Trait Fs 

pub trait Fs {
    // Required methods
    fn read(&self, path: &Path) -> Result<Vec<u8>>;
    fn exists(&self, path: &Path) -> bool;
    fn is_dir(&self, path: &Path) -> bool;
    fn is_file(&self, path: &Path) -> bool;
    fn read_dir(&self, dir: &Path) -> Result<Vec<String>>;
}

Read/write access to the filesystem — the Fs half of the Fs/Git seam (ADR-0001 §2). Domain code (contract loading, journal persistence, sealed plans) goes through this port rather than calling std::fs directly, so it is testable against an in-memory fake. At founding this is a deliberately small surface; it grows (atomic writes, dir listing, metadata) as the journal and plan-sealing units land.

Required Methods

fn read(&self, path: &Path) -> Result<Vec<u8>>

Read a file’s full contents as bytes.

fn exists(&self, path: &Path) -> bool

Whether path exists.

fn is_dir(&self, path: &Path) -> bool

Whether path exists and is a directory (used for the contract’s fragment-dir producer check, which is a directory, not a file).

fn is_file(&self, path: &Path) -> bool

Whether path exists and is a regular file — not a directory, FIFO, socket, or device (mirrors os.path.isfile). The facts detector gates every manifest/config read on this so a non-regular node named Cargo.toml neither marks an ecosystem nor blocks Self::read (a blocking read on a FIFO is a real hang the exists && !is_dir approximation would not prevent).

fn read_dir(&self, dir: &Path) -> Result<Vec<String>>

List the immediate entry names (not full paths) within dir — the facts detector’s CI probe needs to know whether .github/workflows holds at least one entry, not merely that the directory exists. Ok(vec![]) for an empty directory; Err when dir is absent or unreadable (the detector treats that as “no entries”).

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors