Arch Linux

Description:
Redmine 4.0.5-1
Ruby 2.7.0-1
Rubygems 3.1.2-4
Ruby-bundler 2.1.4-1

Running a Redmine instance using the above official packages results in Internal Server Error (500) when trying to view the 'repositories' page of the webapp. The log file shows the issue as:

FrozenError (can't modify frozen String: ""):

This bug was reported to upstream: https://www.redmine.org/issues/33021

Related to this change in Ruby:
https://bugs.ruby-lang.org/issues/16150

Specifically, the issue is this line, which may return a frozen string:
https://github.com/redmine/redmine/blob/caa88a2ed308224edc66f411b1466a7e622994c3/app/controllers/repositories_controller.rb#L320

The issue is that this version of Redmine in the official repo does not yet support the latest version of Ruby.

Workaround:

Manually downgrading the following:
ruby (2.7.0-1 => 2.6.5-1)
rubygems (3.1.2-4 => 3.0.6-1)
ruby-bundler (2.1.4-1 => 2.0.2-1)

Then re-installing gems using "bundle install --without development test" and restarting the httpd service fixes the issue with no other noticeable side effects.

Obviously, downgrading packages is Not Supported Behavior. But hey, it made the app work.