Ruby | Support installing the gem via git and some other small build tweaks

ruby/BUILD.bazel

@@ -172,7 +172,7 @@ genrule(
         set -eux
         mkdir tmp
         for src in $(SRCS); do
-            cp --parents -L "$$src" tmp
+            mkdir -p "tmp/$$(dirname $$src)" && cp -L "$$src" "tmp/$$src"
         done
         mkdir -p "tmp/ruby/ext/google/protobuf_c/third_party/utf8_range"
         for utf in $(execpaths //third_party/utf8_range:utf8_range_srcs) $(execpath //third_party/utf8_range:LICENSE); do
@@ -210,7 +210,7 @@ genrule(
         set -eux
         mkdir tmp
         for src in $(SRCS); do
-            cp --parents -L "$$src" "tmp"
+            mkdir -p "tmp/$$(dirname $$src)" && cp -L "$$src" "tmp/$$src"
         done
         mkdir -p "tmp/ruby/ext/google/protobuf_c/third_party/utf8_range"
         for utf in $(execpaths //third_party/utf8_range:utf8_range_srcs) $(execpath //third_party/utf8_range:LICENSE); do

ruby/Rakefile

@@ -18,6 +18,7 @@ well_known_protos = %w[
   google/protobuf/timestamp.proto
   google/protobuf/type.proto
   google/protobuf/wrappers.proto
+  google/protobuf/compiler/plugin.proto
 ]
 
 test_protos = %w[
@@ -38,12 +39,6 @@ test_protos = %w[
   tests/utf8.proto
 ]
 
-# These are omitted for now because we don't support proto2.
-proto2_protos = %w[
-  google/protobuf/descriptor.proto
-  google/protobuf/compiler/plugin.proto
-]
-
 if !ENV['PROTOC'].nil?
   protoc_command = ENV['PROTOC']
 elsif system('../bazel-bin/protoc --version')
@@ -52,17 +47,27 @@ else
   protoc_command = 'protoc'
 end
 
+tmp_protoc_out = "tmp/protoc-out"
+
+directory tmp_protoc_out
+
 genproto_output = []
 
 # We won't have access to .. from within docker, but the proto files
 # will be there, thanks to the :genproto rule dependency for gem:native.
 unless ENV['IN_DOCKER'] == 'true' or ENV['BAZEL'] == 'true'
   well_known_protos.each do |proto_file|
-    input_file = "../src/" + proto_file
-    output_file = "lib/" + proto_file.sub(/\.proto$/, "_pb.rb")
+    input_file = File.join("../src/", proto_file)
+    output_basename = File.basename(proto_file).sub(/\.proto$/, "_pb.rb")
+    tmp_output_file = File.join(tmp_protoc_out, File.dirname(proto_file), output_basename)
+    # Generated _pb.rb for files in subdirectories of google/protobuf
+    # (eg: ../src/google/protobuf/compiler/plugin.proto) should all still end up
+    # in lib/google/protobuf.
+    output_file = File.join("lib/google/protobuf", output_basename)
     genproto_output << output_file
-    file output_file => input_file do |file_task|
-      sh "#{protoc_command} -I../src --ruby_out=lib #{input_file}"
+    file output_file => [input_file, tmp_protoc_out] do |file_task|
+      sh "#{protoc_command} -I../src --ruby_out=#{tmp_protoc_out} #{input_file}"
+      FileUtils.cp tmp_output_file, output_file
     end
   end
 
@@ -177,6 +182,16 @@ task :clean do
 end
 
 Gem::PackageTask.new(spec) do |pkg|
+  # When packaging the gem via `rake gem`, we only want to define
+  # "ext/google/protobuf_c/extconf.rb" as the extension to build the C
+  # extension.
+  pkg.gem_spec.extensions = pkg.gem_spec.extensions.map do |extension|
+    extension == "Rakefile" ? "ext/google/protobuf_c/extconf.rb" : extension
+  end
+
+  pkg.gem_spec.files.reject! { |f| f == "Rakefile" }
+
+  pkg.package_files.exclude("Rakefile")
 end
 
 # Skip build/genproto in Bazel builds, where we expect this to

ruby/google-protobuf.gemspec

@@ -25,9 +25,17 @@ Gem::Specification.new do |s|
     s.files     += Dir.glob('ext/**/*').reject do |file|
       File.basename(file) =~ /^(BUILD\.bazel)$/
     end
-    s.extensions = %w[
-      ext/google/protobuf_c/extconf.rb
-      ext/google/protobuf_c/Rakefile
+
+    # When installing this gem from git via bundler
+    # (ie: 'gem "google-protobuf", git: "https://.../protobuf.git"' in your
+    # Gemfile), Rakefile is necessary so the prerequisite tasks run to copy
+    # third party C libraries and generate well known protobufs.  When building
+    # the gem via `rake gem`, these steps will have already occurred, and so we
+    # replace the `Rakefile` extension with `ext/google/protobuf_c/extconf.rb`.
+    # See the `Gem::PackageTask.new` declaration in `Rakefile` for more details.
+    s.extensions = [
+      File.exist?("Rakefile") ? "Rakefile" : "ext/google/protobuf_c/extconf.rb",
+      "ext/google/protobuf_c/Rakefile"
     ]
   end
   s.required_ruby_version = '>= 3.1'