Method Check

cel/env.go:417–471

Check performs type-checking on the input Ast and yields a checked Ast and/or set of Issues. If any `ASTValidators` are configured on the environment, they will be applied after a valid type-check result. If any issues are detected, the validators will provide them on the output Issues object. Eith

(ast *Ast)

// It is possible to have both non-nil Ast and Issues values returned from this call: however,
// the mere presence of an Ast does not imply that it is valid for use.
func (e *Env) Check(ast *Ast) (*Ast, *Issues) {
	// Surface any error recorded while the Ast was loaded (e.g. an over-deep AST rejected by
	// ParsedExprToAst / CheckedExprToAst) before recursing into the type checker on it.
	if ast != nil && ast.loadErr != nil {
		errs := common.NewErrors(ast.Source())
		errs.ReportErrorString(common.NoLocation, ast.loadErr.Error())
		return nil, NewIssuesWithSourceInfo(errs, ast.NativeRep().SourceInfo())
	}
	if nodeLimit := e.configuredExpressionNodeLimit(); nodeLimit > 0 && ast != nil && ast.NativeRep() != nil {
		if count := celast.NodeCount(ast.NativeRep()); count > nodeLimit {
			errs := common.NewErrors(ast.Source())
			errs.ReportErrorString(common.NoLocation, fmt.Sprintf("expression node count exceeds limit: count %d, limit %d", count, nodeLimit))
			return nil, NewIssuesWithSourceInfo(errs, ast.NativeRep().SourceInfo())
		}
	}
	// Construct the internal checker env, erroring if there is an issue adding the declarations.
	chk, err := e.initChecker()
	if err != nil {
		errs := common.NewErrors(ast.Source())
		errs.ReportErrorString(common.NoLocation, err.Error())
		return nil, NewIssuesWithSourceInfo(errs, ast.NativeRep().SourceInfo())
	}

	checked, errs := checker.Check(ast.NativeRep(), ast.Source(), chk)
	if len(errs.GetErrors()) > 0 {
		return nil, NewIssuesWithSourceInfo(errs, ast.NativeRep().SourceInfo())
	}
	// Manually create the Ast to ensure that the Ast source information (which may be more
	// detailed than the information provided by Check), is returned to the caller.
	ast = &Ast{
		source: ast.Source(),
		impl:   checked}

	// Avoid creating a validator config if it's not needed.
	if len(e.validators) == 0 {
		return ast, nil
	}

	// Generate a validator configuration from the set of configured validators.
	vConfig := newValidatorConfig()
	for _, v := range e.validators {
		if cv, ok := v.(ASTValidatorConfigurer); ok {
			cv.Configure(vConfig)
		}
	}
	// Apply additional validators on the type-checked result.
	iss := NewIssuesWithSourceInfo(errs, ast.NativeRep().SourceInfo())
	for _, v := range e.validators {
		v.Validate(e, vConfig, checked, iss)
	}
	if iss.Err() != nil {
		return nil, iss
	}
	return ast, nil
}

// configuredExpressionSizeLimit returns the effective expression size code point limit.
// A zero value means "use the parser default".