114 lines
2.2 KiB
Go
114 lines
2.2 KiB
Go
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package rule
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import (
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"fmt"
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"go/ast"
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"go/token"
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"github.com/mgechev/revive/lint"
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)
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// RangeValAddress lints
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type RangeValAddress struct{}
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// Apply applies the rule to given file.
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func (r *RangeValAddress) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
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var failures []lint.Failure
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walker := rangeValAddress{
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onFailure: func(failure lint.Failure) {
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failures = append(failures, failure)
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},
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}
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ast.Walk(walker, file.AST)
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return failures
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}
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// Name returns the rule name.
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func (r *RangeValAddress) Name() string {
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return "range-val-address"
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}
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type rangeValAddress struct {
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onFailure func(lint.Failure)
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}
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func (w rangeValAddress) Visit(node ast.Node) ast.Visitor {
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n, ok := node.(*ast.RangeStmt)
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if !ok {
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return w
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}
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value, ok := n.Value.(*ast.Ident)
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if !ok {
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return w
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}
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ast.Walk(rangeBodyVisitor{
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valueID: value.Obj,
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onFailure: w.onFailure,
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}, n.Body)
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return w
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}
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type rangeBodyVisitor struct {
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valueID *ast.Object
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onFailure func(lint.Failure)
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}
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func (bw rangeBodyVisitor) Visit(node ast.Node) ast.Visitor {
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asgmt, ok := node.(*ast.AssignStmt)
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if !ok {
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return bw
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}
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for _, exp := range asgmt.Lhs {
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e, ok := exp.(*ast.IndexExpr)
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if !ok {
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continue
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}
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if bw.isAccessingRangeValueAddress(e.Index) { // e.g. a[&value]...
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bw.onFailure(bw.newFailure(e.Index))
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}
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}
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for _, exp := range asgmt.Rhs {
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switch e := exp.(type) {
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case *ast.UnaryExpr: // e.g. ...&value
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if bw.isAccessingRangeValueAddress(e) {
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bw.onFailure(bw.newFailure(e))
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}
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case *ast.CallExpr:
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if fun, ok := e.Fun.(*ast.Ident); ok && fun.Name == "append" { // e.g. ...append(arr, &value)
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for _, v := range e.Args {
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if bw.isAccessingRangeValueAddress(v) {
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bw.onFailure(bw.newFailure(e))
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}
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}
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}
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}
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}
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return bw
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}
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func (bw rangeBodyVisitor) isAccessingRangeValueAddress(exp ast.Expr) bool {
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u, ok := exp.(*ast.UnaryExpr)
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if !ok {
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return false
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}
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v, ok := u.X.(*ast.Ident)
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return ok && u.Op == token.AND && v.Obj == bw.valueID
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}
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func (bw rangeBodyVisitor) newFailure(node ast.Node) lint.Failure {
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return lint.Failure{
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Node: node,
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Confidence: 1,
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Failure: fmt.Sprintf("suspicious assignment of '%s'. range-loop variables always have the same address", bw.valueID.Name),
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}
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}
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