fix(skills): misleading DCE advice in setup-harness#350
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`benchmark.pedantic` is not a dead-code-elimination tool; it controls the measurement loop. CPython doesn't perform the kind of DCE that `black_box` guards against in compiled languages, so pure-Python benchmarks don't need an equivalent. List the actual primitives for the languages that do (C++: DoNotOptimize, JMH: Blackhole.consume).
Merging this PR will not alter performance
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Caught by the trailing-whitespace pre-commit hook on PR #350.
`rustup show` stopped auto-installing the active toolchain in rustup 1.28 (March 2025). The change in 9afaef7 happened to keep working because the macOS-15-arm64 runner image at the time still shipped an older rustup; once GitHub rolled out image 20260511.0048 with rustup >= 1.28, /Users/runner/.cargo/bin/cargo stayed as the rustup-init shim and `cargo fmt`/`cargo clippy` started failing in lint (macos-latest) with `unexpected argument 'fmt' found`. Per the rustup 1.28 release notes, the explicit replacement is `rustup toolchain install`, which is what this action used before.
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The skill told users to use
benchmark.pedantic()in Python to prevent dead code elimination, likeblack_box()in Rust. Two problems with that.benchmark.pedanticdoes not prevent dead code elimination. It just lets you set rounds, iterations, and a setup function for the benchmark.CPython does not delete unused function calls. It can't know if a function has side effects, so it always runs it. Pure-Python benchmarks do not need a
black_box.The new wording only mentions compiled languages and uses the right name for each one.