github.com/linchen2chris/hugo@v0.0.0-20230307053224-cec209389705/tpl/internal/go_templates/texttemplate/link_test.go (about)

     1  // Copyright 2019 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build go1.13
     6  // +build go1.13
     7  
     8  package template_test
     9  
    10  import (
    11  	"bytes"
    12  	"github.com/gohugoio/hugo/tpl/internal/go_templates/testenv"
    13  	"os"
    14  	"os/exec"
    15  	"path/filepath"
    16  	"testing"
    17  )
    18  
    19  // Issue 36021: verify that text/template doesn't prevent the linker from removing
    20  // unused methods.
    21  func _TestLinkerGC(t *testing.T) {
    22  	if testing.Short() {
    23  		t.Skip("skipping in short mode")
    24  	}
    25  	testenv.MustHaveGoBuild(t)
    26  	const prog = `package main
    27  
    28  import (
    29  	_ "text/template"
    30  )
    31  
    32  type T struct{}
    33  
    34  func (t *T) Unused() { println("THIS SHOULD BE ELIMINATED") }
    35  func (t *T) Used() {}
    36  
    37  var sink *T
    38  
    39  func main() {
    40  	var t T
    41  	sink = &t
    42  	t.Used()
    43  }
    44  `
    45  	td := t.TempDir()
    46  
    47  	if err := os.WriteFile(filepath.Join(td, "x.go"), []byte(prog), 0644); err != nil {
    48  		t.Fatal(err)
    49  	}
    50  	cmd := exec.Command(testenv.GoToolPath(t), "build", "-o", "x.exe", "x.go")
    51  	cmd.Dir = td
    52  	if out, err := cmd.CombinedOutput(); err != nil {
    53  		t.Fatalf("go build: %v, %s", err, out)
    54  	}
    55  	slurp, err := os.ReadFile(filepath.Join(td, "x.exe"))
    56  	if err != nil {
    57  		t.Fatal(err)
    58  	}
    59  	if bytes.Contains(slurp, []byte("THIS SHOULD BE ELIMINATED")) {
    60  		t.Error("binary contains code that should be deadcode eliminated")
    61  	}
    62  }