len(src) can only be a multiple of typesize (8).

[timbmg]

Hi, I am getting an odd error related to blosc2. Even sime example as the one below results in len(src) can only be a multiple of typesize (8).

from pathlib import Path
from tinydb import TinyDB
from BetterJSONStorage import BetterJSONStorage
with TinyDB(Path("out/github/test.db"), access_mode="r+", storage=BetterJSONStorage) as DB:
    DB.insert({"a": 2})

Error

  File "/Users/tim/projects/test/.venv/lib/python3.13/site-packages/BetterJSONStorage/BetterJSONStorage.py", line 162, in __file_writer
    self._handle.write(compress(dumps(self._data, **self._dump_kwargs)))
  File "/Users/tim/projects/test/.venv/lib/python3.13/site-packages/blosc2/core.py", line 158, in compress
    _check_input_length("src", len_src, typesize, _ignore_multiple_size=_ignore_multiple_size)
  File "/Users/tim/projects/test/.venv/lib/python3.13/site-packages/blosc2/core.py", line 64, in _check_input_length
    raise ValueError(f"len({input_name}) can only be a multiple of typesize ({typesize}).")

Python 3.13.1
tinydb 4.8.2
betterjsonstorage 1.3.2

[jestraw]

This PR in Blosc changed the default value for typesize in the compress method from None to 8. Since BetterJSONStorage isn't compressing NumPy objects, the previous value of None is probably more appropriate.

This change:

diff --git a/src/BetterJSONStorage/BetterJSONStorage.py b/src/BetterJSONStorage/BetterJSONStorage.py
index 86e007b..a1ebe3b 100644
--- a/src/BetterJSONStorage/BetterJSONStorage.py
+++ b/src/BetterJSONStorage/BetterJSONStorage.py
@@ -159,7 +159,7 @@ def __file_writer(self):
             if self._changed:
                 self._changed = False
                 self._handle.seek(0)
-                self._handle.write(compress(dumps(self._data, **self._dump_kwargs)))
+                self._handle.write(compress(dumps(self._data, **self._dump_kwargs), None))
 
         self._shutdown_lock.release()

makes storage work again.