Fixes a bug

Author: fabianfett

Sources/AsyncHTTPClient/ConnectionPool/HTTPRequestStateMachine+Demand.swift

@@ -61,13 +61,18 @@ extension HTTPRequestStateMachine{
 }
 }
 
-mutatingfunc channelReadComplete()->CircularBuffer<ByteBuffer>{
+mutatingfunc channelReadComplete()->CircularBuffer<ByteBuffer>?{
 switchself.state {
 case.waitingForBytes(let buffer):
-varnewBuffer= buffer
- newBuffer.removeAll(keepingCapacity:true)
-self.state =.waitingForReadOrDemand(newBuffer)
-return buffer
+if buffer.isEmpty {
+self.state =.waitingForRead(buffer)
+returnnil
+}else{
+varnewBuffer= buffer
+ newBuffer.removeAll(keepingCapacity:true)
+self.state =.waitingForReadOrDemand(newBuffer)
+return buffer
+}
 
 case.waitingForRead,
 .waitingForDemand,

Sources/AsyncHTTPClient/ConnectionPool/HTTPRequestStateMachine.swift

@@ -426,7 +426,11 @@ struct HTTPRequestStateMachine{
 returnself.avoidingStateMachineCoW{(state)->Actionin
 letbuffer= streamState.channelReadComplete()
  state =.running(requestState,.receivingBody(head, streamState))
-return.forwardResponseBodyParts(buffer)
+iflet buffer = buffer {
+return.forwardResponseBodyParts(buffer)
+}else{
+return.wait
+}
 }
 
 case.modifying:

Tests/AsyncHTTPClientTests/HTTPRequestStateMachineTests+XCTest.swift

@@ -38,6 +38,7 @@ extension HTTPRequestStateMachineTests{
 ("testRequestIsNotSendUntilChannelIsWritable", testRequestIsNotSendUntilChannelIsWritable),
 ("testConnectionBecomesInactiveWhileWaitingForWritable", testConnectionBecomesInactiveWhileWaitingForWritable),
 ("testResponseReadingWithBackpressure", testResponseReadingWithBackpressure),
+("testChannelReadCompleteTriggersButNoBodyDataWasReceivedSoFar", testChannelReadCompleteTriggersButNoBodyDataWasReceivedSoFar),
 ("testResponseReadingWithBackpressureEndOfResponseAllowsReadEventsToTriggerDirectly", testResponseReadingWithBackpressureEndOfResponseAllowsReadEventsToTriggerDirectly),
 ("testCancellingARequestInStateInitializedKeepsTheConnectionAlive", testCancellingARequestInStateInitializedKeepsTheConnectionAlive),
 ("testCancellingARequestBeforeBeingSendKeepsTheConnectionAlive", testCancellingARequestBeforeBeingSendKeepsTheConnectionAlive),

Tests/AsyncHTTPClientTests/HTTPRequestStateMachineTests.swift

@@ -279,6 +279,33 @@ class HTTPRequestStateMachineTests: XCTestCase{
 XCTAssertEqual(state.demandMoreResponseBodyParts(),.wait)
 }
 
+func testChannelReadCompleteTriggersButNoBodyDataWasReceivedSoFar(){
+varstate=HTTPRequestStateMachine(isChannelWritable:true)
+letrequestHead=HTTPRequestHead(version:.http1_1, method:.GET, uri:"/")
+letmetadata=RequestFramingMetadata(connectionClose:false, body:.none)
+XCTAssertEqual(state.startRequest(head: requestHead, metadata: metadata),.sendRequestHead(requestHead, startBody:false))
+
+letresponseHead=HTTPResponseHead(version:.http1_1, status:.ok, headers:HTTPHeaders([("content-length","12")]))
+XCTAssertEqual(state.channelRead(.head(responseHead)),.forwardResponseHead(responseHead, pauseRequestBodyStream:false))
+letpart0=ByteBuffer(bytes:0...3)
+letpart1=ByteBuffer(bytes:4...7)
+letpart2=ByteBuffer(bytes:8...11)
+XCTAssertEqual(state.channelReadComplete(),.wait)
+XCTAssertEqual(state.read(),.read)
+XCTAssertEqual(state.channelRead(.body(part0)),.wait)
+XCTAssertEqual(state.channelRead(.body(part1)),.wait)
+XCTAssertEqual(state.channelReadComplete(),.forwardResponseBodyParts(.init([part0, part1])))
+XCTAssertEqual(state.read(),.wait)
+XCTAssertEqual(state.demandMoreResponseBodyParts(),.read)
+XCTAssertEqual(state.channelReadComplete(),.wait)
+XCTAssertEqual(state.read(),.read)
+XCTAssertEqual(state.channelRead(.body(part2)),.wait)
+XCTAssertEqual(state.channelRead(.end(nil)),.succeedRequest(.none,.init([part2])))
+XCTAssertEqual(state.channelReadComplete(),.wait)
+XCTAssertEqual(state.read(),.read)
+XCTAssertEqual(state.demandMoreResponseBodyParts(),.wait)
+}
+
 func testResponseReadingWithBackpressureEndOfResponseAllowsReadEventsToTriggerDirectly(){
 varstate=HTTPRequestStateMachine(isChannelWritable:true)
 letrequestHead=HTTPRequestHead(version:.http1_1, method:.GET, uri:"/")