Cap preview cols to prevent stall when csv is parsed with the wrong delimiter

[iamllama]

Resolves #3588

Sure, here is an example which takes 25 seconds to load for my pc.

Looking at what passes for the csv spec, the example is considered invalid csv when pipe-delimited. But python's csv.reader parses it in the same way as the crate. I can't speak to how they handle quirks, but my guess is that the last pipe in each row having one unclosed quote after it causes the record terminator to be quoted and ignored, and the file ends up as being 1 header and 1 record long

The stall doesn't seem to be happening on the backend (which parses and responds in ~100ms), but on the webpage itself. Profiling on firefox confirms that it's choking on rendering ~40000 columns in the preview table

This pr proposes to cap the preview table's columns at 1000, a number small enough that it should render reasonably quickly (~1s, prev ~20s), and ludicrously large enough that exceeding it almost certainly means wrong delimiter and/or invalid csv (who has notetypes with >1000 fields?)

This'll allow the user to quickly recover from a wrong guess by the delimiter heuristic, rather than have to wait ~20 seconds for the page to load

A warning is shown when columns have been clipped:

EDIT: failing on an openssl advisory 👀

[dae]

Thank you for digging into this! The way you've addressed it looks good. A couple of minor comments:

Is your thinking with the underscored _tr similar to this? https://github.com/ankitects/anki/pull/3640/files/14c022f6de65491d5832949df802ba2ae7c8074b#diff-5f735d59ca95151c8a3a6aca3a068eef5ea8a3a9d3ff9abdebd7040c9f6722e6

[iamllama]

Is your thinking with the underscored _tr similar to this?

Yep, it'd make svelte treat <tr> as a component otherwise. Might be cleaner to just import the one translation, but i figured having tr. in there would be more greppable 🤔

If this was just for the translation system, you could probably even drop the [one] case, and mention in the translation comment that $count will only ever be 1000 or a similarly-large number, which would allow translators to skip zero/one/few cases.

Included the [one] case for completeness' sake, dropping it seems better than changing it to something like "Only the first 1 column is shown", which sounds off 😅. Added a comment to clarify that as suggested

[dae]

Yep, it'd make svelte treat as a component otherwise. Might be cleaner to just import the one translation, but i figured having tr. in there would be more greppable 🤔

Would you mind elaborating on what you mean by that? I changed the _tr to tr in my local checkout, and it still passes tests/works correctly.

[iamllama]

Well that's embarrassing. I tried it earlier in the morning and got a component_name_lowercase svelte warning, along with the tags silently being removed from the rendered table, but now it seems fine? I must've done something wrong back then, sorry about that!

[dae]

I've experienced that many a time too - don't sweat it :-)

Thank you for this fix!