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20 lines
1.1 KiB
Markdown
20 lines
1.1 KiB
Markdown
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## Philosophy
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Crane is designed around the idea of composing cargo invocations such that they
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can take advantage of the artifacts generated in previous invocations. This
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allows for both flexible configurations and great caching (à la Cachix) in CI
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and local development builds.
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Here's how it works at a high level: when a cargo workspace is built its source
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is first transformed such that only the dependencies listed by the `Cargo.toml`
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and `Cargo.lock` files are built, and none of the crate's real source is
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included. This allows cargo to build all dependency crates and prevents Nix from
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invalidating the derivation whenever the source files are updated. Then, a
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second derivation is built, this time using the real source files, which also
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imports the cargo artifacts generated in the first step.
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This pattern can be used with any arbitrary sequence of commands, regardless of
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whether those commands are running additional lints, performing code coverage
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analysis, or even generating types from a model schema. Let's take a look at two
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examples at how very similar configurations can give us very different behavior!
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