fix: Skip filepath checksum on insert when file exceeds size limit

When `filepath_checksum_size_limit` is set, skip checksum computation
for files larger than the limit during upload/insert. This prevents
transaction timeouts when inserting large files with filepath attributes.

The same config option was already used for download checksum skipping.
Now it applies to uploads as well.

When checksum is skipped:
- A warning is logged
- contents_hash is stored as NULL
- Existing file verification is bypassed

Fixes #1386

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: dimitri-yatsenko

datajoint/external.py

@@ -276,13 +276,25 @@ def upload_filepath(self, local_filepath):
         uuid = uuid_from_buffer(
             init_string=relative_filepath
         )  # hash relative path, not contents
-        contents_hash = uuid_from_file(local_filepath)
+
+        # Check if checksum should be skipped based on file size limit
+        file_size = Path(local_filepath).stat().st_size
+        size_limit = config.get("filepath_checksum_size_limit")
+        skip_checksum = size_limit is not None and file_size > size_limit
+
+        if skip_checksum:
+            contents_hash = None
+            logger.warning(
+                f"Skipping checksum for '{relative_filepath}' ({file_size} bytes > {size_limit} byte limit)"
+            )
+        else:
+            contents_hash = uuid_from_file(local_filepath)
 
         # check if the remote file already exists and verify that it matches
         check_hash = (self & {"hash": uuid}).fetch("contents_hash")
         if check_hash.size:
             # the tracking entry exists, check that it's the same file as before
-            if contents_hash != check_hash[0]:
+            if not skip_checksum and contents_hash != check_hash[0]:
                 raise DataJointError(
                     f"A different version of '{relative_filepath}' has already been placed."
                 )
@@ -291,15 +303,15 @@ def upload_filepath(self, local_filepath):
             self._upload_file(
                 local_filepath,
                 self._make_external_filepath(relative_filepath),
-                metadata={"contents_hash": str(contents_hash)},
+                metadata={"contents_hash": str(contents_hash) if contents_hash else ""},
             )
             self.connection.query(
                 "INSERT INTO {tab} (hash, size, filepath, contents_hash) VALUES (%s, {size}, '{filepath}', %s)".format(
                     tab=self.full_table_name,
-                    size=Path(local_filepath).stat().st_size,
+                    size=file_size,
                     filepath=relative_filepath,
                 ),
-                args=(uuid.bytes, contents_hash.bytes),
+                args=(uuid.bytes, contents_hash.bytes if contents_hash else None),
             )
         return uuid