Check length of fqdn not srv host

Author: aclark4life

pymongo/asynchronous/srv_resolver.py

@@ -96,6 +96,7 @@ def __init__(
         except Exception:
             raise ConfigurationError(_INVALID_HOST_MSG % (fqdn,)) from None
         self.__slen = len(self.__plist)
+        self.nparts = len(self.__fqdn.split("."))
 
     async def get_options(self) -> Optional[str]:
         from dns import resolver
@@ -138,7 +139,7 @@ async def _get_srv_response_and_hosts(
         # Validate hosts
         for node in nodes:
             srv_host = node[0].lower()
-            if self.__fqdn == srv_host and len(srv_host.split(".")) < 3:
+            if self.__fqdn == srv_host and self.nparts < 3:
                 raise ConfigurationError(
                     "Invalid SRV host: return address is identical to SRV hostname"
                 )

pymongo/synchronous/srv_resolver.py

@@ -96,6 +96,7 @@ def __init__(
         except Exception:
             raise ConfigurationError(_INVALID_HOST_MSG % (fqdn,)) from None
         self.__slen = len(self.__plist)
+        self.nparts = len(self.__fqdn.split("."))
 
     def get_options(self) -> Optional[str]:
         from dns import resolver
@@ -138,7 +139,7 @@ def _get_srv_response_and_hosts(
         # Validate hosts
         for node in nodes:
             srv_host = node[0].lower()
-            if self.__fqdn == srv_host and len(srv_host.split(".")) < 3:
+            if self.__fqdn == srv_host and self.nparts < 3:
                 raise ConfigurationError(
                     "Invalid SRV host: return address is identical to SRV hostname"
                 )