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//! Error and result types.
use std::path::PathBuf;
use thiserror::Error;
/// Errors produced by prov.
#[derive(Debug, Error)]
pub enum Error {
/// The embedded-metadata backend (`fig`) failed to parse or serialize.
#[error("metadata error: {0}")]
Meta(#[from] fig::Error),
/// A structural invariant was violated (e.g. malformed frontmatter fence).
#[error("{0}")]
Structure(String),
/// A document a workspace operation names is not on disk — the typed form of
/// the many "X does not exist" guards the mutation ops make before touching a
/// document (`reparent`, `rename`, `duplicate`, `register`, …). A caller can
/// tell a genuinely-missing target from a malformed one by matching the
/// variant, rather than sniffing the message text.
#[error("{0} does not exist")]
NotFound(PathBuf),
/// A workspace operation would create a document where one already exists, and
/// refused rather than overwrite it — the typed form of the "X already exists"
/// guards in `create`/`rename`/`attach`. A destination collision is a distinct
/// outcome from a missing source, and now distinguishable as one.
#[error("{0} already exists")]
AlreadyExists(PathBuf),
/// The storage backend failed.
#[error("io error: {0}")]
Io(#[from] std::io::Error),
/// The `twig` body parser failed — see `content.rs`.
#[error("content error: {0}")]
Content(String),
/// A path handed to a workspace read or write resolved *outside* the
/// workspace root — an absolute path, or one that climbs above the root with
/// `..`. prov clamps every I/O to the tree it was pointed at (a link
/// target is data, and data must never be able to name `/etc/passwd` or a
/// sibling repo), so such a path is refused rather than followed. See
/// [`crate::link::escapes_root`], the guard at [`crate::Workspace`]'s `load`
/// and [`crate::ChangeSet::apply`].
#[error("path escapes the workspace root: {0}")]
Escape(PathBuf),
/// A [`ChangeSet`](crate::ChangeSet) was applied while a previous change's
/// write-ahead journal was still on disk — an earlier mutation was
/// interrupted (a crash) and never recovered. Landing this set would
/// overwrite that journal and lose the record needed to complete the
/// interrupted change, so the apply refuses: run recovery
/// ([`crate::journal::recover`], which `prov check` performs) first, then
/// retry.
#[error(
"a previous change was interrupted and not yet recovered (found {0}); \
recover it first (run `prov check`), then retry"
)]
StaleJournal(PathBuf),
/// A staged write failed *and* the rollback that should have undone it also
/// failed — see [`crate::change::ChangeSet::apply`]. The one case where
/// prov cannot say what is on disk, so it says exactly that instead of
/// reporting the original failure as if the workspace were untouched.
#[error(
"{cause}; and rolling back failed too: {rollback}. \
The workspace may be partially written — run `prov check`."
)]
Torn {
/// The failure that triggered the rollback.
cause: String,
/// The failure the rollback itself hit.
rollback: String,
},
}
/// Convenience alias for results in this crate.
pub type Result<T> = std::result::Result<T, Error>;