gh-126033: Fix crash in _elementtree.c where evil tags/elements occurs

[gougougougougou]

gh-126033: Fix crash in _elementtree.c where evil tags/elements occurs

Throws errors when evil tags/elements was detected.

This also fixes gh-126037.

[ghost]

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[picnixz]

The way to fix this is not necessarily only by checking whether extra is NULL or not. You may also change the size of the list without clearing it and currently we don't check this. I think we should use RuntimeError instead as well because that's the kind of exceptions we usually raise when a list is mutated while iterating over it.

There are also other places where there is a crash (namely in other find* methods). I would appreciate we first discuss the approach for fixing it (one way to fix it is to add versioning but we need to discuss first).

Finally, I would have appreciated if you first asked whether you could open a PR or not since I was also working on it (and self-assigned the issue).

[gougougougougou]

The way to fix this is not necessarily only by checking whether extra is NULL or not. You may also change the size of the list without clearing it and currently we don't check this. I think we should use RuntimeError instead as well because that's the kind of exceptions we usually raise when a list is mutated while iterating over it.

There are also other places where there is a crash (namely in other find* methods). I would appreciate we first discuss the approach for fixing it (one way to fix it is to add versioning but we need to discuss first).

Finally, I would have appreciated if you first asked whether you could open a PR or not since I was also working on it (and self-assigned the issue).

Sorry about that, I didn’t saw the issue carefully about the self-assigning tag. I’ve understand your solution about this issue, For my solution, just adding the error throwing for just few functions, doesn't really fit for this issue. so I’ll close this PR soon.