From bb10b0e301efaa6105ee2fc353e4b552dd5b3da0 Mon Sep 17 00:00:00 2001
From: Shannon Booth <shannon@serenityos.org>
Date: Thu, 28 Nov 2024 02:49:34 +1300
Subject: [PATCH] LibWeb: Always assert that principal realm returns a
 principal realm

There was a bug in the HTML proposal where a synthetic realm settings
object's principal realm was a shadow realm if there were nested shadow
realms, which this assertion catches more directly (rather than later
down the track, where it is used).

We were meant to also assert for this case, but we were previously
returning early.
---
 Libraries/LibWeb/HTML/Scripting/Environments.cpp | 10 +++++-----
 Libraries/LibWeb/HTML/Scripting/Environments.h   |  2 +-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Libraries/LibWeb/HTML/Scripting/Environments.cpp b/Libraries/LibWeb/HTML/Scripting/Environments.cpp
index cbb0f689b9..4b2c0d321b 100644
--- a/Libraries/LibWeb/HTML/Scripting/Environments.cpp
+++ b/Libraries/LibWeb/HTML/Scripting/Environments.cpp
@@ -360,19 +360,19 @@ JS::Realm& current_principal_realm()
 }
 
 // https://whatpr.org/html/9893/webappapis.html#concept-principal-realm-of-realm
-JS::Realm& principal_realm(JS::Realm& realm)
+JS::Realm& principal_realm(GC::Ref<JS::Realm> realm)
 {
-    VERIFY(realm.host_defined());
+    VERIFY(realm->host_defined());
 
     // 1. If realm.[[HostDefined]] is a synthetic realm settings object, then:
-    if (is<Bindings::SyntheticHostDefined>(*realm.host_defined())) {
+    if (is<Bindings::SyntheticHostDefined>(*realm->host_defined())) {
         // 1. Assert: realm is a synthetic realm.
         // 2. Set realm to the principal realm of realm.[[HostDefined]].
-        return static_cast<Bindings::SyntheticHostDefined const&>(*realm.host_defined()).synthetic_realm_settings.principal_realm;
+        realm = static_cast<Bindings::SyntheticHostDefined const&>(*realm->host_defined()).synthetic_realm_settings.principal_realm;
     }
 
     // 2. Assert: realm.[[HostDefined]] is an environment settings object and realm is a principal realm.
-    VERIFY(is<Bindings::PrincipalHostDefined>(*realm.host_defined()));
+    VERIFY(is<Bindings::PrincipalHostDefined>(*realm->host_defined()));
 
     // 3. Return realm.
     return realm;
diff --git a/Libraries/LibWeb/HTML/Scripting/Environments.h b/Libraries/LibWeb/HTML/Scripting/Environments.h
index a2e75de821..8ff26d6606 100644
--- a/Libraries/LibWeb/HTML/Scripting/Environments.h
+++ b/Libraries/LibWeb/HTML/Scripting/Environments.h
@@ -149,7 +149,7 @@ JS::Realm& current_principal_realm();
 EnvironmentSettingsObject& principal_realm_settings_object(JS::Realm&);
 EnvironmentSettingsObject& current_principal_settings_object();
 
-JS::Realm& principal_realm(JS::Realm&);
+JS::Realm& principal_realm(GC::Ref<JS::Realm>);
 JS::Object& current_principal_global_object();
 JS::Realm& relevant_realm(JS::Object const&);
 EnvironmentSettingsObject& relevant_settings_object(JS::Object const&);