mirror of
https://github.com/golang/go
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01f8cd246d
They will be deleted from their current homes once this has landed. Changes made to import paths to make the code compile, and to find errchk in the right place in cmd/vet's Makefile. TODO in a later CL: tidy up vet. R=golang-dev, gri CC=golang-dev https://golang.org/cl/9495043
66 lines
1.5 KiB
Go
66 lines
1.5 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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/*
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This file contains the code to check range loop variables bound inside function
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literals that are deferred or launched in new goroutines. We only check
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instances where the defer or go statement is the last statement in the loop
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body, as otherwise we would need whole program analysis.
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For example:
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for i, v := range s {
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go func() {
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println(i, v) // not what you might expect
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}()
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}
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See: http://golang.org/doc/go_faq.html#closures_and_goroutines
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*/
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package main
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import "go/ast"
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// checkRangeLoop walks the body of the provided range statement, checking if
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// its index or value variables are used unsafely inside goroutines or deferred
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// function literals.
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func checkRangeLoop(f *File, n *ast.RangeStmt) {
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if !vet("rangeloops") {
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return
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}
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key, _ := n.Key.(*ast.Ident)
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val, _ := n.Value.(*ast.Ident)
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if key == nil && val == nil {
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return
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}
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sl := n.Body.List
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if len(sl) == 0 {
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return
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}
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var last *ast.CallExpr
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switch s := sl[len(sl)-1].(type) {
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case *ast.GoStmt:
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last = s.Call
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case *ast.DeferStmt:
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last = s.Call
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default:
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return
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}
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lit, ok := last.Fun.(*ast.FuncLit)
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if !ok {
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return
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}
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ast.Inspect(lit.Body, func(n ast.Node) bool {
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id, ok := n.(*ast.Ident)
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if !ok || id.Obj == nil {
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return true
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}
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if key != nil && id.Obj == key.Obj || val != nil && id.Obj == val.Obj {
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f.Warn(id.Pos(), "range variable", id.Name, "enclosed by function")
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}
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return true
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})
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}
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