fix(runtime): don't crash when window is deleted (#13392)

This commit fixes an error when user deletes "window" global JS
variable. Instead of relying on "window" or "globalThis" to dispatch
"load" and "unload" events, we are default to global scope of the
worker.

4 files changed, 25 insertions, 4 deletions

diff --git a/cli/tests/integration/run_tests.rs b/cli/tests/integration/run_tests.rs
index 2f32fd67f..74a03e055 100644
--- a/cli/tests/integration/run_tests.rs
+++ b/cli/tests/integration/run_tests.rs
@@ -2480,6 +2480,11 @@ itest!(import_assertions_type_check {
   exit_code: 1,
 });
 
+itest!(delete_window {
+  args: "run delete_window.js",
+  output_str: Some("true\n"),
+});
+
 itest!(colors_without_global_this {
   args: "run colors_without_globalThis.js",
   output_str: Some("true\n"),
diff --git a/cli/tests/testdata/delete_window.js b/cli/tests/testdata/delete_window.js
new file mode 100644
index 000000000..f2f16820d
--- /dev/null
+++ b/cli/tests/testdata/delete_window.js
@@ -0,0 +1 @@
+console.log(delete globalThis.window);
diff --git a/ext/web/02_event.js b/ext/web/02_event.js
index f9a69c625..7ba5afa27 100644
--- a/ext/web/02_event.js
+++ b/ext/web/02_event.js
@@ -970,7 +970,11 @@
       webidl.requiredArguments(arguments.length, 1, {
         prefix: "Failed to execute 'dispatchEvent' on 'EventTarget'",
       });
-      const self = this ?? globalThis;
+      // If `this` is not present, then fallback to global scope. We don't use
+      // `globalThis` directly here, because it could be deleted by user.
+      // Instead use saved reference to global scope when the script was
+      // executed.
+      const self = this ?? window;
 
       const { listeners } = self[eventTargetData];
       if (!(event.type in listeners)) {
diff --git a/runtime/worker.rs b/runtime/worker.rs
index ad31cacc6..7a3a6c1c3 100644
--- a/runtime/worker.rs
+++ b/runtime/worker.rs
@@ -313,7 +313,13 @@ impl MainWorker {
     &mut self,
     script_name: &str,
   ) -> Result<(), AnyError> {
-    self.execute_script(script_name, "window.dispatchEvent(new Event('load'))")
+    self.execute_script(
+      script_name,
+      // NOTE(@bartlomieju): not using `globalThis` here, because user might delete
+      // it. Instead we're using global `dispatchEvent` function which will
+      // used a saved reference to global scope.
+      "dispatchEvent(new Event('load'))",
+    )
   }
 
   /// Dispatches "unload" event to the JavaScript runtime.
@@ -323,8 +329,13 @@ impl MainWorker {
     &mut self,
     script_name: &str,
   ) -> Result<(), AnyError> {
-    self
-      .execute_script(script_name, "window.dispatchEvent(new Event('unload'))")
+    self.execute_script(
+      script_name,
+      // NOTE(@bartlomieju): not using `globalThis` here, because user might delete
+      // it. Instead we're using global `dispatchEvent` function which will
+      // used a saved reference to global scope.
+      "dispatchEvent(new Event('unload'))",
+    )
   }
 }