Hi,

I know there are some other similar reports like this already in the database, but I did not find any for this specific case and 4.x:

Using the build from 6th jan 2022 to check for install requirements it complained that config.php isn't writeable. After I fixed this, the installation process went on fine, and turned into a loop cycling between the admin credentials and the databasesetup. it did not show any errors at all.

(somebody else in the forum seemed to have the same issue with 3.x:  https://www.phpbb.com/community/viewtopic.php?f=661&t=2611571 )

After a while I figured out, that I did a mistake on the permissions of other files as well and was able to correct it and finish the installation (btw thanks for the nice help in the #phpbb irc!) 

So I have a suggestion: it would be nice, if the installer for 4.x can not only check for the config.php beeing writeable but also for the other needed locations as well.

For the technical side, maybe it can be a file, where the names that are mentioned in the installguide (https://www.phpbb.com/community/docs/INSTALL.html ) can be listed for the installer?  And also referenced in the installguide, maybe than its easier to keep the installguide up-to-date as well as the installer itself (only one place to look for).

The file content could look like this:

#files and directories that need write permissions (see https://www.phpbb.com/community/docs/INSTALL.html for reference): 

./config.php

./store/

./cache/

./files/

./images/avatars/upload/

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SUMMARY:

what happend? installer turned into endless loop asking again and again for admincredentials after giving database credentials

cause of error? user-too-stupid, did enter wrong file permissions

what has been expected? any kind of error message, like saying which locations are not writeable

fixable? likely very easy

proposed fix: add filesourced check in the installer