114 lines
2.8 KiB
Go
Vendored
114 lines
2.8 KiB
Go
Vendored
package rule
|
|
|
|
import (
|
|
"fmt"
|
|
"go/ast"
|
|
"go/token"
|
|
|
|
"github.com/mgechev/revive/lint"
|
|
)
|
|
|
|
// SuperfluousElseRule lints given else constructs.
|
|
type SuperfluousElseRule struct{}
|
|
|
|
// Apply applies the rule to given file.
|
|
func (r *SuperfluousElseRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
|
|
var failures []lint.Failure
|
|
onFailure := func(failure lint.Failure) {
|
|
failures = append(failures, failure)
|
|
}
|
|
|
|
var branchingFunctions = map[string]map[string]bool{
|
|
"os": map[string]bool{"Exit": true},
|
|
"log": map[string]bool{
|
|
"Fatal": true,
|
|
"Fatalf": true,
|
|
"Fatalln": true,
|
|
"Panic": true,
|
|
"Panicf": true,
|
|
"Panicln": true,
|
|
},
|
|
}
|
|
|
|
w := lintSuperfluousElse{make(map[*ast.IfStmt]bool), onFailure, branchingFunctions}
|
|
ast.Walk(w, file.AST)
|
|
return failures
|
|
}
|
|
|
|
// Name returns the rule name.
|
|
func (r *SuperfluousElseRule) Name() string {
|
|
return "superfluous-else"
|
|
}
|
|
|
|
type lintSuperfluousElse struct {
|
|
ignore map[*ast.IfStmt]bool
|
|
onFailure func(lint.Failure)
|
|
branchingFunctions map[string]map[string]bool
|
|
}
|
|
|
|
func (w lintSuperfluousElse) Visit(node ast.Node) ast.Visitor {
|
|
ifStmt, ok := node.(*ast.IfStmt)
|
|
if !ok || ifStmt.Else == nil {
|
|
return w
|
|
}
|
|
if w.ignore[ifStmt] {
|
|
if elseif, ok := ifStmt.Else.(*ast.IfStmt); ok {
|
|
w.ignore[elseif] = true
|
|
}
|
|
return w
|
|
}
|
|
if elseif, ok := ifStmt.Else.(*ast.IfStmt); ok {
|
|
w.ignore[elseif] = true
|
|
return w
|
|
}
|
|
if _, ok := ifStmt.Else.(*ast.BlockStmt); !ok {
|
|
// only care about elses without conditions
|
|
return w
|
|
}
|
|
if len(ifStmt.Body.List) == 0 {
|
|
return w
|
|
}
|
|
shortDecl := false // does the if statement have a ":=" initialization statement?
|
|
if ifStmt.Init != nil {
|
|
if as, ok := ifStmt.Init.(*ast.AssignStmt); ok && as.Tok == token.DEFINE {
|
|
shortDecl = true
|
|
}
|
|
}
|
|
extra := ""
|
|
if shortDecl {
|
|
extra = " (move short variable declaration to its own line if necessary)"
|
|
}
|
|
|
|
lastStmt := ifStmt.Body.List[len(ifStmt.Body.List)-1]
|
|
switch stmt := lastStmt.(type) {
|
|
case *ast.BranchStmt:
|
|
token := stmt.Tok.String()
|
|
if token != "fallthrough" {
|
|
w.onFailure(newFailure(ifStmt.Else, "if block ends with a "+token+" statement, so drop this else and outdent its block"+extra))
|
|
}
|
|
case *ast.ExprStmt:
|
|
if ce, ok := stmt.X.(*ast.CallExpr); ok { // it's a function call
|
|
if fc, ok := ce.Fun.(*ast.SelectorExpr); ok {
|
|
if id, ok := fc.X.(*ast.Ident); ok {
|
|
fn := fc.Sel.Name
|
|
pkg := id.Name
|
|
if w.branchingFunctions[pkg][fn] { // it's a call to a branching function
|
|
w.onFailure(
|
|
newFailure(ifStmt.Else, fmt.Sprintf("if block ends with call to %s.%s function, so drop this else and outdent its block%s", pkg, fn, extra)))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return w
|
|
}
|
|
|
|
func newFailure(node ast.Node, msg string) lint.Failure {
|
|
return lint.Failure{
|
|
Confidence: 1,
|
|
Node: node,
|
|
Category: "indent",
|
|
Failure: msg,
|
|
}
|
|
}
|