Switch rspec local data to a thread accessor

Changelog.md

@@ -6,6 +6,11 @@ Enchancements
 * Improve diff for `anything` matchers by hiding the value "anything" is matched
   against. (Karl Heitmann, #599)
 
+Bug Fixes:
+
+* Switch current thread data to alias/accessors to avoid issues with mocked systems.
+  (Jon Rowe, #610)
+
 ### 3.13.1 / 2024-02-23
 [Full Changelog](http://github.com/rspec/rspec-support/compare/v3.13.0...v3.13.1)
 

lib/rspec/support.rb

@@ -1,5 +1,13 @@
 # frozen_string_literal: true
 
+class Thread
+  attr_accessor :__rspec_local_data
+
+  class << self
+    alias __rspec_current_thread current
+  end
+end
+
 module RSpec
   module Support
     # @api private
@@ -91,9 +99,9 @@ def self.class_of(object)
     end
 
     # A single thread local variable so we don't excessively pollute that namespace.
-    if RUBY_VERSION.to_f >= 2
+    if RUBY_VERSION.to_f !=  1.9
       def self.thread_local_data
-        Thread.current.thread_variable_get(:__rspec) || Thread.current.thread_variable_set(:__rspec, {})
+        Thread.__rspec_current_thread.__rspec_local_data ||= {}
       end
     else
       def self.thread_local_data

spec/rspec/support_spec.rb

@@ -196,14 +196,45 @@ def object.some_method
       end
 
       if defined?(Fiber) && RUBY_VERSION.to_f >= 2.0
-        it "shares data across fibres" do
+        broken_on_jruby =
+          if RSpec::Support::Ruby.jruby?
+            "As Fiber.new creates a new thread on JRuby this is currently " \
+            "broken. There are alternative implementations that do work but " \
+            "they cause issues for mocks, so given this is a minor edge case " \
+            "and thread data is already broken, its acceptable. Pending " \
+            "because future JRuby may fix this. see: "\
+            "https://github.com/jruby/jruby/issues/1806 and " \
+            "https://github.com/rspec/rspec-support/pull/610"
+          else
+            false
+          end
+
+        it "shares data across fibers", :pending => broken_on_jruby do
           RSpec::Support.thread_local_data[:__for_test] = :oh_hai
 
           Fiber.new do
             expect(RSpec::Support.thread_local_data[:__for_test]).to eq(:oh_hai)
           end.resume
         end
       end
+
+      it "works when Thread.current is mocked" do
+        expect(Thread).to_not receive(:current)
+
+        RSpec::Support.thread_local_data[:__for_test] = :oh_hai
+        expect(RSpec::Support.thread_local_data[:__for_test]).to eq :oh_hai
+      end
+
+      it "works when Thread#thread_variable_get and Thread#thread_variable_set are mocked" do
+        expect(Thread.current).to receive(:thread_variable_set).with(:test, true).once.and_return(true)
+        expect(Thread.current).to receive(:thread_variable_get).with(:test).once.and_return(true)
+
+        Thread.current.thread_variable_set(:test, true)
+        expect(Thread.current.thread_variable_get(:test)).to eq true
+
+        RSpec::Support.thread_local_data[:__for_test] = :oh_hai
+        expect(RSpec::Support.thread_local_data[:__for_test]).to eq :oh_hai
+      end
     end
 
     describe "failure notification" do