Enum Rollback 

#[non_exhaustive]
pub enum Rollback {
    Restored,
    SkippedDiverged,
    Failed(Error),
    NotAttempted,
}

What the concurrency-safe op-log rollback did after a mutation failed — the outcome Jj::rollback_to returns and Jj::transaction reports on its TransactionError. It lets a caller tell a completed rollback apart from one that was deliberately refused (a concurrent process’s work would have been clobbered) or one that failed, instead of guessing by re-probing the op log.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Restored

The repo is back at the captured operation — either op restore ran, or the closure failed before recording any operation, so nothing needed undoing.

SkippedDiverged

The rollback was skipped to avoid clobbering a concurrent process: the operation log diverged between the capture and the restore (jj reconciled a foreign operation with a “reconcile divergent operations” merge), so restoring to the captured operation would have silently reverted that work. The repo is left as the closure and the other process left it; the caller must reconcile. Also returned when the captured operation is no longer within the probed window (ROLLBACK_PROBE_LIMIT operations), so the range cannot be confirmed safe to revert.

Failed(Error)

The rollback itself failed — the divergence probe or the op restore errored. The repo may be left mid-transaction; the carried Error is the cause.

NotAttempted

No rollback was attempted: the transaction failed before it captured a savepoint (e.g. the initial op_head capture itself failed), so there was nothing to roll back.

Implementations

impl Rollback

pub fn is_restored(&self) -> bool

Whether the repo was returned to (or already at) the captured operation.

pub fn failure(&self) -> Option<&Error>

The error, when the rollback itself Failed; None otherwise. Reads it off without destructuring the #[non_exhaustive] enum.

Trait Implementations

impl Debug for Rollback

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Rollback

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.