[rubygems/rubygems] Fix gem install sometimes compiling the wrong source files

If a previous copy of a gem is already installed, RubyGems will not
reinstall the gem but only recompile its extensions. This seems like a
good idea, but only if the gem is being installed from the registry.

If we are installing a locally built package, then the package should be
completely reinstalled and extensions compiled from the sources in the
locally built package, not from the sources in the previous
installation.

1c282d98d5

lib/rubygems/request_set.rb

@@ -181,14 +181,11 @@ class Gem::RequestSet
 
     # Install requested gems after they have been downloaded
     sorted_requests.each do |req|
-      if req.installed?
+      if req.installed? && @always_install.none? {|spec| spec == req.spec.spec }
         req.spec.spec.build_extensions
-
-        if @always_install.none? {|spec| spec == req.spec.spec }
         yield req, nil if block_given?
         next
       end
-      end
 
       spec =
         begin

test/rubygems/test_gem_dependency_installer.rb

@@ -519,6 +519,58 @@ class TestGemDependencyInstaller < Gem::TestCase
     assert_equal %w[a-1], inst.installed_gems.map(&:full_name)
   end
 
+  def test_install_local_with_extensions_already_installed
+    pend "needs investigation" if Gem.java_platform?
+    pend "ruby.h is not provided by ruby repo" if ruby_repo?
+
+    @spec = quick_gem "a" do |s|
+      s.extensions << "extconf.rb"
+      s.files += %w[extconf.rb a.c]
+    end
+
+    write_dummy_extconf "a"
+
+    c_source_path = File.join(@tempdir, "a.c")
+
+    write_file c_source_path do |io|
+      io.write <<-C
+        #include <ruby.h>
+        void Init_a() { }
+      C
+    end
+
+    package_path = Gem::Package.build @spec
+    installer = Gem::Installer.at(package_path)
+
+    # Make sure the gem is installed and backup the correct package
+
+    installer.install
+
+    package_bkp_path = "#{package_path}.bkp"
+    FileUtils.cp package_path, package_bkp_path
+
+    # Break the extension, rebuild it, and try to install it
+
+    write_file c_source_path do |io|
+      io.write "typo"
+    end
+
+    Gem::Package.build @spec
+
+    assert_raise Gem::Ext::BuildError do
+      installer.install
+    end
+
+    # Make sure installing the good package again still works
+
+    FileUtils.cp "#{package_path}.bkp", package_path
+
+    Dir.chdir @tempdir do
+      inst = Gem::DependencyInstaller.new domain: :local
+      inst.install package_path
+    end
+  end
+
   def test_install_minimal_deps
     util_setup_gems