Makes the gem system understand development vs. runtime dependencies [#2195 state:resolved]

The patch also fixes:

* Fixes the chicken/egg problem present in the current gem system when
  gems are defined in the config that are not yet installed.

* Remove the need to have hoe as a dependency of your production app.

* Makes the gem 'unpacking' system a lot less fragile.

Signed-off-by: Matt Jones <al2o3cr@gmail.com>
Signed-off-by: Pratik Naik <pratiknaik@gmail.com>

1 files changed, 117 insertions, 97 deletions

diff --git a/railties/lib/rails/gem_dependency.rb b/railties/lib/rails/gem_dependency.rb
index ea36f69f2f..3062a77104 100644
--- a/railties/lib/rails/gem_dependency.rb
+++ b/railties/lib/rails/gem_dependency.rb
@@ -7,8 +7,8 @@ module Gem
 end
 
 module Rails
-  class GemDependency
-    attr_accessor :lib, :source
+  class GemDependency < Gem::Dependency
+    attr_accessor :lib, :source, :dep
 
     def self.unpacked_path
       @unpacked_path ||= File.join(RAILS_ROOT, 'vendor', 'gems')
@@ -29,18 +29,6 @@ module Rails
       end
     end
 
-    def framework_gem?
-      @@framework_gems.has_key?(name)
-    end
-
-    def vendor_rails?
-      Gem.loaded_specs.has_key?(name) && Gem.loaded_specs[name].loaded_from.empty?
-    end
-
-    def vendor_gem?
-      Gem.loaded_specs.has_key?(name) && Gem.loaded_specs[name].loaded_from.include?(self.class.unpacked_path)
-    end
-
     def initialize(name, options = {})
       require 'rubygems' unless Object.const_defined?(:Gem)
 
@@ -52,10 +40,11 @@ module Rails
         req = Gem::Requirement.default
       end
 
-      @dep = Gem::Dependency.new(name, req)
       @lib      = options[:lib]
       @source   = options[:source]
       @loaded   = @frozen = @load_paths_added = false
+
+      super(name, req)
     end
 
     def add_load_paths
@@ -65,52 +54,74 @@ module Rails
         @load_paths_added = @loaded = @frozen = true
         return
       end
-      gem @dep
+      gem self
       @spec = Gem.loaded_specs[name]
       @frozen = @spec.loaded_from.include?(self.class.unpacked_path) if @spec
       @load_paths_added = true
     rescue Gem::LoadError
     end
 
-    def dependencies(options = {})
-      return [] if framework_gem? || specification.nil?
-
-      all_dependencies = specification.dependencies.map do |dependency|
+    def dependencies
+      return [] if framework_gem?
+      return [] unless installed?
+      specification.dependencies.reject do |dependency|
+        dependency.type == :development
+      end.map do |dependency|
         GemDependency.new(dependency.name, :requirement => dependency.version_requirements)
       end
+    end
 
-      all_dependencies += all_dependencies.map { |d| d.dependencies(options) }.flatten if options[:flatten]
-      all_dependencies.uniq
+    def specification
+      # code repeated from Gem.activate. Find a matching spec, or the currently loaded version.
+      # error out if loaded version and requested version are incompatible.
+      @spec ||= begin
+        matches = Gem.source_index.search(self)
+        matches << @@framework_gems[name] if framework_gem?
+        if Gem.loaded_specs[name] then
+          # This gem is already loaded.  If the currently loaded gem is not in the
+          # list of candidate gems, then we have a version conflict.
+          existing_spec = Gem.loaded_specs[name]
+          unless matches.any? { |spec| spec.version == existing_spec.version } then
+            raise Gem::Exception,
+                  "can't activate #{@dep}, already activated #{existing_spec.full_name}"
+          end
+          # we're stuck with it, so change to match
+          version_requirements = Gem::Requirement.create("=#{existing_spec.version}")
+          existing_spec
+        else
+          # new load
+          matches.last
+        end
+      end
     end
 
-    def gem_dir(base_directory)
-      File.join(base_directory, specification.full_name)
+    def requirement
+      r = version_requirements
+      (r == Gem::Requirement.default) ? nil : r
     end
 
-    def spec_filename(base_directory)
-      File.join(gem_dir(base_directory), '.specification')
+    def built?
+      # TODO: If Rubygems ever gives us a way to detect this, we should use it
+      false
     end
 
-    def load
-      return if @loaded || @load_paths_added == false
-      require(@lib || name) unless @lib == false
-      @loaded = true
-    rescue LoadError
-      puts $!.to_s
-      $!.backtrace.each { |b| puts b }
+    def framework_gem?
+      @@framework_gems.has_key?(name)
     end
 
-    def name
-      @dep.name.to_s
+    def frozen?
+      @frozen ||= vendor_rails? || vendor_gem?
     end
 
-    def requirement
-      r = @dep.version_requirements
-      (r == Gem::Requirement.default) ? nil : r
+    def installed?
+      Gem.loaded_specs.keys.include?(name)
     end
 
-    def frozen?
-      @frozen ||= vendor_rails? || vendor_gem?
+    def load_paths_added?
+      # always try to add load paths - even if a gem is loaded, it may not
+      # be a compatible version (ie random_gem 0.4 is loaded and a later spec
+      # needs >= 0.5 - gem 'random_gem' will catch this and error out)
+      @load_paths_added
     end
 
     def loaded?
@@ -136,48 +147,49 @@ module Rails
       end
     end
 
-    def load_paths_added?
-      # always try to add load paths - even if a gem is loaded, it may not
-      # be a compatible version (ie random_gem 0.4 is loaded and a later spec
-      # needs >= 0.5 - gem 'random_gem' will catch this and error out)
-      @load_paths_added
+    def vendor_rails?
+      Gem.loaded_specs.has_key?(name) && Gem.loaded_specs[name].loaded_from.empty?
     end
 
-    def install
-      cmd = "#{gem_command} #{install_command.join(' ')}"
-      puts cmd
-      puts %x(#{cmd})
+    def vendor_gem?
+      specification && File.exists?(unpacked_gem_directory)
     end
 
-    def unpack_to(directory)
-      return if specification.nil? || File.directory?(gem_dir(directory)) || framework_gem?
-
-      FileUtils.mkdir_p directory
-      Dir.chdir directory do
-        Gem::GemRunner.new.run(unpack_command)
+    def build
+      require 'rails/gem_builder'
+      unless built?
+        return unless File.exists?(unpacked_specification_filename)
+        spec = YAML::load_file(unpacked_specification_filename)
+        Rails::GemBuilder.new(spec, unpacked_gem_directory).build_extensions
+        puts "Built gem: '#{unpacked_gem_directory}'"
       end
-
-      # Gem.activate changes the spec - get the original
-      real_spec = Gem::Specification.load(specification.loaded_from)
-      write_spec(directory, real_spec)
-
+      dependencies.each { |dep| dep.build }
     end
 
-    def write_spec(directory, spec)
-      # copy the gem's specification into GEMDIR/.specification so that
-      # we can access information about the gem on deployment systems
-      # without having the gem installed
-      File.open(spec_filename(directory), 'w') do |file|
-        file.puts spec.to_yaml
+    def install
+      unless installed?
+        cmd = "#{gem_command} #{install_command.join(' ')}"
+        puts cmd
+        puts %x(#{cmd})
       end
     end
 
-    def refresh_spec(directory)
+    def load
+      return if @loaded || @load_paths_added == false
+      require(@lib || name) unless @lib == false
+      @loaded = true
+    rescue LoadError
+      puts $!.to_s
+      $!.backtrace.each { |b| puts b }
+    end
+
+    def refresh
+      Rails::VendorGemSourceIndex.silence_spec_warnings = true
       real_gems = Gem.source_index.installed_source_index
       exact_dep = Gem::Dependency.new(name, "= #{specification.version}")
       matches = real_gems.search(exact_dep)
       installed_spec = matches.first
-      if File.exist?(File.dirname(spec_filename(directory)))
+      if frozen?
         if installed_spec
           # we have a real copy
           # get a fresh spec - matches should only have one element
@@ -185,11 +197,11 @@ module Rails
           # spec is the same as the copy from real_gems - Gem.activate changes
           # some of the fields
           real_spec = Gem::Specification.load(matches.first.loaded_from)
-          write_spec(directory, real_spec)
+          write_specification(real_spec)
           puts "Reloaded specification for #{name} from installed gems."
         else
           # the gem isn't installed locally - write out our current specs
-          write_spec(directory, specification)
+          write_specification(specification)
           puts "Gem #{name} not loaded locally - writing out current spec."
         end
       else
@@ -201,40 +213,35 @@ module Rails
       end
     end
 
-    def ==(other)
-      self.name == other.name && self.requirement == other.requirement
+    def unpack(options={})
+      unless frozen? || framework_gem?
+        FileUtils.mkdir_p unpack_base
+        Dir.chdir unpack_base do
+          Gem::GemRunner.new.run(unpack_command)
+        end
+        # Gem.activate changes the spec - get the original
+        real_spec = Gem::Specification.load(specification.loaded_from)
+        write_specification(real_spec)
+      end
+      dependencies.each { |dep| dep.unpack } if options[:recursive]
     end
-    alias_method :"eql?", :"=="
 
-    def hash
-      @dep.hash
+    def write_specification(spec)
+      # copy the gem's specification into GEMDIR/.specification so that
+      # we can access information about the gem on deployment systems
+      # without having the gem installed
+      File.open(unpacked_specification_filename, 'w') do |file|
+        file.puts spec.to_yaml
+      end
     end
 
-    def specification
-      # code repeated from Gem.activate. Find a matching spec, or the currently loaded version.
-      # error out if loaded version and requested version are incompatible.
-      @spec ||= begin
-        matches = Gem.source_index.search(@dep)
-        matches << @@framework_gems[name] if framework_gem?
-        if Gem.loaded_specs[name] then
-          # This gem is already loaded.  If the currently loaded gem is not in the
-          # list of candidate gems, then we have a version conflict.
-          existing_spec = Gem.loaded_specs[name]
-          unless matches.any? { |spec| spec.version == existing_spec.version } then
-            raise Gem::Exception,
-                  "can't activate #{@dep}, already activated #{existing_spec.full_name}"
-          end
-          # we're stuck with it, so change to match
-          @dep.version_requirements = Gem::Requirement.create("=#{existing_spec.version}")
-          existing_spec
-        else
-          # new load
-          matches.last
-        end
-      end
+    def ==(other)
+      self.name == other.name && self.requirement == other.requirement
     end
+    alias_method :"eql?", :"=="
 
     private
+
       def gem_command
         case RUBY_PLATFORM
           when /win32/
@@ -258,5 +265,18 @@ module Rails
         cmd << "--version" << "= "+specification.version.to_s if requirement
         cmd
       end
+
+      def unpack_base
+        Rails::GemDependency.unpacked_path
+      end
+
+      def unpacked_gem_directory
+        File.join(unpack_base, specification.full_name)
+      end
+
+      def unpacked_specification_filename
+        File.join(unpacked_gem_directory, '.specification')
+      end
+
   end
 end