Add support for RubyGems 3.3.21 or later (#209)

Since Rubygems 3.3.21, the Gem::Platform name always contains the
library version for gnu platforms. So where the rake-compiler config
entries previously were:

```yaml
---
rbconfig-x86_64-linux-gnu-2.7.0: "/usr/local/rake-compiler/ruby/x86_64-redhat-linux/ruby-2.7.0/lib/ruby/2.7.0/x86_64-linux-gnu/rbconfig.rb"
rbconfig-x86_64-linux-2.7.0: "/usr/local/rake-compiler/ruby/x86_64-redhat-linux/ruby-2.7.0/lib/ruby/2.7.0/x86_64-linux-gnu/rbconfig.rb"
```

with later versions of rubygems, it is only

```yaml
---
rbconfig-x86_64-linux-gnu-2.7.0: "/usr/local/rake-compiler/ruby/x86_64-redhat-linux/ruby-2.7.0/lib/ruby/2.7.0/x86_64-linux-gnu/rbconfig.rb"
```

This means that the current way of finding a matching runtime, by doing
a string comparison on the config keys, is no longer appropriate. This
is causing failing builds downstream in `rake-compiler-dock`.

This PR:

- extracts a new CompilerConfig class to encapsulate the logic
- uses `Gem::Platform#=~` to tell if the gem platform matches the
runtime platform

5 files changed, 137 insertions, 28 deletions

diff --git a/lib/rake/baseextensiontask.rb b/lib/rake/baseextensiontask.rb
index cf32147..063a555 100644
--- a/lib/rake/baseextensiontask.rb
+++ b/lib/rake/baseextensiontask.rb
@@ -5,6 +5,8 @@ require 'rbconfig'
 
 require 'pathname'
 
+require_relative "compiler_config"
+
 module Rake
   class BaseExtensionTask < TaskLib
 
diff --git a/lib/rake/compiler_config.rb b/lib/rake/compiler_config.rb
new file mode 100644
index 0000000..e9832dc
--- /dev/null
+++ b/lib/rake/compiler_config.rb
@@ -0,0 +1,38 @@
+module Rake
+  class CompilerConfig
+    def initialize(config_path)
+      require "yaml"
+      @config = YAML.load_file(config_path)
+    end
+
+    def find(ruby_version, gem_platform)
+      gem_platform = Gem::Platform.new(gem_platform)
+
+      @config.each do |config_name, config_location|
+        # There are two variations we might find in the rake-compiler config.yml
+        #
+        # 1. config_name: rbconfig-x86_64-linux-3.0.0
+        #    runtime_platform_name: x86_64-linux
+        #    runtime_version: 3.0.0
+        #
+        # 2. config_name: rbconfig-x86_64-linux-gnu-3.0.0
+        #    runtime_platform_name: x86_64-linux-gnu
+        #    runtime_version: 3.0.0
+        #
+        # With rubygems < 3.3.21, both variations will be present (two entries pointing at the same
+        # installation).
+        #
+        # With rubygems >= 3.3.21, only the second variation will be present.
+        runtime_platform_name = config_name.split("-")[1..-2].join("-")
+        runtime_version = config_name.split("-").last
+        runtime_platform = Gem::Platform.new(runtime_platform_name)
+
+        if (ruby_version == runtime_version) && (gem_platform =~ runtime_platform)
+          return config_location
+        end
+      end
+
+      nil
+    end
+  end
+end
diff --git a/lib/rake/extensiontask.rb b/lib/rake/extensiontask.rb
index 7c69741..0f48520 100644
--- a/lib/rake/extensiontask.rb
+++ b/lib/rake/extensiontask.rb
@@ -393,8 +393,11 @@ Java extension should be preferred.
         return
       end
 
-      require "yaml"
-      config_file = YAML.load_file(config_path)
+      rbconfig_file = Rake::CompilerConfig.new(config_path).find(ruby_ver, for_platform)
+      unless rbconfig_file
+        warn "no configuration section for specified version of Ruby (rbconfig-#{for_platform}-#{ruby_ver})"
+        return
+      end
 
       # tmp_path
       tmp_path = "#{@tmp_dir}/#{for_platform}/#{@name}/#{ruby_ver}"
@@ -405,11 +408,6 @@ Java extension should be preferred.
       # lib_binary_path
       lib_binary_path = "#{lib_path}/#{File.basename(binary(for_platform))}"
 
-      unless rbconfig_file = config_file["rbconfig-#{for_platform}-#{ruby_ver}"] then
-        warn "no configuration section for specified version of Ruby (rbconfig-#{for_platform}-#{ruby_ver})"
-        return
-      end
-
       # mkmf
       mkmf_file = File.expand_path(File.join(File.dirname(rbconfig_file), '..', 'mkmf.rb'))
 
diff --git a/spec/lib/rake/compiler_config_spec.rb b/spec/lib/rake/compiler_config_spec.rb
new file mode 100644
index 0000000..22b1f7f
--- /dev/null
+++ b/spec/lib/rake/compiler_config_spec.rb
@@ -0,0 +1,54 @@
+require File.expand_path(File.dirname(__FILE__) + '/../../spec_helper')
+
+require 'rake/extensiontask'
+require 'rbconfig'
+require 'tempfile'
+
+describe Rake::CompilerConfig do
+  def config_file(contents)
+    Tempfile.new.tap do |tf|
+      tf.write(contents)
+      tf.close
+    end
+  end
+
+  it "returns the matching config for exact platform match" do
+    cc = Rake::CompilerConfig.new(config_file(<<~CONFIG))
+      ---
+      rbconfig-x86_64-linux-3.0.0: "/path/to/aaa/rbconfig.rb"
+      rbconfig-x86_64-darwin-3.1.0: "/path/to/bbb/rbconfig.rb"
+      rbconfig-x86_64-linux-3.1.0: "/path/to/ccc/rbconfig.rb"
+    CONFIG
+
+    expect(cc.find("3.0.0", "x86_64-linux")).to eq("/path/to/aaa/rbconfig.rb")
+    expect(cc.find("3.1.0", "x86_64-darwin")).to eq("/path/to/bbb/rbconfig.rb")
+    expect(cc.find("3.1.0", "x86_64-linux")).to eq("/path/to/ccc/rbconfig.rb")
+
+    expect(cc.find("2.7.0", "x86_64-linux")).to be_nil
+    expect(cc.find("3.1.0", "arm64-linux")).to be_nil
+  end
+
+  it "returns the matching config for inexact platform match" do
+    cc = Rake::CompilerConfig.new(config_file(<<~CONFIG))
+      ---
+      rbconfig-x86_64-linux-gnu-3.0.0: "/path/to/aaa/rbconfig.rb"
+      rbconfig-x86_64-linux-musl-3.1.0: "/path/to/bbb/rbconfig.rb"
+    CONFIG
+
+    expect(cc.find("3.0.0", "x86_64-linux")).to eq("/path/to/aaa/rbconfig.rb")
+    expect(cc.find("3.1.0", "x86_64-linux")).to eq("/path/to/bbb/rbconfig.rb")
+  end
+
+  it "does not match the other way around" do
+    if Gem::Version.new(Gem::VERSION) < Gem::Version.new("3.3.21")
+      skip "rubygems 3.3.21+ only"
+    end
+
+    cc = Rake::CompilerConfig.new(config_file(<<~CONFIG))
+      ---
+      rbconfig-x86_64-linux-3.1.0: "/path/to/bbb/rbconfig.rb"
+    CONFIG
+
+    expect(cc.find("3.1.0", "x86_64-linux-musl")).to be_nil
+  end
+end
diff --git a/spec/lib/rake/extensiontask_spec.rb b/spec/lib/rake/extensiontask_spec.rb
index a7eb5e3..1c4c9bb 100644
--- a/spec/lib/rake/extensiontask_spec.rb
+++ b/spec/lib/rake/extensiontask_spec.rb
@@ -381,9 +381,10 @@ describe Rake::ExtensionTask do
       end
 
       it 'should warn if no section of config file defines running version of ruby' do
-        config = Hash.new
-        expect(config).to receive(:[]).with("rbconfig-#{@platform}-#{@ruby_ver}").and_return(nil)
-        allow(YAML).to receive(:load_file).and_return(config)
+        allow_any_instance_of(Rake::CompilerConfig).to(
+          receive(:find).with(@ruby_ver, @platform).and_return(nil)
+        )
+
         out, err = capture_output do
           Rake::ExtensionTask.new('extension_one') do |ext|
             ext.cross_compile = true
@@ -403,9 +404,9 @@ describe Rake::ExtensionTask do
       end
 
       it 'should generate additional rake tasks if files are added when cross compiling' do
-        config = Hash.new
-        allow(config).to receive(:[]).and_return('/rubies/1.9.1/rbconfig.rb')
-        allow(YAML).to receive(:load_file).and_return(config)
+        allow_any_instance_of(Rake::CompilerConfig).to(
+          receive(:find).and_return("/rubies/1.9.1/rbconfig.rb")
+        )
 
         # Use a real spec instead of a mock because define_native_tasks dups and
         # calls methods on Gem::Specification, which is more than mock can do.
@@ -433,9 +434,11 @@ describe Rake::ExtensionTask do
       end
 
       it 'should allow usage of RUBY_CC_VERSION to indicate a different version of ruby' do
-        config = Hash.new
-        expect(config).to receive(:[]).with("rbconfig-i386-mingw32-1.9.1").and_return('/rubies/1.9.1/rbconfig.rb')
-        allow(YAML).to receive(:load_file).and_return(config)
+        allow_any_instance_of(Rake::CompilerConfig).to(
+          receive(:find)
+            .with("1.9.1", "i386-mingw32")
+            .and_return("/rubies/1.9.1/rbconfig.rb")
+        )
 
         ENV['RUBY_CC_VERSION'] = '1.9.1'
         Rake::ExtensionTask.new('extension_one') do |ext|
@@ -444,10 +447,16 @@ describe Rake::ExtensionTask do
       end
 
       it 'should allow multiple versions be supplied to RUBY_CC_VERSION' do
-        config = Hash.new
-        expect(config).to receive(:[]).once.with("rbconfig-i386-mingw32-1.8.6").and_return('/rubies/1.8.6/rbconfig.rb')
-        expect(config).to receive(:[]).once.with("rbconfig-i386-mingw32-1.9.1").and_return('/rubies/1.9.1/rbconfig.rb')
-        allow(YAML).to receive(:load_file).and_return(config)
+        allow_any_instance_of(Rake::CompilerConfig).to(
+          receive(:find)
+            .with("1.8.6", "i386-mingw32")
+            .and_return("/rubies/1.8.6/rbconfig.rb")
+        )
+        allow_any_instance_of(Rake::CompilerConfig).to(
+          receive(:find)
+            .with("1.9.1", "i386-mingw32")
+            .and_return("/rubies/1.9.1/rbconfig.rb")
+        )
 
         ENV['RUBY_CC_VERSION'] = '1.8.6:1.9.1'
         Rake::ExtensionTask.new('extension_one') do |ext|
@@ -459,18 +468,19 @@ describe Rake::ExtensionTask do
         platforms = ["x86-mingw32", "x64-mingw32"]
         ruby_cc_versions = ["1.8.6", "2.1.10", "2.2.6", "2.3.3", "2.10.1", "2.11.0"]
         ENV["RUBY_CC_VERSION"] = ruby_cc_versions.join(":")
-        config = Hash.new
+
         ruby_cc_versions.each do |ruby_cc_version|
           platforms.each do |platform|
             unless platform == "x64-mingw32" && ruby_cc_version == "2.11.0"
               rbconf = "/rubies/#{ruby_cc_version}/rbconfig.rb"
             end
-            allow(config).to receive(:[]).
-              with("rbconfig-#{platform}-#{ruby_cc_version}").
-              and_return(rbconf)
+            allow_any_instance_of(Rake::CompilerConfig).to(
+              receive(:find)
+                .with(ruby_cc_version, platform)
+                .and_return(rbconf)
+            )
           end
         end
-        allow(YAML).to receive(:load_file).and_return(config)
 
         allow(Gem).to receive_message_chain(:configuration, :verbose=).and_return(true)
 
@@ -515,9 +525,16 @@ describe Rake::ExtensionTask do
 
       context "(cross compile for multiple versions)" do
         before :each do
-          config = Hash.new
-          allow(config).to receive(:[]).and_return('/rubies/1.8.6/rbconfig.rb', '/rubies/1.9.1/rbconfig.rb')
-          allow(YAML).to receive(:load_file).and_return(config)
+          allow_any_instance_of(Rake::CompilerConfig).to(
+            receive(:find)
+              .with("1.8.6", "universal-unknown")
+              .and_return("/rubies/1.8.6/rbconfig.rb")
+          )
+          allow_any_instance_of(Rake::CompilerConfig).to(
+            receive(:find)
+              .with("1.9.1", "universal-unknown")
+              .and_return("/rubies/1.9.1/rbconfig.rb")
+          )
 
           ENV['RUBY_CC_VERSION'] = '1.8.6:1.9.1'
           @ext = Rake::ExtensionTask.new('extension_one') do |ext|