Draft: lock_platform directive in Gemfile

This allows the Gemfile to include a deploy platform by default on first
deploy, and since Gemfiles are often cargo culted or generated, we can
make the deploy platform intention more more clear from the beginning.

bundler/lib/bundler/definition.rb

@@ -55,7 +55,7 @@ def self.build(gemfile, lockfile, unlock)
     #   to be updated or true if all gems should be updated
     # @param ruby_version [Bundler::RubyVersion, nil] Requested Ruby Version
     # @param optional_groups [Array(String)] A list of optional groups
-    def initialize(lockfile, dependencies, sources, unlock, ruby_version = nil, optional_groups = [], gemfiles = [])
+    def initialize(lockfile, dependencies, sources, unlock, ruby_version = nil, optional_groups = [], gemfiles = [], platforms = [])
       if [true, false].include?(unlock)
         @unlocking_bundler = false
         @unlocking = unlock
@@ -89,6 +89,7 @@ def initialize(lockfile, dependencies, sources, unlock, ruby_version = nil, opti
         @locked_gems = LockfileParser.new(@lockfile_contents)
         @locked_platforms = @locked_gems.platforms
         @platforms = @locked_platforms.dup
+        platforms.each {|p| add_platform(p) }
         @locked_bundler_version = @locked_gems.bundler_version
         @locked_ruby_version = @locked_gems.ruby_version
         @originally_locked_specs = SpecSet.new(@locked_gems.specs)
@@ -105,13 +106,14 @@ def initialize(lockfile, dependencies, sources, unlock, ruby_version = nil, opti
         end
       else
         @unlock         = {}
-        @platforms      = []
         @locked_gems    = nil
         @locked_deps    = {}
         @locked_specs   = SpecSet.new([])
         @originally_locked_specs = @locked_specs
         @locked_sources = []
         @locked_platforms = []
+        @platforms = platforms
+        @new_platform = true unless @platforms.empty?
       end
 
       locked_gem_sources = @locked_sources.select {|s| s.is_a?(Source::Rubygems) }
@@ -143,7 +145,7 @@ def initialize(lockfile, dependencies, sources, unlock, ruby_version = nil, opti
         @unlock[:gems] ||= @dependencies.map(&:name)
       else
         eager_unlock = (@unlock[:gems] || []).map {|name| Dependency.new(name, ">= 0") }
-        @unlock[:gems] = @locked_specs.for(eager_unlock, false, platforms).map(&:name).uniq
+        @unlock[:gems] = @locked_specs.for(eager_unlock, false, @platforms).map(&:name).uniq
       end
 
       @dependency_changes = converge_dependencies

bundler/lib/bundler/dsl.rb

@@ -32,6 +32,7 @@ def initialize
       @install_conditionals = []
       @optional_groups      = []
       @platforms            = []
+      @lock_platforms       = []
       @env                  = nil
       @ruby_version         = nil
       @gemspecs             = []
@@ -215,7 +216,7 @@ def github(repo, options = {})
 
     def to_definition(lockfile, unlock)
       check_primary_source_safety
-      Definition.new(lockfile, @dependencies, @sources, unlock, @ruby_version, @optional_groups, @gemfiles)
+      Definition.new(lockfile, @dependencies, @sources, unlock, @ruby_version, @optional_groups, @gemfiles, @lock_platforms)
     end
 
     def group(*args, &blk)
@@ -249,6 +250,19 @@ def platforms(*platforms)
     end
     alias_method :platform, :platforms
 
+    # Name collision, working around it for a proof
+    def lock_platform(*platforms)
+      platforms.each do |p|
+        gem_platform = Gem::Platform.new(p)
+        # TODO: this is copied from lock
+        if gem_platform.to_s == "unknown"
+          Bundler.ui.warn "The platform `#{platform_string}` is unknown to RubyGems " \
+            "and adding it will likely lead to resolution errors"
+        end
+        @lock_platforms << gem_platform
+      end
+    end
+
     def env(name)
       old = @env
       @env = name

bundler/lib/bundler/spec_set.rb

@@ -15,7 +15,7 @@ def initialize(specs, incomplete_specs = [])
     end
 
     def for(dependencies, check = false, platforms = [nil])
-      handled = ["bundler"].product(platforms).map {|k| [k, true] }.to_h
+      handled = ["bundler"].product(platforms).to_h {|k| [k, true] }
       deps = dependencies.product(platforms)
       specs = []
 

bundler/spec/runtime/platform_spec.rb

@@ -467,4 +467,56 @@
       end
     end
   end
+
+  it "will add platform directly specified by a gemfile" do
+    simulate_platform "x86-darwin-100"
+
+    build_repo4 do
+      build_gem "nokogiri", "1.13.8"
+      build_gem "nokogiri", "1.13.8" do |s|
+        s.platform = "aarch64-linux"
+      end
+    end
+
+    install_gemfile <<-G
+      source "#{file_uri_for(gem_repo4)}"
+
+      lock_platform "aarch64-linux"
+
+      gem "nokogiri"
+    G
+
+    checksums = checksum_section do |c|
+      c.repo_gem gem_repo4, "nokogiri", "1.13.8"
+      # TODO: This is wrong, the point is to get the checksum
+      # Figure out why it's not fetching them for other platforms
+      c.no_checksum "nokogiri", "1.13.8", "aarch64-linux"
+      # c.repo_gem gem_repo4, "nokogiri", "1.13.8", "aarch64-linux"
+    end
+
+    expected_lockfile = <<~L
+      GEM
+        remote: #{file_uri_for(gem_repo4)}/
+        specs:
+          nokogiri (1.13.8)
+          nokogiri (1.13.8-aarch64-linux)
+
+      PLATFORMS
+        aarch64-linux
+        x86-darwin-100
+
+      DEPENDENCIES
+        nokogiri
+
+      CHECKSUMS
+        #{checksums}
+
+      BUNDLED WITH
+         #{Bundler::VERSION}
+    L
+
+    # TODO: "nokogiri was expected to be of platform ruby but was ruby"
+    # expect(the_bundle).to include_gems "nokogiri 1.13.8 ruby"
+    expect(lockfile).to eq(expected_lockfile)
+  end
 end

bundler/spec/support/builders.rb

@@ -126,6 +126,11 @@ def build_repo1
           s.write "lib/platform_specific.rb", "PLATFORM_SPECIFIC = '1.0.0 x86-darwin-100'"
         end
 
+        build_gem "platform_specific" do |s|
+          s.platform = "x86_64-linux"
+          s.write "lib/platform_specific.rb", "PLATFORM_SPECIFIC = '1.0.0 x86_64-linux'"
+        end
+
         build_gem "only_java", "1.0" do |s|
           s.platform = "java"
           s.write "lib/only_java.rb", "ONLY_JAVA = '1.0.0 JAVA'"