yoi/crates/manifest/src/cascade.rs
2026-04-27 22:51:07 +09:00

125 lines
4.0 KiB
Rust

//! Cascade-layer collection helpers.
//!
//! Pod manifests are assembled from up to three on-disk layers (see
//! `pod::PodFactory` for the full cascade story):
//!
//! 1. **User manifest** — see [`crate::paths::user_manifest_path`]
//! 2. **Project manifest** at the closest `.insomnia/manifest.toml`
//! found by walking up from a starting directory (typically `cwd`)
//! 3. **Programmatic overlay** supplied at the call site
//!
//! This module owns the project-layer discovery and the parser glue.
//! User-layer path resolution lives in [`crate::paths`].
//!
//! Cascade *merging* and final validation stay outside this module —
//! that's the data layer's responsibility (`PodManifestConfig::merge`
//! and `PodManifest::try_from`). This module only handles the I/O and
//! path-discovery glue around them.
use std::path::{Path, PathBuf};
use crate::PodManifestConfig;
/// Errors returned when reading a single manifest layer from disk.
#[derive(Debug, thiserror::Error)]
pub enum LayerLoadError {
#[error("failed to read manifest {}: {source}", .path.display())]
Io {
path: PathBuf,
#[source]
source: std::io::Error,
},
#[error("failed to parse manifest {}: {source}", .path.display())]
Parse {
path: PathBuf,
#[source]
source: toml::de::Error,
},
}
/// Walk up from `start` looking for `.insomnia/manifest.toml`. Returns
/// the closest match, or `None` if none is found before reaching the
/// filesystem root.
pub fn find_project_manifest_from(start: &Path) -> Option<PathBuf> {
let start = start
.canonicalize()
.ok()
.unwrap_or_else(|| start.to_path_buf());
let mut cur: Option<&Path> = Some(start.as_path());
while let Some(dir) = cur {
let candidate = dir.join(".insomnia").join("manifest.toml");
if candidate.is_file() {
return Some(candidate);
}
cur = dir.parent();
}
None
}
/// Read a manifest file from `path` and parse it as a partial
/// [`PodManifestConfig`]. Path resolution against a base directory and
/// merging with other layers are the caller's responsibility.
pub fn load_layer(path: &Path) -> Result<PodManifestConfig, LayerLoadError> {
let toml = std::fs::read_to_string(path).map_err(|source| LayerLoadError::Io {
path: path.to_path_buf(),
source,
})?;
PodManifestConfig::from_toml(&toml).map_err(|source| LayerLoadError::Parse {
path: path.to_path_buf(),
source,
})
}
#[cfg(test)]
mod tests {
use super::*;
use tempfile::TempDir;
#[test]
fn find_project_manifest_walks_up() {
let tmp = TempDir::new().unwrap();
let root = tmp.path().canonicalize().unwrap();
let manifest = root.join(".insomnia").join("manifest.toml");
std::fs::create_dir_all(manifest.parent().unwrap()).unwrap();
std::fs::write(&manifest, "").unwrap();
let nested = root.join("a").join("b");
std::fs::create_dir_all(&nested).unwrap();
let found = find_project_manifest_from(&nested).unwrap();
assert_eq!(found, manifest);
}
#[test]
fn find_project_manifest_returns_none_when_absent() {
let tmp = TempDir::new().unwrap();
assert!(find_project_manifest_from(tmp.path()).is_none());
}
#[test]
fn load_layer_round_trips_partial_config() {
let tmp = TempDir::new().unwrap();
let path = tmp.path().join("manifest.toml");
std::fs::write(
&path,
r#"
[pod]
name = "from-disk"
"#,
)
.unwrap();
let cfg = load_layer(&path).unwrap();
assert_eq!(cfg.pod.name.as_deref(), Some("from-disk"));
}
#[test]
fn load_layer_io_error_carries_path() {
let bogus = PathBuf::from("/definitely/does/not/exist/manifest.toml");
let err = load_layer(&bogus).unwrap_err();
match err {
LayerLoadError::Io { path, .. } => assert_eq!(path, bogus),
_ => panic!("expected Io variant"),
}
}
}