Upgrading Snappymail in Nextcloud from 2.20.0 to 2.20.1 or 2.20.2 causes "Internal Server Error" page

[jimbolaya]

Describe the bug
After upgrading Snappymail in Nextcloud, I get an "Internal Server Error" page

To Reproduce
Steps to reproduce the behavior:

1. Upgrade Snappymail in Nextcloud from 2.20.0 to 2.20.1 or 2.20.2
2. Open Snappymail in the Nextcloud interface and get an "Internal Server Error" page
3. Reverting to 2.20.0 allows Snappymail to work.

Expected behavior
I did not expect to see an "Internal Server Error" page on Nextcloud

Please complete the following information:

• Browser: Firefox firefox-esr 102.4.0esr-1~deb11u1
• IMAP daemon: dovecot
• PHP version: 7.4
• SnappyMail Version: 2.20 (0,1,2)
• Nextcloud Version: Nextcloud Hub II / 23.0.11
• Web Server Version: apache2 2.4.54-1~deb11u1

Debug/logging information
{"reqId":"Y2e1NZqCrTn3PLLx1YN95AAAAAk","level":3,"time":"2022-11-06T13:23:01+00:00","remoteAddr":"10.20.30.40","user":"user","app":"index","method":"GET","url":"/index.php/apps/snappymail/","message":"Call to undefined method OCP\\AppFramework\\Http\\ContentSecurityPolicy::useStrictDynamic() in file '/var/www/nextcloud/apps/snappymail/lib/Controller/PageController.php' line 87","userAgent":"Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0","version":"23.0.11.1","exception":{"Exception":"Exception","Message":"Call to undefined method OCP\\AppFramework\\Http\\ContentSecurityPolicy::useStrictDynamic() in file '/var/www/nextcloud/apps/snappymail/lib/Controller/PageController.php' line 87","Code":0,"Trace":[{"file":"/var/www/nextcloud/lib/private/AppFramework/App.php","line":157,"function":"dispatch","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->"},{"file":"/var/www/nextcloud/lib/private/Route/Router.php","line":302,"function":"main","class":"OC\\AppFramework\\App","type":"::"},{"file":"/var/www/nextcloud/lib/base.php","line":1015,"function":"match","class":"OC\\Route\\Router","type":"->"},{"file":"/var/www/nextcloud/index.php","line":36,"function":"handleRequest","class":"OC","type":"::"}],"File":"/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php","Line":158,"Previous":{"Exception":"Error","Message":"Call to undefined method OCP\\AppFramework\\Http\\ContentSecurityPolicy::useStrictDynamic()","Code":0,"Trace":[{"file":"/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php","line":217,"function":"index","class":"OCA\\SnappyMail\\Controller\\PageController","type":"->"},{"file":"/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php","line":126,"function":"executeController","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->"},{"file":"/var/www/nextcloud/lib/private/AppFramework/App.php","line":157,"function":"dispatch","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->"},{"file":"/var/www/nextcloud/lib/private/Route/Router.php","line":302,"function":"main","class":"OC\\AppFramework\\App","type":"::"},{"file":"/var/www/nextcloud/lib/base.php","line":1015,"function":"match","class":"OC\\Route\\Router","type":"->"},{"file":"/var/www/nextcloud/index.php","line":36,"function":"handleRequest","class":"OC","type":"::"}],"File":"/var/www/nextcloud/apps/snappymail/lib/Controller/PageController.php","Line":87},"CustomMessage":"--"}}

I can also try to add Snappymail logs, but I'm pretty sure this is an issue with the Nextcloud App.

Additional context
Rolling back to 2.20.0 allows it to work:

• Go to the Apps page, Disable, then Remove Snappymail
• Go to the nextcloud/apps directory and unpack snappymail-2.20.0-nextcloud.tar.gz
• chown -R www-user:www-user snappymail
• Go back to the Admin interface and Enable Snappymail
• Reload any Snappymail pages in Nextcloud

[jimbolaya]

I applied the fix noted. While I no longer get a "Internal Server Error" page, SnappyMail just spins and doesn't show the interface

[the-djmaze]

Check browser developer window and see the errors there.
Then tell us what they are

[jimbolaya]

In the Console there are some CSP errors:

Content Security Policy: The page’s settings blocked the loading of a resource at https://myserver.org/index.php/apps/snappymail/?/AppData/0/8793419088302674/ (“script-src”). snappymail:1075:428
Uncaught (in promise) Error: Failed loading ./?/AppData/0/8793419088302674/
    onerror https://myserver.org/index.php/apps/snappymail/:1075
    i https://myserver.org/index.php/apps/snappymail/:1075
    i https://myserver.org/index.php/apps/snappymail/:1075
    <anonymous> https://myserver.org/index.php/apps/snappymail/:1075
    <anonymous> https://myserver.org/index.php/apps/snappymail/:1075
snappymail:1075:382
Content Security Policy: The page’s settings blocked the loading of a resource at inline (“script-src”).

[the-djmaze]

Released v2.20.4 to workaround this Nextcloud bug #35013