Ensure two RemoteSpecifications are comparable

The RemoteSpecification#sort_obj method was added in e5d936e7 (which
was cherry-picked from #3767) to fix #3762, but it still fails when
comparing two instances of RemoteSpecification.

As #sort_obj is private, the check for other.respond_to?(:sort_obj)
returns false, which means the <=> check falls back to the default
(from Object) which returns nil if the objects being compared don't
match. This then results in an ArgumentError when (e.g.) sorting an
array containing multiple instances of RemoteSpecification.

The fix is simple: make RemoteSpecification#sort_obj public.

2 files changed, 45 insertions, 2 deletions

diff --git a/lib/bundler/remote_specification.rb b/lib/bundler/remote_specification.rb
index 36f62af7e4..5a32bd2435 100644
--- a/lib/bundler/remote_specification.rb
+++ b/lib/bundler/remote_specification.rb
@@ -52,8 +52,6 @@ module Bundler
       @_remote_specification = spec
     end
 
-  private
-
     # Create a delegate used for sorting. This strategy is copied from
     # RubyGems 2.23 and ensures that Bundler's specifications can be
     # compared and sorted with RubyGems' own specifications.
@@ -67,6 +65,8 @@ module Bundler
       [@name, @version, @platform == Gem::Platform::RUBY ? -1 : 1]
     end
 
+  private
+
     def _remote_specification
       @_remote_specification ||= @spec_fetcher.fetch_spec([@name, @version, @platform])
     end
diff --git a/spec/bundler/remote_specification_spec.rb b/spec/bundler/remote_specification_spec.rb
index c93d6f908b..83b0cd794b 100644
--- a/spec/bundler/remote_specification_spec.rb
+++ b/spec/bundler/remote_specification_spec.rb
@@ -16,6 +16,49 @@ describe Bundler::RemoteSpecification do
       Bundler::RemoteSpecification.new(name, version, platform, nil)
     end
 
+    context "given a Bundler::RemoteSpecification" do
+      let(:same_gem) do
+        Bundler::RemoteSpecification.new(name, version, platform, nil)
+      end
+
+      let(:different_name) do
+        Bundler::RemoteSpecification.new("bar", version, platform, nil)
+      end
+
+      let(:newer_gem) do
+        Bundler::RemoteSpecification.new(name, newer_version, platform, nil)
+      end
+
+      let(:older_gem) do
+        Bundler::RemoteSpecification.new(name, older_version, platform, nil)
+      end
+
+      let(:different_platform) do
+        plt = Gem::Platform.new "x86-mswin32"
+        Bundler::RemoteSpecification.new(name, version, plt, nil)
+      end
+
+      it "compares based on name" do
+        expect(subject <=> different_name).not_to eq(0)
+      end
+
+      it "compares based on the same version" do
+        expect(subject <=> same_gem).to eq(0)
+      end
+
+      it "compares based on an older version" do
+        expect(subject).to be < newer_gem
+      end
+
+      it "compares based on a newer version" do
+        expect(subject).to be > older_gem
+      end
+
+      it "compares based on platform" do
+        expect(subject <=> different_platform).not_to eq(0)
+      end
+    end
+
     context "given a Gem::Specification" do
       let(:same_gem) do
         Gem::Specification.new(name, version)