Function _Validate_call_subquery

src/ast/ast_validations.c:1254–1381

validate a CALL {} (subquery) clause

// validate a CALL {} (subquery) clause
static VISITOR_STRATEGY _Validate_call_subquery
(
	const cypher_astnode_t *n,  // ast-node
	bool start,                 // first traversal
	ast_visitor *visitor        // visitor
) {
	validations_ctx *vctx = AST_Visitor_GetContext(visitor);

	vctx->clause = cypher_astnode_type(n);

	// create a query astnode with the body of the subquery as its body
	cypher_astnode_t *body = cypher_ast_call_subquery_get_query(n);
	uint nclauses = cypher_ast_query_nclauses(body);

	// clone the bound vars context.
	rax *in_env = raxClone(vctx->defined_identifiers);

	// if there are no imports, set the env of bound-vars to the empty env
	const cypher_astnode_t *first_clause = cypher_ast_query_get_clause(body, 0);
	if(cypher_astnode_type(first_clause) !=
	   CYPHER_AST_WITH) {
		raxFree(vctx->defined_identifiers);
		vctx->defined_identifiers = raxNew();
	} else {
		// validate that the with imports (if exist) are simple, i.e., 'WITH a'
		if(!_ValidateCallInitialWith(first_clause, vctx)) {
			raxFree(in_env);
			ErrorCtx_SetError(
				"WITH imports in CALL {} must consist of only simple references\
 to outside variables");
			return VISITOR_BREAK;
		}
	}

	// visit the subquery clauses
	bool last_is_union = false;
	for(uint i = 0; i < nclauses; i++) {
		const cypher_astnode_t *clause =
			cypher_ast_query_get_clause(body, i);
		cypher_astnode_type_t type = cypher_astnode_type(clause);

		// if the current clause is a `UNION` clause, it has reset the bound
		// vars env to the empty env. We compensate for that in case there is no
		// initial `WITH` clause
		if(last_is_union && type == CYPHER_AST_WITH) {
			// set the env of bound-vars to the input env
			raxFree(vctx->defined_identifiers);
			vctx->defined_identifiers = raxClone(in_env);

			// validate that the with imports (if exist) are simple, i.e.,
			// 'WITH a'
			if(!_ValidateCallInitialWith(clause, vctx)) {
				raxFree(in_env);
				ErrorCtx_SetError(
					"WITH imports in CALL {} must consist of only simple \
references to outside variables");
				return VISITOR_BREAK;
			}