114 lines
2.3 KiB
Go
114 lines
2.3 KiB
Go
package rule
|
|
|
|
import (
|
|
"go/ast"
|
|
|
|
"github.com/mgechev/revive/lint"
|
|
)
|
|
|
|
// UnreachableCodeRule lints unreachable code.
|
|
type UnreachableCodeRule struct{}
|
|
|
|
// Apply applies the rule to given file.
|
|
func (r *UnreachableCodeRule) 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 := lintUnreachableCode{onFailure, branchingFunctions}
|
|
ast.Walk(w, file.AST)
|
|
return failures
|
|
}
|
|
|
|
// Name returns the rule name.
|
|
func (r *UnreachableCodeRule) Name() string {
|
|
return "unreachable-code"
|
|
}
|
|
|
|
type lintUnreachableCode struct {
|
|
onFailure func(lint.Failure)
|
|
branchingFunctions map[string]map[string]bool
|
|
}
|
|
|
|
func (w lintUnreachableCode) Visit(node ast.Node) ast.Visitor {
|
|
blk, ok := node.(*ast.BlockStmt)
|
|
if !ok {
|
|
return w
|
|
}
|
|
|
|
if len(blk.List) < 2 {
|
|
return w
|
|
}
|
|
loop:
|
|
for i, stmt := range blk.List[:len(blk.List)-1] {
|
|
// println("iterating ", len(blk.List))
|
|
next := blk.List[i+1]
|
|
if _, ok := next.(*ast.LabeledStmt); ok {
|
|
continue // skip if next statement is labeled
|
|
}
|
|
|
|
switch s := stmt.(type) {
|
|
case *ast.ReturnStmt:
|
|
w.onFailure(newUnreachableCodeFailure(s))
|
|
break loop
|
|
case *ast.BranchStmt:
|
|
token := s.Tok.String()
|
|
if token != "fallthrough" {
|
|
w.onFailure(newUnreachableCodeFailure(s))
|
|
break loop
|
|
}
|
|
case *ast.ExprStmt:
|
|
ce, ok := s.X.(*ast.CallExpr)
|
|
if !ok {
|
|
continue
|
|
}
|
|
// it's a function call
|
|
fc, ok := ce.Fun.(*ast.SelectorExpr)
|
|
if !ok {
|
|
continue
|
|
}
|
|
|
|
id, ok := fc.X.(*ast.Ident)
|
|
|
|
if !ok {
|
|
continue
|
|
}
|
|
fn := fc.Sel.Name
|
|
pkg := id.Name
|
|
if !w.branchingFunctions[pkg][fn] { // it isn't a call to a branching function
|
|
continue
|
|
}
|
|
|
|
if _, ok := next.(*ast.ReturnStmt); ok { // return statement needed to satisfy function signature
|
|
continue
|
|
}
|
|
|
|
w.onFailure(newUnreachableCodeFailure(s))
|
|
break loop
|
|
}
|
|
}
|
|
|
|
return w
|
|
}
|
|
|
|
func newUnreachableCodeFailure(node ast.Node) lint.Failure {
|
|
return lint.Failure{
|
|
Confidence: 1,
|
|
Node: node,
|
|
Category: "logic",
|
|
Failure: "unreachable code after this statement",
|
|
}
|
|
}
|