Fix handling of spurious wake-ups.

Author: ioquatix

lib/async/promise.rb

@@ -86,7 +86,9 @@ def wait
 
 				begin
 					# Wait for resolution if not already resolved:
-					@condition.wait(@mutex) unless @resolved
+					until @resolved
+						@condition.wait(@mutex)
+					end
 
 					# Return value or raise exception based on resolution type:
 					if @resolved == :completed

releases.md

@@ -1,5 +1,9 @@
 # Releases
 
+## Unreleased
+
+  - Fix incorrect handling of spurious wakeups in `Async::Promise#wait`, which could lead to premature (incorrect) resolution of the promise.
+
 ## v2.35.0
 
   - `Process.fork` is now properly handled by the Async fiber scheduler, ensuring that the scheduler state is correctly reset in the child process after a fork. This prevents issues where the child process inherits the scheduler state from the parent, which could lead to unexpected behavior.

test/async/promise.rb

@@ -91,7 +91,6 @@
 	end
 
 	with "#wait" do
-		
 		it "blocks until resolved" do
 			result = nil
 
@@ -703,3 +702,34 @@
 		end
 	end
 end
+
+describe Async::Promise do
+	include Sus::Fixtures::Async::ReactorContext
+	
+	let(:promise) {subject.new}
+	
+	describe "#wait" do
+		it "handles spurious wake-ups gracefully" do
+			promise = Async::Promise.new
+			result = nil
+			
+			thread = Thread.new do
+				result = promise.wait
+			rescue => error
+				# Pass.
+			end
+			
+			Thread.pass until thread.stop?
+			
+			10.times do
+				thread.wakeup # Trigger spurious wake-up.
+				Thread.pass
+			end
+			
+			promise.resolve(:success)
+			thread.join
+			
+			expect(result).to be == :success
+		end
+	end
+end