_shared

Author: l0lawrence

sdk/storage/azure-storage-queue/azure/storage/queue/_shared/response_handlers.py

@@ -96,8 +96,14 @@ def process_storage_error(storage_error) -> NoReturn:  # type: ignore [misc] # p
         )
     if not storage_error.response or storage_error.response.status_code in [200, 204]:
         raise storage_error
-    # If it is one of those three then it has been serialized prior by the generated layer.
-    if isinstance(
+        # The generated layer now pre-maps 412 (Precondition Failed) responses to typed
+    # exceptions based on the request's match condition (e.g. ResourceExistsError for
+    # IfMissing, ResourceNotFoundError for IfPresent). Historically 412 was not
+    # pre-mapped and always flowed through the error-code mapping below, surfacing as
+    # ResourceModifiedError. Skip the "already serialized" shortcut for 412 so it is
+    # re-mapped from x-ms-error-code (ConditionNotMet -> ResourceModifiedError) and the
+    # public exception type is preserved for users.
+    if storage_error.response.status_code != 412 and isinstance(
         storage_error,
         (
             PartialBatchErrorException,