lint: add more linters for using absl:: over std::

[rebello95]

Follow up to #13040. Some of these examples are based on absl docs and C++ docs.

These linters are here to prevent additional breakages of Envoy Mobile on iOS due to usages of std:: types/functions that are not supported on iOS 11. More discussion in #12341.

Risk Level: Low
Testing: In PR

Signed-off-by: Michael Rebello [email protected]

[mk46]

Sorry, format check fails and run ci/run_envoy_docker.sh 'ci/do_ci.sh fix_format' to fix it.

[htuch]

LGTM modulo format fix.

[rebello95]

Thanks. Running the docker command didn't work for me but I fixed locally and pushed

[ggreenway]

I think we should add the entire (commonly used) API for variants, which unfortunately for this purpose are free functions, not members, so they all need a linter entry:

std::holds_alternative
std::get
std::monostate
std::get_if

[mattklein123]

Also, while you are in here did we ever add a linter for string_view? We need that also.

[rebello95]

Done, added additional linters / test cases.

[ggreenway]

Thank you!

[rebello95]

Hm, looks like there are a lot of usages of std::get in the codebase today, which is why the linter is failing. Are you sure we need that one @ggreenway?

[ggreenway]

Hm, looks like there are a lot of usages of std::get in the codebase today, which is why the linter is failing. Are you sure we need that one @ggreenway?

Huh, std::get is used for both tuples and variants. We want to lint for only the uses with variant, not tuple, probably. But that's well into the realm of needing clang-tidy. So for now, I'd say remove the std::get one.

[rebello95]

Sounds good, removed.

[rebello95]

Looks like we also have existing usages of string_view which don't seem to be breaking Envoy Mobile @mattklein123: https://dev.azure.com/cncf/envoy/_build/results?buildId=50922&view=logs&jobId=9fd74226-df5b-5f29-39da-76fc341cc763&j=9fd74226-df5b-5f29-39da-76fc341cc763&t=068b98b1-acf0-52d0-fc6e-f6d1a5b1d5ef

[mattklein123]

I thought we had decided somehow that string_view doesn't work on Envoy Mobile? I'm confused. cc @junr03 @goaway

[junr03]

@rebello95 looks like those uses are all in extensions code we don't include/compile into Envoy Mobile. Hence why they are in the codebase here but causes no trouble to Envoy Mobile.

But yes, the decision was to not use std::string_view, so the linter change here to prohibit it is great, thanks!

[rebello95]

Thanks for confirming @junr03! I pushed a change to fix the violations from the main branch.

[mattklein123]

Awesome, thank you!

[rebello95]

Coverage failure looks unrelated

[mattklein123]

I think coverage on main branch is broken somehow due to recent limit changes. I will merge this and we can sort it out there.

[rebello95]

Thanks!