Using pest_derive without std under a workspace fails in Windows.

[Shaddy]

Describe the bug

I have a project that requires no_std, using following dependencies in Cargo.toml

pest = { git = "https://github.com/pest-parser/pest.git", version = "2.7.8", default-features = false }
pest_derive = { git = "https://github.com/pest-parser/pest.git", version = "2.7.8", default-features = false, features = ["not-bootstrap-in-src"] }

That fails to locate the bootstrap file under Windows, while in MacOS or Linux is working properly.

To Reproduce

• Use pest_derive under a workspace project with no_std.

NOTE: I can provide a project to reproduce the bug if necessary.

Expected behavior

pest_bootstrap.exe not panicking trying to locate /meta/src/grammar.pest

Additional context

After debugging generated pest_bootstrap.exe I came to the conclusion that the problematic part is the path retrieved by env!("CARGO_MANIFEST_DIR") here:

    let pest = Path::new(concat!(
        env!("CARGO_MANIFEST_DIR"),
        "/../meta/src/grammar.pest"
    ));

It seems to prepend \\?\ to the Path, making it fail when trying to resolve the relative "../meta" path.

I managed to fix this issue here:

Shaddy@9ea1515

But probably is not the best way to do it, it is just a workaround.

[tomtau]

I wonder why that would be: is it this https://superuser.com/questions/1069055/what-is-the-function-of-question-marks-in-file-system-paths-in-windows-registry ?

I have seen the ?\C:... path used a lot to get access to files/paths longer than 260 characters. At least when dealing with Win32 API calls. (...)

It could also be a bug in Cargo / Rust tooling in how it populates those env vars on Windows?

[tomtau]

rust-lang/cargo#9770

[tomtau]

Maybe a proper fix is to use something like normpath: wasmCloud/wasmCloud@8b876f1 ?

[tomtau]

or call canonicalize on env!("CARGO_MANIFEST_DIR") and then use .push(es) to construct the path?

[Shaddy]

or call canonicalize on env!("CARGO_MANIFEST_DIR") and then use .push(es) to construct the path?

I tried with canonicalize but it has the same problem, as soon as you enter relative path with the prefix "canonicalize" it simply does not find the file. And if the prefix is already there, it won't be removed.

I also don't understand that if I create a simple project with a build.rs and load the CARGO_MANIFEST_DIR path is not prepended with \\?\, but that's another story (tested just in case, if was because the Cargo.toml rustc version but it seems only happens when running from a different directory).

normpath sounds like the best approach probably at this moment