githaven/vendor/github.com/mgechev/revive/rule/modifies-param.go

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package rule
import (
"fmt"
"go/ast"
"github.com/mgechev/revive/lint"
)
// ModifiesParamRule lints given else constructs.
type ModifiesParamRule struct{}
// Apply applies the rule to given file.
func (r *ModifiesParamRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
var failures []lint.Failure
onFailure := func(failure lint.Failure) {
failures = append(failures, failure)
}
w := lintModifiesParamRule{onFailure: onFailure}
ast.Walk(w, file.AST)
return failures
}
// Name returns the rule name.
func (r *ModifiesParamRule) Name() string {
return "modifies-parameter"
}
type lintModifiesParamRule struct {
params map[string]bool
onFailure func(lint.Failure)
}
func retrieveParamNames(pl []*ast.Field) map[string]bool {
result := make(map[string]bool, len(pl))
for _, p := range pl {
for _, n := range p.Names {
if n.Name == "_" {
continue
}
result[n.Name] = true
}
}
return result
}
func (w lintModifiesParamRule) Visit(node ast.Node) ast.Visitor {
switch v := node.(type) {
case *ast.FuncDecl:
w.params = retrieveParamNames(v.Type.Params.List)
case *ast.IncDecStmt:
if id, ok := v.X.(*ast.Ident); ok {
checkParam(id, &w)
}
case *ast.AssignStmt:
lhs := v.Lhs
for _, e := range lhs {
id, ok := e.(*ast.Ident)
if ok {
checkParam(id, &w)
}
}
}
return w
}
func checkParam(id *ast.Ident, w *lintModifiesParamRule) {
if w.params[id.Name] {
w.onFailure(lint.Failure{
Confidence: 0.5, // confidence is low because of shadow variables
Node: id,
Category: "bad practice",
Failure: fmt.Sprintf("parameter '%s' seems to be modified", id),
})
}
}