Gem in gemspec without ruby platform version is resolved to a wrong platform

[toy]

I've stumbled upon an issue with using bundler for developing a gem that has a dependency on sys-proctable gem. The issue seems to be caused by two characteristics of sys-proctable gem: it has only platform specific versions and two of them (darwin and freebsd) have additional dependency on ffi gem. I was able to reproduce the behaviour on freebsd (10.3) and osx (darwin 16).

Given Gemfile:

source 'https://rubygems.org'
gemspec

and test.gemspec:

Gem::Specification.new do |s|
  s.name        = 'test'
  s.version     = '1.0.0'
  s.summary     = 'test summary'
  s.authors     = ['Max Mustermann']
  s.add_dependency 'sys-proctable', '~> 1.0'
end

and running bundle on freebsd, produces:

Fetching gem metadata from https://rubygems.org/.........
Fetching version metadata from https://rubygems.org/.
Resolving dependencies...
Unable to use the platform-specific (universal-freebsd) version of sys-proctable (1.1.5) because it has different dependencies from the universal-aix5 version. To use the platform-specific version of the gem, run `bundle config specific_platform true` and install again.
Using bundler 1.15.4
Fetching sys-proctable 1.1.5 (universal-aix5)
Installing sys-proctable 1.1.5 (universal-aix5)
Using test 1.0.0 from source at `.`
Bundle complete! 1 Gemfile dependency, 3 gems now installed.
Use `bundle info [gemname]` to see where a bundled gem is installed.

Running bundle config specific_platform true, removing the sys-proctable gem from the system and repeating bundle will remove the warning, but will still fetch the universal-aix5 platform specific gem.

[segiddins]

Reproduces on my machine, thanks for the report!

[segiddins]

Following spec reproduces the issue:

diff --git a/spec/runtime/platform_spec.rb b/spec/runtime/platform_spec.rb
index f38f73384..64a616de6 100644
--- a/spec/runtime/platform_spec.rb
+++ b/spec/runtime/platform_spec.rb
@@ -115,4 +115,27 @@ RSpec.describe "Bundler.setup with multi platform stuff" do
       expect(the_bundle).to include_gems "platform_specific 1.0 RUBY"
     end
   end
+
+  it "works with a `gemspec` that depends upon a multi-platform gem" do
+    simulate_platform "x86-darwin-100"
+
+    build_repo4 do
+      %w[universal-aix5 universal-darwin].each do |pl|
+        build_gem("bar") do |s|
+          s.platform = pl
+        end
+      end
+    end
+
+    build_lib("foo", "1.0", :path => bundled_app) do |s|
+      s.add_runtime_dependency "bar"
+    end
+
+    install_gemfile! <<-G
+      source "file:#{gem_repo4}"
+      gemspec
+    G
+
+    expect(the_bundle).to include_gems 'foo 1.0', "bar 1.0 universal-darwin"
+  end
 end

[deivid-rodriguez]

Hello! 👋 👋

I run Samuel's spec and it passes now! So it sounds like we might've fixed this with the recent multiplatform improvements! 🎉

@toy Could you verify that this is now working fine?

[toy]

@deivid-rodriguez Using bundler 2.2.0.rc.2 if I change the dependency to s.add_dependency 'sys-proctable', '~> 1.1.0' (as sys-proctable 1.2.x doesn't have platform specific versions) I still see the warning and universal-aix5 version is installed.

[deivid-rodriguez]

Interesting, I guess the issue doesn't repro with that spec after all. It does work if you set specific_platform setting as suggested, right?

[toy]

Setting the specific_platform makes it get and lock on right platform gem.
It is even a bit easier to reproduce than in my original post, given Gemfile:

source 'https://rubygems.org'
gemspec

and test.gemspec:

Gem::Specification.new do |s|
  s.name        = 'test'
  s.version     = '1.0.0'
  s.summary     = 'test summary'
  s.authors     = ['Max Mustermann']
  s.add_dependency 'sys-proctable', '~> 1.1.0'
end

and running bundle on osx will contain in the output:

Unable to use the platform-specific (universal-darwin) version of sys-proctable (1.1.5) because it has different dependencies from the universal-aix-5 version. To use the platform-specific version of the gem, run `bundle config set specific_platform true` and install again.
Using bundler 2.2.0.rc.2
Using sys-proctable 1.1.5 (universal-aix-5)

It is enough to delete Gemfile.lock and to run:

bundle config specific_platform true
bundle

To lock on the right gem.

It may be important that sys-proctable doesn't have version 1.1.5 with platform ruby.

[deivid-rodriguez]

Great! The plan is currently to remove the specific_platform setting and enable it by default. So I guess this can be closed once we do that?