Fix Windows CRLF Issue

[timbess]

Cargo configs are injected as a literal string which, on Windows, can end up with escaped CRLF line endings in cargo-bazel.json causing the digests to be different on Linux/Windows. This PR parses the inner string literal to prevent platform specific differences in the config.toml. There might be a better way to do this, but adding a new top level command to cargo-bazel to parse TOML into JSON felt wrong, and adding a second binary seems even worse. I'm open to solving this another way if ya'll have a better idea.

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[timbess]

@UebelAndre Not sure who to ask about this, are there any changes required to get this merged? I'm just checking back in so we can hopefully delete our patch soon.

[UebelAndre]

Sorry, about the delay! How does this fix the issue?

[timbess]

@UebelAndre

Previously the cargo config was stored as a Value::String(... literal file contents). Parsing the inner String into a Value removes the platform specific line endings which caused Windows/Unix to have diverging digests. It would probably be cleaner to parse the TOML into JSON earlier on, but that's done in Starlark so it was a lot easier to handle this in Rust while parsing the config. I'm open to suggestions for better alternatives, but this does fix the issue on our Windows build.

[timbess]

@UebelAndre Sorry to ping you again, but just wanted to check in and see if you had any thoughts.

[UebelAndre]

Thank you for the ping (I unfortunately need them)! Can you add a regression test for this? I suspect this is something that will change over time and with changes such as bazelbuild/bazel#27659 might make doing things in starlark more efficient.

[timbess]

That's cool! Native TOML parsing in Bazel would definitely make this much easier. I added a test that I confirmed fails to replicate the digest without my change.

[timbess]

@UebelAndre Sorry forgot to tag you in my comment. I added a test to ensure Windows/Unix line endings don't change the digest.

[illicitonion]

Thanks for adding the test!

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