crate-seq-manifest

Overview

crate-seq-manifest provides safe Cargo.toml manipulation that preserves comments and formatting. It supports version rewriting and path dependency scanning. Used by crate-seq-core during the publish pipeline to set version fields and validate manifests.

Version rewriting — rewrite.rs

rewrite_version

pub fn rewrite_version(
    cargo_toml_path: &Path,
    version: &semver::Version,
) -> Result<(), Error>

Unconditionally rewrites the [package].version field in the specified Cargo.toml to match version. All other fields, comments, and formatting are left intact. The write is idempotent — if the version already matches, the file is still rewritten for consistency. Uses an atomic write for crash safety.

Atomic write

1. Writes content to {path}.toml.tmp
2. Calls fs::rename to atomically replace the original
3. If rename fails, removes the .tmp file before returning the error

This ensures a crash mid-write never leaves a corrupted Cargo.toml.

Error conditions

• Error::Io — file cannot be read or written
• Error::Toml — file is not valid TOML
• Error::MissingVersion — [package] table or version key is absent

Path dependency scanning — deps.rs

path_dependencies

pub fn path_dependencies(
    cargo_toml_path: &Path,
) -> Result<Vec<PathDep>, Error>

Scans [dependencies], [dev-dependencies], and [build-dependencies] for entries with a path = "..." field. Returns an empty Vec when no path dependencies are present. Handles both inline tables (dep = { path = "...", version = "..." }) and regular tables ([dependencies.dep] with a path key).

PathDep

pub struct PathDep {
    pub name: String,        // dependency name as declared
    pub path: PathBuf,       // the path value from the table
}

Error type — error.rs

#[derive(Debug, thiserror::Error)]
pub enum Error {
    Io { path: PathBuf, source: std::io::Error },
    Toml { path: PathBuf, source: toml_edit::TomlError },
    MissingVersion(PathBuf),
    PathDependency { name: String, path: PathBuf },
}

All I/O and TOML errors carry the path that triggered them for actionable diagnostics.

Source files