ExchangeCtx: Fix issue with response timer cancellation (#26215)

* ExchangeCtx: Fix issue with response timer cancellation

* Add a boolean to record whether the message starts the reponse timer

src/messaging/ExchangeContext.cpp

@@ -156,6 +156,7 @@ CHIP_ERROR ExchangeContext::SendMessage(Protocols::Id protocolId, uint8_t msgTyp
  bool reliableTransmissionRequested =
  GetSessionHandle()->RequireMRP() && !sendFlags.Has(SendMessageFlags::kNoAutoRequestAck) && !IsGroupExchangeContext();
 
+ bool startedResponseTimer = false;
  // If a response message is expected...
  if (sendFlags.Has(SendMessageFlags::kExpectResponse) && !IsGroupExchangeContext())
  {
@@ -177,6 +178,7 @@ CHIP_ERROR ExchangeContext::SendMessage(Protocols::Id protocolId, uint8_t msgTyp
  SetResponseExpected(false);
  return err;
  }
+ startedResponseTimer = true;
  }
  }
 
@@ -217,8 +219,8 @@ CHIP_ERROR ExchangeContext::SendMessage(Protocols::Id protocolId, uint8_t msgTyp
 #if CONFIG_BUILD_FOR_HOST_UNIT_TEST
  }
 #endif
-
- if (err != CHIP_NO_ERROR && IsResponseExpected())
+ // We should only cancel the response timer if the ExchangeContext fails to send the message that starts the response timer.
+ if (err != CHIP_NO_ERROR && startedResponseTimer)
  {
  CancelResponseTimer();
  SetResponseExpected(false);
@@ -267,8 +269,11 @@ void ExchangeContext::DoClose(bool clearRetransTable)
  mExchangeMgr->GetReliableMessageMgr()->ClearRetransTable(this);
  }
 
- // Cancel the response timer.
- CancelResponseTimer();
+ if (IsResponseExpected())
+ {
+ // Cancel the response timer.
+ CancelResponseTimer();
+ }
 }
 
 /**
@@ -590,12 +595,15 @@ CHIP_ERROR ExchangeContext::HandleMessage(uint32_t messageCounter, const Payload
  return CHIP_ERROR_INCORRECT_STATE;
  }
 
- // Since we got the response, cancel the response timer.
- CancelResponseTimer();
+ if (IsResponseExpected())
+ {
+ // Since we got the response, cancel the response timer.
+ CancelResponseTimer();
 
- // If the context was expecting a response to a previously sent message, this message
- // is implicitly that response.
- SetResponseExpected(false);
+ // If the context was expecting a response to a previously sent message, this message
+ // is implicitly that response.
+ SetResponseExpected(false);
+ }
 
  // Don't send messages on to our delegate if our dispatch does not allow
  // those messages.