* Add ruby 2.6 gem build for linux

* Add docker hub organization

* Add ruby2.6 in cross compile targets

* Fix tests

* Check mac version

* No need to install php in preparation for mac

* Add ruby 2.6 test

* Fix broken tests

* Fix compatibility test

* Fix bundler version

* Use new docker image

* Fix broken test

* Use new docker image in ruby26 test

* Install ruby for mac

This adds the ability for the MRI Ruby library to optionally pass in a
ignore_unknown_fields option when decoding JSON. The functionality was
added upstream in upb, this change exposes that option.

Lower the severity of lower-case ruby enum to warning. Add conformance test for allow_alias with lower_case enums

* Fix most of the unused variable warnings in Ruby tests

* Add encoded_field_b back in tests/common_tests.rb

Given an argument, the previous implementation was off by one
(`.first(2)` would return 3 elements) compared to the `Enumerable#first`
method.

* Add ruby 2.3, 2.4 and 2.5 test for linux.

* Update kokoro files

* Add back commented gc test

* Fix gc_test failure

* Remove unused code

* Update ruby 2.5.0 to 2.5.1

* Update ruby 2.3 to 2.3.8

* Remove useless comment

* Replace assert_true/assert_false with assert, because they are not provided in newer version of test/unit

* Use rescue to handle exception subclass

* Commented out the require that caused gc_test failure.

* Commented out test

* Fix typo

This change only adds basic proto2 support without advanced features
like extensions, custom options, maps, etc.

The protoc binary now generates ruby code for proto2 syntax.
However, for now, it is restricted to proto2 files without advanced features
like extensions, in which case it still errors out.

This change also modifies the DSL to add proto messages to the DescriptorPool.
There is a new DSL Builder#add_file to create a new FileDescriptor. With this,
the generated ruby DSL looks something like:

Google::Protobuf::DescriptorPool.generated_pool.build do
  add_file "test.proto" do
    add_message "foo" do
      optional :val, :int32, 1
    end
  end
end

* Check the message to be encoded is the wrong type. (#4885)

* Change TypeError to ArgumentError

* Add continuous test for ruby 2.3, 2.4 and 2.5

* Change ruby 2.5 to 2.5.0

* No need to provide argument to rb_funcall when argc is 0

* Fix tests for ruby 2.5

* Use rescue instead of assert_raise to accept subclass of error

* Add continuous test for ruby 2.3, 2.4 and 2.5

* Change ruby 2.5 to 2.5.0

* No need to provide argument to rb_funcall when argc is 0

* Fix tests for ruby 2.5

* Use rescue instead of assert_raise to accept subclass of error

* This allows for ruby code to catch and handle Protobuf
    TypeErrors separately from the standard Ruby TypeError

  * Maintains backwards compatibility by having the new
    Google::Protobuf::TypeError inherit from the base
    TypeError. Any code that was catching TypeError should
    continue to work.

* Install rake compiler

* Add kokoro config to build ruby gem on linux

* Rename from linix to linux

* Fix prepare_build.sh name

* Clean up

* Install bundler

* Install bundler

* Use c99 in order to build gem on mingw-32 on ruby 2.0.0

See https://github.com/rake-compiler/rake-compiler-dock/issues/4

* Move c99 config to extcofig.rb

* Adopt ruby_package in ruby generated code.

* Add test for ruby_package

* Adopt ruby_package in ruby generated code.

* Add test for ruby_package

Make RepeatedField#delete_if consistent with Array#delete_if.

From:
https://github.com/rake-compiler/rake-compiler/issues/146#issuecomment-368539245

* Fix setup.py for windows build.

* Bump version number to 3.5.2

* Cat the test-suite.log on errors for presubits

This makes it behave the same way as the other implementations.
It is also nice to always encode an empty message as {}.

* Fix ruby gc_test in ruby 2.4

* Initialize global variables to Qnil.