clone_test.go

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