Script-ey or CLI-ey things that can still run when main project won't compile | Rust Programming Language Community | Page 1

opal dove May 31, 2025, 9:17 AM

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I have e.g. a codegen task that (say) creates a file generated.rs. This is partly in Rust and it also calls out to an external command.

I tried having a cli binary and adding a codegen subcommand with clap etc. but my problem is that, when my codegen is misconfigured, generated.rs may have compiler errors that prevent the whole project from compiling, and thus I can't re-run my codegen command to fix the problem.

I've moved to a completely external script using rust-script, but of course this means I can't re-use code easily from the project, and (at least my) IDE support for rust-script is pretty poor.

Is there a better way to do this? Maybe this is a case for workspaces? Although I've not used them before.

worthy dagger May 31, 2025, 11:05 AM

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maybe generating in build.rs then using include! ?

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or using a proc macro ig

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id prefer build.rs

opal dove May 31, 2025, 11:28 AM

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yeah I considered these but in reality it's generating types from my DB and I kind of like controlling when the gen happens manually, since otherwise running the DB becomes a dep for building the project... although maybe doing that does give tighter guarantees that the types are matching up with the DB state at all times

rustic bronze May 31, 2025, 2:55 PM

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a workspace will solve this problem

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define your cli in a separate package, in the same workspace, which does not depend on the package that uses the generated code

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such tool packages are often named xtask and set up to be easily runnable https://github.com/matklad/cargo-xtask

#Script-ey or CLI-ey things that can still run when main project won't compile