Never render .in files in interactive problems

[Matistjati]

.in and .ans files are shown in the statement if no .interaction file exists.
In the vast majority of interactive problems, the .in files are completely useless and undocumented. Even worse, what should the .ans file be? At that point, just use a .interaction file as we intended. This really feels like a footgun.

There are legitimate usecases for having .in files without a corresponding interaction, though: I ran into this when I had an interactive problem where a .interaction file was unsuitable (you call a function defined in an include runner, which is very common in IOI), but I still wanted the sample to be run. Of course we should still warn in the case where we hide it.

[gkreitz]

This really feels like a footgun.

I agree. This should probably be fixed in https://www.kattis.com/problem-package-format/spec/2025-09.html#samples-for-interactive-and-multi-pass-problems (which just strongly recommends a .interaction). My inclination would be to require samples for interactive/multi-pass problems to either have an .interaction or the override files (e.g., .in.statement, .ans.statement). Defaulting to .in and .ans indeed feels like a footgun.

For problemtools, I think I'll need to do a larger rewrite for sample rendering to fix this. The logic for sample file rendering is mostly done in latex, which is... not great. :)

There are legitimate usecases for having .in files without a corresponding interaction, though [...]

Now, this has me confused. Your issue is titled "Never render .in files in interactive prolems", and then you say there are legitimate use cases where it sounds like you do want to render an in file? If you don't want to render anything in this case, why is it in sample?

[Matistjati]

To be clear, I want to run it, but not render it.

In problems where you don't use STDIO for input/output, but instead call function using an include file, it is sometimes impossible to use a sample to describe the interaction. But you still want Kattis to run the samples.