Fix Ruby version support + more tests.

Author: ioquatix

.github/workflows/test.yaml

@@ -23,6 +23,7 @@ jobs:
 
         ruby:
           - "3.2"
+          - "3.2.6"
           - "3.3"
           - "3.4"
           - "head"

lib/io/event/selector/select.rb

@@ -199,7 +199,7 @@ def io_read(fiber, io, buffer, length, offset = 0)
 							result = Fiber.blocking{buffer.read(io, 0, offset)}
 
 							if result < 0
-								if again?(result)
+								if length > 0 and again?(result)
 									self.io_wait(fiber, io, IO::READABLE)
 								else
 									return result
@@ -229,7 +229,7 @@ def io_write(fiber, io, buffer, length, offset = 0)
 							result = Fiber.blocking{buffer.write(io, 0, offset)}
 
 							if result < 0
-								if again?(result)
+								if length > 0 and again?(result)
 									self.io_wait(fiber, io, IO::READABLE)
 								else
 									return result

lib/io/event/support.rb

@@ -18,22 +18,24 @@ def self.buffer?
 			#
 			# To be removed on 31 Mar 2026.
 			def self.fiber_scheduler_v2?
-				# Some interface changes were back-ported incorrectly:
-				# https://github.com/ruby/ruby/pull/10778
-				# Specifically "Improvements to IO::Buffer read/write/pread/pwrite."
-				# Missing correct size calculation.
-				return false if RUBY_VERSION >= "3.2.5"
-				
-				IO.const_defined?(:Buffer) and Fiber.respond_to?(:blocking) and IO::Buffer.instance_method(:read).arity == -1
+				if RUBY_VERSION >= "3.2"
+					return true if RUBY_VERSION >= "3.2.6"
+					
+					# Some interface changes were back-ported incorrectly and released in 3.2.5 <https://github.com/ruby/ruby/pull/10778> - Specifically "Improvements to IO::Buffer read/write/pread/pwrite." is missing correct size calculation.
+					return false if RUBY_VERSION >= "3.2.5"
+					
+					# Feature detection:
+					IO.const_defined?(:Buffer) and Fiber.respond_to?(:blocking) and IO::Buffer.instance_method(:read).arity == -1
+				end
 			end
 
 			# Updated inferfaces for read/write and IO::Buffer were introduced in Ruby 3.3, including pread/pwrite.
 			#
 			# To become the default 31 Mar 2026.
 			def self.fiber_scheduler_v3?
+				return true if RUBY_VERSION >= "3.3"
+				
 				if fiber_scheduler_v2?
-					return true if RUBY_VERSION >= "3.3"
-					
 					# Feature detection if required:
 					begin
 						IO::Buffer.new.slice(0, 0).write(STDOUT)