integrations: Fix config_options type.

The “validator” component of the tuple does not follow the Validator
contract as of 7e9db327b3 (#15498).
Define a separate type for it.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

zerver/lib/integrations.py

@@ -1,6 +1,6 @@
 import os
 from dataclasses import dataclass, field
-from typing import Any, Dict, List, Optional, Sequence, Tuple
+from typing import Any, Callable, Dict, List, Optional, Sequence, Tuple
 
 from django.contrib.staticfiles.storage import staticfiles_storage
 from django.urls import path
@@ -10,7 +10,6 @@ from django.utils.module_loading import import_string
 from django.utils.translation import gettext as gettext_lazy
 
 from zerver.lib.storage import static_path
-from zerver.lib.types import Validator
 
 """This module declares all of the (documented) integrations available
 in the Zulip server.  The Integration class is used as part of
@@ -31,6 +30,8 @@ Over time, we expect this registry to grow additional convenience
 features for writing and configuring integrations efficiently.
 """
 
+OptionValidator = Callable[[str, str], Optional[str]]
+
 CATEGORIES: Dict[str, Promise] = {
     "meta-integration": gettext_lazy("Integration frameworks"),
     "continuous-integration": gettext_lazy("Continuous integration"),
@@ -66,7 +67,7 @@ class Integration:
         doc: Optional[str] = None,
         stream_name: Optional[str] = None,
         legacy: bool = False,
-        config_options: Sequence[Tuple[str, str, Validator[object]]] = [],
+        config_options: Sequence[Tuple[str, str, OptionValidator]] = [],
     ) -> None:
         self.name = name
         self.client_name = client_name
@@ -188,7 +189,7 @@ class WebhookIntegration(Integration):
         doc: Optional[str] = None,
         stream_name: Optional[str] = None,
         legacy: bool = False,
-        config_options: Sequence[Tuple[str, str, Validator[object]]] = [],
+        config_options: Sequence[Tuple[str, str, OptionValidator]] = [],
     ) -> None:
         if client_name is None:
             client_name = self.DEFAULT_CLIENT_NAME.format(name=name.title())

zerver/lib/users.py

@@ -101,7 +101,7 @@ def check_valid_bot_config(bot_type: int, service_name: str, config_data: Dict[s
         for key, validator in config_options.items():
             value = config_data[key]
             error = validator(key, value)
-            if error:
+            if error is not None:
                 raise JsonableError(_("Invalid {} value {} ({})").format(key, value, error))
 
     elif bot_type == UserProfile.EMBEDDED_BOT:

zerver/tests/test_bots.py

@@ -29,8 +29,8 @@ from zerver.models import (
 
 
 # A test validator
-def _check_string(var_name: str, val: object) -> Optional[str]:
-    if str(val).startswith("_"):
+def _check_string(var_name: str, val: str) -> Optional[str]:
+    if val.startswith("_"):
         return f'{var_name} starts with a "_" and is hence invalid.'
     return None