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// Copyright 2020 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 testinggoroutine
import (
"go/ast"
"golang.org/x/tools/go/analysis"
"golang.org/x/tools/go/analysis/passes/inspect"
"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
"golang.org/x/tools/go/ast/inspector"
)
const Doc = `report calls to (*testing.T).Fatal from goroutines started by a test.
Functions that abruptly terminate a test, such as the Fatal, Fatalf, FailNow, and
Skip{,f,Now} methods of *testing.T, must be called from the test goroutine itself.
This checker detects calls to these functions that occur within a goroutine
started by the test. For example:
func TestFoo(t *testing.T) {
go func() {
t.Fatal("oops") // error: (*T).Fatal called from non-test goroutine
}()
}
`
var Analyzer = &analysis.Analyzer{
Name: "testinggoroutine",
Doc: Doc,
Requires: []*analysis.Analyzer{inspect.Analyzer},
Run: run,
}
var forbidden = map[string]bool{
"FailNow": true,
"Fatal": true,
"Fatalf": true,
"Skip": true,
"Skipf": true,
"SkipNow": true,
}
func run(pass *analysis.Pass) (interface{}, error) {
inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
if !analysisutil.Imports(pass.Pkg, "testing") {
return nil, nil
}
// Filter out anything that isn't a function declaration.
onlyFuncs := []ast.Node{
(*ast.FuncDecl)(nil),
}
inspect.Nodes(onlyFuncs, func(node ast.Node, push bool) bool {
fnDecl, ok := node.(*ast.FuncDecl)
if !ok {
return false
}
if !hasBenchmarkOrTestParams(fnDecl) {
return false
}
// Now traverse the benchmark/test's body and check that none of the
// forbidden methods are invoked in the goroutines within the body.
ast.Inspect(fnDecl, func(n ast.Node) bool {
goStmt, ok := n.(*ast.GoStmt)
if !ok {
return true
}
checkGoStmt(pass, goStmt)
// No need to further traverse the GoStmt since right
// above we manually traversed it in the ast.Inspect(goStmt, ...)
return false
})
return false
})
return nil, nil
}
func hasBenchmarkOrTestParams(fnDecl *ast.FuncDecl) bool {
// Check that the function's arguments include "*testing.T" or "*testing.B".
params := fnDecl.Type.Params.List
for _, param := range params {
if _, ok := typeIsTestingDotTOrB(param.Type); ok {
return true
}
}
return false
}
func typeIsTestingDotTOrB(expr ast.Expr) (string, bool) {
starExpr, ok := expr.(*ast.StarExpr)
if !ok {
return "", false
}
selExpr, ok := starExpr.X.(*ast.SelectorExpr)
if !ok {
return "", false
}
varPkg := selExpr.X.(*ast.Ident)
if varPkg.Name != "testing" {
return "", false
}
varTypeName := selExpr.Sel.Name
ok = varTypeName == "B" || varTypeName == "T"
return varTypeName, ok
}
// goStmtFunc returns the ast.Node of a call expression
// that was invoked as a go statement. Currently, only
// function literals declared in the same function, and
// static calls within the same package are supported.
func goStmtFun(goStmt *ast.GoStmt) ast.Node {
switch goStmt.Call.Fun.(type) {
case *ast.Ident:
id := goStmt.Call.Fun.(*ast.Ident)
// TODO(cuonglm): improve this once golang/go#48141 resolved.
if id.Obj == nil {
break
}
if funDecl, ok := id.Obj.Decl.(ast.Node); ok {
return funDecl
}
case *ast.FuncLit:
return goStmt.Call.Fun
}
return goStmt.Call
}
// checkGoStmt traverses the goroutine and checks for the
// use of the forbidden *testing.(B, T) methods.
func checkGoStmt(pass *analysis.Pass, goStmt *ast.GoStmt) {
fn := goStmtFun(goStmt)
// Otherwise examine the goroutine to check for the forbidden methods.
ast.Inspect(fn, func(n ast.Node) bool {
selExpr, ok := n.(*ast.SelectorExpr)
if !ok {
return true
}
_, bad := forbidden[selExpr.Sel.Name]
if !bad {
return true
}
// Now filter out false positives by the import-path/type.
ident, ok := selExpr.X.(*ast.Ident)
if !ok {
return true
}
if ident.Obj == nil || ident.Obj.Decl == nil {
return true
}
field, ok := ident.Obj.Decl.(*ast.Field)
if !ok {
return true
}
if typeName, ok := typeIsTestingDotTOrB(field.Type); ok {
var fnRange analysis.Range = goStmt
if _, ok := fn.(*ast.FuncLit); ok {
fnRange = selExpr
}
pass.ReportRangef(fnRange, "call to (*%s).%s from a non-test goroutine", typeName, selExpr.Sel)
}
return true
})
}