nodedb 0.4.0

// SPDX-License-Identifier: BUSL-1.1

//! MERGE/RESOLVE wire format shared by the autocommit orchestrator
//! ([`super::orchestrator::run_merge`]) and the COMMIT-time in-transaction
//! expander ([`super::expand_staged_merge`]): both resolve a merge's arms
//! through the SAME Data-Plane RESOLVE pass and decode its payload here.
//! Target-identity derivation (primary-key classification, surrogate
//! assignment, etc.) lives in [`crate::control::target_identity`] and is
//! shared with `INSERT ... SELECT` / `UPDATE ... FROM`.

/// The three resolved arms of a MERGE, decoded from the Data-Plane RESOLVE
/// pass. `updates` / `deletes` carry the EXISTING target row's storage key
/// (`doc_id`), its registered `surrogate` (`None` only for a legacy
/// non-surrogate-keyed row — unreachable for any surrogate-keyed collection),
/// and the arm's resolved body (post-image for updates, the deleted row for
/// deletes so its PK can be extracted). `inserts` carry `(join_key, body)`.
#[derive(Default)]
pub(crate) struct ResolvedMergeArms {
    pub(crate) updates: Vec<(String, Option<u32>, Vec<u8>)>,
    pub(crate) deletes: Vec<(String, Option<u32>, Vec<u8>)>,
    pub(crate) inserts: Vec<(String, Vec<u8>)>,
}

/// Decode the RESOLVE pass payload (a msgpack 3-tuple `(updates, deletes,
/// inserts)`; see `execute_merge_resolve`) into [`ResolvedMergeArms`].
pub(crate) fn decode_resolve(payload: &[u8]) -> crate::Result<ResolvedMergeArms> {
    if payload.is_empty() {
        return Ok(ResolvedMergeArms::default());
    }
    type Wire = (
        Vec<(String, Option<u32>, Vec<u8>)>,
        Vec<(String, Option<u32>, Vec<u8>)>,
        Vec<(String, Vec<u8>)>,
    );
    let (updates, deletes, inserts): Wire =
        zerompk::from_msgpack(payload).map_err(|e| crate::Error::Serialization {
            format: "msgpack".into(),
            detail: format!("merge resolve rows: {e}"),
        })?;
    Ok(ResolvedMergeArms {
        updates,
        deletes,
        inserts,
    })
}