From 48db0e23c42ca0a98ed7027aa10a1c799ef2ec34 Mon Sep 17 00:00:00 2001
From: Adrian Wielgosik <adrian.wielgosik@gmail.com>
Date: Fri, 12 Jul 2024 21:49:14 +0200
Subject: [PATCH] core: Fix panic on unsetting self-referential masker

---
 core/src/display_object.rs                        |   6 ++++--
 .../displayobject_mask_self_referential/Test.as   |  14 ++++++++++++++
 .../output.txt                                    |   0
 .../displayobject_mask_self_referential/test.swf  | Bin 0 -> 526 bytes
 .../displayobject_mask_self_referential/test.toml |   3 +++
 5 files changed, 21 insertions(+), 2 deletions(-)
 create mode 100644 tests/tests/swfs/avm2/displayobject_mask_self_referential/Test.as
 create mode 100644 tests/tests/swfs/avm2/displayobject_mask_self_referential/output.txt
 create mode 100644 tests/tests/swfs/avm2/displayobject_mask_self_referential/test.swf
 create mode 100644 tests/tests/swfs/avm2/displayobject_mask_self_referential/test.toml

diff --git a/core/src/display_object.rs b/core/src/display_object.rs
index ab512a917..a892cccfc 100644
--- a/core/src/display_object.rs
+++ b/core/src/display_object.rs
@@ -1666,7 +1666,8 @@ pub trait TDisplayObject<'gc>:
         remove_old_link: bool,
     ) {
         if remove_old_link {
-            if let Some(old_masker) = self.base().masker() {
+            let old_masker = self.base().masker();
+            if let Some(old_masker) = old_masker {
                 old_masker.set_maskee(gc_context, None, false);
             }
             if let Some(parent) = self.parent() {
@@ -1686,7 +1687,8 @@ pub trait TDisplayObject<'gc>:
         remove_old_link: bool,
     ) {
         if remove_old_link {
-            if let Some(old_maskee) = self.base().maskee() {
+            let old_maskee = self.base().maskee();
+            if let Some(old_maskee) = old_maskee {
                 old_maskee.set_masker(gc_context, None, false);
             }
             self.invalidate_cached_bitmap(gc_context);
diff --git a/tests/tests/swfs/avm2/displayobject_mask_self_referential/Test.as b/tests/tests/swfs/avm2/displayobject_mask_self_referential/Test.as
new file mode 100644
index 000000000..05a503955
--- /dev/null
+++ b/tests/tests/swfs/avm2/displayobject_mask_self_referential/Test.as
@@ -0,0 +1,14 @@
+// compiled with mxmlc
+
+
+package {
+    import flash.display.MovieClip;
+
+    public class Test extends MovieClip {
+        public function Test(){
+            var mc = new MovieClip();
+            this.mask = this;
+            this.mask = mc;
+        }
+    }
+}
\ No newline at end of file
diff --git a/tests/tests/swfs/avm2/displayobject_mask_self_referential/output.txt b/tests/tests/swfs/avm2/displayobject_mask_self_referential/output.txt
new file mode 100644
index 000000000..e69de29bb
diff --git a/tests/tests/swfs/avm2/displayobject_mask_self_referential/test.swf b/tests/tests/swfs/avm2/displayobject_mask_self_referential/test.swf
new file mode 100644
index 0000000000000000000000000000000000000000..9eee45e3db5dc20513bd2146e9461f1a307f2c66
GIT binary patch
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diff --git a/tests/tests/swfs/avm2/displayobject_mask_self_referential/test.toml b/tests/tests/swfs/avm2/displayobject_mask_self_referential/test.toml
new file mode 100644
index 000000000..e2f387966
--- /dev/null
+++ b/tests/tests/swfs/avm2/displayobject_mask_self_referential/test.toml
@@ -0,0 +1,3 @@
+# tests a probable (no access to original repro) cause of
+# https://github.com/ruffle-rs/ruffle/issues/14747
+num_frames = 1