set required_rubygems_version for native gems that specify the linu…

…x libc (#236)

### Problem I'm trying to solve

Rubygems does not correctly recognize `-musl` or `-gnu` platform
suffixes until v3.3.22.

### Solution

If rake-compiler is building a linux native gem that specifies a libc in
its platform object, then add ">= 3.3.22" to the
required_rubygems_version requirement.


https://github.com/rubygems/rubygems/blob/master/CHANGELOG.md#3322--2022-09-07

### Context

While working on musl support in the precompilation toolchain:

- rake-compiler/rake-compiler-dock#111
- flavorjones/ruby-c-extensions-explained#27
- sparklemotion/sqlite3-ruby#442
- sparklemotion/nokogiri#3111

I noticed that Ruby 3.0 is still shipping with Rubygems 3.2.33, which
does not recognize these gem platforms.

Specifying the rubygems requirement changes the error experienced by
users during gem installation from:

> ERROR:  While executing gem ... (Gem::Exception)
> Unable to find spec for #<Gem::NameTuple rcee_precompiled,
0.6.test.2024.0128.1724, aarch64-linux>

to:

> ERROR: Error installing
rcee_precompiled-0.6.test.2024.0128.1735-x86_64-linux-musl.gem:
> rcee_precompiled-0.6.test.2024.0128.1735-x86_64-linux-musl requires
RubyGems version >= 3.3.22.
> The current RubyGems version is 3.2.33. Try 'gem update --system' to
update RubyGems itself.

lib/rake/extensiontask.rb

@@ -278,6 +278,16 @@ def define_native_tasks(for_platform = nil, ruby_ver = RUBY_VERSION, callback =
             "< #{ruby_api_version(sorted_ruby_versions.last).succ}.dev"
           ]
 
+          # set rubygems version constraints
+          if Gem::Version.new(Gem::VERSION) >= Gem::Version.new("3.3.22") &&
+             spec.platform.os == "linux" && !spec.platform.version.nil?
+            spec.required_rubygems_version = if spec.required_rubygems_version == Gem::Requirement.default
+              [">= 3.3.22"]
+            else
+              Gem::Requirement.new(gem_spec.required_rubygems_version, ">= 3.3.22")
+            end
+          end
+
           # clear the extensions defined in the specs
           spec.extensions.clear
 

spec/lib/rake/extensiontask_spec.rb

@@ -620,6 +620,93 @@
         spec.metadata['allowed_push_host'].should eq 'http://test'
       end
 
+      it "should set required_rubygems_version when building a gem for `-linux-gnu` or `-linux-musl`" do
+        platforms = ["arm64-darwin", "arm-linux", "arm-linux-gnu", "arm-linux-musl"]
+        ruby_cc_versions = ["3.3.0"]
+        ENV["RUBY_CC_VERSION"] = ruby_cc_versions.join(":")
+
+        ruby_cc_versions.each do |ruby_cc_version|
+          platforms.each do |platform|
+            rbconf = "/rubies/#{ruby_cc_version}/rbconfig.rb"
+            allow_any_instance_of(Rake::CompilerConfig).to(
+              receive(:find)
+                .with(ruby_cc_version, platform)
+                .and_return(rbconf)
+            )
+          end
+        end
+
+        allow(Gem).to receive_message_chain(:configuration, :verbose=).and_return(true)
+
+        spec = Gem::Specification.new do |s|
+          s.name = 'my_gem'
+          s.platform = Gem::Platform::RUBY
+          s.extensions = ['ext/somegem/extconf.rb']
+        end
+
+        cross_specs = {} # platform => spec
+        Rake::ExtensionTask.new("extension_one", spec) do |ext|
+          ext.cross_platform = platforms
+          ext.cross_compile = true
+          ext.cross_compiling do |cross_spec|
+            cross_specs[cross_spec.platform.to_s] = cross_spec
+          end
+        end
+        platforms.each do |platform|
+          Rake::Task["native:my_gem:#{platform}"].execute
+        end
+
+        cross_specs["arm64-darwin"].required_rubygems_version.should eq(Gem::Requirement.default)
+        cross_specs["arm-linux"].required_rubygems_version.should eq(Gem::Requirement.default)
+
+        if Gem::Version.new(Gem::VERSION) >= Gem::Version.new("3.3.22")
+          expected_rubygems_version = Gem::Requirement.new([">= 3.3.22"])
+          cross_specs["arm-linux-gnu"].required_rubygems_version.should eq(expected_rubygems_version)
+          cross_specs["arm-linux-musl"].required_rubygems_version.should eq(expected_rubygems_version)
+        end
+      end
+
+      it "should append to required_rubygems_version if it's set" do
+        platform = "arm-linux-musl"
+        ruby_cc_versions = ["3.3.0"]
+        ENV["RUBY_CC_VERSION"] = ruby_cc_versions.join(":")
+
+        ruby_cc_versions.each do |ruby_cc_version|
+          rbconf = "/rubies/#{ruby_cc_version}/rbconfig.rb"
+          allow_any_instance_of(Rake::CompilerConfig).to(
+            receive(:find)
+              .with(ruby_cc_version, platform)
+              .and_return(rbconf)
+          )
+        end
+
+        allow(Gem).to receive_message_chain(:configuration, :verbose=).and_return(true)
+
+        spec = Gem::Specification.new do |s|
+          s.name = 'my_gem'
+          s.platform = Gem::Platform::RUBY
+          s.extensions = ['ext/somegem/extconf.rb']
+          s.required_rubygems_version = "!= 3.4.1" # keep this around
+        end
+
+        actual_cross_spec = nil
+        Rake::ExtensionTask.new("extension_one", spec) do |ext|
+          ext.cross_platform = [platform]
+          ext.cross_compile = true
+          ext.cross_compiling do |cross_spec|
+            actual_cross_spec = cross_spec
+          end
+        end
+        Rake::Task["native:my_gem:#{platform}"].execute
+
+        if Gem::Version.new(Gem::VERSION) < Gem::Version.new("3.3.22")
+          actual_cross_spec.required_rubygems_version.should eq(Gem::Requirement.new(["!= 3.4.1"]))
+        else
+          expected_rubygems_version = Gem::Requirement.new(["!= 3.4.1", ">= 3.3.22"])
+          actual_cross_spec.required_rubygems_version.should eq(expected_rubygems_version)
+        end
+      end
+
       after :each do
         ENV.delete('RUBY_CC_VERSION')
       end