import blosc2 hangs on macOS -- causes problems with tiled.client.register

[edbarnard]

When trying to import tiled.client.register I encountered a hang up that happens when trying to import the blosc2 file format library. The import will never return. When terminated I get the following response. A subprocess call to cpu_info never returns. macOS 15.1.1 on arm64

(tiled-client) esbarnard@esbstudio ~ % python
Python 3.11.11 (main, Dec 11 2024, 10:28:39) [Clang 14.0.6 ] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import tiled
>>> tiled.__version__
'0.1.0b11'
>>> from tiled.client.register import register
^CTraceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/esbarnard/opt/anaconda3/envs/tiled-client/lib/python3.11/site-packages/tiled/client/register.py", line 12, in <module>
    from ..mimetypes import (
  File "/Users/esbarnard/opt/anaconda3/envs/tiled-client/lib/python3.11/site-packages/tiled/mimetypes.py", line 4, in <module>
    from .serialization.table import XLSX_MIME_TYPE
  File "/Users/esbarnard/opt/anaconda3/envs/tiled-client/lib/python3.11/site-packages/tiled/serialization/table.py", line 4, in <module>
    from ..media_type_registration import deserialization_registry, serialization_registry
  File "/Users/esbarnard/opt/anaconda3/envs/tiled-client/lib/python3.11/site-packages/tiled/media_type_registration.py", line 332, in <module>
    import blosc2
  File "/Users/esbarnard/opt/anaconda3/envs/tiled-client/lib/python3.11/site-packages/blosc2/__init__.py", line 191, in <module>
    cpu_info = get_cpu_info()
               ^^^^^^^^^^^^^^
  File "/Users/esbarnard/opt/anaconda3/envs/tiled-client/lib/python3.11/site-packages/blosc2/core.py", line 1192, in get_cpu_info
    cpu_info_dict = _get_cpu_info()
                    ^^^^^^^^^^^^^^^
  File "/Users/esbarnard/opt/anaconda3/envs/tiled-client/lib/python3.11/site-packages/blosc2/core.py", line 1156, in _get_cpu_info
    cpu_info = cpuinfo.get_cpu_info()
               ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/esbarnard/opt/anaconda3/envs/tiled-client/lib/python3.11/site-packages/cpuinfo/cpuinfo.py", line 2759, in get_cpu_info
    output = get_cpu_info_json()
             ^^^^^^^^^^^^^^^^^^^
  File "/Users/esbarnard/opt/anaconda3/envs/tiled-client/lib/python3.11/site-packages/cpuinfo/cpuinfo.py", line 2742, in get_cpu_info_json
    output = p1.communicate()[0]
             ^^^^^^^^^^^^^^^^
  File "/Users/esbarnard/opt/anaconda3/envs/tiled-client/lib/python3.11/subprocess.py", line 1209, in communicate
    stdout, stderr = self._communicate(input, endtime, timeout)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/esbarnard/opt/anaconda3/envs/tiled-client/lib/python3.11/subprocess.py", line 2115, in _communicate
    ready = selector.select(timeout)
            ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/esbarnard/opt/anaconda3/envs/tiled-client/lib/python3.11/selectors.py", line 415, in select
    fd_event_list = self._selector.poll(timeout)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
KeyboardInterrupt

[edbarnard]

Blosc2 version

(tiled-client) esbarnard@esbstudio ~ % conda list blosc2
# packages in environment at /Users/esbarnard/opt/anaconda3/envs/tiled-client:
#
# Name                    Version                   Build  Channel
blosc2                    3.0.0                    pypi_0    pypi

[edbarnard]

Upon more investigation this is a bug in the py-cpuinfo that fails specifically on some macs / OS versions.

tested examples:

Computer	macOS	python	works?
M3 Macbook Air	macOS 14.4	Native Python 3.12	WORKS
M3 Macbook Air	macOS 15.2	Native Python 3.12	WORKS
M1 Ultra Mac Studio	macOS 15.1.1	Rosetta Python 3.12	FAILS
M1 iMac	macOS 14.6.1	Rosetta Python 3.12	WORKS
Intel i9 MacBook Pro	macOS 15.0	Native x86 Python 3.12	WORKS

[danielballan]

Thanks for the thorough investigation. As a workaround, blosc2 is an optional dependency of Tiled. If it is not installed, blosc2 compression will not be used. Try uninstalling?

tiled/tiled/client/decoders.py

Lines 6 to 29 in 6314f1d

	if modules_available("blosc2"):
	class Blosc2Decoder:
	def __init__(self):
	# Blosc seems to have no streaming interface.
	# Accumulate response data in a cache here,
	# and concatenate and decode at the end.
	self._data = []
	def decode(self, data: bytes) -> bytes:
	self._data.append(data)
	return b""
	def flush(self) -> bytes:
	# Hide this here to defer the numpy import that it triggers.
	import blosc2
	if len(self._data) == 1:
	(data,) = self._data
	else:
	data = b"".join(self._data)
	return blosc2.decompress(data)
	SUPPORTED_DECODERS["blosc2"] = Blosc2Decoder

[edbarnard]

pip uninstall blosc2 does the trick for now. I'll submit a issue to Blosc2 and py-cpuinfo

Blosc2 Issue posted: Blosc/python-blosc2#356