[rubygems/rubygems] Warn dangling symlinks

https://github.com/rubygems/rubygems/commit/425b78637f

lib/rubygems/installer.rb

@@ -490,15 +490,7 @@ class Gem::Installer
     spec.executables.each do |filename|
       filename.tap(&Gem::UNTAINT)
       bin_path = File.join gem_dir, spec.bindir, filename
-
-      unless File.exist? bin_path
-        if File.symlink? bin_path
-          alert_warning "`#{bin_path}` is dangling symlink pointing to `#{File.readlink bin_path}`"
-        else
-          alert_warning "`#{bin_path}` does not exist, maybe `gem pristine #{spec.name}` will fix it?"
-        end
-        next
-      end
+      next unless File.exist? bin_path
 
       mode = File.stat(bin_path).mode
       dir_mode = options[:prog_mode] || (mode | 0111)

lib/rubygems/package.rb

@@ -409,6 +409,8 @@ EOM
 
   def extract_tar_gz(io, destination_dir, pattern = "*") # :nodoc:
     directories = []
+    symlinks = []
+
     open_tar_gz io do |tar|
       tar.each do |entry|
         full_name = entry.full_name
@@ -422,6 +424,8 @@ EOM
 
           raise Gem::Package::SymlinkError.new(full_name, real_destination, destination_dir) unless
             normalize_path(real_destination).start_with? normalize_path(destination_dir + "/")
+
+          symlinks << [full_name, link_target, destination, real_destination]
         end
 
         FileUtils.rm_rf destination
@@ -445,12 +449,18 @@ EOM
           FileUtils.chmod file_mode(entry.header.mode), destination
         end if entry.file?
 
-        File.symlink(entry.header.linkname, destination) if entry.symlink?
-
         verbose destination
       end
     end
 
+    symlinks.each do |name, target, destination, real_destination|
+      if File.exist?(real_destination)
+        File.symlink(target, destination)
+      else
+        alert_warning "#{@spec.full_name} ships with a dangling symlink named #{name} pointing to missing #{target} file. Ignoring"
+      end
+    end
+
     if dir_mode
       File.chmod(dir_mode, *directories)
     end

test/rubygems/test_gem_installer.rb

@@ -756,7 +756,10 @@ gem 'other', version
       end
     end
 
-    assert_match %r{bin/ascii_binder` is dangling symlink pointing to `bin/asciibinder`}, @ui.error
+    errors = @ui.error.split("\n")
+    assert_equal "WARNING:  ascii_binder-0.1.10.1 ships with a dangling symlink named bin/ascii_binder pointing to missing bin/asciibinder file. Ignoring", errors.shift
+    assert_empty errors
+
     assert_empty @ui.output
   end
 

test/rubygems/test_gem_package.rb

@@ -529,6 +529,7 @@ class TestGemPackage < Gem::Package::TarTestCase
 
   def test_extract_tar_gz_symlink_relative_path
     package = Gem::Package.new @gem
+    package.verify
 
     tgz_io = util_tar_gz do |tar|
       tar.add_file "relative.rb", 0644 do |io|
@@ -557,6 +558,27 @@ class TestGemPackage < Gem::Package::TarTestCase
                  File.read(extracted)
   end
 
+  def test_extract_tar_gz_symlink_broken_relative_path
+    package = Gem::Package.new @gem
+    package.verify
+
+    tgz_io = util_tar_gz do |tar|
+      tar.mkdir       "lib", 0755
+      tar.add_symlink "lib/foo.rb", "../broken.rb", 0644
+    end
+
+    ui = Gem::MockGemUi.new
+
+    use_ui ui do
+      package.extract_tar_gz tgz_io, @destination
+    end
+
+    assert_equal "WARNING:  a-2 ships with a dangling symlink named lib/foo.rb pointing to missing ../broken.rb file. Ignoring\n", ui.error
+
+    extracted = File.join @destination, "lib/foo.rb"
+    assert_path_not_exist extracted
+  end
+
   def test_extract_symlink_parent
     package = Gem::Package.new @gem