Bundler doesn't respect other than the native platform while resolving the gems to install

[larskanis]

Original issue is oneclick/rubyinstaller2#7 : Nokogiri installs successfully on RubyInstaller2 when --platform=ruby is used. There is also a fat binary gem for x86-mingw32, but it is limited to Ruby versions 2.0 to 2.3. It can not be installed on Ruby-2.4.0 due to this ruby version constraint, which is expected behavior. However bundler doesn't use the platform=ruby gem version as an alternative, regardless whether it is already installed or not.

Installed versions (with nokogiri installed as platform=ruby):

C:\Users\lars\railstest>ruby --version
ruby 2.4.0p0 (2016-12-24 revision 57164) [i386-mingw32]

C:\Users\lars\railstest>bundle --version
Bundler version 1.14.0.pre.2

C:\Users\lars\railstest>gem list nokogiri
*** LOCAL GEMS ***
nokogiri (1.7.0.1)

Using a fresh Rails-5.0.1 project (generated per rails new railstest) with this Gemfile .

When platform ruby is added per bundle lock, I would expect, that the installed version will be used. But instead an older nokogiri version (1.6.6.4) for x86-mingw32 is installed. This version doesn't work on Ruby-2.4, since it doesn't contain the Ruby-2.4 binary extension, but it wasn't labeled with proper ruby version constraints to that point in time:

C:\Users\lars\railstest>bundle lock --add-platform=ruby
Fetching gem metadata from https://rubygems.org/..........
Fetching version metadata from https://rubygems.org/..
Fetching dependency metadata from https://rubygems.org/.
Resolving dependencies........................................................................................................................................................................................................................................
Writing lockfile to C:/Users/lars/railstest/Gemfile.lock

C:\Users\lars\railstest>bundle
Fetching gem metadata from https://rubygems.org/.........
Fetching version metadata from https://rubygems.org/..
Fetching dependency metadata from https://rubygems.org/.
Using rake 12.0.0
[...]
Installing nokogiri 1.6.6.4 (x86-mingw32)
[...]
Bundle complete! 12 Gemfile dependencies, 56 gems now installed.

When the platform x86-mingw32 is explicit removed, the bundle install fails with a dependency issue - although the nokogiri gem is already locally installed in the latest version 1.7.0.1 :

C:\Users\lars\railstest>rm Gemfile.lock

C:\Users\lars\railstest>bundle lock --add-platform=ruby --remove-platform=x86-mingw32
The dependency tzinfo-data (>= 0) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for x86-mingw32, x86-mswin32, x64-mingw32, java. To add those platforms to the bundle, run `bundle lock --add-platform mingw, mswin, x64_mingw, jruby`.
Fetching gem metadata from https://rubygems.org/..........
Fetching version metadata from https://rubygems.org/..
Fetching dependency metadata from https://rubygems.org/.
Resolving dependencies..............................................
Writing lockfile to C:/Users/lars/railstest/Gemfile.lock

C:\Users\lars\railstest>bundle
Fetching gem metadata from https://rubygems.org/..........
Fetching version metadata from https://rubygems.org/..
Fetching dependency metadata from https://rubygems.org/.
Resolving dependencies......
Bundler could not find compatible versions for gem "ruby ":
  In Gemfile:
    ruby

    ruby  x86-mingw32

    jquery-rails was resolved to 4.2.2, which depends on
      rails-dom-testing (< 3, >= 1) was resolved to 2.0.2, which depends on
        nokogiri (~> 1.6) was resolved to 1.7.0.1, which depends on
          ruby  (< 2.4) x86-mingw32

Could not find gem 'ruby  (< 2.4) x86-mingw32', which is required by gem
'nokogiri (~> 1.6)', in any of the sources.

C:\Users\lars\railstest>gem list nokogiri
*** LOCAL GEMS ***
nokogiri (1.7.0.1)

Is there a way to let bundler choose the platform=ruby version of the gem? Why is the bundle lock platform setting not respected?

[segiddins]

You might want to look at the force_ruby_platform setting introduced in 1.14

[larskanis]

If I use the setting force_ruby_platform , I get a bundler crash. See #5344

[larskanis]

Using force_ruby_platform works. However since it forces the installation of platform=ruby gems exclusively, it is IMHO it's not a real solution. In case of nokogiri it should install the platform=ruby gem, because the native gem doesn't fit to the running ruby version.

[larskanis]

rake-compiler-1.0.3+ adds ruby version constraints to all generated native gems. This issue will therefore probably affect many future gems that are built via rake-compiler (or rake-compiler-dock).

[twk3]

@segiddins if we were able to set force_ruby_platform for specific gems rather than the entire gemfile, I think that would help.

[segiddins]

I dont think that is likely to happen any time soon, sorry

[larskanis]

Having looked into the bundler code (especially #4836 ) I realized, that the ruby version constraints of gems aren't currently considered as a best match criteria for the gem resolution process. So I think the above expectation is more a feature request than a bug report. Maybe the title should be changed accordingly?

[kasunvp]

This is a viable solution tzinfo/tzinfo-data#12 (comment)
And just removing the line gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby] from the generated Gemfile and doing a budle update resolves the issue for me on Linux (Ubuntu 16.04).

[segiddins]

Closing, I don't think there's anything actionable for us here, given force_ruby_platform exists.