build: raise MSRV 1.97.0 -> 1.97.1 (1.97.0 miscompiles gp-core's shape)#71
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rust#159035: under optimizations, `Option::map` over nested enum/struct types segfaults instead of yielding None -- which is what gp-core is made of. An LLVM optimizer pass emits an unconditional `trunc nuw` that is poison for a -1 niche tag; the trigger was a rustc change. 1.97.1 ships the LLVM fix plus a revert of that trigger (stable backport rust#159288; beta backport rust#159072 -> 1.98). 1.96.1 unaffected; 1.97.0 is the only released stable that ever carried it. rust-version is the only lever that refuses the broken compiler: CI pins no stable toolchain (setup-rust-toolchain@v1 defaults to stable, which already resolves 1.97.1); the sole 1.97.0 in ci.yml was a comment. The advisory miri lane pins nightly but was never exposed -- Miri interprets MIR and never runs the LLVM optimizer. The bug is fixed everywhere and 1.97.0 is dead, so the docs just state the MSRV; this message is the durable home for the why, reachable from `git blame Cargo.toml`. Historical 1.97.0 references in ai-docs/plans/done/**, learnings.md, INDEX.md and _inbox.jsonl are deliberately untouched -- they record what was true when those tasks ran. 0 new tests; 103 workspace tests green on 1.97.1.
The cargo test comment read '97 gp-core + 2 gp-gen' (= 99). #11 added gp-render's tessellation smoke test and golden guard, and the workspace runs 2 doc-tests. Pre-existing staleness, unrelated to the MSRV bump.
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Summary
Raises the workspace MSRV from 1.97.0 to 1.97.1. 1.97.0 miscompiles: under optimizations,
Option::mapover nested enum/struct types segfaults instead of yieldingNone(rust#159035) — which is whatgp-coreis made of. An LLVM optimizer pass emits an unconditionaltrunc nuwthat is poison for a-1niche tag; the trigger was a rustc change. 1.97.1 ships the LLVM fix plus a revert of that trigger.Fixed everywhere — stable backport rust#159288 (→ 1.97.1), beta backport rust#159072 (→ 1.98). 1.96.1 unaffected; 1.97.0 is the only released stable that ever carried it.
rust-versionis the only lever that refuses the broken compiler. CI pins no stable toolchain (setup-rust-toolchain@v1defaults to stable, which already resolves 1.97.1), and there is norust-toolchain.toml— the sole1.97.0inci.ymlwas a comment. The advisorymirilane pinsnightlybut was never exposed: Miri interprets MIR and never runs the LLVM optimizer.The docs just state the MSRV. The rationale lives in the commit message, reachable from
git blame Cargo.toml— the bug is fixed everywhere and 1.97.0 is dead, so carrying its history inREADME.mdwould be archaeology that rots.Commits
1db57e0Cargo.toml, plus aci.ymlcomment and three live doc claimsad130deREADME'scargo testcomment said 99, actual is 103Deliberately untouched
~24 other
1.97.0references are historical records and stay:ai-docs/plans/done/**(completed-task specs/designs),ai-docs/learnings.md(append-only per AGENTS.md Boundary rule 1),ai-docs/plans/INDEX.md,ai-docs/deferred/_inbox.jsonl. They record what was true when those tasks ran; rewriting them would falsify history.Tracking
No tracking issue — direct product-owner instruction.
Test plan
cargo build --workspace✅cargo test --workspace— 103 passed, 0 failed ✅ (on 1.97.1)cargo clippy --workspace --all-targets -- -D warnings✅cargo fmt --check✅RUSTDOCFLAGS="-D warnings" cargo doc --no-deps --workspace✅actionlint .github/workflows/ci.yml✅ (run beforegit add— AGENTS.md AXIOM;ci.ymlchanged)cargo metadata— all 5 crates resolverust-version = 1.97.1viarust-version.workspace = true0 new tests — a toolchain floor bump has no new behaviour to cover.
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