"Unable to detect bundler spec under <gem path>"

[seanstory]

Environment:

• rbenv 1.2.0
• jruby 9.3.3.0
• bundler 2.4.6
• warbler 2.0.5
• OSX 13.2

Issue

When running bundle exec warble I get this error:

Unable to detect bundler spec under '/opt/homebrew/Cellar/rbenv/1.2.0/versions/jruby-9.3.3.0/lib/ruby/gems/shared/gems/bundler-2.4.6'' and its sub-dirs

This makes sense, as there's no gemspec file there, just a exe/ dir with bundle and bundler executables. The gemspec for bundler lives in

/opt/homebrew/Cellar/rbenv/1.2.0/versions/jruby-9.3.3.0/lib/ruby/gems/shared/specifications/default/bundler-2.4.6.gemspec 

Workaround

I copied the gemspec to where warbler seems to be looking for it, and now it's working. However, I expect this will fall apart if/when I update my bundler gem.

cp /opt/homebrew/Cellar/rbenv/1.2.0/versions/jruby-9.3.3.0/lib/ruby/gems/shared/specifications/default/bundler-2.4.6.gemspec opt/homebrew/Cellar/rbenv/1.2.0/versions/jruby-9.3.3.0/lib/ruby/gems/shared/gems/bundler-2.4.6/bundler.gemspec

[olleolleolle]

@seanstory Yes, we have had valiant efforts to try to support Bundler 2.x.

Thanks for your report!

[dolzenko]

So there is no fix for this at the moment?

[dometto]

While I can reproduce this error with bundler v2.3, I no longer can with bundler v2.5. (I did not try with 2.4).

[dub357]

FYI - this isn't a Bundler 2.x issue...its an issue when Bundler is installed as a 'default' gem, which is the case for newer JRubies (9.3.0+).
If you install bundler as a 'standard' gem (basically one that isn't the same as the one installed by default and gets installed in the typical location), and that version is what is referenced in your Gemfile.lock, then things will work properly because warbler will find the bundler.gemspec file.

The problematic warbler code is the following:

warbler/lib/warbler/traits/bundler.rb

Lines 43 to 56 in 5ce7ec0

	if spec.name == 'bundler'
	full_gem_path = Pathname.new(spec.full_gem_path)
	while ! full_gem_path.join('bundler.gemspec').exist?
	full_gem_path = full_gem_path.dirname
	# if at top of the path, meaning we cannot find bundler.gemspec, abort.
	if full_gem_path.to_s =~ /^[\.\/]$/
	warn("Unable to detect bundler spec under '#{spec.full_gem_path}'' and its sub-dirs")
	exit
	end
	end
	spec.loaded_from = full_gem_path.join('bundler.gemspec').to_s
	spec.full_gem_path = full_gem_path.to_s
	end

I say 'problematic' because this code does not work when Bundler is a default gem. This code here seems to have been introduced in 89978dd because when asked for dependencies, Bundler seems to report itself with a specification that includes a 'fake' loaded_from attribute. To work around that, this warbler code tries to find the 'real' loaded_from (the gemspec file location) so that bundler can be included in the archive its building.

It might be best to alter this code, detect if Bundler is a default gem and then simply skip it from being included in the archive...