[DRAFT] refactor: remove frequency-bridging feature and related configurations

[mattheworris]

Goal

The goal of this PR is to remove the frequency-bridging feature flag and refactor the code so that it is easier to read and maintain.

Closes #2515

Discussion

• Must ensure the frequency-no-relay continues to work correctly. XCM features require some cumulus features.
• Code readability should improve.

Checklist

• Updated Pallet Readme?
• Updated js/api-augment for Custom RPC APIs?
• Design doc(s) updated?
• Unit Tests added?
• e2e Tests added?
• Benchmarks added?
• Spec version incremented?

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[shannonwells]

non-blocking, but it is odd that the commented-out features are all misspelled

[JoeCap08055]

Is there a reason we're keeping all of the commented-out stuff in the Makefile?

[mattheworris]

I just haven't cleaned it up yet.

[JoeCap08055]

So, are we just getting rid of all Westend-related code, the idea being that we're focusing on bridging on Paseo (and then Mainnet)?

[mattheworris]

Westend-local was kind of a hack for testing with Snowbridge Zombienet, so removing it to clean that up. The westend release still remains.

[JoeCap08055]

Hmmm... initially I was confused by:

#[cfg(any(not(feature = "frequency-no-relay"), feature = "frequency-lint-check"))]

that's used in so many places; it seems like adding feature = "frequency-lint-check" to the any(...) ONLY enables the use case: --features frequency-no-relay,frequency-lint-check. I was going to let it slide, but here I think I see a problem. If we run --features frequency-no-relay,frequency-lint-check, here we'll end up with:

use crate::no_relay::prelude as runtime_mode; // enabled by "frequency-no-relay"
use crate::relay::prelude as runtime_mode; // enabled by "frequency-lint-check"

I think this would like be problematic...so, by that logic, it seems like we should NEVER allow both frequency-no-relay AND frequency-lint-check at the same time. And, therefore, we can reduce all of the instances of:

#[cfg(any(not(feature = "frequency-no-relay"), feature = "frequency-lint-check"))]

to simply

#[cfg(not(feature = "frequency-no-relay"))]

[mattheworris]

frequency-lint-check is meant to include both the relay and no-relay configurations so that everything will be checked by the linter. This flag is only meant to be used for tests and lints, it's not meant to be a proper build.

We have an existing issue (#2367) to remove the frequency-lint-check feature and duplicate any tests that use the flag, which would make the code maintenance easier. I think the effort to remove the lint flag needs to wait until we merge/remove the bridging feature.