From 02d2cb4854c7d5bba8ac35ddf9cd054d1f36f8e3 Mon Sep 17 00:00:00 2001
From: David Mendes <david.mendes@outsystems.com>
Date: Wed, 21 Oct 2026 18:17:58 +0100
Subject: [PATCH] fix(server): a preview dialog the browser already closed no
 longer blocks the tab

---
 apps/server/src/preview/ServerBrowser.test.ts | 41 +++++++++++++++++++
 apps/server/src/preview/ServerBrowser.ts      | 14 ++++---
 2 files changed, 50 insertions(+), 5 deletions(-)

diff --git a/apps/server/src/preview/ServerBrowser.test.ts b/apps/server/src/preview/ServerBrowser.test.ts
index ac4a785f207f3..f3a178ef16052 100644
--- a/apps/server/src/preview/ServerBrowser.test.ts
+++ b/apps/server/src/preview/ServerBrowser.test.ts
@@ -673,6 +673,47 @@ it.live("reports a pending dialog without evaluating the page and resolves it ex
   ).pipe(Effect.provide(layer)),
 );
 
+it.live("a dialog the browser already closed stops blocking the tab", () =>
+  Effect.scoped(
+    Effect.gen(function* () {
+      const { broker, tabId } = yield* ready;
+      const page = contexts[0]!.page;
+      yield* broker.invoke({
+        scope,
+        tabId,
+        operation: "navigate",
+        input: { url: "http://localhost:5173" },
+      });
+      page.emit("dialog", {
+        type: () => "beforeunload",
+        message: () => "",
+        defaultValue: () => "",
+        accept: vi.fn(async () => {
+          throw new Error("Protocol error (Page.handleJavaScriptDialog): No dialog is showing");
+        }),
+        dismiss: vi.fn(async () => {}),
+      });
+      yield* broker
+        .invoke<void>({ scope, tabId, operation: "dialog", input: { accept: true } })
+        .pipe(Effect.flip);
+      const status = yield* broker.invoke<PreviewAutomationStatus>({
+        scope,
+        tabId,
+        operation: "status",
+        input: {},
+      });
+      expect(status.dialog).toBeNull();
+      yield* broker.invoke({
+        scope,
+        tabId,
+        operation: "navigate",
+        input: { url: "http://localhost:5173/other" },
+      });
+      expect(page.goto).toHaveBeenCalledTimes(2);
+    }),
+  ).pipe(Effect.provide(layer)),
+);
+
 it.live("a tab opened to a file the browser cannot show reports the file to download", () =>
   Effect.scoped(
     Effect.gen(function* () {
diff --git a/apps/server/src/preview/ServerBrowser.ts b/apps/server/src/preview/ServerBrowser.ts
index 5b386e5f0797a..52605d352e7f9 100644
--- a/apps/server/src/preview/ServerBrowser.ts
+++ b/apps/server/src/preview/ServerBrowser.ts
@@ -537,11 +537,15 @@ const make = Effect.gen(function* () {
   const resolveDialog = async (tab: ServerTab, input: PreviewAutomationDialogInput) => {
     const dialog = tab.dialog;
     if (!dialog) throw new Error("No dialog is pending.");
-    if (input.accept) await dialog.accept(input.promptText);
-    else await dialog.dismiss();
-    if (tab.dialog === dialog) tab.dialog = null;
-    ServerBrowserPage.invalidateRefs(tab.page);
-    broadcastControl(tab);
+    try {
+      if (input.accept) await dialog.accept(input.promptText);
+      else await dialog.dismiss();
+    } finally {
+      // A failed answer means the browser already closed the dialog. Keeping it would block the tab.
+      if (tab.dialog === dialog) tab.dialog = null;
+      ServerBrowserPage.invalidateRefs(tab.page);
+      broadcastControl(tab);
+    }
   };
 
   const report = (tab: ServerTab, navStatus: PreviewNavStatus) => {