Problem with installing Ruby 3.2.2 under Homebrew rbenv/ruby-build on Ubuntu 22.04 under WSL2

[alexeyr-ci]

When trying to do the above, I ran into this a failure on this late step

./miniruby -I./lib -I. -I.ext/common  ./tool/runruby.rb --extout=.ext  -- --disable-gems -r./x86_64-linux-fake ./tool/rbinstall.rb --make="make" --dest-dir="" --extout=".ext" --ext-build-dir="./ext" --mflags="" --make-flags="" --data-mode=0644 --prog-mode=0755 --installed-list .installed.list --mantype="doc"  --gnumake --install=all --rdoc-output=".ext/rdoc" --html-output=".ext/html"
installing binary commands:         /home/alexey/.rbenv/versions/3.2.2/bin
installing base libraries:          /home/alexey/.rbenv/versions/3.2.2/lib
installing arch files:              /home/alexey/.rbenv/versions/3.2.2/lib/ruby/3.2.0/x86_64-linux
installing pkgconfig data:          /home/alexey/.rbenv/versions/3.2.2/lib/pkgconfig
installing extension objects:       /home/alexey/.rbenv/versions/3.2.2/lib/ruby/3.2.0/x86_64-linux
installing extension objects:       /home/alexey/.rbenv/versions/3.2.2/lib/ruby/site_ruby/3.2.0/x86_64-linux
installing extension objects:       /home/alexey/.rbenv/versions/3.2.2/lib/ruby/vendor_ruby/3.2.0/x86_64-linux
installing extension headers:       /home/alexey/.rbenv/versions/3.2.2/include/ruby-3.2.0/x86_64-linux
installing extension scripts:       /home/alexey/.rbenv/versions/3.2.2/lib/ruby/3.2.0
installing extension scripts:       /home/alexey/.rbenv/versions/3.2.2/lib/ruby/site_ruby/3.2.0
installing extension scripts:       /home/alexey/.rbenv/versions/3.2.2/lib/ruby/vendor_ruby/3.2.0
installing extension headers:       /home/alexey/.rbenv/versions/3.2.2/include/ruby-3.2.0/ruby
installing rdoc:                    /home/alexey/.rbenv/versions/3.2.2/share/ri/3.2.0/system
installing html-docs:               /home/alexey/.rbenv/versions/3.2.2/share/doc/ruby
installing capi-docs:               /home/alexey/.rbenv/versions/3.2.2/share/doc/ruby
installing command scripts:         /home/alexey/.rbenv/versions/3.2.2/bin
installing library scripts:         /home/alexey/.rbenv/versions/3.2.2/lib/ruby/3.2.0
installing common headers:          /home/alexey/.rbenv/versions/3.2.2/include/ruby-3.2.0
installing manpages:                /home/alexey/.rbenv/versions/3.2.2/share/man/man1
installing default gems from lib:   /home/linuxbrew/.linuxbrew/lib/ruby/gems/3.2.0
                                    abbrev 0.1.1
/tmp/ruby-build.20230613155129.33254.YOt65c/ruby-3.2.2/lib/rubygems.rb:785:in `initialize': Permission denied @ rb_sysopen - /home/linuxbrew/.linuxbrew/lib/ruby/gems/3.2.0/specifications/default/abbrev-0.1.1.gemspec (Errno::EACCES)
        from /tmp/ruby-build.20230613155129.33254.YOt65c/ruby-3.2.2/lib/rubygems.rb:785:in `open'
        from /tmp/ruby-build.20230613155129.33254.YOt65c/ruby-3.2.2/lib/rubygems.rb:785:in `open_file'
        from /tmp/ruby-build.20230613155129.33254.YOt65c/ruby-3.2.2/lib/rubygems.rb:772:in `write_binary'
        from /tmp/ruby-build.20230613155129.33254.YOt65c/ruby-3.2.2/lib/rubygems/installer.rb:467:in `write_default_spec'
        from ./tool/rbinstall.rb:873:in `write_default_spec'
        from /tmp/ruby-build.20230613155129.33254.YOt65c/ruby-3.2.2/lib/rubygems/installer.rb:322:in `install'
        from ./tool/rbinstall.rb:881:in `block in install'
        from ./tool/rbinstall.rb:721:in `no_write'
        from ./tool/rbinstall.rb:881:in `install'
        from ./tool/rbinstall.rb:989:in `block in install_default_gem'
        from ./tool/rbinstall.rb:976:in `each'
        from ./tool/rbinstall.rb:976:in `install_default_gem'
        from ./tool/rbinstall.rb:913:in `block in <main>'
        from ./tool/rbinstall.rb:1080:in `block in <main>'
        from ./tool/rbinstall.rb:1077:in `each'
        from ./tool/rbinstall.rb:1077:in `<main>'

I was able to figure out that /home/linuxbrew/.linuxbrew/lib/ruby/gems/3.2.0/specifications/default/*.gemspec were readable and writable, they were symlinks to /home/linuxbrew/.linuxbrew/Cellar/ruby/3.2.2/lib/ruby/gems/3.2.0/specifications/default/, and the files there were not writable and making them so fixed the problem. So posting more in case this helps someone else with the same problem. I am not sure if it's a Homebrew problem or a ruby-build one.

ruby-build version is 20230608.

[mislav]

Strange that a ruby installation with prefix /home/alexey/.rbenv/versions/3.2.2 would need write access to /home/linuxbrew/.linuxbrew/lib/ruby/gems/3.2.0, a directory that looks completely unrelated.

Do you have GEM_HOME or GEM_PATH environment variables set, by any chance?