Feature/add parent dir check

[ScottGibb]

Description

This PR Aims to add the ability for cargo metadata to handle git repos in which the cargo.toml file is in a subdirectory. It also aims to test out the cargo metadata functionality inside Docker, Balena and MacOS

Type of change

Please Tick the options that are relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Tested on MacOS

Your Specific Test Case

Checklist

• My code follows the style guidelines of this project (this should be caught by the CI)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings (this should be caught by the CI)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[ScottGibb]

When running on MacOS
fn main() {
println!("cargo:rerun-if-changed=./.git/");
// println!("cargo:rustc-link-arg=-Tmetadata.x");
}

[github-actions]

🦙 MegaLinter status: ⚠️ WARNING

Descriptor	Linter	Files	Fixed	Errors	Warnings	Elapsed time
✅ ACTION	actionlint	3		0	0	0.02s
✅ JSON	jsonlint	3		0	0	0.13s
✅ JSON	prettier	3	0	0	0	0.33s
⚠️ MARKDOWN	markdownlint	6	0	4	0	0.56s
✅ MARKDOWN	markdown-link-check	6		0	0	3.33s
✅ MARKDOWN	markdown-table-formatter	6	0	0	0	0.19s
✅ RUST	clippy	yes		no	no	49.32s
✅ YAML	prettier	5	0	0	0	0.36s
✅ YAML	yamllint	5		0	0	0.4s

See detailed report in MegaLinter reports

[ScottGibb]

Addressing Issue
#1
and
#9

[petekubiak]

When running on MacOS
fn main() {
println!("cargo:rerun-if-changed=./.git/");
// println!("cargo:rustc-link-arg=-Tmetadata.x");
}

For the first line we'll need to sub in whatever the path to the git folder is based on the find_parent() function.

As for the second, you'll need something like that, but it might need adjusting for Mac. The linker script is there to ensure that the section is always included in the binary, even if you don't reference it in your code (otherwise the linker throws it away)

[ScottGibb]

@doublebasil

[ScottGibb]

// println!("cargo:rustc-link-arg=-Tmetadata.x");

#[cfg(not(target_os = "macos"))]
println!("cargo:rustc-link-arg=-Tmetadata.x");

[ScottGibb]

Need to investigate further into Mac Linkers and making sure we link correclty. There seems to be no command line option for declaring this...

[ScottGibb]

@petekubiak I believe this works but im unsure how I can get the git_path and put it into build.rs for example:

within lib.rs

fn find_valid_git_root(mut path: &str) -> Result<Repository, Error> {
    let mut depth = 0;
    loop {
        depth += 1;
        // Find last path separator position
        let pos_slash = path.rfind('/');
        let pos_backslash = path.rfind('\\');
        let last = match (pos_slash, pos_backslash) {
            (Some(s), Some(b)) => core::cmp::max(s, b),
            (Some(s), None) => s,
            (None, Some(b)) => b,
            (None, None) => break, // Reached the top level
        };

        // Take the parent part
        path = &path[..last];

        // If this is a valid repository return it otherwise keep going
        if let Ok(repo) = Repository::open(path) {
            // Tell build.rs what the path is?
            return Ok(repo);
        }
    }
    Err(Error::new(
        Span::call_site(),
        format!("failed to find .git folder after {depth} parents"),
    ))
}

Theres that function ^. However in build.rs I was going to an env variable to get the GIT_DIR

use std::env;

fn main() {
    let git_dir = env::var("PROJECT_GIT_DIR").unwrap_or_else(|_| "./.git/".to_string());
    println!("cargo:rerun-if-changed={}", git_dir);
    #[cfg(not(target_os = "macos"))]
    println!("cargo:rustc-link-arg=-Tmetadata.x");
}

But then I cant use env inside the crate because its no-std . Do you have any thoughts?

[petekubiak]

I think I'd need to have a proper chat with you to understand the issue. Let's catch up on Monday :)

[petekubiak]

Couple minor tweaks - thanks for your work on this!