From b5712cbcc779b555b8f2add2270ba819f22223e2 Mon Sep 17 00:00:00 2001
From: Local Dev <dev@localhost>
Date: Sun, 2 Aug 2026 18:50:58 +0200
Subject: [PATCH] Theseus: 'unsaved changes' confirmation on programmatic
 navigation
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Adds a will-prevent-unload handler on each tab. When a page has a beforeunload
handler that returns non-null (typical for forms with unsaved input, in-browser
editors with a dirty document, etc.), Electron would silently cancel any
navigation attempt. Now we show a native two-button dialog — 'Stay on page' /
'Leave anyway' — matching how mainstream browsers behave.

Works for both user-initiated navigation (link clicks) AND our own programmatic
loads (address bar, chip switcher, in-tab collision prompt). Answers the
operator's ask: 'only if there is unsaved work that can be lost, should a
warning appear' (2026-08-02).
---
 main.js | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/main.js b/main.js
index 1ac035d..fcca960 100644
--- a/main.js
+++ b/main.js
@@ -4,7 +4,7 @@
 // h, Sia s3, direct ip, redirect u). Tabs, nav controls, a search box, a home
 // page, and optional Tor onion routing. No system daemon; the app is the trust
 // boundary.
-const { app, BrowserWindow, WebContentsView, ipcMain, protocol, session, Menu, clipboard, nativeTheme, shell } = require("electron");
+const { app, BrowserWindow, WebContentsView, ipcMain, protocol, session, Menu, clipboard, nativeTheme, shell, dialog } = require("electron");
 const path = require("path");
 const http = require("http");
 const https = require("https");
@@ -795,6 +795,24 @@ function createTab(initial, opts = {}) {
       if (isBnsHost(parsed.hostname)) { e.preventDefault(); navigateTab(id, parsed.hostname + parsed.pathname); }
     } catch {}
   });
+  // "You have unsaved changes" confirmation: fires when the page's beforeunload
+  // handler is trying to keep the user on the page (e.g. an unsent form draft,
+  // an editor with a dirty document). Show a native confirm; on "Leave", call
+  // preventDefault to override the block. Applies to both link clicks AND our
+  // programmatic loads (chip switcher, address-bar navigation).
+  wc.on("will-prevent-unload", (e) => {
+    const parent = BrowserWindow.getFocusedWindow() || win;
+    const choice = dialog.showMessageBoxSync(parent, {
+      type: "question",
+      buttons: ["Stay on page", "Leave anyway"],
+      defaultId: 0,
+      cancelId: 0,
+      title: "Unsaved changes",
+      message: "This page is asking you to stay.",
+      detail: "You may have unsaved changes that will be lost if you leave.",
+    });
+    if (choice === 1) e.preventDefault(); // Leave anyway -> override the beforeunload
+  });
   // Links that open a new tab: target="_blank", window.open, Ctrl/middle-click.
   wc.setWindowOpenHandler(({ url, disposition }) => {
     if (url && url !== "about:blank") createTab(url, { background: disposition === "background-tab" });