[roger-zhangg]

Which issue(s) does this change fix?

N/A

Why is this change necessary?

Rust 1.98.0 (2026-08-18) adds the -Wl,--fix-cortex-a53-843419 linker argument for AArch64 Linux targets. Zig 0.16 rejects it, so every arm64 Rust build fails:

error: unsupported linker arg: --fix-cortex-a53-843419

install-rust.sh tracks the moving stable channel, so CI upgraded the runner image's 1.97.1 to 1.98.0 in place and broke build-arm64, tier1-finch and tier1-windows-build-2 on both nightly runs since (2026-08-21). x86 is unaffected — the flag is an ARM erratum workaround. The surfaced assertion is misleading ('template.yaml' not found in []) because the build produces nothing.

How does it address the issue?

cargo-zigbuild 0.23.0 filters the argument before invoking zig, and cargo-lambda v1.9.2 picks it up (cargo-lambda#937). v1.9.1 is not sufficient — it still embeds cargo-zigbuild 0.20.1, which predates the fix.

The pins move into a rust-tests extra in pyproject.toml rather than a version string per workflow. Dependabot's pip ecosystem already edits that file and already bumps packages inside extras (ruff lives in pre-dev), so these stay current instead of drifting — 0.17.1 was 20 releases behind by the time Rust broke it. This also pins ziglang, previously unpinned and able to cause the same class of failure on any zig release.

What side effects does this change have?

install-rust.sh reads the pins from the extra instead of taking a version argument, so it installs exactly what it did before — no project install, no dependency-resolution change — and CARGO_LAMBDA_VERSION disappears from both workflows. A separate extra (not dev) keeps the large cargo-lambda wheel out of non-Rust jobs.

The Windows branch installs zig from chocolatey rather than the wheel, so the choco version is derived from the same declaration, and the wheel fallback is gated on the reported zig version rather than mere presence — otherwise a zig already resolvable on PATH could win over the pin. Without this the pin would have governed Linux only, leaving Windows with a floating zig — the very failure mode being fixed.

Reproducible requirements are unaffected: uv pip compile pyproject.toml passes no --extra, which is why pytest is absent from them today.

The appveyor-*.yml files pin this version separately but are deprecated, so they are left alone; each already defines and consumes its own variable.

It leaves the Rust channel itself unpinned. A rust-toolchain.toml plus a rust_toolchain Dependabot entry is the matching follow-up.

Testing

Verified locally against rustc 1.98.0 and zig 0.16.0 — same host and fixtures, only cargo-lambda differing:

cargo-lambda	x86	arm64
0.17.1 (previous pin)	OK	FAIL (unsupported linker arg)
1.9.1	OK	FAIL (embeds cargo-zigbuild 0.20.1)
1.9.2	OK	OK

Dispatched this branch on CI (run 32763066938): build-arm64 and tier1-windows-build-2 both passed. The Windows log shows the extra resolving as intended — + cargo-lambda==1.9.2, + ziglang==0.16.0 — and choco installing the pinned zig v0.16.0.

Ran the rewritten install step end to end under bash against a clean interpreter: it resolves cargo-lambda==1.9.2 ziglang==0.16.0 from the extra, installs both, and the resulting toolchain builds the arm64 fixture. All four invocations aws_lambda_builders emits succeed — plain, --arm64, and the provided.al2 glibc-pinned aarch64/x86_64 targets — as do the cargo_workspace and multi-binaries fixtures (2 binaries each).

Mandatory Checklist

PRs will only be reviewed after checklist is complete

• Review the generative AI contribution guidelines
• Add input/output type hints to new functions/methods
• Write design document if needed (Do I need to write a design document?)
• Write/update unit tests
• Write/update integration tests
• Write/update functional tests if needed
• make pr passes
• make update-reproducible-reqs if dependencies were changed
• Write documentation

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[roger-zhangg]

https://github.com/aws/aws-sam-cli/actions/runs/32763066938
integ test triggered

[aws-sam-tooling-bot]

Code Review Results

Reviewed: 880ac91..094a57a
Files: 4
Comments: 2

[aws-sam-tooling-bot]

Code Review Results

Reviewed: 880ac91..16fdae4
Files: 4
Comments: 3

[aws-sam-tooling-bot]

Code Review Results

Reviewed: 880ac91..df97741
Files: 4
Comments: 1