tools/protogem: Generate version file ad-hoc

On every version bump the GitLab Release Tools bot updates the version
in two different files: first in our top-level `VERSION` file, and
second in the Ruby Protobuf files at `ruby/proto/version.rb`. Both files
basically contain the same information, but serve different purposes.

We're about to drop our generated Ruby Protobuf code though in favor of
creating the Protobuf Gem ad-hoc. This also means it doesn't make a
whole lot of sense anymore to carry around the version file in our tree.
Consequentially, we've adjusted the Release Tools bot to stop writing
the `version.rb` file completely. Instead, we now generate the file via
the information we already have in our `VERSION` file.

1 files changed, 16 insertions, 0 deletions

diff --git a/tools/protogem/generate-proto-ruby b/tools/protogem/generate-proto-ruby
index cfbbbed75..d4b807d37 100755
--- a/tools/protogem/generate-proto-ruby
+++ b/tools/protogem/generate-proto-ruby
@@ -11,7 +11,10 @@ RUBY_VERSION_FILE = File.join('gitaly', 'version.rb')
 def main
   proto_output_dir = File.absolute_path(File.join(SOURCE_DIR, 'ruby', 'proto', 'gitaly'))
 
+  version = File.read(File.join(SOURCE_DIR, 'VERSION')).strip
+
   FileUtils.rm(Dir[File.join(proto_output_dir, '**/*_pb.rb')])
+  FileUtils.rm(Dir[File.join(proto_output_dir, 'version.rb')])
   FileUtils.mkdir_p(proto_output_dir)
 
   proto_dir = File.join(SOURCE_DIR, 'proto')
@@ -22,9 +25,22 @@ def main
     File.join(SOURCE_DIR, 'tools', 'protogem')
   )
 
+  write_version_file(SOURCE_DIR, version)
   write_ruby_requires(SOURCE_DIR)
 end
 
+def write_version_file(output_dir, version)
+  path = File.join(output_dir, 'ruby', 'proto', RUBY_VERSION_FILE)
+  content = <<~EOF
+    # This file is generated by #{File.basename($0)}. Do not edit.
+    module Gitaly
+      VERSION = '#{version}'
+    end
+  EOF
+
+  open(path, 'w') { |f| f.write(content) }
+end
+
 def write_ruby_requires(output_dir)
   requires = Dir.glob(File.join('gitaly', '*_services_pb.rb'), base: File.join(output_dir, 'ruby', 'proto')).sort
   abort "No auto-generated Ruby service files found" if requires.empty?