Introduce Async::Promise.fulfill.

Author: ioquatix

lib/async/promise.rb

@@ -184,5 +184,19 @@ def fulfill(&block)
 				self.resolve(nil) unless @resolved
 			end
 		end
+		
+		# If a promise is given, fulfill it with the result of the block.
+		# If no promise is given, simply yield to the block.
+		# This is useful for methods that may optionally take a promise to fulfill.
+		# @parameter promise [Promise | Nil] The optional promise to fulfill.
+		# @yields {...} The block to call to resolve the promise or return a value.
+		# @returns [Object] The result of the block.
+		def self.fulfill(promise, &block)
+			if promise
+				return promise.fulfill(&block)
+			else
+				return yield
+			end
+		end
 	end
 end

releases.md

@@ -1,5 +1,9 @@
 # Releases
 
+## Unreleased
+
+  - Introduce `Async::Promise.fulfill` for optional promise resolution.
+
 ## v2.32.1
 
   - Fix typo in documentation.

test/async/promise.rb

@@ -648,4 +648,58 @@
 			expect(promise.wait).to be == :first
 		end
 	end
+	
+	with ".fulfill" do
+		it "fulfills the promise when given" do
+			promise = Async::Promise.new
+			
+			result = Async::Promise.fulfill(promise) do
+				:block_result
+			end
+			
+			expect(result).to be == :block_result
+			expect(promise.resolved?).to be == true
+			expect(promise.wait).to be == :block_result
+		end
+		
+		it "simply yields when no promise is given" do
+			result = Async::Promise.fulfill(nil) do
+				:direct_result
+			end
+			
+			expect(result).to be == :direct_result
+		end
+		
+		it "handles exceptions when promise is given" do
+			promise = Async::Promise.new
+			test_error = StandardError.new("test error")
+			
+			result = Async::Promise.fulfill(promise) do
+				raise test_error
+			end
+			
+			expect(result).to be_nil
+			expect(promise.failed?).to be == true
+			expect(promise.value).to be == test_error
+		end
+		
+		it "propagates exceptions when no promise is given" do
+			test_error = StandardError.new("test error")
+			
+			expect do
+				Async::Promise.fulfill(nil) do
+					raise test_error
+				end
+			end.to raise_exception(StandardError, message: be =~ /test error/)
+		end
+		
+		it "works with falsy promise values" do
+			# Test that it properly checks for nil/false, not just truthiness
+			result = Async::Promise.fulfill(false) do
+				:should_yield_directly
+			end
+			
+			expect(result).to be == :should_yield_directly
+		end
+	end
 end