Remove WIF autodetect and all its problems (error messages, issuer checks, explicit timeouts), support explicit client_id for Azure VMs (#2457)

Author: sfc-gh-pmansour

src/snowflake/connector/connection.py

@@ -1326,13 +1326,21 @@ def __open_connection(self):
                 )
             elif self._authenticator == WORKLOAD_IDENTITY_AUTHENTICATOR:
                 self._check_experimental_authentication_flag()
-                # Standardize the provider enum.
-                if self._workload_identity_provider and isinstance(
-                    self._workload_identity_provider, str
-                ):
+
+                if isinstance(self._workload_identity_provider, str):
                     self._workload_identity_provider = AttestationProvider.from_string(
                         self._workload_identity_provider
                     )
+                if not self._workload_identity_provider:
+                    Error.errorhandler_wrapper(
+                        self,
+                        None,
+                        ProgrammingError,
+                        {
+                            "msg": f"workload_identity_provider must be set to one of {','.join(AttestationProvider.all_string_values())} when authenticator is WORKLOAD_IDENTITY.",
+                            "errno": ER_INVALID_WIF_SETTINGS,
+                        },
+                    )
                 self.auth_class = AuthByWorkloadIdentity(
                     provider=self._workload_identity_provider,
                     token=self._token,
@@ -1487,7 +1495,10 @@ def __config(self, **kwargs):
                     self,
                     None,
                     ProgrammingError,
-                    {"msg": "User is empty", "errno": ER_NO_USER},
+                    {
+                        "msg": f"User is empty, but it must be provided unless authenticator is one of {', '.join(empty_user_allowed_authenticators)}.",
+                        "errno": ER_NO_USER,
+                    },
                 )
 
             if self._private_key or self._private_key_file: