[Content Addressable] Support content addressable gem builds / gem naming in PackageTask

lib/rubygems/commands/build_command.rb

@@ -26,7 +26,11 @@ def initialize
       options[:output] = value
     end
 
-    add_ruby_abi_option("build", "  (builds a content addressable gem)")
+    add_ruby_abi_option("build")
+
+    add_option "--content-addressable", "build a content-addressable gem" do |_value, options|
+      options[:content_addressable] = true
+    end
   end
 
   def arguments # :nodoc:
@@ -54,10 +58,19 @@ def description # :nodoc:
 
   $ gem build my_gem-1.0.gemspec --output=release.gem
 
-Platform gems can be built for a single Ruby ABI with the --ruby-abi option:
+Use the --ruby-abi option to set a specific Ruby ABI for the gem being built:
 
   $ gem build my_gem-1.0.gemspec --ruby-abi=3.4
 
+Use the --content-addressable option to build a content-addressable gem using
+the platform and required_ruby_version declared in the gemspec:
+
+  $ gem build my_gem-1.0.gemspec --content-addressable
+
+The options can be combined to set the Ruby ABI explicitly:
+
+  $ gem build my_gem-1.0.gemspec --ruby-abi=3.4 --content-addressable
+
     EOF
   end
 
@@ -95,12 +108,25 @@ def build_package(gemspec)
         spec.platform = Gem::Platform.local
       end
 
+      ruby_abi = options[:ruby_abi]
+      if ruby_abi
+        requirement = Gem::ContentAddress.ruby_abi_requirement(ruby_abi)
+        existing = spec.required_ruby_version
+
+        unless existing.none? || existing == requirement
+          alert_warning "required_ruby_version was changed from \"#{existing}\" to \"#{requirement}\" for this build " \
+            "because --ruby-abi #{ruby_abi} was given."
+        end
+
+        spec.required_ruby_version = requirement
+      end
+
       Gem::Package.build(
         spec,
         options[:force],
         options[:strict],
         options[:output],
-        options[:ruby_abi]
+        content_addressable: options[:content_addressable]
       )
     else
       alert_error "Error loading gemspec. Aborting."

lib/rubygems/content_address.rb

@@ -90,6 +90,23 @@ def self.eligible?(spec, validate_ruby_abi: true)
     !ruby_abi_for(spec.required_ruby_version).nil?
   end
 
+  ##
+  # Raises ArgumentError unless +spec+ is eligible for content addressing
+
+  def self.eligible!(spec)
+    unless platform_eligible?(spec.platform)
+      raise ArgumentError,
+        "Cannot build a content-addressable gem as no platform or a Ruby platform has been set"
+    end
+
+    return unless ruby_abi_for(spec.required_ruby_version).nil?
+
+    raise ArgumentError,
+      "Cannot build a content-addressable gem because required_ruby_version is set to " \
+      "#{spec.required_ruby_version}. Please set required_ruby_version to \"~> X.Y.0\" " \
+      "so that it identifies a single Ruby ABI."
+  end
+
   ##
   # Whether +spec+ is content-addressed: it is eligible for content
   # addressing and has a valid content address set. See eligible? for
@@ -114,20 +131,6 @@ def self.content_addressed_row?(suffix, platform, required_ruby_version = nil, v
     !ruby_abi_for(required_ruby_version).nil?
   end
 
-  ##
-  # Whether +spec+'s required_ruby_version permits building for +ruby_abi+:
-  # an unset or default requirement can still be pinned to the ABI, and
-  # anything else must already pin exactly that ABI. Used at build time,
-  # before the requirement is injected, where eligible? would be
-  # premature.
-
-  def self.ruby_abi_compatible?(spec, ruby_abi)
-    required_ruby_version = spec.required_ruby_version
-    return true if required_ruby_version.nil? || required_ruby_version.none?
-
-    ruby_abi_for(required_ruby_version) == ruby_abi
-  end
-
   ##
   # Generates the content address for +bytes+: the first +length+
   # characters of the hexadecimal SHA256 digest of the contents.

lib/rubygems/package.rb

@@ -137,18 +137,20 @@ class TarInvalidError < Error; end
   MINIMUM_RUBYGEMS_VERSION = ">= 4.1.0.a"
 
   ##
-  # Builds the gem described by +spec+ and returns the built file name;
-  # passing +ruby_abi+ ("X.Y") builds a content-addressable gem named by the
-  # SHA-256 of its contents, updates +spec.required_ruby_version+ to
-  # "~> X.Y.0", and constrains +spec.required_rubygems_version+ to at least
-  # MINIMUM_RUBYGEMS_VERSION (incompatible with
-  # +file_name+).
-
-  def self.build(spec, skip_validation = false, strict_validation = false, file_name = nil, ruby_abi = nil)
-    if ruby_abi && file_name
-      raise ArgumentError, "Cannot specify both a Ruby ABI and an output file name because content addressable gems must use the generated file name."
-    end
-    if ruby_abi
+  # Builds the gem described by +spec+ and returns the built file name.
+  #
+  # When +content_addressable+ is true, builds a gem named by the SHA-256
+  # digest of its contents. The spec must declare a non-Ruby platform and a
+  # +required_ruby_version+ identifying a single Ruby ABI. Its
+  # +required_rubygems_version+ is constrained to at least
+  # MINIMUM_RUBYGEMS_VERSION. Content-addressable builds are incompatible
+  # with +file_name+.
+
+  def self.build(spec, skip_validation = false, strict_validation = false, file_name = nil, content_addressable: false)
+    if content_addressable && file_name
+      raise ArgumentError, "Cannot specify an output file name for a content-addressable gem as these gems must use the generated file name."
+    end
+    if content_addressable
       require "digest"
       require "stringio"
 
@@ -157,9 +159,8 @@ def self.build(spec, skip_validation = false, strict_validation = false, file_na
 
       package = new io
       package.spec = spec.dup
-      gem_file = package.build_content_addressable_file ruby_abi, skip_validation, strict_validation
+      gem_file = package.build_content_addressable_file skip_validation, strict_validation
 
-      spec.required_ruby_version = package.spec.required_ruby_version
       spec.required_rubygems_version = package.spec.required_rubygems_version
     else
       gem_file = file_name || spec.file_name
@@ -375,20 +376,18 @@ def build(skip_validation = false, strict_validation = false)
   end
 
   ##
-  # Builds this package scoped to +ruby_abi+ ("X.Y"), then writes it to a
-  # content-addressable file name derived from the SHA-256 digest of the gem
-  # contents, e.g. "example-1.0-01234567.gem". Returns the file name of the
-  # written gem.
+  # Builds this package and writes it to a content-addressable file name
+  # derived from the SHA-256 digest of the gem contents, for example
+  # "example-1.0-01234567.gem". Returns the written file name.
   #
-  # The spec is validated for an ABI-scoped build and its
-  # +required_ruby_version+ and +required_rubygems_version+ are constrained
-  # before building, so every gem this method produces is eligible for
-  # content addressing.
+  # The spec is validated for content addressing. Its
+  # +required_ruby_version+ determines the Ruby ABI, while its
+  # +required_rubygems_version+ is constrained before building.
 
-  def build_content_addressable_file(ruby_abi, skip_validation = false, strict_validation = false)
-    validate_ruby_abi ruby_abi
+  def build_content_addressable_file(skip_validation = false, strict_validation = false)
+    Gem::ContentAddress.eligible!(@spec)
+    ruby_abi = Gem::ContentAddress.ruby_abi_for(@spec.required_ruby_version)
     @spec.required_rubygems_version = normalized_required_rubygems_version(ruby_abi)
-    @spec.required_ruby_version = Gem::ContentAddress.ruby_abi_requirement(ruby_abi)
 
     build skip_validation, strict_validation
 
@@ -789,22 +788,6 @@ def satisfies_rubygems_floor?(requirement, floor)
     end
   end
 
-  ##
-  # Validates that the spec can be built as a content-addressable gem scoped
-  # to +ruby_abi+ ("X.Y"): the ABI must be well-formed, the spec must declare
-  # a non-Ruby platform, and any existing +required_ruby_version+ must match
-  # the ABI.
-
-  def validate_ruby_abi(ruby_abi)
-    if !Gem::ContentAddress.valid_ruby_abi?(ruby_abi)
-      raise ArgumentError, "Ruby ABI must be in X.Y format"
-    elsif !Gem::ContentAddress.platform_eligible?(@spec.platform)
-      raise ArgumentError, "Cannot build a gem scoped to a single Ruby ABI as no platform or a Ruby platform has been set"
-    elsif !Gem::ContentAddress.ruby_abi_compatible?(@spec, ruby_abi)
-      raise ArgumentError, "Cannot build gem for Ruby ABI #{ruby_abi} because required_ruby_version is set to #{@spec.required_ruby_version}. Please set required_ruby_version to \"~> #{ruby_abi}.0\"."
-    end
-  end
-
   ##
   # Returns the full path for installing +filename+ into +destination_dir+,
   # which must already be resolved with File.realpath by the caller.

lib/rubygems/package_task.rb

@@ -65,6 +65,10 @@ class Gem::PackageTask < Rake::PackageTask
 
   attr_accessor :gem_spec
 
+  ##
+  # Indicates whether this package should be built as a content-addressable gem.
+  attr_accessor :content_addressable
+
   ##
   # Create a Gem Package task library.  Automatically define the gem if a
   # block is given.  If no block is supplied, then #define needs to be called
@@ -82,6 +86,7 @@ def initialize(gem_spec)
   def init(gem)
     super gem.full_name, :noversion
     @gem_spec = gem
+    @content_addressable = false
     @package_files += gem_spec.files if gem_spec.files
     @fileutils_output = $stdout
   end
@@ -91,33 +96,97 @@ def init(gem)
   # (+define+ is automatically called if a block is given to +new+).
 
   def define
+    Gem::ContentAddress.eligible!(gem_spec) if content_addressable
+
     super
 
     gem_file = File.basename gem_spec.cache_file
     gem_path = File.join package_dir, gem_file
-    gem_dir  = File.join package_dir, gem_spec.full_name
+    gem_dir = package_dir_path
+
+    if content_addressable
+      build_target = stamp_file
+      gem_description = "content-addressable gem #{gem_spec.name}-#{gem_spec.version} " \
+        "(Platform: #{gem_spec.platform}, Ruby ABI: #{content_addressable_ruby_abi})"
+
+      discard_stale_stamp_file
+    else
+      build_target = gem_path
+      gem_description = "gem file #{gem_file}"
+    end
 
     task package: [:gem]
 
     directory package_dir
     directory gem_dir
 
-    desc "Build the gem file #{gem_file}"
-    task gem: [gem_path]
+    desc "Build the #{gem_description}"
+    task gem: [build_target]
 
     trace = Rake.application.options.trace
     Gem.configuration.verbose = trace
 
-    file gem_path => [package_dir, gem_dir] + @gem_spec.files do
+    file build_target => [package_dir, gem_dir] + @gem_spec.files do
+      previous_gem = recorded_gem_path if content_addressable
+      built_gem_path = nil
+
       chdir(gem_dir) do
-        when_writing "Creating #{gem_spec.file_name}" do
-          built_gem_file = Gem::Package.build gem_spec
+        when_writing "Creating #{gem_description}" do
+          built_gem_file = Gem::Package.build gem_spec, content_addressable: content_addressable
 
           verbose trace do
             mv built_gem_file, ".."
           end
+
+          if content_addressable
+            built_gem_path = File.join(package_dir, built_gem_file)
+            File.write File.join("..", File.basename(stamp_file)), built_gem_path
+          end
+        end
+      end
+
+      if previous_gem && built_gem_path && previous_gem != built_gem_path
+        verbose trace do
+          rm_f previous_gem
         end
       end
     end
   end
+
+  ##
+  # The name of this package. Content-addressable builds append the Ruby ABI
+  # so per-ABI builds of the same +full_name+ do not share a staging
+  # directory.
+
+  def package_name
+    name = super
+    ruby_abi = content_addressable_ruby_abi
+    ruby_abi ? "#{name}-#{ruby_abi}" : name
+  end
+
+  private
+
+  def content_addressable_ruby_abi
+    return unless content_addressable
+
+    Gem::ContentAddress.ruby_abi_for(gem_spec.required_ruby_version)
+  end
+
+  def stamp_file
+    File.join package_dir, "#{package_name}.gem-built"
+  end
+
+  def recorded_gem_path
+    return unless File.file?(stamp_file)
+
+    path = File.read(stamp_file).strip
+    path unless path.empty?
+  end
+
+  def discard_stale_stamp_file
+    return unless File.file?(stamp_file)
+
+    path = recorded_gem_path
+    File.delete(stamp_file) unless path && File.file?(path)
+  end
 end

spec/commands/clean_spec.rb

@@ -391,7 +391,7 @@ def should_not_have_gems(*gems)
     expect(vendored_gems("bin/myrackup")).not_to exist
   end
 
-  it "removes orphaned gemspecs from ABI-scoped specification dirs", rubygems: ">= 4.1.0.dev" do
+  it "removes orphaned gemspecs from ABI-scoped specification dirs", rubygems: ">= 4.1.0.a" do
     gemfile <<-G
       source "https://gem.repo1"
 
@@ -412,20 +412,22 @@ def should_not_have_gems(*gems)
     should_have_gems "foo-1.0"
   end
 
-  it "does not remove gemspecs for content-addressed gems in the bundle", :compact_index, rubygems: ">= 4.1.0.dev" do
+  it "does not remove gemspecs for content-addressed gems in the bundle", :compact_index, rubygems: ">= 4.1.0.a" do
     skip "Gem::ContentAddress not available" if ruby_core?
+    skip "ABI-scoped requirements do not match prerelease Ruby versions" if Gem.ruby_version.prerelease?
 
     simulate_platform "x86_64-linux" do
+      current_abi = "#{Gem.ruby_version.segments[0]}.#{Gem.ruby_version.segments[1]}"
       build_repo2 do
         build_gem "mygem", "1.0" do |s|
           s.platform = Gem::Platform.new("x86_64-linux")
           s.write "lib/mygem.rb", "MYGEM = '1.0 not_content_addressed'"
         end
       end
 
-      build_gem "mygem", "1.0", ruby_abi: Gem.ruby_abi, path: gem_repo2("gems") do |s|
+      build_gem "mygem", "1.0", content_addressable: true, path: gem_repo2("gems") do |s|
         s.platform = Gem::Platform.new("x86_64-linux")
-        s.required_ruby_version = "~> #{Gem.ruby_abi}.0"
+        s.required_ruby_version = "~> #{current_abi}.0"
         s.write "lib/mygem.rb", "MYGEM = '1.0 content_addressed'"
       end