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Add attributes to tomllib.TOMLDecodeError #126175
Description
Feature or enhancement
Proposal:
Add the same attributes to tomllib.TOMLDecodeError that json.JSONDecodeError also has, namely: msg, doc, pos, lineno, colno. This will help user facing apps show customized errors to users.
This draft PR in Tomli shows the proposed changes.
Has this already been discussed elsewhere?
I have already discussed this feature proposal on Discourse
Links to previous discussion of this feature:
https://discuss.python.org/t/69546
Activity
hukkin commentedon Oct 30, 2024
Pinging codeowners @hauntsaninja and @encukou
Thoughts on my concern in Discourse about the change breaking TOMLDecodeError init with no arguments would be much appreciated:
nineteendo commentedon Oct 30, 2024
I would use keywords arguments defaulting to None. Also see PEP-387.
picnixz commentedon Oct 30, 2024
You can instantiate those errors if you create a custom
tomllibextension (e.g., to handle extended syntax not supported by TOML but you still want to use the same exceptions for that).Agreed.
hukkin commentedon Oct 30, 2024
Thanks all for the feedback! I've updated my PoC draft PR in Tomli to be fully backwards compatible. It also adds a deprecation warning for use of positional arguments, which is simple to remove if folks think it's unnecessary. With it I think we could eventually move to the same exact signature that
json.JSONDecodeErrorhas.gh-126175: Add attributes to TOMLDecodeError. Deprecate free-form `__…
pythongh-126175: Add attributes to TOMLDecodeError. Deprecate free-fo…
pythongh-126175: Add attributes to TOMLDecodeError. Deprecate free-fo…