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Source file src/html/template/clone_test.go

Documentation: html/template

  // Copyright 2011 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
  
  import (
  	"bytes"
  	"errors"
  	"fmt"
  	"io/ioutil"
  	"sync"
  	"testing"
  	"text/template/parse"
  )
  
  func TestAddParseTree(t *testing.T) {
  	root := Must(New("root").Parse(`{{define "a"}} {{.}} {{template "b"}} {{.}} "></a>{{end}}`))
  	tree, err := parse.Parse("t", `{{define "b"}}<a href="{{end}}`, "", "", nil, nil)
  	if err != nil {
  		t.Fatal(err)
  	}
  	added := Must(root.AddParseTree("b", tree["b"]))
  	b := new(bytes.Buffer)
  	err = added.ExecuteTemplate(b, "a", "1>0")
  	if err != nil {
  		t.Fatal(err)
  	}
  	if got, want := b.String(), ` 1&gt;0 <a href=" 1%3e0 "></a>`; got != want {
  		t.Errorf("got %q want %q", got, want)
  	}
  }
  
  func TestClone(t *testing.T) {
  	// The {{.}} will be executed with data "<i>*/" in different contexts.
  	// In the t0 template, it will be in a text context.
  	// In the t1 template, it will be in a URL context.
  	// In the t2 template, it will be in a JavaScript context.
  	// In the t3 template, it will be in a CSS context.
  	const tmpl = `{{define "a"}}{{template "lhs"}}{{.}}{{template "rhs"}}{{end}}`
  	b := new(bytes.Buffer)
  
  	// Create an incomplete template t0.
  	t0 := Must(New("t0").Parse(tmpl))
  
  	// Clone t0 as t1.
  	t1 := Must(t0.Clone())
  	Must(t1.Parse(`{{define "lhs"}} <a href=" {{end}}`))
  	Must(t1.Parse(`{{define "rhs"}} "></a> {{end}}`))
  
  	// Execute t1.
  	b.Reset()
  	if err := t1.ExecuteTemplate(b, "a", "<i>*/"); err != nil {
  		t.Fatal(err)
  	}
  	if got, want := b.String(), ` <a href=" %3ci%3e*/ "></a> `; got != want {
  		t.Errorf("t1: got %q want %q", got, want)
  	}
  
  	// Clone t0 as t2.
  	t2 := Must(t0.Clone())
  	Must(t2.Parse(`{{define "lhs"}} <p onclick="javascript: {{end}}`))
  	Must(t2.Parse(`{{define "rhs"}} "></p> {{end}}`))
  
  	// Execute t2.
  	b.Reset()
  	if err := t2.ExecuteTemplate(b, "a", "<i>*/"); err != nil {
  		t.Fatal(err)
  	}
  	if got, want := b.String(), ` <p onclick="javascript: &#34;\u003ci\u003e*/&#34; "></p> `; got != want {
  		t.Errorf("t2: got %q want %q", got, want)
  	}
  
  	// Clone t0 as t3, but do not execute t3 yet.
  	t3 := Must(t0.Clone())
  	Must(t3.Parse(`{{define "lhs"}} <style> {{end}}`))
  	Must(t3.Parse(`{{define "rhs"}} </style> {{end}}`))
  
  	// Complete t0.
  	Must(t0.Parse(`{{define "lhs"}} ( {{end}}`))
  	Must(t0.Parse(`{{define "rhs"}} ) {{end}}`))
  
  	// Clone t0 as t4. Redefining the "lhs" template should not fail.
  	t4 := Must(t0.Clone())
  	if _, err := t4.Parse(`{{define "lhs"}} OK {{end}}`); err != nil {
  		t.Errorf(`redefine "lhs": got err %v want nil`, err)
  	}
  	// Cloning t1 should fail as it has been executed.
  	if _, err := t1.Clone(); err == nil {
  		t.Error("cloning t1: got nil err want non-nil")
  	}
  	// Redefining the "lhs" template in t1 should fail as it has been executed.
  	if _, err := t1.Parse(`{{define "lhs"}} OK {{end}}`); err == nil {
  		t.Error(`redefine "lhs": got nil err want non-nil`)
  	}
  
  	// Execute t0.
  	b.Reset()
  	if err := t0.ExecuteTemplate(b, "a", "<i>*/"); err != nil {
  		t.Fatal(err)
  	}
  	if got, want := b.String(), ` ( &lt;i&gt;*/ ) `; got != want {
  		t.Errorf("t0: got %q want %q", got, want)
  	}
  
  	// Clone t0. This should fail, as t0 has already executed.
  	if _, err := t0.Clone(); err == nil {
  		t.Error(`t0.Clone(): got nil err want non-nil`)
  	}
  
  	// Similarly, cloning sub-templates should fail.
  	if _, err := t0.Lookup("a").Clone(); err == nil {
  		t.Error(`t0.Lookup("a").Clone(): got nil err want non-nil`)
  	}
  	if _, err := t0.Lookup("lhs").Clone(); err == nil {
  		t.Error(`t0.Lookup("lhs").Clone(): got nil err want non-nil`)
  	}
  
  	// Execute t3.
  	b.Reset()
  	if err := t3.ExecuteTemplate(b, "a", "<i>*/"); err != nil {
  		t.Fatal(err)
  	}
  	if got, want := b.String(), ` <style> ZgotmplZ </style> `; got != want {
  		t.Errorf("t3: got %q want %q", got, want)
  	}
  }
  
  func TestTemplates(t *testing.T) {
  	names := []string{"t0", "a", "lhs", "rhs"}
  	// Some template definitions borrowed from TestClone.
  	const tmpl = `
  		{{define "a"}}{{template "lhs"}}{{.}}{{template "rhs"}}{{end}}
  		{{define "lhs"}} <a href=" {{end}}
  		{{define "rhs"}} "></a> {{end}}`
  	t0 := Must(New("t0").Parse(tmpl))
  	templates := t0.Templates()
  	if len(templates) != len(names) {
  		t.Errorf("expected %d templates; got %d", len(names), len(templates))
  	}
  	for _, name := range names {
  		found := false
  		for _, tmpl := range templates {
  			if name == tmpl.text.Name() {
  				found = true
  				break
  			}
  		}
  		if !found {
  			t.Error("could not find template", name)
  		}
  	}
  }
  
  // This used to crash; https://golang.org/issue/3281
  func TestCloneCrash(t *testing.T) {
  	t1 := New("all")
  	Must(t1.New("t1").Parse(`{{define "foo"}}foo{{end}}`))
  	t1.Clone()
  }
  
  // Ensure that this guarantee from the docs is upheld:
  // "Further calls to Parse in the copy will add templates
  // to the copy but not to the original."
  func TestCloneThenParse(t *testing.T) {
  	t0 := Must(New("t0").Parse(`{{define "a"}}{{template "embedded"}}{{end}}`))
  	t1 := Must(t0.Clone())
  	Must(t1.Parse(`{{define "embedded"}}t1{{end}}`))
  	if len(t0.Templates())+1 != len(t1.Templates()) {
  		t.Error("adding a template to a clone added it to the original")
  	}
  	// double check that the embedded template isn't available in the original
  	err := t0.ExecuteTemplate(ioutil.Discard, "a", nil)
  	if err == nil {
  		t.Error("expected 'no such template' error")
  	}
  }
  
  // https://golang.org/issue/5980
  func TestFuncMapWorksAfterClone(t *testing.T) {
  	funcs := FuncMap{"customFunc": func() (string, error) {
  		return "", errors.New("issue5980")
  	}}
  
  	// get the expected error output (no clone)
  	uncloned := Must(New("").Funcs(funcs).Parse("{{customFunc}}"))
  	wantErr := uncloned.Execute(ioutil.Discard, nil)
  
  	// toClone must be the same as uncloned. It has to be recreated from scratch,
  	// since cloning cannot occur after execution.
  	toClone := Must(New("").Funcs(funcs).Parse("{{customFunc}}"))
  	cloned := Must(toClone.Clone())
  	gotErr := cloned.Execute(ioutil.Discard, nil)
  
  	if wantErr.Error() != gotErr.Error() {
  		t.Errorf("clone error message mismatch want %q got %q", wantErr, gotErr)
  	}
  }
  
  // https://golang.org/issue/16101
  func TestTemplateCloneExecuteRace(t *testing.T) {
  	const (
  		input   = `<title>{{block "a" .}}a{{end}}</title><body>{{block "b" .}}b{{end}}<body>`
  		overlay = `{{define "b"}}A{{end}}`
  	)
  	outer := Must(New("outer").Parse(input))
  	tmpl := Must(Must(outer.Clone()).Parse(overlay))
  
  	var wg sync.WaitGroup
  	for i := 0; i < 10; i++ {
  		wg.Add(1)
  		go func() {
  			defer wg.Done()
  			for i := 0; i < 100; i++ {
  				if err := tmpl.Execute(ioutil.Discard, "data"); err != nil {
  					panic(err)
  				}
  			}
  		}()
  	}
  	wg.Wait()
  }
  
  func TestTemplateCloneLookup(t *testing.T) {
  	// Template.escape makes an assumption that the template associated
  	// with t.Name() is t. Check that this holds.
  	tmpl := Must(New("x").Parse("a"))
  	tmpl = Must(tmpl.Clone())
  	if tmpl.Lookup(tmpl.Name()) != tmpl {
  		t.Error("after Clone, tmpl.Lookup(tmpl.Name()) != tmpl")
  	}
  }
  
  func TestCloneGrowth(t *testing.T) {
  	tmpl := Must(New("root").Parse(`<title>{{block "B". }}Arg{{end}}</title>`))
  	tmpl = Must(tmpl.Clone())
  	Must(tmpl.Parse(`{{define "B"}}Text{{end}}`))
  	for i := 0; i < 10; i++ {
  		tmpl.Execute(ioutil.Discard, nil)
  	}
  	if len(tmpl.DefinedTemplates()) > 200 {
  		t.Fatalf("too many templates: %v", len(tmpl.DefinedTemplates()))
  	}
  }
  
  // https://golang.org/issue/17735
  func TestCloneRedefinedName(t *testing.T) {
  	const base = `
  {{ define "a" -}}<title>{{ template "b" . -}}</title>{{ end -}}
  {{ define "b" }}{{ end -}}
  `
  	const page = `{{ template "a" . }}`
  
  	t1 := Must(New("a").Parse(base))
  
  	for i := 0; i < 2; i++ {
  		t2 := Must(t1.Clone())
  		t2 = Must(t2.New(fmt.Sprintf("%d", i)).Parse(page))
  		err := t2.Execute(ioutil.Discard, nil)
  		if err != nil {
  			t.Fatal(err)
  		}
  	}
  }
  

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