pass_target_unittests.cc
+../../../flutter/impeller/entity/entity_pass_unittests.cc
 ../../../flutter/impeller/entity/entity_unittests.cc
 ../../../flutter/impeller/entity/geometry/geometry_unittests.cc
 ../../../flutter/impeller/entity/render_target_cache_unittests.cc