logproto: Add deprecated annotation to LegacySample and LegacyLabelPair

[tpaschalis]

Signed-off-by: Paschalis Tsilias paschalis.tsilias@grafana.com

What this PR does / why we need it:
The PR adds a docstring to those two messages, to discourage accidental use.

The changes were just
a) Adding a docstring on the LegacySample and LegacyLabelPair messages
b) Run make protos

Basically just familiarizing myself with the contributing process for Loki :)

Which issue(s) this PR fixes:
Fixes #5312

Special notes for your reviewer:
I initially tried adding an option like option deprecated = true; or a comment like // Deprecated: Use Sample instead, as I thought that this might translate better for other languages' proto compilers.

Unfortunately, both these approaches trip staticheck, which complains about using a deprecated struct in tests and code. From its source, it seems that it will flag all structs where there's a docstring line with the prefix Deprecated:.

So instead of littering the codebase with annotations such as //nolint:staticcheck // Ignore SA1019 for deprecated fields, I opted for a more generic annotation.

The drawback is that it wouldn't autogenerate language-specific deprecation notices for other proto compilers (like @Deprecated in Java). Would you be okay with that?

Also, I'm not sure if this warrants a change in the changelog or documentation (I'd say no), but let me know if you think otherwise.

Checklist

• Documentation added (N/A)
• Tests updated (N/A)
• Add an entry in the CHANGELOG.md about the changes. (N/A)

[CLAassistant]

All committers have signed the CLA.

[tpaschalis]

cc @DylanGuedes

[DylanGuedes]

Thanks! 🎉

Sad to hear that adding the deprecated annotation would cause so much trouble. Anyway, having this comment/annotation is better than not having it, so LGTM.

And yeah, I think this shouldn't be listed in the changelog, as it is a kinda internal change.

[kavirajk]

LGTM. thanks @tpaschalis