Fix a number of errors in the config.gem mechanism.

* Rails::GemDependency was missing definitions for hash and eql?, causing Array#uniq to not work.

* If several versions of a gem are unpacked in vendor, now chooses the highest if no version is specified.

* streamlined add_load_path. Now sets up Rubygems correctly to allow 'gem' to find frozen gems, with
  gems frozen to vendor/gems and specifications in vendor/gems/<gem-name>/.specification

* Rails::GemDependency#specification would return a spec for the highest installed version, even for
  frozen gems and/or previously loaded lower versions. See in part ticket #1123.

* removed vendor from default_load_paths - it was causing autoloading to append Gems::Gems::<gem-dir> to
  constant names

* added additional tests for loading frozen gems.

* incorporates the fix from #1107 for vendor rails

* defers to freeze:gems for handling the Rails framework. gems:unpack WILL NOT place a copy of Rails
  in vendor/gems. Should close #1123 completely.

* incorporates, via using the gem loader for frozen gems, fixes corresponding to #227, #324, #362, #527, and #742.

* gem plugins now work the same whether frozen or not. Correctness of the behavior is a matter for another ticket...

Signed-off-by: rick <technoweenie@gmail.com>

1 files changed, 111 insertions, 31 deletions

diff --git a/railties/lib/rails/gem_dependency.rb b/railties/lib/rails/gem_dependency.rb
index d58ae450eb..3b2f4846a6 100644
--- a/railties/lib/rails/gem_dependency.rb
+++ b/railties/lib/rails/gem_dependency.rb
@@ -1,50 +1,76 @@
+require 'rails/vendor_gem_source_index'
+
+module Gem
+  def self.source_index=(index)
+    @@source_index = index
+  end
+end
+
 module Rails
   class GemDependency
-    attr_accessor :name, :requirement, :version, :lib, :source
+    attr_accessor :lib, :source
 
     def self.unpacked_path
       @unpacked_path ||= File.join(RAILS_ROOT, 'vendor', 'gems')
     end
 
+    @@framework_gems = {}
+
+    def self.add_frozen_gem_path
+      @@paths_loaded ||= begin
+        Gem.source_index = Rails::VendorGemSourceIndex.new(Gem.source_index)
+        # loaded before us - we can't change them, so mark them
+        Gem.loaded_specs.each do |name, spec|
+          @@framework_gems[name] = spec
+        end
+      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)
 
       if options[:requirement]
-        @requirement = options[:requirement]
+        req = options[:requirement]
       elsif options[:version]
-        @requirement = Gem::Requirement.create(options[:version])
+        req = Gem::Requirement.create(options[:version])
+      else
+        req = Gem::Requirement.default
       end
 
-      @version  = @requirement.instance_variable_get("@requirements").first.last if @requirement
-      @name     = name.to_s
+      @dep = Gem::Dependency.new(name, req)
       @lib      = options[:lib]
       @source   = options[:source]
       @loaded   = @frozen = @load_paths_added = false
-      @unpack_directory = nil
-    end
-
-    def unpacked_paths
-      Dir[File.join(self.class.unpacked_path, "#{@name}-#{@version || "*"}")]
     end
 
     def add_load_paths
+      self.class.add_frozen_gem_path
       return if @loaded || @load_paths_added
-      unpacked_paths = self.unpacked_paths
-      if unpacked_paths.empty?
-        args = [@name]
-        args << @requirement.to_s if @requirement
-        gem *args
-      else
-        $LOAD_PATH.unshift File.join(unpacked_paths.first, 'lib')
-        ext = File.join(unpacked_paths.first, 'ext')
-        $LOAD_PATH.unshift(ext) if File.exist?(ext)
-        @frozen = true
+      if framework_gem?
+        @load_paths_added = @loaded = @frozen = true
+        return
       end
+      gem @dep
+      @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
+      return [] if framework_gem?
       all_dependencies = specification.dependencies.map do |dependency|
         GemDependency.new(dependency.name, :requirement => dependency.version_requirements)
       end
@@ -58,22 +84,51 @@ module Rails
 
     def load
       return if @loaded || @load_paths_added == false
-      require(@lib || @name) unless @lib == false
+      require(@lib || name) unless @lib == false
       @loaded = true
     rescue LoadError
       puts $!.to_s
       $!.backtrace.each { |b| puts b }
     end
 
+    def name
+      @dep.name.to_s
+    end
+
+    def requirement
+      r = @dep.version_requirements
+      (r == Gem::Requirement.default) ? nil : r
+    end
+
     def frozen?
-      @frozen
+      @frozen ||= vendor_rails? || vendor_gem?
     end
 
     def loaded?
-      @loaded
+      @loaded ||= begin
+        if vendor_rails?
+          true
+        else
+          # check if the gem is loaded by inspecting $"
+          # specification.files lists all the files contained in the gem
+          gem_files = specification.files
+          # select only the files contained in require_paths - typically in bin and lib
+          require_paths_regexp = Regexp.new("^(#{specification.require_paths*'|'})/")
+          gem_lib_files = gem_files.select { |f| require_paths_regexp.match(f) }
+          # chop the leading directory off - a typical file might be in
+          # lib/gem_name/file_name.rb, but it will be 'require'd as gem_name/file_name.rb
+          gem_lib_files.map! { |f| f.split('/', 2)[1] }
+          # if any of the files from the above list appear in $", the gem is assumed to
+          # have been loaded
+          !(gem_lib_files & $").empty?
+        end
+      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
     end
 
@@ -93,17 +148,44 @@ module Rails
       # we can access information about the gem on deployment systems
       # without having the gem installed
       spec_filename = File.join(gem_dir(directory), '.specification')
+      # Gem.activate changes the spec - get the original
+      spec = Gem::Specification.load(specification.loaded_from)
       File.open(spec_filename, 'w') do |file|
-        file.puts specification.to_yaml
+        file.puts spec.to_yaml
       end
     end
 
     def ==(other)
       self.name == other.name && self.requirement == other.requirement
     end
+    alias_method :"eql?", :"=="
+
+    def hash
+      @dep.hash
+    end
 
     def specification
-      @spec ||= Gem.source_index.search(Gem::Dependency.new(@name, @requirement)).sort_by { |s| s.version }.last
+      # 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
     end
 
     private
@@ -112,17 +194,15 @@ module Rails
       end
 
       def install_command
-        cmd = %w(install) << @name
-        cmd << "--version" << %("#{@requirement.to_s}") if @requirement
+        cmd = %w(install) << name
+        cmd << "--version" << %("#{requirement.to_s}") if requirement
         cmd << "--source"  << @source  if @source
         cmd
       end
 
       def unpack_command
-        cmd = %w(unpack) << @name
-        # We don't quote this requirement as it's run through GemRunner instead
-        # of shelling out to gem
-        cmd << "--version" << @requirement.to_s if @requirement
+        cmd = %w(unpack) << name
+        cmd << "--version" << "= "+specification.version.to_s if requirement
         cmd
       end
   end