Function process_edges

src/cypher/cypher.c:3121–3169

Process edges: look up target node, filter by label/props, add binding. * `inbound` controls which end of the edge is the target id. */

/* Process edges: look up target node, filter by label/props, add binding.
 * `inbound` controls which end of the edge is the target id. */
static void process_edges(cbm_store_t *store, cbm_edge_t *edges, int edge_count, bool inbound,
                          const cbm_node_pattern_t *target_node, binding_t *b, const char *to_var,
                          const char *rel_var, binding_t *new_bindings, int *new_count, int max_new,
                          int *match_count) {
    /* When the terminal node variable is ALREADY bound (e.g. the second pattern
     * `(c)-[:CALLS]->(f)` where `f` came from an earlier MATCH), we must FILTER
     * to edges that actually reach the bound node — not overwrite the caller's
     * `f` binding with whatever node the edge leads to. Overwriting corrupted
     * the result of dead-code queries and produced wrong rows (#627). */
    cbm_node_t *bound_to = binding_get(b, to_var);
    int64_t bound_to_id = bound_to ? bound_to->id : 0;
    /* The budget caps MATERIALISATION, not detection: `match_count` must stay
     * truthful even after `new_count` hits `max_new`. Gating the loop itself
     * (`ei < edge_count && *new_count < max_new`) stopped fetching entirely, so
     * a saturated source reported `match_count == 0` despite having neighbours —
     * and the OPTIONAL fallback in expand_pattern_rels then emitted an unbound
     * "no match" row for it. `WHERE x IS NULL` reads those rows as "nothing
     * points here", i.e. it reported live code as dead. Losing rows is
     * recoverable; asserting a match does not exist when it does is not. */
    for (int ei = 0; ei < edge_count; ei++) {
        int64_t tid = inbound ? edges[ei].source_id : edges[ei].target_id;
        if (bound_to && tid != bound_to_id) {
            continue; /* edge does not reach the already-bound terminal node */
        }
        cbm_node_t found = {0};
        if (cbm_store_find_node_by_id(store, tid, &found) != CBM_STORE_OK) {
            continue;
        }
        if (target_node->label && !label_alt_matches(found.label, target_node->label)) {
            node_fields_free(&found);
            continue;
        }
        if (!check_inline_props(&found, target_node->props, target_node->prop_count, store)) {
            node_fields_free(&found);
            continue;
        }
        (*match_count)++; /* a real neighbour exists, budget or not */
        if (*new_count < max_new) {
            binding_t nb = {0};
            binding_copy(&nb, b);
            binding_set(&nb, to_var, &found);
            if (rel_var) {
                binding_set_edge(&nb, rel_var, &edges[ei]);
            }
            new_bindings[(*new_count)++] = nb;
        }
        node_fields_free(&found);
    }
}

/* Expand variable-length relationship via BFS */
/* Set when a variable-length hop range is clamped to the engine ceiling