Inform dep-info users about used environment variables #40364
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C-feature-request
Category: A feature request, i.e: not implemented / a PR.
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I don't have any great ideas, but if we could get this out of the compiler in the same invocation where we get dep-info that would be ideal. Whether it goes to a separate file or is mixed into the dep-info somehow is not particularly important to me. |
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Right now A bit of a hack, but could get the job done. |
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Jun 25, 2020
Print environment variables accessed by rustc as special comments into depinfo files So cargo (and perhaps others tools) can use them for linting (at least) or for actually rebuilding crates on env var changes. --- I've recently observed one more forgotten environment variable in a build script rust-lang@8a77d1c and thought it would be nice to provide the list of accessed variables to cargo automatically as a part of depinfo. Unsurprisingly, I wasn't the first who had this idea - cc rust-lang#70517 rust-lang#40364 rust-lang#44074. Also, there are dozens of uses of `(option_)env!` in rustc repo and, like, half of them are not registered in build scripts. --- Description: - depinfo files are extended with special comments containing info about environment variables accessed during compilation. - Comment format for environment variables with successfully retrieved value: `# env-dep:KEY=VALUE`. - Comment format for environment variables without successfully retrieved value: `# env-dep:KEY` (can happen with `option_env!`). - `KEY` and `VALUE` are minimally escaped (`\n`, `\r`, `\\`) so they don't break makefile comments and can be unescaped by anything that can unescape standard `escape_default` and friends. FCP report: rust-lang#71858 (comment) Closes rust-lang#70517 Closes rust-lang#40364 Closes rust-lang#44074 A new issue in the cargo repo will be needed to track the cargo side of this feature. r? @ehuss
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It'd be great for caching servers like sccache if the compiler could inform them about used environment variables for the compilation through macros like
env!andoption_env!. I'm not precisely sure what the format would look like, but via some means would be great!The text was updated successfully, but these errors were encountered: