Comment 4 for bug 1878163

Not exactly the same but I'm not shure to report it here and avoid duplicates:

1) After a apt upgrade today redmine fails to install complaining
-----
Setting up passenger-doc (1:6.0.16-1~focal1) ...
Setting up passenger (1:6.0.16-1~focal1) ...
Setting up libnginx-mod-http-passenger (1:6.0.16-1~focal1) ...
Installing new version of config file /etc/nginx/conf.d/mod-http-passenger.conf ...
Setting up passenger-dev (1:6.0.16-1~focal1) ...
Processing triggers for redmine (4.0.6-2) ...
Could not find gem 'webmock' in any of the gem sources listed in your Gemfile.
#########################################################################
# Failed to detect redmine dependencies; if you are in the middle of an #
# upgrade, this is probably fine, there will be another attempt later. #
# #
# If you are NOT in the middle of an upgrade, there is probably a real #
# issue. Please report a bug. #
#########################################################################
-----
State is now:
/usr/bin/ruby2.7
ruby 1:2.7+1
redmine 4.0.6-2
redmine-mysql 4.0.6-2
passenger-dev:amd64 1:6.0.16-1~focal1
libnginx-mod-http-passenger:amd64 1:6.0.16-1~focal1
passenger:amd64 1:6.0.16-1~focal1

2) going to /usr/share/redmine and trying "bundle install" fails too:
Bundler::GemNotFound: Could not find thread_safe-0.3.6.gem for installation
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/source/rubygems.rb:159:in `install'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/installer/gem_installer.rb:54:in `install'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/installer/gem_installer.rb:16:in `install_from_spec'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/installer/parallel_installer.rb:155:in `do_install'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/installer/parallel_installer.rb:146:in `block in worker_pool'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:62:in `apply_func'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:57:in `block in process_queue'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:54:in `loop'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:54:in `process_queue'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:90:in `block (2 levels) in create_threads'

An error occurred while installing thread_safe (0.3.6), and Bundler cannot continue.

In Gemfile:
  rails was resolved to 5.2.8.1, which depends on
    actioncable was resolved to 5.2.8.1, which depends on
      actionpack was resolved to 5.2.8.1, which depends on
        actionview was resolved to 5.2.8.1, which depends on
          rails-dom-testing was resolved to 2.0.3, which depends on
            activesupport was resolved to 5.2.8.1, which depends on
              tzinfo was resolved to 1.2.10, which depends on
                thread_safe

Bundler::GemNotFound: Could not find arel-9.0.0.gem for installation
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/source/rubygems.rb:159:in `install'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/installer/gem_installer.rb:54:in `install'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/installer/gem_installer.rb:16:in `install_from_spec'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/installer/parallel_installer.rb:155:in `do_install'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/installer/parallel_installer.rb:146:in `block in worker_pool'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:62:in `apply_func'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:57:in `block in process_queue'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:54:in `loop'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:54:in `process_queue'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:90:in `block (2 levels) in create_threads'

An error occurred while installing arel (9.0.0), and Bundler cannot continue.

In Gemfile:
  rails was resolved to 5.2.8.1, which depends on
    activestorage was resolved to 5.2.8.1, which depends on
      activerecord was resolved to 5.2.8.1, which depends on
        arel

Bundler::GemNotFound: Could not find rmagick-2.16.0.gem for installation
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/source/rubygems.rb:159:in `install'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/installer/gem_installer.rb:54:in `install'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/installer/gem_installer.rb:16:in `install_from_spec'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/installer/parallel_installer.rb:155:in `do_install'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/installer/parallel_installer.rb:146:in `block in worker_pool'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:62:in `apply_func'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:57:in `block in process_queue'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:54:in `loop'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:54:in `process_queue'
  /var/lib/gems/2.7.0/gems/bundler-2.4.1/lib/bundler/worker.rb:90:in `block (2 levels) in create_threads'

An error occurred while installing rmagick (2.16.0), and Bundler cannot continue.

In Gemfile:
  rmagick

3) Later I've tried:
apt install --reinstall redmine redmine-mysql with result:
Preconfiguring packages ...
dpkg: warning: files list file for package 'redmine-mysql' missing; assuming package has no files currently installed
dpkg: warning: files list file for package 'redmine' missing; assuming package has no files currently installed
(Reading database ... 72577 files and directories currently installed.)
Preparing to unpack .../redmine_4.0.6-2_all.deb ...
Unpacking redmine (4.0.6-2) over (4.0.6-2) ...
Preparing to unpack .../redmine-mysql_4.0.6-2_all.deb ...
Unpacking redmine-mysql (4.0.6-2) over (4.0.6-2) ...
Setting up redmine-mysql (4.0.6-2) ...
Setting up redmine (4.0.6-2) ...
Don't run Bundler as root. Installing your bundle as root will break this application for all non-root users on this machine.
Could not find gem 'webmock' in cached gems or installed locally.
dpkg: error processing package redmine (--configure):
 installed redmine package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
 redmine
E: Sub-process /usr/bin/dpkg returned an error code (1)

4) This could not be repeated, as the next results in:
apt install --reinstall redmine redmine-mysql
E: Internal Error, No file name for redmine:amd64

5) Result after apt upgrade:
Setting up redmine (4.0.6-2) ...
Don't run Bundler as root. Installing your bundle as root will break this application for all non-root users on this machine.
Could not find gem 'webmock' in cached gems or installed locally.
dpkg: error processing package redmine (--configure):
 installed redmine package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
 redmine
E: Sub-process /usr/bin/dpkg returned an error code (1)

6) Result after apt remove redmine*
Removing redmine (4.0.6-2) ...
/var/lib/dpkg/info/redmine.prerm: 33: [: =: unexpected operator
Removing redmine-mysql (4.0.6-2) ...

7) Result after apt install redmine redmine-mysql
is the same as in step 2) now