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This post is auto-generated from RSS feed The Rust Programming Language Forum - Latest topics. Source: What happens when you output the same variable with `cargo::metadata` in a build script?

The links documentation doesn't mention what happens when the same variable is set with cargo::metadata in a build script.

For example in a build.rs file:

println!("cargo::metadata=MYVAR=1");
println!("cargo::metadata=MYVAR=2");
// ...

Scanning the cargo code, it looks like the latest print statement will overrule all others before it and my experimentation appears to confirm this; downstream build scripts will see DEP_<LINKS_NAME>_MYVAR set to 2 only. Perhaps this gap should be documented in the cargo documentation?

I noticed the openssl-sys crate had a scenario where this cargo directive was being printed in a loop which I found confusing (I know it isn't explicitly printing cargo::metadata but this is just the old way to set metadata). Why not just print the last one since the last one overrules all the others?

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