wifi-densepose-core uses std items without feature gate #2009

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1. ruvnet

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   bugSomething isn't workingSomething isn't working

   on Sep 27, 2026
2. ruvnet commented on Oct 2, 2026

   

   ruvnet

   on Oct 2, 2026 – with Claude

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   core::fmt::Display is available in no_std environments — the core crate's fmt module provides the same trait. Replacing std::fmt::Display with core::fmt::Display (or changing the import to use core::fmt) at the affected location would resolve this without needing a feature gate, which is the standard Rust no_std compatibility pattern.

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3. aepod commented on Oct 2, 2026

   

   aepod

   on Oct 2, 2026

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   Confirmed on main 03a89793: cargo check -p wifi-densepose-core --no-default-features fails with 80 errors. MEASURED, software-only, macOS native, rustc 1.89.0 (pinned toolchain), host target.

   The issue cites std::fmt, std::cmp and std::f64::consts. The failure is wider than that: most errors are String/Vec not in scope, because the alloc types aren't imported when std is off.

   cd v2 && cargo check -p wifi-densepose-core --no-default-features
   error: could not compile `wifi-densepose-core` (lib) due to 80 previous errors
   

   Error	Count
   E0412 cannot find type String	44
   E0412 cannot find type Vec	20
   E0433 unresolved module or unlinked crate std	8
   E0433 undeclared type Vec	5
   E0433 undeclared type String	1

   By file: error.rs 42, types.rs 30, traits.rs 7, utils.rs 1. The crate declares #![cfg_attr(not(feature = "std"), no_std)] and extern crate alloc (lib.rs:43,47) with default = ["std"].

   #2018 applied on top of current main builds clean and the crate's tests pass (39 + 3 doctests). A CI job for the no-default build would keep it that way.
4. danalec commented on Oct 22, 2026

   

   danalec

   on Oct 22, 2026

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   Confirmed and fixed. The crate declares #![cfg_attr(not(feature = "std"), no_std)] and an extern crate alloc;, but its own code used String, Vec, format!, ToString and std::fmt / std::cmp / std::f64::consts paths, so the configuration the declaration promises did not compile:

   $ cargo check -p wifi-densepose-core --no-default-features
   error: cannot find macro `format` in this scope
   error[E0425]: cannot find type `String` in this scope
   error[E0433]: cannot find module or crate `std` in this scope
   ...
   error: could not compile `wifi-densepose-core` (lib) due to 80 previous errors
   

   80 errors across error.rs (42), types.rs (30), traits.rs (7) and utils.rs (1).

   Why it was not caught

   Feature unification. A workspace build unifies features across the members, and several depend on wifi-densepose-core with its default features, so the crate's std feature comes back on even under cargo test --workspace --no-default-features:

   $ cargo tree --workspace -e features --no-default-features
   │   ├── wifi-densepose-core feature "default"
   │   │   └── wifi-densepose-core feature "std"
   

   The no_std configuration was therefore never compiled.

   The fix

   #2324 moves the allocating types to alloc and the formatting and comparison items to core, and drops the cfg-gated alloc_vec alias in traits.rs — alloc::vec::Vec and std::vec::Vec are the same type, so the public signature of CanonicalFrame::to_canonical_bytes is unchanged. extern crate alloc; becomes unconditional.

   CI now checks the no_std build of the crates that promise it, each on its own:

   - name: Check the no_std build of the crates that promise it
     working-directory: v2
     run: cargo check -p wifi-densepose-core -p wifi-densepose-bfld --no-default-features

   wifi-densepose-bfld already passed; wifi-densepose-core did not.

   Verified: the no_std check, the default / serde / --all-features builds, the crate's 39 tests, clippy, and cargo check --workspace --no-default-features all pass. The gate fails on the pre-fix tree.

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