Detected blocking call to import_module with args ('zstandard',) inside the event loop by custom integration 'pyscript'

[Young-Grandad]

I'm trying to run an ASYNC function to read some CSV data using PANDAS DataFrames. When I run my code from Developer Tools (Actions) within HA the (calling) function indicates a successful run (green tick) but the code returns error "The truth value of a DataFrame is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().".
In my code I have "if matching_days.empty:", but this code is never exercised, even if I change the code to "if NOT matching_days.empty:". So I conclude the issue is somewhere within the pyscript integration.

The Logger information is:
Detected blocking call to import_module with args ('zstandard',) inside the event loop by custom integration 'pyscript' at custom_components/pyscript/eval.py, line 1983: return func(*args, **kwargs) (offender: /usr/local/lib/python3.13/site-packages/pandas/compat/_optional.py, line 135: module = importlib.import_module(name)), please create a bug report at https://github.com/custom-components/pyscript/issues For developers, please see https://developers.home-assistant.io/docs/asyncio_blocking_operations/#import_module Traceback (most recent call last): File "", line 198, in _run_module_as_main File "", line 88, in _run_code File "/usr/src/homeassistant/homeassistant/main.py", line 223, in sys.exit(main()) File "/usr/src/homeassistant/homeassistant/main.py", line 209, in main exit_code = runner.run(runtime_conf) File "/usr/src/homeassistant/homeassistant/runner.py", line 154, in run return loop.run_until_complete(setup_and_run_hass(runtime_config)) File "/usr/local/lib/python3.13/asyncio/base_events.py", line 706, in run_until_complete self.run_forever() File "/usr/local/lib/python3.13/asyncio/base_events.py", line 677, in run_forever self._run_once() File "/usr/local/lib/python3.13/asyncio/base_events.py", line 2034, in _run_once handle._run() File "/usr/local/lib/python3.13/asyncio/events.py", line 89, in _run self._context.run(self._callback, *self._args) File "/config/custom_components/pyscript/function.py", line 448, in run_coro result = await coro File "/config/custom_components/pyscript/eval.py", line 509, in do_service_call retval = await func.call(ast_ctx, **data) File "/config/custom_components/pyscript/eval.py", line 801, in call val = await self.try_aeval(ast_ctx, arg1) File "/config/custom_components/pyscript/eval.py", line 701, in try_aeval return await ast_ctx.aeval(arg) File "/config/custom_components/pyscript/eval.py", line 941, in aeval val = await getattr(self, name, self.ast_not_implemented)(arg) File "/config/custom_components/pyscript/eval.py", line 1469, in ast_assign rhs = await self.aeval(arg.value) File "/config/custom_components/pyscript/eval.py", line 941, in aeval val = await getattr(self, name, self.ast_not_implemented)(arg) File "/config/custom_components/pyscript/eval.py", line 2024, in ast_await coro = await self.aeval(arg.value) File "/config/custom_components/pyscript/eval.py", line 941, in aeval val = await getattr(self, name, self.ast_not_implemented)(arg) File "/config/custom_components/pyscript/eval.py", line 1938, in ast_call return await self.call_func(func, func_name, *args, **kwargs) File "/config/custom_components/pyscript/eval.py", line 1953, in call_func return await func.call(self, *args, **kwargs) File "/config/custom_components/pyscript/eval.py", line 853, in call return await self.func.call(ast_ctx, *args, **kwargs) File "/config/custom_components/pyscript/eval.py", line 801, in call val = await self.try_aeval(ast_ctx, arg1) File "/config/custom_components/pyscript/eval.py", line 701, in try_aeval return await ast_ctx.aeval(arg) File "/config/custom_components/pyscript/eval.py", line 941, in aeval val = await getattr(self, name, self.ast_not_implemented)(arg) File "/config/custom_components/pyscript/eval.py", line 1225, in ast_try val = await self.aeval(arg1) File "/config/custom_components/pyscript/eval.py", line 941, in aeval val = await getattr(self, name, self.ast_not_implemented)(arg) File "/config/custom_components/pyscript/eval.py", line 1469, in ast_assign rhs = await self.aeval(arg.value) File "/config/custom_components/pyscript/eval.py", line 941, in aeval val = await getattr(self, name, self.ast_not_implemented)(arg) File "/config/custom_components/pyscript/eval.py", line 2024, in ast_await coro = await self.aeval(arg.value) File "/config/custom_components/pyscript/eval.py", line 941, in aeval val = await getattr(self, name, self.ast_not_implemented)(arg) File "/config/custom_components/pyscript/eval.py", line 1938, in ast_call return await self.call_func(func, func_name, *args, **kwargs) File "/config/custom_components/pyscript/eval.py", line 1953, in call_func return await func.call(self, *args, **kwargs) File "/config/custom_components/pyscript/eval.py", line 853, in call return await self.func.call(ast_ctx, *args, **kwargs) File "/config/custom_components/pyscript/eval.py", line 801, in call val = await self.try_aeval(ast_ctx, arg1) File "/config/custom_components/pyscript/eval.py", line 701, in try_aeval return await ast_ctx.aeval(arg) File "/config/custom_components/pyscript/eval.py", line 941, in aeval val = await getattr(self, name, self.ast_not_implemented)(arg) File "/config/custom_components/pyscript/eval.py", line 1469, in ast_assign rhs = await self.aeval(arg.value) File "/config/custom_components/pyscript/eval.py", line 941, in aeval val = await getattr(self, name, self.ast_not_implemented)(arg) File "/config/custom_components/pyscript/eval.py", line 1938, in ast_call return await self.call_func(func, func_name, *args, **kwargs) File "/config/custom_components/pyscript/eval.py", line 1983, in call_func return func(*args, **kwargs)

[craigbarratt]

The error message suggests that zstd uses lazy loading - the full module isn't loaded initially, and just the necessary portions are loaded when needed. Such modules won't work with pyscript, since the lazy-loading happens later and blocks the HASS main event loop. See the documentation for why you need to avoid any blocking calls.

Pandas is a large complex module and it's quite likely that pyscript doesn't handle its complex object types correctly.

I'd recommend you put all your pandas code in functions that have a @pyscript_executor decorator. Although less efficient, it will ensure that every function call is executed in a separate task, so lazy loading etc is then ok. The code will also be compiled as native python, ensuring it matches real python.

[Young-Grandad]

Hello Craig, thank you for you reply and comments.
I did read the documentation earlier and that is what prompted me to use asyncio etc as suggested in the docs.
I know that the asyncio to the CSV file to create a PANDAS DataFrame works because I can run that part on its own.
The problem, I think, is analysis of the DataFrame by the next function. It doesn't use async because I didn't think I needed to.
All of the I/O, analysis and calculations are performed in a .py script stored in /config/pyscript/modules, so the calling script calls that "module" asynchronously.
I am a bit of a novice at this as this is my first time using async methods.
I will, as per your recommendation, explore the @pyscript_executor decorator and see how I can adapt my functions accordingly.

Thanks again for your help.

Regards, Steve

[Young-Grandad]

Hello Craig, I've given up completely with pandas DataFrames as I couldn't solve the error "DataFrame is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all()." In the end I opted for aiofiles.open and csv.DictReader all run synchronously in pyscript.
I think it might be just how pyscript runs DataFrames as I can run the same code in IDLE on Windows 11 and it works successfully. I know this isn't a fair comparison but I thought it was worth a mention.