Fix issue when plugin stubs would sometimes not be properly removed by gem uninstall

[deivid-rodriguez]

What was the end-user or developer problem that led to this PR?

gem uninstall <gem> --install-dir <dir> will fail to remove plugin stubs if the version being removed is also installed globally.

See for example how, without rubygems-server installed globally, plugin is properly removed from --install-dir:

$ gem list rubygems-server

*** LOCAL GEMS ***


$ gem install rubygems-server --install-dir foo && gem uninstall rubygems-server --install-dir foo && tree foo/plugins
Fetching rubygems-server-0.3.0.gem
Successfully installed rubygems-server-0.3.0
1 gem installed
Successfully uninstalled rubygems-server-0.3.0
foo/plugins

0 directories, 0 files

However, if I have rubygems-server installed in my standard GEM_HOME, gem uninstall will fail to clean it up from --install-dir:

$ gem install rubygems-server --install-dir foo && gem uninstall rubygems-server --install-dir foo && tree foo/plugins
/home/deivid/code/rubygems/rubygems/foo/gems/rubygems-server-0.3.0/lib/rubygems/server.rb:36: warning: already initialized constant Gem::Server::SEARCH
/home/deivid/.asdf/installs/ruby/3.3.1/lib/ruby/gems/3.3.0/gems/rubygems-server-0.3.0/lib/rubygems/server.rb:36: warning: previous definition of SEARCH was here
/home/deivid/code/rubygems/rubygems/foo/gems/rubygems-server-0.3.0/lib/rubygems/server.rb:46: warning: already initialized constant Gem::Server::DOC_TEMPLATE
/home/deivid/.asdf/installs/ruby/3.3.1/lib/ruby/gems/3.3.0/gems/rubygems-server-0.3.0/lib/rubygems/server.rb:46: warning: previous definition of DOC_TEMPLATE was here
/home/deivid/code/rubygems/rubygems/foo/gems/rubygems-server-0.3.0/lib/rubygems/server.rb:130: warning: already initialized constant Gem::Server::RDOC_CSS
/home/deivid/.asdf/installs/ruby/3.3.1/lib/ruby/gems/3.3.0/gems/rubygems-server-0.3.0/lib/rubygems/server.rb:130: warning: previous definition of RDOC_CSS was here
/home/deivid/code/rubygems/rubygems/foo/gems/rubygems-server-0.3.0/lib/rubygems/server.rb:340: warning: already initialized constant Gem::Server::RDOC_NO_DOCUMENTATION
/home/deivid/.asdf/installs/ruby/3.3.1/lib/ruby/gems/3.3.0/gems/rubygems-server-0.3.0/lib/rubygems/server.rb:340: warning: previous definition of RDOC_NO_DOCUMENTATION was here
/home/deivid/code/rubygems/rubygems/foo/gems/rubygems-server-0.3.0/lib/rubygems/server.rb:374: warning: already initialized constant Gem::Server::RDOC_SEARCH_TEMPLATE
/home/deivid/.asdf/installs/ruby/3.3.1/lib/ruby/gems/3.3.0/gems/rubygems-server-0.3.0/lib/rubygems/server.rb:374: warning: previous definition of RDOC_SEARCH_TEMPLATE was here
Successfully installed rubygems-server-0.3.0
1 gem installed
Successfully uninstalled rubygems-server-0.3.0
foo/plugins
└── rubygems-server_plugin.rb

1 directory, 1 file

What is your fix for the problem, implemented in this PR?

In order to keep plugins up to date, gem uninstall does the following:

• First removes the plugin stub for the gem being removed.
• Then check whether any versions of the gem are still installed, and regenerates the plugin stub again to point to the latest installed version.

The second check, however, was checking globally installed gems instead of gems in --install-dir.

The solution is to make sure that check uses --install-dir rather than the default GEM_HOME.

To implement it, I extracted the functionality that deals with the list of know specifications to a separate SpecificationRecord class that can take a custom directory (--install-dir in this case).

Make sure the following tasks are checked

• Describe the problem / feature
• Write tests for features and bug fixes
• Write code to solve the problem
• Make sure you follow the current code style and write meaningful commit messages without tags