Function expand_additional_patterns

src/cypher/cypher.c:4747–4791

Expand additional MATCH patterns (pi >= 1) */

/* Expand additional MATCH patterns (pi >= 1) */
static int expand_additional_patterns(cbm_store_t *store, cbm_query_t *q, const char *project,
                                      int max_rows, binding_t **bindings, int *bind_count,
                                      int *bind_cap) {
    for (int pi = SKIP_ONE; pi < q->pattern_count; pi++) {
        cbm_pattern_t *patn = &q->patterns[pi];
        bool opt = q->pattern_optional[pi];
        const char *nvar = patn->nodes[0].variable ? patn->nodes[0].variable : "_n_extra";
        bool start_bound = *bind_count > 0 && binding_get(&(*bindings)[0], nvar) != NULL;

        if (start_bound && patn->rel_count > 0) {
            const char *tv = nvar;
            expand_pattern_rels(store, patn, bindings, bind_count, bind_cap, &tv, opt);
            continue;
        }

        /* Single-rel pattern whose START is unbound but whose TERMINAL is already
         * bound: drive from the bound terminal instead of scanning all nodes for
         * the start var (avoids the int-overflow OOB write and the c-IS-NULL
         * corruption of #627). */
        if (!start_bound && patn->rel_count == 1 && *bind_count > 0) {
            const char *term_var = patn->nodes[1].variable;
            bool term_bound = term_var && binding_get(&(*bindings)[0], term_var) != NULL;
            if (term_bound) {
                expand_from_bound_terminal(store, patn, bindings, bind_count, nvar, opt);
                continue;
            }
        }

        cbm_node_t *extra_nodes = NULL;
        int extra_count = 0;
        scan_pattern_nodes(store, project, max_rows, &patn->nodes[0], &extra_nodes, &extra_count);
        int rc = 0;
        if (patn->rel_count == 0) {
            rc = cross_join_nodes(bindings, bind_count, extra_nodes, extra_count, nvar, opt);
        } else {
            cross_join_with_rels(store, patn, bindings, bind_count, extra_nodes, extra_count, nvar,
                                 opt);
        }
        cbm_store_free_nodes(extra_nodes, extra_count);
        if (rc != 0) {
            return rc; /* allocation refused/failed: propagate as a query error */
        }
    }
    return 0;
}

/* Project RETURN clause results */
static void execute_return_clause(cbm_query_t *q, cbm_return_clause_t *ret, binding_t *bindings,