Function _Validate_rel_pattern

src/ast/ast_validations.c:748–825

validate a relation-pattern

// validate a relation-pattern
static VISITOR_STRATEGY _Validate_rel_pattern
(
	const cypher_astnode_t *n,  // ast-node (rel-pattern)s
	bool start,                 // first traversal
	ast_visitor *visitor        // visitor
) {
	validations_ctx *vctx = AST_Visitor_GetContext(visitor);
	if(!start) {
		return VISITOR_CONTINUE;
	}

	const cypher_astnode_t *range = cypher_ast_rel_pattern_get_varlength(n);
	if(vctx->clause == CYPHER_AST_CREATE) {
		// validate that the relation alias is not bound
		if(_ValidateCreateRelation(n, vctx->defined_identifiers) == AST_INVALID) {
			return VISITOR_BREAK;
		}

		// Validate that each relation has exactly one type
		uint reltype_count = cypher_ast_rel_pattern_nreltypes(n);
		if(reltype_count != 1) {
			ErrorCtx_SetError("Exactly one relationship type must be specified for CREATE");
			return VISITOR_BREAK;
		}

		// Validate that each relation being created is directed
		if(cypher_ast_rel_pattern_get_direction(n) == CYPHER_REL_BIDIRECTIONAL) {
			ErrorCtx_SetError("Only directed relationships are supported in CREATE");
			return VISITOR_BREAK;
		}

		// Validate that each relation being created is not variable length relationship
		if(range) {
			ErrorCtx_SetError("Variable length relationships cannot be used in CREATE");
			return VISITOR_BREAK;
		}
	}

	if(_ValidateInlinedProperties(cypher_ast_rel_pattern_get_properties(n)) == AST_INVALID) {
		return VISITOR_BREAK;
	}

	if(vctx->clause == CYPHER_AST_MERGE &&
		_ValidateMergeRelation(n, vctx->defined_identifiers) == AST_INVALID) {
		return VISITOR_BREAK;
	}

	const cypher_astnode_t *alias_node = cypher_ast_rel_pattern_get_identifier(n);
	if(!alias_node && !range) {
		return VISITOR_RECURSE; // Skip unaliased, single-hop entities.
	}

	// If this is a multi-hop traversal, validate it accordingly
	if(range && _ValidateMultiHopTraversal(n, range) == AST_INVALID) {
		return VISITOR_BREAK;
	}

	if(alias_node) {