[StubSpecification] Avoid loading the full spec when possible

5 files changed, 92 insertions, 3 deletions

diff --git a/lib/bundler/lazy_specification.rb b/lib/bundler/lazy_specification.rb
index 231bffcae8..46f50844e1 100644
--- a/lib/bundler/lazy_specification.rb
+++ b/lib/bundler/lazy_specification.rb
@@ -79,6 +79,7 @@ module Bundler
             "To use the platform-specific version of the gem, run `bundle config specific_platform true` and install again."
           search = source.specs.search(self).last
         end
+        search.dependencies = dependencies if search.is_a?(RemoteSpecification)
         search
       end
     end
diff --git a/lib/bundler/remote_specification.rb b/lib/bundler/remote_specification.rb
index e5f9c78b00..c689af46c5 100644
--- a/lib/bundler/remote_specification.rb
+++ b/lib/bundler/remote_specification.rb
@@ -11,6 +11,7 @@ module Bundler
     include Comparable
 
     attr_reader :name, :version, :platform
+    attr_writer :dependencies
     attr_accessor :source, :remote
 
     def initialize(name, version, platform, spec_fetcher)
@@ -18,6 +19,7 @@ module Bundler
       @version      = Gem::Version.create version
       @platform     = platform
       @spec_fetcher = spec_fetcher
+      @dependencies = nil
     end
 
     # Needed before installs, since the arch matters then and quick
@@ -76,8 +78,16 @@ module Bundler
       "#<#{self.class} name=#{name} version=#{version} platform=#{platform}>"
     end
 
+    def dependencies
+      @dependencies || method_missing(:dependencies)
+    end
+
   private
 
+    def to_ary
+      nil
+    end
+
     def _remote_specification
       @_remote_specification ||= @spec_fetcher.fetch_spec([@name, @version, @platform])
       @_remote_specification || raise(GemspecError, "Gemspec data for #{full_name} was" \
diff --git a/lib/bundler/rubygems_integration.rb b/lib/bundler/rubygems_integration.rb
index 86912376c1..666d36a346 100644
--- a/lib/bundler/rubygems_integration.rb
+++ b/lib/bundler/rubygems_integration.rb
@@ -323,11 +323,12 @@ module Bundler
     def replace_gem(specs, specs_by_name)
       reverse_rubygems_kernel_mixin
 
-      executables = specs.map(&:executables).flatten
+      executables = nil
 
       kernel = (class << ::Kernel; self; end)
       [kernel, ::Kernel].each do |kernel_class|
         redefine_method(kernel_class, :gem) do |dep, *reqs|
+          executables ||= specs.map(&:executables).flatten
           if executables.include? File.basename(caller.first.split(":").first)
             break
           end
diff --git a/lib/bundler/stub_specification.rb b/lib/bundler/stub_specification.rb
index cbcadee269..9e43f06364 100644
--- a/lib/bundler/stub_specification.rb
+++ b/lib/bundler/stub_specification.rb
@@ -9,12 +9,14 @@ module Bundler
       spec
     end
 
-    attr_accessor :stub
+    attr_accessor :stub, :ignored
 
     def to_yaml
       _remote_specification.to_yaml
     end
 
+    # @!group Stub Delegates
+
     if Bundler.rubygems.provides?(">= 2.3")
       # This is defined directly to avoid having to load every installed spec
       def missing_extensions?
@@ -22,10 +24,62 @@ module Bundler
       end
     end
 
+    def activated
+      stub.activated
+    end
+
+    def activated=(activated)
+      stub.instance_variable_set(:@activated, activated)
+    end
+
+    def default_gem
+      stub.default_gem
+    end
+
+    def full_gem_path
+      stub.full_gem_path
+    end
+
+    def full_require_paths
+      stub.full_require_paths
+    end
+
+    def loaded_from
+      stub.loaded_from
+    end
+
+    def matches_for_glob
+      stub.matches_for_glob
+    end
+
+    def raw_require_paths
+      stub.raw_require_paths
+    end
+
+    # This is what we do in bundler/rubygems_ext
+    # full_require_paths is always implemented in versions that have stubs
+    def load_paths
+      full_require_paths
+    end
+
   private
 
     def _remote_specification
-      stub.to_spec
+      @_remote_specification ||= begin
+        rs = stub.to_spec
+        if rs.equal?(self) # happens when to_spec gets the spec from Gem.loaded_specs
+          rs = Gem::Specification.load(loaded_from)
+          stub.instance_variable_set(:@spec, rs)
+        end
+
+        unless rs
+          raise GemspecError, "The gemspec for #{full_name} at #{loaded_from}" \
+            " was missing or broken. Try running `gem pristine #{name} -v #{version}`" \
+            " to fix the cached spec."
+        end
+
+        rs
+      end
     end
   end
 end
diff --git a/spec/runtime/require_spec.rb b/spec/runtime/require_spec.rb
index 2d8935d2af..716080deb0 100644
--- a/spec/runtime/require_spec.rb
+++ b/spec/runtime/require_spec.rb
@@ -360,6 +360,29 @@ RSpec.describe "Bundler.require" do
       end
     end
   end
+
+  it "does not load rubygems gemspecs that are used", :rubygems => ">= 2.3" do
+    install_gemfile! <<-G
+      source "file://#{gem_repo1}"
+      gem "rack"
+    G
+
+    run! <<-R
+      path = File.join(Gem.dir, "specifications", "rack-1.0.0.gemspec")
+      contents = File.read(path)
+      contents = contents.lines.insert(-2, "\n  raise 'broken gemspec'\n").join
+      File.open(path, "w") do |f|
+        f.write contents
+      end
+    R
+
+    run! <<-R
+      Bundler.require
+      puts "WIN"
+    R
+
+    expect(out).to eq("WIN")
+  end
 end
 
 RSpec.describe "Bundler.require with platform specific dependencies" do