Function find_unrecord_set

atomic-repository/src/unrecord.rs:504–553

Find all changes that would need to be unrecorded to safely remove a change. This includes the target change plus any dependents (in topological order). # Arguments `txn` - Read transaction `view` - View to analyze `hash` - Hash of the change to unrecord `max_depth` - Maximum cascade depth # Returns A vector of hashes in the order they should be unrecorded (dependents first).

(
    txn: &T,
    view: &ViewState,
    hash: &Hash,
    max_depth: Option<usize>,
)

///
/// A vector of hashes in the order they should be unrecorded (dependents first).
pub fn find_unrecord_set<T: ViewTxnT>(
    txn: &T,
    view: &ViewState,
    hash: &Hash,
    max_depth: Option<usize>,
) -> UnrecordResult<Vec<Hash>> {
    let max_depth = max_depth.unwrap_or(100);
    let mut result = Vec::new();
    let mut visited = HashSet::new();
    let mut to_process = vec![(*hash, 0)];

    while let Some((current_hash, depth)) = to_process.pop() {
        if depth > max_depth {
            return Err(UnrecordError::Inconsistent {
                reason: format!("Cascade depth exceeded maximum of {}", max_depth),
            });
        }

        if visited.contains(&current_hash) {
            continue;
        }
        visited.insert(current_hash);

        // Get internal ID
        let node_id = match txn.get_internal(&current_hash) {
            Ok(Some(id)) => id,
            Ok(None) => continue,
            Err(e) => return Err(UnrecordError::Database(e.to_string())),
        };

        // Check if in view
        if txn
            .get_change_seq(view, node_id)
            .map_err(|e| UnrecordError::Database(e.to_string()))?
            .is_none()
        {
            continue;
        }

        result.push(current_hash);

        // Note: Finding dependents requires traversing all changes
        // In a full implementation, we'd use the rev_deps table
    }

    // Reverse so dependents come first
    result.reverse();

    Ok(result)
}

/// Compute the new Merkle state after unrecording changes.
///