fix: protect ak.to_parquet against memory explosion when args are swapped.

[jpivarski]

If an Awkward Array is passed as destination to fsspec.core.url_to_fs(destination), the memory use explodes before Python crashes. The array doesn't even need to be very large to send fsspec into dozens of GB; I think it might be converting the array into a string and interpreting [ ] { } as wildcards, a combinatorially large file list.

Anyway, it's very common for me to forget the argument order in I/O functions (ak.to_parquet, json.dump, etc.) and I just try one until it works. It needs to be the case that trying the wrong one produces an immediate error message.

[jpivarski]

Improvements: this function isn't going through the standard ErrorContext, so the error message contains text about the fact that this is happening in ak.to_parquet and what the correct order of arguments ought to be. These tidbits wouldn't be necessary if there was an error context.

Also, only strings for destination? That's what the docstring says. What about accepting a pathlib.Path? pq.ParquetWriter accepts a file-like object—we could in principle pass on that capability, but we'd have to bypass a lot of fsspec to do it.

[codecov]

Codecov Report

Merging #2523 (5d3ea7e) into main (e627d4a) will decrease coverage by 0.01%.
The diff coverage is 60.00%.

❗ Current head 5d3ea7e differs from pull request most recent head faac18c. Consider uploading reports for the commit faac18c to get more accurate results

Additional details and impacted files

Impacted Files	Coverage Δ
src/awkward/operations/ak_to_parquet.py	52.88% <60.00%> (+0.35%)	⬆️

... and 3 files with indirect coverage changes

[raymondEhlers]

Just poking around and saw this, so feel free to disregard - although it's just a nice quality of life thing, it would be nice to have support for Path. Every time I use to_parquet, I forget to convert from Path, so if it's not a big burden, it would be a helpful addition

[jpivarski]

That one's easy. Allowing file-like objects to pass through to the ParquetWriter, to take advantage of its ability to use them, would be harder.

[agoose77]

This looks good! I made a change to open up support for any path-likes, are you happy with these modifications? I'll just test them locally to ensure that there are no corner-cases.