MSRV bump plan for v0.8

[lo48576]

Though I don't intend to rush into v0.8 with breaking changes, I need a place to put a memo about what the next MSRV should be.

[lo48576]

• quote v1.0.45 requires rustc >=1.71
  • failed CI task: BUILD_PROFILE=dev, OPT_FEATURES=--features=alloc,serde, RUST_DEP_VERSIONS=direct-minimal, step=clippy and run doctests
• unicode-ident v1.0.24 requires rustc >=1.71
  • failed CI task: BUILD_PROFILE=dev, OPT_FEATURES=--features=alloc,serde, RUST_DEP_VERSIONS=direct-minimal, step=build
• proc-macro2 v1.0.106 requires rustc >=1.68
  • failed CI task: BUILD_PROFILE=dev, OPT_FEATURES=--features=alloc,serde, RUST_DEP_VERSIONS=direct-minimal, step=run tests
• serde_derive v1.0.228 requires rustc >=1.61
  • failed CI task: BUILD_PROFILE=dev, OPT_FEATURES=--features=alloc,serde, RUST_DEP_VERSIONS=updated, step=run build

[lo48576]

• cargo sparse-registry requires Rust >=1.68
  • 1.68 and 1.69 requires CARGO_REGISTRIES_CRATES_IO_PROTOCOL=sparse envvar
  • With 1.70 and above, no configuration needed
• Rust edition 2024 requires Rust >= 1.85
• dependency resolver respecting MSRV: requires Rust >=1.84
  • 1.84 requires CARGO_RESOLVER_INCOMPATIBLE_RUST_VERSIONS=fallback envvar or [workspace] resolver = "3" in Cargo.toml
  • With 1.85 and above (i.e., with edition 2024), no configuration needed.
  • Dependency Resolution - The Cargo Book

[lo48576]

• Debian 12 (bookworm): Rust 1.63.0
  • EOL: 2026-06-10
  • End of LTS: 2028-06-30
  • End of ETLS: 2033-06-30
• Debian 13 (trixie): Rust 1.85.0
  • EOL: 2028-08-09
  • End of LTS: 2030-06-30
  • End of ETLS: 2035-06-30

[lo48576]

CI takes unreasonably long time (just to get index!) without cargo sparse-registry support, so I strongly prefer Rust >=1.68.
Above that, I don't have strong reasons to choose for now.
Maybe Edition 2024 (>=1.85, 2025-02-20) would be good but is it too new?

[lo48576]

(snip), so I strongly prefer Rust >=1.68. Above that, I don't have strong reasons to choose for now.

Rust >=1.71 also looks good to bump dependencies and to resolve warnings and errors from outside iri-string crate, but it won't be permanent because they eventually become old and MSRV bump of the deps will happen again.

[lo48576]

• dependencies table in Cargo.toml: requires Rust >=1.64
  • Workspaces - The Cargo Book

[silverpill]

I develop a library that depends on iri-string and uses the "Debian stable" MSRV policy. So I would appreciate if you keep MSRV at <=1.85 until the next Debian release