propagate critical-section feature selection into portable-atomic; other minor updates for v1.20.0

[brody4hire]

(updated)

• propagate critical-section feature selection into portable-atomic
• update TEST_BETA - push RUSTFLAGS = -A unreachable_patterns - WORKAROUND ref: unreachable patterns on 1.82 beta #261
• add cargo test --workspace to beginning of TEST task - resolves CI: detect cargo fmt issues #262
• other minor updates
• bump minor version in Cargo.toml & update change log

CI build now fixed with TEMPORARY WORKAROUND in TEST_BETA task.

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ORIGINAL RATIONALE RE: propagate critical-section feature selection into portable-atomic

Normally just using critical-section should be good enough for targets like super-outdated thumbv6m-none-eabi target. But in rustls/rustls#2088 I would like to preserve existing use of alloc option, in which case I had to add explicit portable-atomic dependency with its critical-section feature enabled.

IMO it would be nice if I didn't have to add explicit sub-depencencies with this option. This is my proposal to enable critical-section for portable-atomic if portable-atomic is wanted.

Please let me know if you have any other idea or perspective concerning this.

[matklad]

Yes, this makes sense! Could you:

• bump the minor version in Cargo.toml
• add an entry to the changelog
• fix the CI (I think you need to update the Cargo.lock.msrv which we used to test old versions of Rust)

[brody4hire]

I just force-pushed an update to update the Unreleased section of CHANGELOG.md, will try to fix the CI, update the minor version, and add the minor version heading to CHANGELOG.md next. Thanks!

[brody4hire]

@matklad I think this should be ready (yet again), with a TEMPORARY WORKAROUND in I made in the TEST_BETA task. Please let me know if you need anything else for this. Thanks!

[matklad]

Ahh, I didn't realize this percolated all the way up to the beta! But, anyway, you've found the perfect solution here, which places the fine-grained work-around where it belongs, thanks a bunch for this!

[matklad]

Looks awesome to me now, thanks for persevering here!

[matklad]

published at https://crates.io/crates/once_cell/1.20.0

[brody4hire]

🎉

[kaspar030]

• propagate critical-section feature selection into portable-atomic

This breaks our use case. portable-atomic treats critical-section and unsafe-assume-single-core as mutually exclusive. E.g., we depend on esp-rs, which for some platforms (e.g., esp32c2, c3) explicitly enables the latter.

Could we make this optional?

[brody4hire]

I would like to state my assumption that despite issue #264, all other changes from this PR should be considered valid and should remain in master (and be part of the next release):

• cargo fmt updates that would be needed to pass cargo fmt --check
• fix default-features flag for parking_lot_core in dependencies (in response to a warning message I noticed)
• CI-related updates:
  • add cargo test --workspace to beginning of TEST task (as discussed above, this is needed to ensure we check formatting in CI workflow)
  • temporary workaround for Rust compiler bug in RUSTFLAGS, as was needed for TEST_BETA task to succeed

matklad please comment in case this is mistaken ... apologies for commenting on an already merged & closed PR!

P.S. This also updated Cargo.lock, assume we want to keep this update.