Bundler requires pathname eagerly and prevents using a newer version of the gem

[eregon]

Describe the problem as clearly as you can

Bundler loads Pathname early on, notably in

rubygems/bundler/lib/bundler/shared_helpers.rb

Line 60 in f22a1a9

Pathname.pwd

with

rubygems/bundler/lib/bundler/shared_helpers.rb

Line 7 in f22a1a9

autoload :Pathname, "pathname"

This prevents using an installed pathname gem, and forces using the pathname stdlib always.

Did you try upgrading rubygems & bundler?

I'm using the latest Bundler, 2.7.2.

Post steps to reproduce the problem

$ cat Gemfile.lock 
GEM
  remote: https://rubygems.org/
  specs:
    pathname (0.4.0)

PLATFORMS
  ruby
  x86_64-linux

DEPENDENCIES
  pathname

BUNDLED WITH
   2.7.2
$ bundle install

As we can see stdlib pathname is unexpectedly used, even though the gem lib is earlier in $LOAD_PATH:

$ ruby -e 'require "bundler/setup"; require "pathname"; puts $".grep(/pathname/); puts; puts $:'                                                             
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/x86_64-linux/pathname.so
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/pathname.rb

/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib
/home/eregon/tmp/bundler-pathname/vendor/bundle/ruby/3.4.0/gems/pathname-0.4.0/lib
/home/eregon/tmp/bundler-pathname/vendor/bundle/ruby/3.4.0/extensions/x86_64-linux/3.4.0/pathname-0.4.0
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/site_ruby/3.4.0
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/site_ruby/3.4.0/x86_64-linux
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/site_ruby
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/vendor_ruby/3.4.0
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/vendor_ruby/3.4.0/x86_64-linux
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/vendor_ruby
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/x86_64-linux

And this is because Bundler itself loads Pathname early:

$ ruby -e 'Kernel.prepend Module.new { def require(path); puts path, caller, nil if path.include?("pathname"); super; end }; require "bundler/setup"; require "pathname"; puts $".grep(/pathname/); puts; puts $:'
pathname
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:60:in 'block in Bundler::SharedHelpers#pwd'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:59:in 'Monitor#synchronize'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:59:in 'Bundler::SharedHelpers#pwd'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:281:in 'Bundler::SharedHelpers#search_up'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:268:in 'Bundler::SharedHelpers#find_file'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:260:in 'Bundler::SharedHelpers#find_gemfile'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:49:in 'Bundler::SharedHelpers#in_bundle?'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/setup.rb:5:in '<top (required)>'
<internal:/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require'
<internal:/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require'
-e:1:in 'require'
-e:1:in '<main>'

pathname.so
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/pathname.rb:13:in '<top (required)>'
<internal:/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require'
<internal:/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require'
-e:1:in 'require'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:60:in 'block in Bundler::SharedHelpers#pwd'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:59:in 'Monitor#synchronize'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:59:in 'Bundler::SharedHelpers#pwd'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:281:in 'Bundler::SharedHelpers#search_up'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:268:in 'Bundler::SharedHelpers#find_file'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:260:in 'Bundler::SharedHelpers#find_gemfile'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/shared_helpers.rb:49:in 'Bundler::SharedHelpers#in_bundle?'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/setup.rb:5:in '<top (required)>'
<internal:/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require'
<internal:/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require'
-e:1:in 'require'
-e:1:in '<main>'

pathname
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler.rb:5:in '<top (required)>'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/setup.rb:6:in 'Kernel#require_relative'
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib/bundler/setup.rb:6:in '<top (required)>'
<internal:/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require'
<internal:/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/rubygems/core_ext/kernel_require.rb>:136:in 'Kernel#require'
-e:1:in 'require'
-e:1:in '<main>'

pathname
-e:1:in '<main>'

/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/x86_64-linux/pathname.so
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/pathname.rb

/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0/gems/bundler-2.7.2/lib
/home/eregon/tmp/bundler-pathname/vendor/bundle/ruby/3.4.0/gems/pathname-0.4.0/lib
/home/eregon/tmp/bundler-pathname/vendor/bundle/ruby/3.4.0/extensions/x86_64-linux/3.4.0/pathname-0.4.0
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/site_ruby/3.4.0
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/site_ruby/3.4.0/x86_64-linux
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/site_ruby
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/vendor_ruby/3.4.0
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/vendor_ruby/3.4.0/x86_64-linux
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/vendor_ruby
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0
/home/eregon/.rubies/ruby-3.4.7/lib/ruby/3.4.0/x86_64-linux

If not included with the output of your command, run bundle env and paste the output below

Environment

Bundler       2.7.2
  Platforms   ruby, x86_64-linux
Ruby          3.4.7p58 (2025-10-08 revision 7a5688e2a27668e48f8d6ff4af5b2208b98a2f5e) [x86_64-linux]
  Full Path   /home/eregon/.rubies/ruby-3.4.7/bin/ruby
  Config Dir  /home/eregon/.rubies/ruby-3.4.7/etc
RubyGems      3.6.9
  Gem Home    /home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0
  Gem Path    /home/eregon/.gem/ruby/3.4.0:/home/eregon/.rubies/ruby-3.4.7/lib/ruby/gems/3.4.0
  User Home   /home/eregon
  User Path   /home/eregon/.gem/ruby/3.4.0
  Bin Dir     /home/eregon/.rubies/ruby-3.4.7/bin
Tools         
  Git         2.51.0
  RVM         not installed
  rbenv       not installed
  chruby      0.3.9

Bundler Build Metadata

Timestamp  2025-09-09
Git SHA    b463ced1459

Bundler settings

path
  Set for the current user (/home/eregon/.bundle/config): "vendor/bundle"

Gemfile

Gemfile

source "https://rubygems.org"

gem "pathname"

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    pathname (0.4.0)

PLATFORMS
  ruby
  x86_64-linux

DEPENDENCIES
  pathname

BUNDLED WITH
   2.7.2

[eregon]

Discovered as part of https://bugs.ruby-lang.org/issues/21640, but this bug is independent of that, it already exists on Ruby 3.4.7 as the repro shows.

A good solution would be to vendor the pathname gem in Bundler.
This should be fairly easy now that I defined all methods in Ruby and not in C in the pathname gem (the C extension only speeds up a couple methods, it's fully optional).

In fact @deivid-rodriguez already did most of that effort in #4992 (from comment https://bugs.ruby-lang.org/issues/17473#note-15). That was a manual translation of C code to Ruby, now we could just copy-paste the source of the gem.

[deivid-rodriguez]

Feel free to reuse my work as you see fit. Unsubscribing!