use std::{    borrow::Cow,    path::{Component, Path},}; use crate::path; pub mod existing {    use std::path::PathBuf;     #[derive(Debug, thiserror::Error)]    pub enum Error {        #[error("Failed to access a directory, or path is not a directory: '{}'", .path.display())]        InaccessibleDirectory { path: PathBuf },        #[error("Could find a git repository in '{}' or in any of its parents", .path.display())]        NoGitRepository { path: PathBuf },    }} /// Returns the work tree if possible and the found repository is not bare or the git repository itself,/// and traverse parent directories until a Repository is found.pub fn existing(directory: impl AsRef<Path>) -> Result<crate::Path, existing::Error> {    // Canonicalize the path so that `Path::parent` _actually_ gives    // us the parent directory. (`Path::parent` just strips off the last    // path component, which means it will not do what you expect when    // working with paths paths that contain '..'.)    let directory = maybe_canonicalize(directory.as_ref()).map_err(|_| existing::Error::InaccessibleDirectory {        path: directory.as_ref().into(),    })?;    if !directory.is_dir() {        return Err(existing::Error::InaccessibleDirectory {            path: directory.into_owned(),        });    }     let mut cursor: &Path = &directory;    loop {        if let Ok(kind) = path::is_git(cursor) {            break Ok(crate::Path::from_dot_git_dir(cursor, kind));        }        let git_dir = cursor.join(".git");        if let Ok(kind) = path::is_git(&git_dir) {            break Ok(crate::Path::from_dot_git_dir(git_dir, kind));        }        match cursor.parent() {            Some(parent) => cursor = parent,            None => {                break Err(existing::Error::NoGitRepository {                    path: directory.into_owned(),                })            }        }    }} fn maybe_canonicalize(path: &Path) -> std::io::Result<Cow<'_, Path>> {    let ends_with_relative_component = path        .components()        .last()        .map_or(true, |c| matches!(c, Component::CurDir | Component::ParentDir));    if ends_with_relative_component {        path.canonicalize().map(Into::into)    } else {        Ok(path.into())    }} #[cfg(test)]mod maybe_canonicalize {    use super::*;     fn relative_component_count(path: impl AsRef<Path>) -> usize {        path.as_ref()            .components()            .filter(|c| matches!(c, Component::CurDir | Component::ParentDir))            .count()    }     #[test]    fn empty_paths_are_invalid() {        assert!(            maybe_canonicalize(Path::new("")).is_err(),            "empty paths are not equivalent to '.' but are non-existing"        );    }     #[test]    fn paths_starting_with_dot_but_end_with_normal_path_are_not_canonicalized() {        assert_eq!(            relative_component_count(maybe_canonicalize(&Path::new(".").join("hello")).unwrap()),            1,        );    }     #[test]    fn paths_ending_with_non_normal_component_are_canonicalized() {        assert_eq!(            relative_component_count(maybe_canonicalize(&Path::new(".").join(".")).unwrap()),            0,        );    }}