Rust Coding Style — mmap-guard#

Crate-specific delta only. Authoritative source for this crate:
AGENTS.md + GOTCHAS.md.

Toolchain#

• Edition 2024, stable toolchain, MSRV 1.85 (rust-version in Cargo.toml).
• Format with cargo fmt; lint via just lint (Rust, GitHub Actions, docs, and justfile lints).
• just ci-check is full local CI parity.

Error handling (differs from generic ECC advice)#

• This crate returns std::io::Error (io::Result<_>) — it does not use
  thiserror or anyhow. Do not add either. Deps are memmap2 + fs4 only.
• unwrap_used and panic are clippy deny (hard build failure), not advice.
  Use ?. expect_used is warn — prefer ? there too.
• Full pedantic/nursery/cargo clippy groups are on and promoted to deny via
  -D warnings. New code may trip lints you didn't opt into. See
  GOTCHAS.md § Clippy Lints before silencing anything (e.g. indexing_slicing,
  unseparated_literal_suffix, uninlined_format_args, multiple_crate_versions).

Ownership & API#

• Borrow (&[u8], &str) by default; the crate exposes data via Deref<Target=[u8]>
  and AsRef<[u8]>.
• All public functions carry #[must_use] — maintain this for any new public API.