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go/cmd/vet/atomic.go
Rob Pike 95c9b7bad1 go.tools/cmd/vet: replace warnings by errors
Over time, a number of modules were added that used Warn instead of Bad
to report problems with the code, but the documentation states that
if there is a problem, the exit code must be 1, not 0. Warn does not set the
exit code and should be used only for internal errors and messages
triggered by the -v flag.

There's nothing substantive here except calling the other function in a few
places.

Fixes golang/go#7017.

LGTM=crawshaw
R=golang-codereviews, crawshaw
CC=golang-codereviews
https://golang.org/cl/71860044
2014-03-07 15:31:28 +11:00

60 lines
1.4 KiB
Go

// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"go/ast"
"go/token"
)
// checkAtomicAssignment walks the assignment statement checking for common
// mistaken usage of atomic package, such as: x = atomic.AddUint64(&x, 1)
func (f *File) checkAtomicAssignment(n *ast.AssignStmt) {
if !vet("atomic") {
return
}
if len(n.Lhs) != len(n.Rhs) {
return
}
for i, right := range n.Rhs {
call, ok := right.(*ast.CallExpr)
if !ok {
continue
}
sel, ok := call.Fun.(*ast.SelectorExpr)
if !ok {
continue
}
pkg, ok := sel.X.(*ast.Ident)
if !ok || pkg.Name != "atomic" {
continue
}
switch sel.Sel.Name {
case "AddInt32", "AddInt64", "AddUint32", "AddUint64", "AddUintptr":
f.checkAtomicAddAssignment(n.Lhs[i], call)
}
}
}
// checkAtomicAddAssignment walks the atomic.Add* method calls checking for assigning the return value
// to the same variable being used in the operation
func (f *File) checkAtomicAddAssignment(left ast.Expr, call *ast.CallExpr) {
arg := call.Args[0]
broken := false
if uarg, ok := arg.(*ast.UnaryExpr); ok && uarg.Op == token.AND {
broken = f.gofmt(left) == f.gofmt(uarg.X)
} else if star, ok := left.(*ast.StarExpr); ok {
broken = f.gofmt(star.X) == f.gofmt(arg)
}
if broken {
f.Bad(left.Pos(), "direct assignment to atomic value")
}
}