The project's Cargo.toml and .cargo/config.toml both set
`incremental = true`, which makes rustc emit per-query save-analysis
artifacts that sccache does not cache. Result: even though
RUSTC_WRAPPER=sccache was set, the rustc calls wrote incremental
state that subsequent builds saw as stale and recompiled anyway.
Setting CARGO_INCREMENTAL=0 in the ensure-binary env forces rustc
to emit pure object output that sccache hashes uniformly on
(source + args). Same SHA → full cache hit; small source change →
only dirty crates recompile.
Does not change the service compile-and-deploy-template path,
which intentionally uses cargo-incremental against a persistent
/cargo-target-cpu PVC for repeated rebuilds of a narrow set of
service binaries.
Applies from the next workflow submission onward (train-5wb4n
already compiled under the old config and is running).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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