What were you trying to do that didn't work?

Method operating_system_defaults at https://gitlab.com/redhat/centos-stream/rpms/ruby/-/blob/c9s/operating_system.rb#L98-110 forces binary files to be written to bin/ in the user's home directory when `gem install` is executed as a non-root user, ignoring the GEM_HOME environment setting.

From https://guides.rubygems.org/command-reference/#gem-environment: "RubyGems' default local repository can be overridden with the GEM_PATH and GEM_HOME environment variables. GEM_HOME sets the default repository to install into. "

The expected behavior is for binstubs to be installed to the $GEM_HOME/bin by default, which differs from the CentOS Stream 8 & 9 implementations.

Referring to the line at https://gitlab.com/redhat/centos-stream/rpms/ruby/-/blob/c9s/operating_system.rb#L103 :

If the user specifies `-no-user-install`, having the operating_system_defaults method inject `-bindir #{File.join [Dir.home, 'bin']}` to put binstubs in the user's home directory (as it does now) doesn't make sense.

If the user specifies `-install-dir`, `gem install` will fail with output "ERROR: Use --install-dir or --user-install but not both" because operating_system_defaults adds `user-install`. This renders the `-install-dir` option unusable on its own.

Both issues can be worked around by passing in additional arguments (see Steps to Reproduce section), but the solutions are unintuitive.

Suggestion: how about not adding both `-user-install` and `bindir...` if the user specifies either `no-user-install` or `-install-dir`?

What is the impact of this issue to you?

Please provide the package NVR for which the bug is seen:

ruby-3.0.7-162.el9

How reproducible is this bug?:

Always

Steps to reproduce

As a user other than root:
> mkdir gem_home
> export GEM_HOME=$PWD/gem_home
> gem install bundler -v 1.17.3
> ls ~/bin/bundler # confirm that the bundler executable was written to ~/bin
> ls $GEM_HOME/bin # fails, directory doesn't exist

Work-around:
> gem install bundler -v 1.17.3 --bindir $GEM_HOME/bin

Also,
> gem install bundler --install-dir $GEM_HOME
ERROR: Use --install-dir or --user-install but not both

Work-around:
> gem install bundler --install-dir $GEM_HOME --no-user-install

Expected results

The bin directory should be created at $GEM_HOME/bin.

Actual results

The bin directory is created in the user's home directory, ~/bin.