mirror of
https://github.com/golang/go
synced 2024-10-01 16:18:32 -06:00
f895b43688
This removes much of the AST logic out of main.go, and makes it easier to build custom vet binaries The trade-off in this change is for flexibility. There's very little change in the per-check files, a lot less code in main.go (specifically the AST walking logic has shrunk), and it makes it much easier to build custom vet binaries simply by dropping new source files in the directory. LGTM=josharian, r R=r, josharian, kamil.kisiel CC=golang-codereviews https://golang.org/cl/83400043
71 lines
1.7 KiB
Go
71 lines
1.7 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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func init() {
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register("rangeloops",
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"check that range loop variables are used correctly",
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checkRangeLoop,
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rangeStmt)
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}
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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, node ast.Node) {
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n := node.(*ast.RangeStmt)
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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.Bad(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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