blob: 9dc70dfc0dae4457bed670dad14d1761a1429d97 [file] [log] [blame]
// Copyright 2019 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 template_test
import (
"bytes"
"internal/testenv"
"os"
"os/exec"
"path/filepath"
"testing"
)
// Issue 36021: verify that text/template doesn't prevent the linker from removing
// unused methods.
func TestLinkerGC(t *testing.T) {
if testing.Short() {
t.Skip("skipping in short mode")
}
testenv.MustHaveGoBuild(t)
const prog = `package main
import (
_ "text/template"
)
type T struct{}
func (t *T) Unused() { println("THIS SHOULD BE ELIMINATED") }
func (t *T) Used() {}
var sink *T
func main() {
var t T
sink = &t
t.Used()
}
`
td, err := os.MkdirTemp("", "text_template_TestDeadCodeElimination")
if err != nil {
t.Fatal(err)
}
defer os.RemoveAll(td)
if err := os.WriteFile(filepath.Join(td, "x.go"), []byte(prog), 0644); err != nil {
t.Fatal(err)
}
cmd := exec.Command(testenv.GoToolPath(t), "build", "-o", "x.exe", "x.go")
cmd.Dir = td
if out, err := cmd.CombinedOutput(); err != nil {
t.Fatalf("go build: %v, %s", err, out)
}
slurp, err := os.ReadFile(filepath.Join(td, "x.exe"))
if err != nil {
t.Fatal(err)
}
if bytes.Contains(slurp, []byte("THIS SHOULD BE ELIMINATED")) {
t.Error("binary contains code that should be deadcode eliminated")
}
}