Ignore notifications sent from sourcekit-lsp when waiting for a request reply

If sourcekit-lsp sent a `publishDiagnostics` notification, we would try to interpret it as a request reply. This failed because the notification wasn’t actually the reply to the request we were expecting.

Ignore all notifications or requests from sourcekit-lsp when waiting for a request reply to fix this issue.

Author: ahoppen

test-sourcekit-lsp/test-sourcekit-lsp.py

@@ -44,21 +44,11 @@ def send_data(self, dict: Dict[str, object]):
         self.process.stdin.write(data)
         self.process.stdin.flush()
 
-    def send_request(self, method: str, params: Dict[str, object]) -> str:
+    def read_message_from_lsp_server(self) -> str:
         """
-        Send a request of the given method and parameters to the LSP server and wait for the response.
+        Read a single message sent from the LSP server to the client.
+        This can be a request reply, notification or request sent from the server to the client.
         """
-        self.request_id += 1
-
-        self.send_data(
-            {
-                "jsonrpc": "2.0",
-                "id": self.request_id,
-                "method": method,
-                "params": params,
-            }
-        )
-
         assert self.process.stdout
         # Read Content-Length: 123\r\n
         # Note: Even though the Content-Length header ends with \r\n, `readline` returns it with a single \n.
@@ -71,11 +61,44 @@ def send_request(self, method: str, params: Dict[str, object]) -> str:
         assert empty_line == "\n", f"Expected empty line, got '{empty_line}'"
 
         # Read the actual response
-        response = self.process.stdout.read(int(match.group(1)))
+        return self.process.stdout.read(int(match.group(1)))
+
+    def read_request_reply_from_lsp_server(self, request_id: int) -> str:
+        """
+        Read all messages sent from the LSP server until we see a request reply.
+        Assert that this request reply was for the given request_id and return it.
+        """
+        message = self.read_message_from_lsp_server()
+        message_obj = json.loads(message)
+        if "result" not in message_obj:
+            # We received a message that wasn't the request reply. 
+            # Log it, ignore it and wait for the next message.
+            print("Received message")
+            print(message)
+            return self.read_request_reply_from_lsp_server(request_id)
+        # We always wait for a request reply before sending the next request.
+        # If we received a request reply, it should thus have the request ID of the last request that we sent.
         assert (
-            f'"id":{self.request_id}' in response
-        ), f"Expected response for request {self.request_id}, got '{response}'"
-        return response
+            message_obj["id"] == self.request_id
+        ), f"Expected response for request {self.request_id}, got '{message}'"
+        return message
+
+    def send_request(self, method: str, params: Dict[str, object]) -> str:
+        """
+        Send a request of the given method and parameters to the LSP server and wait for the response.
+        """
+        self.request_id += 1
+
+        self.send_data(
+            {
+                "jsonrpc": "2.0",
+                "id": self.request_id,
+                "method": method,
+                "params": params,
+            }
+        )
+
+        return self.read_request_reply_from_lsp_server(self.request_id)
 
     def send_notification(self, method: str, params: Dict[str, object]):
         """