Can't uninstall gems installed with --user-install if /usr/local/lib/ruby/gems/3.4.0 does not exist

[classy-crustacean]

I am using an Intel Macbook, and I installed ruby through Homebrew.

I never installed any gems without the --user-install flag. I installed boop: gem install --user-install boop

Then I tried uninstalling boop: gem uninstall --user-install boop
I got the following output:

ERROR:  While executing gem ... (Errno::ENOENT)
    No such file or directory @ rb_check_realpath_internal - /usr/local/lib/ruby/gems/3.4.0
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/uninstaller.rb:52:in 'File.realpath'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/uninstaller.rb:52:in 'Gem::Uninstaller#initialize'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/commands/uninstall_command.rb:202:in 'Class#new'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/commands/uninstall_command.rb:202:in 'Gem::Commands::UninstallCommand#uninstall'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/commands/uninstall_command.rb:188:in 'Gem::Commands::UninstallCommand#uninstall_gem'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/commands/uninstall_command.rb:183:in 'block in Gem::Commands::UninstallCommand#uninstall_specific'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/commands/uninstall_command.rb:175:in 'Array#each'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/commands/uninstall_command.rb:175:in 'Gem::Commands::UninstallCommand#uninstall_specific'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/commands/uninstall_command.rb:136:in 'Gem::Commands::UninstallCommand#execute'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/command.rb:326:in 'Gem::Command#invoke_with_build_args'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/command_manager.rb:253:in 'Gem::CommandManager#invoke_command'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/command_manager.rb:194:in 'Gem::CommandManager#process_args'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/command_manager.rb:152:in 'Gem::CommandManager#run'
	/usr/local/Cellar/ruby/3.4.7/lib/ruby/3.4.0/rubygems/gem_runner.rb:57:in 'Gem::GemRunner#run'
	/usr/local/opt/ruby/bin/gem:12:in '<main>'

Then I tried creating the /usr/local/lib/ruby/gems/3.4.0 directory and didn't put anything in it. I was able to successfully uninstall boop from by user directory.

Is there a way to be able to uninstall user-installed gems without creating /usr/local/lib/ruby/gems/3.4.0? I know /usr/local/lib/ruby/gems/3.4.0 is automatically created when installing gems without --user-install, but it seems weird to me that uninstalling user-installed gems is not possible without first installing a gem globally.

Make sure you're using the latest version of both RubyGems by running gem update --system.

Here is my gem env output:

RubyGems Environment:
  - RUBYGEMS VERSION: 3.7.2
  - RUBY VERSION: 3.4.7 (2025-10-08 patchlevel 58) [x86_64-darwin23]
  - INSTALLATION DIRECTORY: /usr/local/lib/ruby/gems/3.4.0
  - USER INSTALLATION DIRECTORY: /Users/joseph.rosloniec/.gem/ruby/3.4.0
  - CREDENTIALS FILE: /Users/joseph.rosloniec/.local/share/gem/credentials
  - RUBY EXECUTABLE: /usr/local/opt/ruby/bin/ruby
  - GIT EXECUTABLE: /usr/bin/git
  - EXECUTABLE DIRECTORY: /usr/local/lib/ruby/gems/3.4.0/bin
  - SPEC CACHE DIRECTORY: /Users/joseph.rosloniec/.gem/specs
  - SYSTEM CONFIGURATION DIRECTORY: /usr/local/Cellar/ruby/3.4.7/etc
  - RUBYGEMS PLATFORMS:
     - ruby
     - x86_64-darwin-23
  - GEM PATHS:
     - /usr/local/lib/ruby/gems/3.4.0
     - /Users/joseph.rosloniec/.gem/ruby/3.4.0
     - /usr/local/Cellar/ruby/3.4.7/lib/ruby/gems/3.4.0
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :backtrace => true
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - https://rubygems.org/
  - SHELL PATH:
     - /Users/joseph.rosloniec/.user-python-env/bin
     - /Users/joseph.rosloniec/.gem/ruby/3.4.0/bin
     - /usr/local/opt/ruby/bin
     - /usr/local/bin
     - /System/Cryptexes/App/usr/bin
     - /usr/bin
     - /bin
     - /usr/sbin
     - /sbin
     - /var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin
     - /var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin
     - /var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin

[classy-crustacean]

I looked through the gem uninstall --help, and it looks like I could achieve this by using --install-dir DIR. However, it would be really nice if I didn't have to do that. Is there a reason the uninstaller could't check the user gem path if the normal gem path does not exist?

[tenderlove]

Is there a reason the uninstaller could't check the user gem path if the normal gem path does not exist?

I don't think so. This seems like just a bug, and it should be fixed. I think something like this would do it (but I haven't tested):

diff --git a/lib/rubygems/uninstaller.rb b/lib/rubygems/uninstaller.rb
index fe4c3a80cf..bffce04087 100644
--- a/lib/rubygems/uninstaller.rb
+++ b/lib/rubygems/uninstaller.rb
@@ -64,7 +64,8 @@ def initialize(gem, options = {})
     @gem                = gem
     @version            = options[:version] || Gem::Requirement.default
     @install_dir        = options[:install_dir]
-    @gem_home           = File.realpath(@install_dir || Gem.dir)
+    @gem_home           = @install_dir || Gem.dir
+    @gem_home = File.exist?(@gem_home) ? File.realpath(@gem_home) : nil
     @user_dir           = File.exist?(Gem.user_dir) ? File.realpath(Gem.user_dir) : Gem.user_dir
     @force_executables  = options[:executables]
     @force_all          = options[:all]