Custom user agent and devtool breaks again in PySide6, with segmentation fault when closing the window

[TransparentLC]

Specification

• pywebview version: 5.0.5
• operating system: Windows 11/Ubuntu 22.04
• web renderer: qt (PySide6)

I believe this issue is not related to OS. PyQt5 is not tested.

Description

pip install pywebview[pyside6]

import webview
webview.create_window('Hello world', 'https://www.cloudflare.com/cdn-cgi/trace')
webview.start(user_agent='Custom UA', debug=True, gui='qt')

The custom user agent breaks again, and the devtool also breaks. Moreover, if I close one window, then the whole program freezes and crashes. On the Linux terminal it gives a segmentation fault.

I tried moving the code of customizing user agent after os.environ['QTWEBENGINE_REMOTE_DEBUGGING'] = BrowserView.inspector_port in webview/platforms/qt.py and getting the devtool fixed. Though I don't know why it works:

        if is_webengine:
            environ_append(
                'QTWEBENGINE_CHROMIUM_settings',
                '--use-fake-ui-for-media-stream',
                '--enable-features=AutoplayIgnoreWebAudio',
            )

-        user_agent = _settings['user_agent']
-        if user_agent and is_webengine:
-            self.view.page().profile().setHttpUserAgent(user_agent)

        if _settings['debug'] and is_webengine:
            # Initialise Remote debugging (need to be done only once)
            if not BrowserView.inspector_port:
                BrowserView.inspector_port = BrowserView._get_debug_port()
                os.environ['QTWEBENGINE_REMOTE_DEBUGGING'] = BrowserView.inspector_port
        else:
            self.view.setContextMenuPolicy(
                QtCore.Qt.NoContextMenu
            )  # disable right click context menu

+        user_agent = _settings['user_agent']
+        if user_agent and is_webengine:
+            self.view.page().profile().setHttpUserAgent(user_agent)

        if is_webengine:
            if _settings['private_mode']:
                self.profile = QWebEngineProfile()

For the other two issues. I compared the commits and found the changes related to them:

A commit between f27786832c18685576dbe6ccebba79fb7d8a5245 and 54cd806ead92076dfe897c41e1d105b653470657 (I checked the repo's commit history) breaks the custom user agent:

        if is_webengine:
            if _settings['private_mode']:
                self.profile = QWebEngineProfile()
            else:
                self.profile = QWebEngineProfile('pywebview')
                self.profile.setPersistentStoragePath(_profile_storage_path)
                self.cookies = {}
                cookie_store = self.profile.cookieStore()
                cookie_store.cookieAdded.connect(self.on_cookie_added)
                cookie_store.cookieRemoved.connect(self.on_cookie_removed)

-                self.view.setPage(BrowserView.WebPage(self.view, profile=self.profile))
+            self.view.setPage(BrowserView.WebPage(self, profile=self.profile))
        elif not is_webengine and not _settings['private_mode']:
            logger.warning('qtwebkit does not support private_mode')

Commit 307786101e104c29c7c18216428a66faccd14e57 causes the segmentation fault when closing the window:

        del BrowserView.instances[self.uid]
+        self.view.page().deleteLater()
        self.close()

If I revert the above two changes then the issue is resolved. Though I don't know why it works (again).

Practicalities

• YES I am willing to work on this issue myself.

• NO I am prepared to support this issue financially.

[r0x0r]

Sorry for the late response. I have not tested with PyQT6, I am still on 5. i will try to test to reproduce these issues, but meanwhile could you create a PR with your fixes?

self.view.page().deleteLater() was added to address page not being released after the window close.

[TransparentLC]

I can create PR for fixing the devtool. But for the other two changes I'm not sure about the revert.

[github-actions[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[TransparentLC]

Can you reproduce it? @r0x0r

[r0x0r]

Yes, I found the bug and fixed it in master.

[TransparentLC]

I tested the latest commit and user agent and devtools works now, but the segmentation fault problem still exists.

https://github.com/r0x0r/pywebview/assets/47057319/1c0bab40-a824-4a31-93cf-f4d8aca3d30c

[r0x0r]

Alright, this one should be fixed in master as well now.