Function save_reasoning_to_change

atomic-cli/src/commands/agent/explain.rs:502–531

Save reasoning back into the change's unhashed section. Reads the existing unhashed data, adds the reasoning, and writes the change back to the store. The change hash is NOT affected (unhashed section doesn't contribute to the hash).

(
    repo: &Repository,
    hash: &atomic_core::types::Hash,
    change: &atomic_core::change::Change,
    reasoning: &TurnReasoning,
)

/// the change back to the store. The change hash is NOT affected
/// (unhashed section doesn't contribute to the hash).
fn save_reasoning_to_change(
    repo: &Repository,
    hash: &atomic_core::types::Hash,
    change: &atomic_core::change::Change,
    reasoning: &TurnReasoning,
) -> CliResult<()> {
    let mut updated_change = change.clone();

    // Get or create the unhashed data
    let mut unhashed_data = extract_unhashed(&updated_change).unwrap_or_else(|| {
        // Create minimal unhashed data if none exists
        UnhashedTurnData::new("", 0, "unknown", Vec::new(), &[])
    });

    // Set the reasoning
    unhashed_data = unhashed_data.with_reasoning(reasoning.clone());

    // Attach to the change
    attach_unhashed(&mut updated_change, &unhashed_data)
        .map_err(|e| CliError::Internal(anyhow::anyhow!("Failed to attach reasoning: {}", e)))?;

    // Save the change back to the store.
    // The hash doesn't change because the unhashed section doesn't affect it,
    // so this overwrites the same file at the same content-addressed path.
    let _ = hash; // same hash — save_change recomputes and writes to the same path
    repo.save_change(&updated_change)
        .map_err(CliError::Repository)?;

    Ok(())
}

// Tests