DOC: Validate versions.json before building docs #61573

[iabhi4]

Adds a JSON validity check for versions.json directly inside pandas_web during context generation. This ensures malformed JSON (e.g., trailing commas) is caught early, preventing issues like the broken version dropdown in #61572

• Closes WEB: Test that our versions JSON is valid #61573

[datapythonista]

Thanks for the contribution @iabhi4

Can you move this check to main, and just open the file and load it as json, with a comment about what's for.

Also, can you add the comma to versions so we can see how this fails, and if we really need to reraise the exception (which I'm not sure we need).

Thanks!

[iabhi4]

Can you move this check to main, and just open the file and load it as json, with a comment about what's for.

Thanks for the review @datapythonista, just to confirm: when you say "move this check to main", do you mean the main() function itself, or the __main__ block. My assumption is the __main__ block, so we catch the error before any file system operations, just want to double check!

Added the trailing comma to versions.json to test the failure. Leaving the sys.exit(1) in place for now. Once we see the CI result, happy to adjust that if we want to just warn instead of fail

[datapythonista]

Better inside the main function. The idea is that the if __name__ == "__main__": block is only executed when the script is called. If for whatever reason I want to import the script from another file to generate the website, that block won't execute, but I still want to validate the file.

We don't want to warn. What I'm saying is that when you do json.load() this will already raise an exception, show an error message and crash the script. So, catching the exception to show an error and crash the script is probably not needed, since it'll already happen, and the code is significantly simpler, just two lines.

If the default error message is not great, then I'm happy with your approach. But instead of sys.exit I think it's better to raise a new exception from the previous one (Python can chain exceptions).

Btw, when this is done, if you are interested, it'd be nice to open a new PR to use pathlib instead of os.path in the whole script. For this PR is better to use os.path for consistency.

[iabhi4]

Thanks for such a detailed clarification. Have pushed the updated changes.

Btw, when this is done, if you are interested, it'd be nice to open a new PR to use pathlib instead of os.path in the whole script

happy to follow up with a separate PR for the pathlib changes once this one is in

[datapythonista]

Thanks for the update. I think catching the exception as you did was indeed better, the error message here is not helpful enough. But personally, I would just raise a RuntimeError with the good error message from the original one.

Feel free to remove the comma, after those changes I think we can get this merged. Thanks!

[iabhi4]

Raising RuntimeError now as suggested. Thank you so much for your help in this

[datapythonista]

Thanks @iabhi4, very nice!