Make RSpec::Support.thread_local_data thread but not fiber local

Author: JonRowe

lib/rspec/support.rb

@@ -90,7 +90,7 @@ def self.class_of(object)
 
     # A single thread local variable so we don't excessively pollute that namespace.
     def self.thread_local_data
-      Thread.current[:__rspec] ||= {}
+      Thread.current.thread_variable_get(:__rspec) || Thread.current.thread_variable_set(:__rspec, {})
     end
 
     # @api private

spec/rspec/support_spec.rb

@@ -186,6 +186,26 @@ def object.some_method
       end
     end
 
+    describe ".thread_local_data" do
+      it "contains data local to the current thread" do
+        RSpec::Support.thread_local_data[:__for_test] = :oh_hai
+
+        Thread.new do
+          expect(RSpec::Support.thread_local_data).to eq({})
+        end.join
+      end
+
+      if defined?(Fiber)
+        it "shares data across fibres" 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
+    end
+
     describe "failure notification" do
       before { @failure_notifier = RSpec::Support.failure_notifier }
       after  { RSpec::Support.failure_notifier = @failure_notifier }