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- package rule
-
- import (
- "go/ast"
-
- "github.com/mgechev/revive/lint"
- )
-
- // ErrorReturnRule lints given else constructs.
- type ErrorReturnRule struct{}
-
- // Apply applies the rule to given file.
- func (r *ErrorReturnRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
- var failures []lint.Failure
-
- fileAst := file.AST
- walker := lintErrorReturn{
- file: file,
- fileAst: fileAst,
- onFailure: func(failure lint.Failure) {
- failures = append(failures, failure)
- },
- }
-
- ast.Walk(walker, fileAst)
-
- return failures
- }
-
- // Name returns the rule name.
- func (r *ErrorReturnRule) Name() string {
- return "error-return"
- }
-
- type lintErrorReturn struct {
- file *lint.File
- fileAst *ast.File
- onFailure func(lint.Failure)
- }
-
- func (w lintErrorReturn) Visit(n ast.Node) ast.Visitor {
- fn, ok := n.(*ast.FuncDecl)
- if !ok || fn.Type.Results == nil {
- return w
- }
- ret := fn.Type.Results.List
- if len(ret) <= 1 {
- return w
- }
- if isIdent(ret[len(ret)-1].Type, "error") {
- return nil
- }
- // An error return parameter should be the last parameter.
- // Flag any error parameters found before the last.
- for _, r := range ret[:len(ret)-1] {
- if isIdent(r.Type, "error") {
- w.onFailure(lint.Failure{
- Category: "arg-order",
- Confidence: 0.9,
- Node: fn,
- Failure: "error should be the last type when returning multiple items",
- })
- break // only flag one
- }
- }
- return w
- }
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