Method Validate

cel/validator.go:415–447

Validate implements the ASTValidator interface method.

(e *Env, _ ValidatorConfig, a *ast.AST, iss *Issues)

// Validate implements the ASTValidator interface method.
func (v nestingLimitValidator) Validate(e *Env, _ ValidatorConfig, a *ast.AST, iss *Issues) {
	root := ast.NavigateAST(a)
	comprehensions := ast.MatchDescendants(root, ast.KindMatcher(ast.ComprehensionKind))
	if len(comprehensions) <= v.limit {
		return
	}
	for _, comp := range comprehensions {
		count := 0
		e := comp
		hasParent := true
		for hasParent {
			// When the expression is not a comprehension, continue to the next ancestor.
			if e.Kind() != ast.ComprehensionKind {
				e, hasParent = e.Parent()
				continue
			}
			// When the comprehension has an empty range, continue to the next ancestor
			// as this comprehension does not have any associated cost.
			iterRange := e.AsComprehension().IterRange()
			if iterRange.Kind() == ast.ListKind && iterRange.AsList().Size() == 0 {
				e, hasParent = e.Parent()
				continue
			}
			// Otherwise check the nesting limit.
			count++
			if count > v.limit {
				iss.ReportErrorAtID(comp.ID(), "comprehension exceeds nesting limit")
				break
			}
			e, hasParent = e.Parent()
		}
	}
}