stability: drop async module completions after termination

Assisted-By: devx/c74ae588-eb01-43ac-9c5d-2e6938841883

src/browser/js/Context.zig

@@ -912,6 +912,12 @@ fn dynamicModuleSourceCallback(ctx: *anyopaque, module_source_: anyerror!ScriptM
     const state: *DynamicModuleResolveState = @ptrCast(@alignCast(ctx));
     var self = state.context;
 
+    if (self.env.terminatePending()) {
+        var module_source = module_source_ catch return;
+        module_source.deinit();
+        return;
+    }
+
     var ls: js.Local.Scope = undefined;
     self.localScope(&ls);
     defer ls.deinit();
@@ -1024,6 +1030,39 @@ fn resolveDynamicModule(self: *Context, state: *DynamicModuleResolveState, modul
     };
 }
 
+const testing = @import("../../testing.zig");
+test "Context: terminated async module completion does not re-enter V8" {
+    const frame = try testing.createFrame();
+    defer testing.test_session.closeAllPages();
+
+    var ls: js.Local.Scope = undefined;
+    frame.js.localScope(&ls);
+    defer ls.deinit();
+    const local = &ls.local;
+
+    const resolver = local.createPromiseResolver();
+    const promise = resolver.promise();
+    const resolver_global = try resolver.persist();
+    defer resolver_global.deinit();
+
+    var state = DynamicModuleResolveState{
+        .module = null,
+        .context_id = frame.js.id,
+        .context = frame.js,
+        .specifier = "https://example.com/late-module.js",
+        .resolver = resolver_global,
+    };
+
+    const env = frame.js.env;
+    env.terminate();
+    js.v8.v8__Isolate__CancelTerminateExecution(env.isolate.handle);
+    defer env.cancelTerminate();
+
+    dynamicModuleSourceCallback(&state, error.Abort);
+
+    try testing.expectEqual(js.Promise.State.pending, promise.state());
+}
+
 // Used to make temporarily enter and exit a context, updating and restoring
 // frame.js:
 //    var hs: js.HandleScope = undefined;