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Actually, it goes away with pip install jinja2. We don't use jinja2 at all, so either this is some kind of weird effect on garbage collection (a timing issue?), or dask is doing something differently as soon as jinja2 is available.

Edit: most likely this is a timing issue... the offending line tries to make use of the internal acquire function, which I think at that point has already been destroyed. To fix that, I think we need to somehow store a reference on the file manager?

I can reproduce this locally: - download and unpack the files from https://github.com/pydata/xarray/issues/7814#issuecomment-1535168128 - use mamba create -n test python=3.11 xarray netcdf4 to create the environment (note: no dask) - use pip install "dask[array]" to install dask (does not pull distributed like the package from conda-forge) - put the code into a script and execute it

For reference, the full traceback is: pytb Exception ignored in: <function CachingFileManager.__del__ at 0x7fbdb237b430> Traceback (most recent call last): File "/home/jmagin/.local/opt/mambaforge/envs/test/lib/python3.9/site-packages/xarray/backends/file_manager.py", line 246, in __del__ TypeError: 'NoneType' object is not callable

As far as I can tell, this means we're using something from distributed with a broken fallback, since the error goes away as soon as I install distributed.

Thanks Kai, I have attached the output of xr.show_versions() and of pip list.

Does this happen only with these special files, or do you experience this every time?

I tried with two netcdf files from https://www.northwestknowledge.net/metdata/data/ and got the same TypeError: 'NoneType' object is not callable

Does the problem persists when specifying engine="netcdf4" or engine="h5netcdf" in the call to open_mfdataset?

Only engine="netcdf4" works as a parameter but I get the same error, h5netcdf is not recognized as an engine.

Does this also happen, if you open the files one-by-one (with xr.open_dataset) and combine the Datasets with xr.concat?

Yes, opening files with xr.open_dataset and combining them with xr.concat gives the same error.

Please note the following that I just realized, the resulting combined netCDF file is actually created even though the errors are displayed. Also, as I mentioned in my first message, if I run the commands line by line in the python console no error message is displayed, this happens only when the code is ran as a script.

Paul

pip_list.txt xr.show_versions.txt

@paul0207 Thanks for providing the datafiles. I can't reproduce on my machine. Please provide more information, the output of xr.show_versions() would help and a complete traceback of the error you are experiencing.

A complete list of installed Python Packages would be nice (eg. by pip list), too.

Another couple of questions to get some more insight:

• Does this happen only with these special files, or do you experience this every time?
• Does the problem persists when specifying engine="netcdf4" or engine="h5netcdf" in the call to open_mfdataset?
• Does this also happen, if you open the files one-by-one (with xr.open_dataset) and combine the Datasets with xr.concat?

Deepak, thanks for replying, I have attached a couple of my netCDF files. Hopefully these will help for reproducing the issue.

Archive.zip

We;ll need a reproducible example

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