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Source file src/html/template/clone_test.go

Documentation: html/template

     1  // Copyright 2011 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  package template
     6  
     7  import (
     8  	"bytes"
     9  	"errors"
    10  	"fmt"
    11  	"io/ioutil"
    12  	"strings"
    13  	"sync"
    14  	"testing"
    15  	"text/template/parse"
    16  )
    17  
    18  func TestAddParseTree(t *testing.T) {
    19  	root := Must(New("root").Parse(`{{define "a"}} {{.}} {{template "b"}} {{.}} "></a>{{end}}`))
    20  	tree, err := parse.Parse("t", `{{define "b"}}<a href="{{end}}`, "", "", nil, nil)
    21  	if err != nil {
    22  		t.Fatal(err)
    23  	}
    24  	added := Must(root.AddParseTree("b", tree["b"]))
    25  	b := new(bytes.Buffer)
    26  	err = added.ExecuteTemplate(b, "a", "1>0")
    27  	if err != nil {
    28  		t.Fatal(err)
    29  	}
    30  	if got, want := b.String(), ` 1&gt;0 <a href=" 1%3e0 "></a>`; got != want {
    31  		t.Errorf("got %q want %q", got, want)
    32  	}
    33  }
    34  
    35  func TestClone(t *testing.T) {
    36  	// The {{.}} will be executed with data "<i>*/" in different contexts.
    37  	// In the t0 template, it will be in a text context.
    38  	// In the t1 template, it will be in a URL context.
    39  	// In the t2 template, it will be in a JavaScript context.
    40  	// In the t3 template, it will be in a CSS context.
    41  	const tmpl = `{{define "a"}}{{template "lhs"}}{{.}}{{template "rhs"}}{{end}}`
    42  	b := new(bytes.Buffer)
    43  
    44  	// Create an incomplete template t0.
    45  	t0 := Must(New("t0").Parse(tmpl))
    46  
    47  	// Clone t0 as t1.
    48  	t1 := Must(t0.Clone())
    49  	Must(t1.Parse(`{{define "lhs"}} <a href=" {{end}}`))
    50  	Must(t1.Parse(`{{define "rhs"}} "></a> {{end}}`))
    51  
    52  	// Execute t1.
    53  	b.Reset()
    54  	if err := t1.ExecuteTemplate(b, "a", "<i>*/"); err != nil {
    55  		t.Fatal(err)
    56  	}
    57  	if got, want := b.String(), ` <a href=" %3ci%3e*/ "></a> `; got != want {
    58  		t.Errorf("t1: got %q want %q", got, want)
    59  	}
    60  
    61  	// Clone t0 as t2.
    62  	t2 := Must(t0.Clone())
    63  	Must(t2.Parse(`{{define "lhs"}} <p onclick="javascript: {{end}}`))
    64  	Must(t2.Parse(`{{define "rhs"}} "></p> {{end}}`))
    65  
    66  	// Execute t2.
    67  	b.Reset()
    68  	if err := t2.ExecuteTemplate(b, "a", "<i>*/"); err != nil {
    69  		t.Fatal(err)
    70  	}
    71  	if got, want := b.String(), ` <p onclick="javascript: &#34;\u003ci\u003e*/&#34; "></p> `; got != want {
    72  		t.Errorf("t2: got %q want %q", got, want)
    73  	}
    74  
    75  	// Clone t0 as t3, but do not execute t3 yet.
    76  	t3 := Must(t0.Clone())
    77  	Must(t3.Parse(`{{define "lhs"}} <style> {{end}}`))
    78  	Must(t3.Parse(`{{define "rhs"}} </style> {{end}}`))
    79  
    80  	// Complete t0.
    81  	Must(t0.Parse(`{{define "lhs"}} ( {{end}}`))
    82  	Must(t0.Parse(`{{define "rhs"}} ) {{end}}`))
    83  
    84  	// Clone t0 as t4. Redefining the "lhs" template should not fail.
    85  	t4 := Must(t0.Clone())
    86  	if _, err := t4.Parse(`{{define "lhs"}} OK {{end}}`); err != nil {
    87  		t.Errorf(`redefine "lhs": got err %v want nil`, err)
    88  	}
    89  	// Cloning t1 should fail as it has been executed.
    90  	if _, err := t1.Clone(); err == nil {
    91  		t.Error("cloning t1: got nil err want non-nil")
    92  	}
    93  	// Redefining the "lhs" template in t1 should fail as it has been executed.
    94  	if _, err := t1.Parse(`{{define "lhs"}} OK {{end}}`); err == nil {
    95  		t.Error(`redefine "lhs": got nil err want non-nil`)
    96  	}
    97  
    98  	// Execute t0.
    99  	b.Reset()
   100  	if err := t0.ExecuteTemplate(b, "a", "<i>*/"); err != nil {
   101  		t.Fatal(err)
   102  	}
   103  	if got, want := b.String(), ` ( &lt;i&gt;*/ ) `; got != want {
   104  		t.Errorf("t0: got %q want %q", got, want)
   105  	}
   106  
   107  	// Clone t0. This should fail, as t0 has already executed.
   108  	if _, err := t0.Clone(); err == nil {
   109  		t.Error(`t0.Clone(): got nil err want non-nil`)
   110  	}
   111  
   112  	// Similarly, cloning sub-templates should fail.
   113  	if _, err := t0.Lookup("a").Clone(); err == nil {
   114  		t.Error(`t0.Lookup("a").Clone(): got nil err want non-nil`)
   115  	}
   116  	if _, err := t0.Lookup("lhs").Clone(); err == nil {
   117  		t.Error(`t0.Lookup("lhs").Clone(): got nil err want non-nil`)
   118  	}
   119  
   120  	// Execute t3.
   121  	b.Reset()
   122  	if err := t3.ExecuteTemplate(b, "a", "<i>*/"); err != nil {
   123  		t.Fatal(err)
   124  	}
   125  	if got, want := b.String(), ` <style> ZgotmplZ </style> `; got != want {
   126  		t.Errorf("t3: got %q want %q", got, want)
   127  	}
   128  }
   129  
   130  func TestTemplates(t *testing.T) {
   131  	names := []string{"t0", "a", "lhs", "rhs"}
   132  	// Some template definitions borrowed from TestClone.
   133  	const tmpl = `
   134  		{{define "a"}}{{template "lhs"}}{{.}}{{template "rhs"}}{{end}}
   135  		{{define "lhs"}} <a href=" {{end}}
   136  		{{define "rhs"}} "></a> {{end}}`
   137  	t0 := Must(New("t0").Parse(tmpl))
   138  	templates := t0.Templates()
   139  	if len(templates) != len(names) {
   140  		t.Errorf("expected %d templates; got %d", len(names), len(templates))
   141  	}
   142  	for _, name := range names {
   143  		found := false
   144  		for _, tmpl := range templates {
   145  			if name == tmpl.text.Name() {
   146  				found = true
   147  				break
   148  			}
   149  		}
   150  		if !found {
   151  			t.Error("could not find template", name)
   152  		}
   153  	}
   154  }
   155  
   156  // This used to crash; https://golang.org/issue/3281
   157  func TestCloneCrash(t *testing.T) {
   158  	t1 := New("all")
   159  	Must(t1.New("t1").Parse(`{{define "foo"}}foo{{end}}`))
   160  	t1.Clone()
   161  }
   162  
   163  // Ensure that this guarantee from the docs is upheld:
   164  // "Further calls to Parse in the copy will add templates
   165  // to the copy but not to the original."
   166  func TestCloneThenParse(t *testing.T) {
   167  	t0 := Must(New("t0").Parse(`{{define "a"}}{{template "embedded"}}{{end}}`))
   168  	t1 := Must(t0.Clone())
   169  	Must(t1.Parse(`{{define "embedded"}}t1{{end}}`))
   170  	if len(t0.Templates())+1 != len(t1.Templates()) {
   171  		t.Error("adding a template to a clone added it to the original")
   172  	}
   173  	// double check that the embedded template isn't available in the original
   174  	err := t0.ExecuteTemplate(ioutil.Discard, "a", nil)
   175  	if err == nil {
   176  		t.Error("expected 'no such template' error")
   177  	}
   178  }
   179  
   180  // https://golang.org/issue/5980
   181  func TestFuncMapWorksAfterClone(t *testing.T) {
   182  	funcs := FuncMap{"customFunc": func() (string, error) {
   183  		return "", errors.New("issue5980")
   184  	}}
   185  
   186  	// get the expected error output (no clone)
   187  	uncloned := Must(New("").Funcs(funcs).Parse("{{customFunc}}"))
   188  	wantErr := uncloned.Execute(ioutil.Discard, nil)
   189  
   190  	// toClone must be the same as uncloned. It has to be recreated from scratch,
   191  	// since cloning cannot occur after execution.
   192  	toClone := Must(New("").Funcs(funcs).Parse("{{customFunc}}"))
   193  	cloned := Must(toClone.Clone())
   194  	gotErr := cloned.Execute(ioutil.Discard, nil)
   195  
   196  	if wantErr.Error() != gotErr.Error() {
   197  		t.Errorf("clone error message mismatch want %q got %q", wantErr, gotErr)
   198  	}
   199  }
   200  
   201  // https://golang.org/issue/16101
   202  func TestTemplateCloneExecuteRace(t *testing.T) {
   203  	const (
   204  		input   = `<title>{{block "a" .}}a{{end}}</title><body>{{block "b" .}}b{{end}}<body>`
   205  		overlay = `{{define "b"}}A{{end}}`
   206  	)
   207  	outer := Must(New("outer").Parse(input))
   208  	tmpl := Must(Must(outer.Clone()).Parse(overlay))
   209  
   210  	var wg sync.WaitGroup
   211  	for i := 0; i < 10; i++ {
   212  		wg.Add(1)
   213  		go func() {
   214  			defer wg.Done()
   215  			for i := 0; i < 100; i++ {
   216  				if err := tmpl.Execute(ioutil.Discard, "data"); err != nil {
   217  					panic(err)
   218  				}
   219  			}
   220  		}()
   221  	}
   222  	wg.Wait()
   223  }
   224  
   225  func TestTemplateCloneLookup(t *testing.T) {
   226  	// Template.escape makes an assumption that the template associated
   227  	// with t.Name() is t. Check that this holds.
   228  	tmpl := Must(New("x").Parse("a"))
   229  	tmpl = Must(tmpl.Clone())
   230  	if tmpl.Lookup(tmpl.Name()) != tmpl {
   231  		t.Error("after Clone, tmpl.Lookup(tmpl.Name()) != tmpl")
   232  	}
   233  }
   234  
   235  func TestCloneGrowth(t *testing.T) {
   236  	tmpl := Must(New("root").Parse(`<title>{{block "B". }}Arg{{end}}</title>`))
   237  	tmpl = Must(tmpl.Clone())
   238  	Must(tmpl.Parse(`{{define "B"}}Text{{end}}`))
   239  	for i := 0; i < 10; i++ {
   240  		tmpl.Execute(ioutil.Discard, nil)
   241  	}
   242  	if len(tmpl.DefinedTemplates()) > 200 {
   243  		t.Fatalf("too many templates: %v", len(tmpl.DefinedTemplates()))
   244  	}
   245  }
   246  
   247  // https://golang.org/issue/17735
   248  func TestCloneRedefinedName(t *testing.T) {
   249  	const base = `
   250  {{ define "a" -}}<title>{{ template "b" . -}}</title>{{ end -}}
   251  {{ define "b" }}{{ end -}}
   252  `
   253  	const page = `{{ template "a" . }}`
   254  
   255  	t1 := Must(New("a").Parse(base))
   256  
   257  	for i := 0; i < 2; i++ {
   258  		t2 := Must(t1.Clone())
   259  		t2 = Must(t2.New(fmt.Sprintf("%d", i)).Parse(page))
   260  		err := t2.Execute(ioutil.Discard, nil)
   261  		if err != nil {
   262  			t.Fatal(err)
   263  		}
   264  	}
   265  }
   266  
   267  // Issue 24791.
   268  func TestClonePipe(t *testing.T) {
   269  	a := Must(New("a").Parse(`{{define "a"}}{{range $v := .A}}{{$v}}{{end}}{{end}}`))
   270  	data := struct{ A []string }{A: []string{"hi"}}
   271  	b := Must(a.Clone())
   272  	var buf strings.Builder
   273  	if err := b.Execute(&buf, &data); err != nil {
   274  		t.Fatal(err)
   275  	}
   276  	if got, want := buf.String(), "hi"; got != want {
   277  		t.Errorf("got %q want %q", got, want)
   278  	}
   279  }
   280  

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