SNOW-2324060 don't attempt non working bucket accelerate endpoint for internal stages (#2556)

Author: sfc-gh-dszmolka

DESCRIPTION.md

@@ -26,6 +26,7 @@ Source code is also available at: https://github.com/snowflakedb/snowflake-conne
     - As part of this fix, `DictCursor` is no longer a subclass of `SnowflakeCursor`; use `SnowflakeCursorBase` as a superclass of both.
   - Fix "No AWS region was found" error if AWS region was set in `AWS_DEFAULT_REGION` variable instead of `AWS_REGION` for `WORKLOAD_IDENTITY` authenticator
   - Add `ocsp_root_certs_dict_lock_timeout` connection parameter to set the timeout (in seconds) for acquiring the lock on the OCSP root certs dictionary. Default value for this parameter is -1 which indicates no timeout.
+  - Fixed behaviour of trying S3 Transfer Accelerate endpoint by default for internal stages, and always getting HTTP403 due to permissions missing on purpose. Now /accelerate is not attempted.
 
 - v3.17.4(September 22,2025)
   - Added support for intermediate certificates as roots when they are stored in the trust store

src/snowflake/connector/s3_storage_client.py

@@ -120,9 +120,17 @@ def transfer_accelerate_config(
             return False
         else:
             if use_accelerate_endpoint is None:
-                use_accelerate_endpoint = self._get_bucket_accelerate_config(
-                    self.s3location.bucket_name
-                )
+                if str(self.s3location.bucket_name).lower().startswith("sfc-"):
+                    # SNOW-2324060: no s3:GetAccelerateConfiguration and no intention to add either
+                    # for internal stage, thus previously the client got HTTP403 on /accelerate call
+                    logger.debug(
+                        "Not attempting to get bucket transfer accelerate endpoint for internal stage."
+                    )
+                    use_accelerate_endpoint = False
+                else:
+                    use_accelerate_endpoint = self._get_bucket_accelerate_config(
+                        self.s3location.bucket_name
+                    )
 
             if use_accelerate_endpoint:
                 self.endpoint = (
@@ -132,6 +140,7 @@ def transfer_accelerate_config(
                 self.endpoint = (
                     f"https://{self.s3location.bucket_name}.s3.amazonaws.com"
                 )
+            logger.debug(f"Using {self.endpoint} as storage endpoint.")
             return use_accelerate_endpoint
 
     @staticmethod