0014. Share one MSRV floor, 1.89.0, with the maintainer’s other crates

• Status: proposed
• Date: 2026-10-13
• Authors: Noyalib contributors

Context

The lockstep family (noyalib, noya-cli, noyalib-lsp, noyalib-mcp, noyalib-serde-yaml, noyalib-wasm) declared 1.86.0, except noyalib-mcp, whose MCP SDK needs 1.88.0. The maintainer’s other Rust crates sit at several floors between 1.56 and 1.92, which makes the support promise different for every crate a user combines.

docs/POLICIES.md §1 says the MSRV moves only when the toolchain the project builds and tests at moves, never for tidiness. Nothing in the family needs 1.89: criterion 0.8 (a dev-dependency) sets the toolchain-driven floor at 1.86, and the MCP SDK sets noyalib-mcp’s at 1.88.

Decision

Every crate in the family declares rust-version = "1.89.0", the floor the maintainer chose for all of his Rust crates. This is a maintainer decision, made explicitly, and is the only raise recorded without a toolchain reason. The rule in docs/POLICIES.md §1 stands for every later raise.

Consequences

• Positive: one floor across the family and the maintainer’s other crates; noyalib-mcp no longer differs from the rest; the opt-in compare-saphyr feature (1.88+) is now inside the floor.
• Negative: users on 1.86, 1.87 or 1.88 lose new releases with no technical gain. They can stay on v0.0.57.
• Neutral: the 12-month guarantee holds (1.89.0 shipped 2025-08-07).

Alternatives considered

Keep 1.86.0 (1.88.0 for noyalib-mcp)

Would have followed the written policy. Rejected by the maintainer in favour of one floor across all of his crates.

References

• docs/POLICIES.md §1, docs/MSRV-AND-DEPRECATION.md
• The v0.0.16 raise from 1.85 to 1.86 (its CHANGELOG entry)