feat: add arm-linux-musl

note that we have to patch rake-compiler to build ruby 2.7 on 32-byte
arm because of coroutine issues that weren't fixed until 3.0.

ci: extract testing matrices for arm-linux gnu and musl

Author: flavorjones

.github/workflows/ci.yml

@@ -49,6 +49,7 @@ jobs:
             alias:    aarch64-linux
           - platform: arm-linux-gnu
             alias:    arm-linux
+          - platform: arm-linux-musl
           - platform: arm64-darwin
           - platform: jruby
           - platform: x64-mingw-ucrt
@@ -317,6 +318,68 @@ jobs:
               ruby -rrcd_test -S rake test
             "
 
+  test_arm-linux-gnu:
+    name: arm-linux-gnu
+    needs: build_native_gem
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby: ["3.3", "3.2", "3.1", "3.0", "2.7", "2.6", "2.5", "2.4"]
+        platform: [arm-linux]
+        include:
+          # ruby 3.0 and earlier ship rubygems < 3.2.33, so can't recognize the -gnu suffix
+          - ruby: "3.3"
+            platform: arm-linux-gnu
+          - ruby: "3.2"
+            platform: arm-linux-gnu
+          - ruby: "3.1"
+            platform: arm-linux-gnu
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Download gem-${{ matrix.platform }}
+        uses: actions/download-artifact@v3
+        with:
+          name: gem-${{ matrix.platform }}
+      - name: Run tests
+        run: |
+          docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
+          docker run --rm -v $PWD:/work -w /work \
+            --platform=linux/arm/v7 ruby:${{ matrix.ruby }} \
+            sh -c "
+              gem install --local *.gem --verbose &&
+              cd test/rcd_test/ &&
+              bundle install &&
+              ruby -rrcd_test -S rake test
+            "
+
+  test_arm-linux-musl:
+    name: arm-linux-musl
+    needs: build_native_gem
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby: ["3.3", "3.2", "3.1"] # TODO can we update rubygems and get earlier images working?
+        platform: [arm-linux-musl]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Download gem-${{ matrix.platform }}
+        uses: actions/download-artifact@v3
+        with:
+          name: gem-${{ matrix.platform }}
+      - name: Run tests
+        run: |
+          docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
+          docker run --rm -v $PWD:/work -w /work \
+            --platform=linux/arm/v7 ruby:${{ matrix.ruby }}-alpine \
+            sh -c "
+              gem install --local *.gem --verbose &&
+              cd test/rcd_test/ &&
+              bundle install &&
+              ruby -rrcd_test -S rake test
+            "
+
   test_native_gem:
     name: test native
     needs: build_native_gem

.gitignore

@@ -2,6 +2,7 @@
 /.yardoc
 /Dockerfile.mri.aarch64-linux-gnu
 /Dockerfile.mri.arm-linux-gnu
+/Dockerfile.mri.arm-linux-musl
 /Dockerfile.mri.arm64-darwin
 /Dockerfile.mri.x64-mingw-ucrt
 /Dockerfile.mri.x64-mingw32

Dockerfile.mri.erb

@@ -148,11 +148,9 @@ else
   ]
 end
 
-xrubies_build_plan.each do |xrubies, bootstrap_ruby_version| %>
-ENV XRUBIES <%= xrubies %>
+strip = '-s' if platform !~ /darwin/
 
-<% strip = '-s' if platform !~ /darwin/ %>
-# Build xruby versions, then cleanup all build artifacts
+xrubies_build_plan.each do |xrubies, bootstrap_ruby_version| %>
 RUN bash -c " \
       rbenv shell <%= bootstrap_ruby_version %> && \
       export CPPFLAGS='<%= "-D__USE_MINGW_ANSI_STDIO=1" if platform =~ /x64-mingw-ucrt/ %>' && \
@@ -161,7 +159,7 @@ RUN bash -c " \
       <%= "export LIBS='-l:libssp.a' &&" if platform =~ /mingw/ %> \
       <%= "export CC=#{target}-clang &&" if platform =~ /darwin/ %> \
       export MAKE='make V=1' && \
-      rake-compiler cross-ruby VERSION=$XRUBIES HOST=<%= target %> && \
+      rake-compiler cross-ruby VERSION=<%= xrubies %> HOST=<%= target %> && \
       rm -rf ~/.rake-compiler/builds ~/.rake-compiler/sources \
     "
 <% end %>

Rakefile

@@ -12,6 +12,7 @@ platforms = [
   # tuple is [platform, target]
   ["aarch64-linux-gnu", "aarch64-linux-gnu"],
   ["arm-linux-gnu", "arm-linux-gnueabihf"],
+  ["arm-linux-musl", "arm-linux-musleabihf"],
   ["arm64-darwin", "aarch64-apple-darwin"],
   ["x64-mingw-ucrt", "x86_64-w64-mingw32"],
   ["x64-mingw32", "x86_64-w64-mingw32"],

build/patches2/rake-compiler-1.2.5/0004-Enable-build-of-static-libruby.patch

@@ -2,7 +2,7 @@ diff --git a/tasks/bin/cross-ruby.rake b/tasks/bin/cross-ruby.rake
 index 8317a2a..5a1b3ea 100644
 --- a/tasks/bin/cross-ruby.rake
 +++ b/tasks/bin/cross-ruby.rake
-@@ -116,10 +116,22 @@ RUBY_CC_VERSIONS.split(":").each do |ruby_cc_version|
+@@ -116,10 +116,26 @@ RUBY_CC_VERSIONS.split(":").each do |ruby_cc_version|
          "--host=#{mingw_host}",
          "--target=#{mingw_target}",
          "--build=#{RUBY_BUILD}",
@@ -12,7 +12,8 @@ index 8317a2a..5a1b3ea 100644
          '--disable-install-doc',
          '--with-ext=',
        ]
-+      if mingw_host=~/darwin/
+
++      if mingw_host =~ /darwin/
 +        options += [
 +          '--enable-static',
 +          '--disable-shared',
@@ -23,6 +24,9 @@ index 8317a2a..5a1b3ea 100644
 +          '--enable-shared',
 +        ]
 +      end
- 
++
++      # https://github.com/docker-library/ruby/issues/308
++      options << "--with-coroutine=arm32" if major == "2.7" && mingw_target =~ /arm-linux-musl/
++
        # Force Winsock2 for Ruby 1.8, 1.9 defaults to it
        options << "--with-winsock2" if major == "1.8"

test/rcd_test/Rakefile

@@ -23,6 +23,7 @@ else
       aarch64-linux-gnu
       arm-linux
       arm-linux-gnu
+      arm-linux-musl
       arm64-darwin
       x64-mingw-ucrt
       x64-mingw32