exceptions: Add ValidationFailureError.

zerver/lib/exceptions.py

@@ -1,6 +1,7 @@
 from enum import Enum
 from typing import Any, Dict, List, NoReturn, Optional, Tuple, Type, TypeVar
 
+from django.core.exceptions import ValidationError
 from django.utils.translation import gettext as _
 
 T = TypeVar("T", bound="AbstractEnum")
@@ -390,3 +391,14 @@ class AccessDeniedError(JsonableError):
 
 class ResourceNotFoundError(JsonableError):
     http_status_code = 404
+
+
+class ValidationFailureError(JsonableError):
+    # This class translations a Django ValidationError into a
+    # Zulip-style JsonableError, sending back just the first error for
+    # consistency of API.
+    data_fields = ["errors"]
+
+    def __init__(self, error: ValidationError) -> None:
+        super().__init__(error.messages[0])
+        self.errors = dict(error)

zerver/views/realm_linkifiers.py

@@ -4,9 +4,9 @@ from django.utils.translation import gettext as _
 
 from zerver.decorator import require_realm_admin
 from zerver.lib.actions import do_add_linkifier, do_remove_linkifier, do_update_linkifier
-from zerver.lib.exceptions import JsonableError
+from zerver.lib.exceptions import JsonableError, ValidationFailureError
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.models import RealmFilter, UserProfile, linkifiers_for_realm
 
 
@@ -32,7 +32,7 @@ def create_linkifier(
         )
         return json_success({"id": linkifier_id})
     except ValidationError as e:
-        return json_error(e.messages[0], data={"errors": dict(e)})
+        raise ValidationFailureError(e)
 
 
 @require_realm_admin
@@ -66,4 +66,4 @@ def update_linkifier(
     except RealmFilter.DoesNotExist:
         raise JsonableError(_("Linkifier not found."))
     except ValidationError as e:
-        return json_error(e.messages[0], data={"errors": dict(e)})
+        raise ValidationFailureError(e)

zerver/views/realm_playgrounds.py

@@ -6,8 +6,9 @@ from django.utils.translation import gettext as _
 
 from zerver.decorator import require_realm_admin
 from zerver.lib.actions import do_add_realm_playground, do_remove_realm_playground
+from zerver.lib.exceptions import ValidationFailureError
 from zerver.lib.request import REQ, JsonableError, has_request_variables
-from zerver.lib.response import json_error, json_success
+from zerver.lib.response import json_success
 from zerver.lib.validator import check_capped_string, check_url
 from zerver.models import Realm, RealmPlayground, UserProfile
 
@@ -50,7 +51,7 @@ def add_realm_playground(
             url_prefix=url_prefix.strip(),
         )
     except ValidationError as e:
-        return json_error(e.messages[0], data={"errors": dict(e)})
+        raise ValidationFailureError(e)
     return json_success({"id": playground_id})