## Issue
When an object that is an instance of a string-derived class is passed to a string field in a protobuf message in Ruby, it results in a `Google::Protobuf::TypeError`.
### Steps to reproduce
```rb
~/src/github.com/protocolbuffers/protobuf/ruby/tests ❯❯❯ irb -I .
irb(main):001:0> require 'basic_test_pb'
=> true
irb(main):002:0> myString = Class.new(String)
=> #<Class:0x00000001531540d8>
irb(main):003:0> str = myString.new("foo")
=> "foo"
irb(main):004:0> BasicTest::TestMessage.new(optional_string: "foo")
=> <BasicTest::TestMessage: optional_string: "foo", repeated_int32: [], repeated_int64: [], repeated_uint32: [], repeated_uint64: [], repeated_bool: [], repeated_float: [], repeated_double: [], repeated_string: [], repeated_bytes: [], repeated_msg: [], repeated_enum: []>
irb(main):005:0> BasicTest::TestMessage.new(optional_string: str)
(irb):5:in `initialize': Invalid argument for string field 'optional_string' (given #<Class:0x00000001531540d8>). (Google::Protobuf::TypeError)
irb(main):006:0>
```
## Fix
The issue appears to be caused by the field checking mechanism not properly handling instances of classes that inherit from basic types like String. My proposed solution is to improve the type checking for string fields to consider not just String instances but also instances of subclasses of String.
## Impact
The changes will allow instances of classes derived from String to be passed to string fields without any error.
This is a backwards-compatible change and will not affect the existing behaviour with standard String instances.
Closes#13818
COPYBARA_INTEGRATE_REVIEW=https://github.com/protocolbuffers/protobuf/pull/13818 from NotFounds:support-string-subclass-for-ruby 2d2796c4f9
PiperOrigin-RevId: 590941235
When attempting to run the Ruby tests, I noticed that the README is slightly off; it points to a target that doesn't exist:
```
charles@AlterCation:~/protobuf$ bazel test //ruby/tests/... //ruby:ffi=enabled --test_env=PROTOCOL_BUFFERS_RUBY_IMPLEMENTATION=FFI
ERROR: Skipping '//ruby:ffi=enabled': no such target '//ruby:ffi=enabled': target 'ffi=enabled' not declared in package 'ruby' defined by /home/charles/protobuf/ruby/BUILD.bazel (did you mean 'ffi_enabled'? Tip: use `query "//ruby:*"` to see all the targets in that package)
ERROR: no such target '//ruby:ffi=enabled': target 'ffi=enabled' not declared in package 'ruby' defined by /home/charles/protobuf/ruby/BUILD.bazel (did you mean 'ffi_enabled'? Tip: use `query "//ruby:*"` to see all the targets in that package)
INFO: Elapsed time: 0.679s
INFO: 0 processes.
ERROR: Build did NOT complete successfully
ERROR: Couldn't start the build. Unable to run tests
charles@AlterCation:~/protobuf$
```
Instead, it looks like `//ruby:ffi_enabled` is what you're supposed to use, which sets the flag on:
https://github.com/protocolbuffers/protobuf/blob/main/ruby/BUILD.bazel#L28-L30Closes#15041
COPYBARA_INTEGRATE_REVIEW=https://github.com/protocolbuffers/protobuf/pull/15041 from shaldengeki:ouguoc/fix-ruby-readme-ffi-enabled 245d84942d
PiperOrigin-RevId: 590501532
Users should migrate to corresponding feature accessors (e.g. FieldDescriptor.hasPresence, EnumDescriptor.isClosed) instead of deriving these based on syntax, which will break after under Editions (https://protobuf.dev/editions/overview/)
PiperOrigin-RevId: 586518687
There is no canonical rules_ruby repo today, and we don't want our fork to become one. In order to unblock inclusion of Protobuf in the bzlmod registry, we're making this a dev dependency and dropping support for Bazel/Ruby.
Fixes#14569
PiperOrigin-RevId: 584393841
Protobuf Team Bot
Protobuf Team Bot
Iori IKEDA
Charles OuGuo
Eric Salo
Sandy Zhang
Mike Kruskal
Jason Lunn