Source file src/html/template/escape_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  	"bytes"
     9  	"encoding/json"
    10  	"fmt"
    11  	"os"
    12  	"strings"
    13  	"testing"
    14  	"text/template"
    15  	"text/template/parse"
    16  )
    17  
    18  type badMarshaler struct{}
    19  
    20  func (x *badMarshaler) MarshalJSON() ([]byte, error) {
    21  	// Keys in valid JSON must be double quoted as must all strings.
    22  	return []byte("{ foo: 'not quite valid JSON' }"), nil
    23  }
    24  
    25  type goodMarshaler struct{}
    26  
    27  func (x *goodMarshaler) MarshalJSON() ([]byte, error) {
    28  	return []byte(`{ "<foo>": "O'Reilly" }`), nil
    29  }
    30  
    31  func TestEscape(t *testing.T) {
    32  	data := struct {
    33  		F, T       bool
    34  		C, G, H, I string
    35  		A, E       []string
    36  		B, M       json.Marshaler
    37  		N          int
    38  		U          any  // untyped nil
    39  		Z          *int // typed nil
    40  		W          HTML
    41  	}{
    42  		F: false,
    43  		T: true,
    44  		C: "<Cincinnati>",
    45  		G: "<Goodbye>",
    46  		H: "<Hello>",
    47  		A: []string{"<a>", "<b>"},
    48  		E: []string{},
    49  		N: 42,
    50  		B: &badMarshaler{},
    51  		M: &goodMarshaler{},
    52  		U: nil,
    53  		Z: nil,
    54  		W: HTML(`&iexcl;<b class="foo">Hello</b>, <textarea>O'World</textarea>!`),
    55  		I: "${ asd `` }",
    56  	}
    57  	pdata := &data
    58  
    59  	tests := []struct {
    60  		name   string
    61  		input  string
    62  		output string
    63  	}{
    64  		{
    65  			"if",
    66  			"{{if .T}}Hello{{end}}, {{.C}}!",
    67  			"Hello, &lt;Cincinnati&gt;!",
    68  		},
    69  		{
    70  			"else",
    71  			"{{if .F}}{{.H}}{{else}}{{.G}}{{end}}!",
    72  			"&lt;Goodbye&gt;!",
    73  		},
    74  		{
    75  			"overescaping1",
    76  			"Hello, {{.C | html}}!",
    77  			"Hello, &lt;Cincinnati&gt;!",
    78  		},
    79  		{
    80  			"overescaping2",
    81  			"Hello, {{html .C}}!",
    82  			"Hello, &lt;Cincinnati&gt;!",
    83  		},
    84  		{
    85  			"overescaping3",
    86  			"{{with .C}}{{$msg := .}}Hello, {{$msg}}!{{end}}",
    87  			"Hello, &lt;Cincinnati&gt;!",
    88  		},
    89  		{
    90  			"assignment",
    91  			"{{if $x := .H}}{{$x}}{{end}}",
    92  			"&lt;Hello&gt;",
    93  		},
    94  		{
    95  			"withBody",
    96  			"{{with .H}}{{.}}{{end}}",
    97  			"&lt;Hello&gt;",
    98  		},
    99  		{
   100  			"withElse",
   101  			"{{with .E}}{{.}}{{else}}{{.H}}{{end}}",
   102  			"&lt;Hello&gt;",
   103  		},
   104  		{
   105  			"rangeBody",
   106  			"{{range .A}}{{.}}{{end}}",
   107  			"&lt;a&gt;&lt;b&gt;",
   108  		},
   109  		{
   110  			"rangeElse",
   111  			"{{range .E}}{{.}}{{else}}{{.H}}{{end}}",
   112  			"&lt;Hello&gt;",
   113  		},
   114  		{
   115  			"nonStringValue",
   116  			"{{.T}}",
   117  			"true",
   118  		},
   119  		{
   120  			"untypedNilValue",
   121  			"{{.U}}",
   122  			"",
   123  		},
   124  		{
   125  			"typedNilValue",
   126  			"{{.Z}}",
   127  			"&lt;nil&gt;",
   128  		},
   129  		{
   130  			"constant",
   131  			`<a href="/search?q={{"'a<b'"}}">`,
   132  			`<a href="/search?q=%27a%3cb%27">`,
   133  		},
   134  		{
   135  			"multipleAttrs",
   136  			"<a b=1 c={{.H}}>",
   137  			"<a b=1 c=&lt;Hello&gt;>",
   138  		},
   139  		{
   140  			"urlStartRel",
   141  			`<a href='{{"/foo/bar?a=b&c=d"}}'>`,
   142  			`<a href='/foo/bar?a=b&amp;c=d'>`,
   143  		},
   144  		{
   145  			"urlStartAbsOk",
   146  			`<a href='{{"http://example.com/foo/bar?a=b&c=d"}}'>`,
   147  			`<a href='http://example.com/foo/bar?a=b&amp;c=d'>`,
   148  		},
   149  		{
   150  			"protocolRelativeURLStart",
   151  			`<a href='{{"//example.com:8000/foo/bar?a=b&c=d"}}'>`,
   152  			`<a href='//example.com:8000/foo/bar?a=b&amp;c=d'>`,
   153  		},
   154  		{
   155  			"pathRelativeURLStart",
   156  			`<a href="{{"/javascript:80/foo/bar"}}">`,
   157  			`<a href="/javascript:80/foo/bar">`,
   158  		},
   159  		{
   160  			"dangerousURLStart",
   161  			`<a href='{{"javascript:alert(%22pwned%22)"}}'>`,
   162  			`<a href='#ZgotmplZ'>`,
   163  		},
   164  		{
   165  			"dangerousURLStart2",
   166  			`<a href='  {{"javascript:alert(%22pwned%22)"}}'>`,
   167  			`<a href='  #ZgotmplZ'>`,
   168  		},
   169  		{
   170  			"nonHierURL",
   171  			`<a href={{"mailto:Muhammed \"The Greatest\" Ali <m.ali@example.com>"}}>`,
   172  			`<a href=mailto:Muhammed%20%22The%20Greatest%22%20Ali%20%3cm.ali@example.com%3e>`,
   173  		},
   174  		{
   175  			"urlPath",
   176  			`<a href='http://{{"javascript:80"}}/foo'>`,
   177  			`<a href='http://javascript:80/foo'>`,
   178  		},
   179  		{
   180  			"urlQuery",
   181  			`<a href='/search?q={{.H}}'>`,
   182  			`<a href='/search?q=%3cHello%3e'>`,
   183  		},
   184  		{
   185  			"urlFragment",
   186  			`<a href='/faq#{{.H}}'>`,
   187  			`<a href='/faq#%3cHello%3e'>`,
   188  		},
   189  		{
   190  			"urlBranch",
   191  			`<a href="{{if .F}}/foo?a=b{{else}}/bar{{end}}">`,
   192  			`<a href="/bar">`,
   193  		},
   194  		{
   195  			"urlBranchConflictMoot",
   196  			`<a href="{{if .T}}/foo?a={{else}}/bar#{{end}}{{.C}}">`,
   197  			`<a href="/foo?a=%3cCincinnati%3e">`,
   198  		},
   199  		{
   200  			"jsStrValue",
   201  			"<button onclick='alert({{.H}})'>",
   202  			`<button onclick='alert(&#34;\u003cHello\u003e&#34;)'>`,
   203  		},
   204  		{
   205  			"jsNumericValue",
   206  			"<button onclick='alert({{.N}})'>",
   207  			`<button onclick='alert( 42 )'>`,
   208  		},
   209  		{
   210  			"jsBoolValue",
   211  			"<button onclick='alert({{.T}})'>",
   212  			`<button onclick='alert( true )'>`,
   213  		},
   214  		{
   215  			"jsNilValueTyped",
   216  			"<button onclick='alert(typeof{{.Z}})'>",
   217  			`<button onclick='alert(typeof null )'>`,
   218  		},
   219  		{
   220  			"jsNilValueUntyped",
   221  			"<button onclick='alert(typeof{{.U}})'>",
   222  			`<button onclick='alert(typeof null )'>`,
   223  		},
   224  		{
   225  			"jsObjValue",
   226  			"<button onclick='alert({{.A}})'>",
   227  			`<button onclick='alert([&#34;\u003ca\u003e&#34;,&#34;\u003cb\u003e&#34;])'>`,
   228  		},
   229  		{
   230  			"jsObjValueScript",
   231  			"<script>alert({{.A}})</script>",
   232  			`<script>alert(["\u003ca\u003e","\u003cb\u003e"])</script>`,
   233  		},
   234  		{
   235  			"jsObjValueNotOverEscaped",
   236  			"<button onclick='alert({{.A | html}})'>",
   237  			`<button onclick='alert([&#34;\u003ca\u003e&#34;,&#34;\u003cb\u003e&#34;])'>`,
   238  		},
   239  		{
   240  			"jsStr",
   241  			"<button onclick='alert(&quot;{{.H}}&quot;)'>",
   242  			`<button onclick='alert(&quot;\u003cHello\u003e&quot;)'>`,
   243  		},
   244  		{
   245  			"badMarshaler",
   246  			`<button onclick='alert(1/{{.B}}in numbers)'>`,
   247  			`<button onclick='alert(1/ /* json: error calling MarshalJSON for type *template.badMarshaler: invalid character &#39;f&#39; looking for beginning of object key string */null in numbers)'>`,
   248  		},
   249  		{
   250  			"jsMarshaler",
   251  			`<button onclick='alert({{.M}})'>`,
   252  			`<button onclick='alert({&#34;\u003cfoo\u003e&#34;:&#34;O&#39;Reilly&#34;})'>`,
   253  		},
   254  		{
   255  			"jsStrNotUnderEscaped",
   256  			"<button onclick='alert({{.C | urlquery}})'>",
   257  			// URL escaped, then quoted for JS.
   258  			`<button onclick='alert(&#34;%3CCincinnati%3E&#34;)'>`,
   259  		},
   260  		{
   261  			"jsRe",
   262  			`<button onclick='alert(/{{"foo+bar"}}/.test(""))'>`,
   263  			`<button onclick='alert(/foo\u002bbar/.test(""))'>`,
   264  		},
   265  		{
   266  			"jsReBlank",
   267  			`<script>alert(/{{""}}/.test(""));</script>`,
   268  			`<script>alert(/(?:)/.test(""));</script>`,
   269  		},
   270  		{
   271  			"jsReAmbigOk",
   272  			`<script>{{if true}}var x = 1{{end}}</script>`,
   273  			// The {if} ends in an ambiguous jsCtx but there is
   274  			// no slash following so we shouldn't care.
   275  			`<script>var x = 1</script>`,
   276  		},
   277  		{
   278  			"styleBidiKeywordPassed",
   279  			`<p style="dir: {{"ltr"}}">`,
   280  			`<p style="dir: ltr">`,
   281  		},
   282  		{
   283  			"styleBidiPropNamePassed",
   284  			`<p style="border-{{"left"}}: 0; border-{{"right"}}: 1in">`,
   285  			`<p style="border-left: 0; border-right: 1in">`,
   286  		},
   287  		{
   288  			"styleExpressionBlocked",
   289  			`<p style="width: {{"expression(alert(1337))"}}">`,
   290  			`<p style="width: ZgotmplZ">`,
   291  		},
   292  		{
   293  			"styleTagSelectorPassed",
   294  			`<style>{{"p"}} { color: pink }</style>`,
   295  			`<style>p { color: pink }</style>`,
   296  		},
   297  		{
   298  			"styleIDPassed",
   299  			`<style>p{{"#my-ID"}} { font: Arial }</style>`,
   300  			`<style>p#my-ID { font: Arial }</style>`,
   301  		},
   302  		{
   303  			"styleClassPassed",
   304  			`<style>p{{".my_class"}} { font: Arial }</style>`,
   305  			`<style>p.my_class { font: Arial }</style>`,
   306  		},
   307  		{
   308  			"styleQuantityPassed",
   309  			`<a style="left: {{"2em"}}; top: {{0}}">`,
   310  			`<a style="left: 2em; top: 0">`,
   311  		},
   312  		{
   313  			"stylePctPassed",
   314  			`<table style=width:{{"100%"}}>`,
   315  			`<table style=width:100%>`,
   316  		},
   317  		{
   318  			"styleColorPassed",
   319  			`<p style="color: {{"#8ff"}}; background: {{"#000"}}">`,
   320  			`<p style="color: #8ff; background: #000">`,
   321  		},
   322  		{
   323  			"styleObfuscatedExpressionBlocked",
   324  			`<p style="width: {{"  e\\78preS\x00Sio/**/n(alert(1337))"}}">`,
   325  			`<p style="width: ZgotmplZ">`,
   326  		},
   327  		{
   328  			"styleMozBindingBlocked",
   329  			`<p style="{{"-moz-binding(alert(1337))"}}: ...">`,
   330  			`<p style="ZgotmplZ: ...">`,
   331  		},
   332  		{
   333  			"styleObfuscatedMozBindingBlocked",
   334  			`<p style="{{"  -mo\\7a-B\x00I/**/nding(alert(1337))"}}: ...">`,
   335  			`<p style="ZgotmplZ: ...">`,
   336  		},
   337  		{
   338  			"styleFontNameString",
   339  			`<p style='font-family: "{{"Times New Roman"}}"'>`,
   340  			`<p style='font-family: "Times New Roman"'>`,
   341  		},
   342  		{
   343  			"styleFontNameString",
   344  			`<p style='font-family: "{{"Times New Roman"}}", "{{"sans-serif"}}"'>`,
   345  			`<p style='font-family: "Times New Roman", "sans-serif"'>`,
   346  		},
   347  		{
   348  			"styleFontNameUnquoted",
   349  			`<p style='font-family: {{"Times New Roman"}}'>`,
   350  			`<p style='font-family: Times New Roman'>`,
   351  		},
   352  		{
   353  			"styleURLQueryEncoded",
   354  			`<p style="background: url(/img?name={{"O'Reilly Animal(1)<2>.png"}})">`,
   355  			`<p style="background: url(/img?name=O%27Reilly%20Animal%281%29%3c2%3e.png)">`,
   356  		},
   357  		{
   358  			"styleQuotedURLQueryEncoded",
   359  			`<p style="background: url('/img?name={{"O'Reilly Animal(1)<2>.png"}}')">`,
   360  			`<p style="background: url('/img?name=O%27Reilly%20Animal%281%29%3c2%3e.png')">`,
   361  		},
   362  		{
   363  			"styleStrQueryEncoded",
   364  			`<p style="background: '/img?name={{"O'Reilly Animal(1)<2>.png"}}'">`,
   365  			`<p style="background: '/img?name=O%27Reilly%20Animal%281%29%3c2%3e.png'">`,
   366  		},
   367  		{
   368  			"styleURLBadProtocolBlocked",
   369  			`<a style="background: url('{{"javascript:alert(1337)"}}')">`,
   370  			`<a style="background: url('#ZgotmplZ')">`,
   371  		},
   372  		{
   373  			"styleStrBadProtocolBlocked",
   374  			`<a style="background: '{{"vbscript:alert(1337)"}}'">`,
   375  			`<a style="background: '#ZgotmplZ'">`,
   376  		},
   377  		{
   378  			"styleStrEncodedProtocolEncoded",
   379  			`<a style="background: '{{"javascript\\3a alert(1337)"}}'">`,
   380  			// The CSS string 'javascript\\3a alert(1337)' does not contain a colon.
   381  			`<a style="background: 'javascript\\3a alert\28 1337\29 '">`,
   382  		},
   383  		{
   384  			"styleURLGoodProtocolPassed",
   385  			`<a style="background: url('{{"http://oreilly.com/O'Reilly Animals(1)<2>;{}.html"}}')">`,
   386  			`<a style="background: url('http://oreilly.com/O%27Reilly%20Animals%281%29%3c2%3e;%7b%7d.html')">`,
   387  		},
   388  		{
   389  			"styleStrGoodProtocolPassed",
   390  			`<a style="background: '{{"http://oreilly.com/O'Reilly Animals(1)<2>;{}.html"}}'">`,
   391  			`<a style="background: 'http\3a\2f\2foreilly.com\2fO\27Reilly Animals\28 1\29\3c 2\3e\3b\7b\7d.html'">`,
   392  		},
   393  		{
   394  			"styleURLEncodedForHTMLInAttr",
   395  			`<a style="background: url('{{"/search?img=foo&size=icon"}}')">`,
   396  			`<a style="background: url('/search?img=foo&amp;size=icon')">`,
   397  		},
   398  		{
   399  			"styleURLNotEncodedForHTMLInCdata",
   400  			`<style>body { background: url('{{"/search?img=foo&size=icon"}}') }</style>`,
   401  			`<style>body { background: url('/search?img=foo&size=icon') }</style>`,
   402  		},
   403  		{
   404  			"styleURLMixedCase",
   405  			`<p style="background: URL(#{{.H}})">`,
   406  			`<p style="background: URL(#%3cHello%3e)">`,
   407  		},
   408  		{
   409  			"stylePropertyPairPassed",
   410  			`<a style='{{"color: red"}}'>`,
   411  			`<a style='color: red'>`,
   412  		},
   413  		{
   414  			"styleStrSpecialsEncoded",
   415  			`<a style="font-family: '{{"/**/'\";:// \\"}}', &quot;{{"/**/'\";:// \\"}}&quot;">`,
   416  			`<a style="font-family: '\2f**\2f\27\22\3b\3a\2f\2f  \\', &quot;\2f**\2f\27\22\3b\3a\2f\2f  \\&quot;">`,
   417  		},
   418  		{
   419  			"styleURLSpecialsEncoded",
   420  			`<a style="border-image: url({{"/**/'\";:// \\"}}), url(&quot;{{"/**/'\";:// \\"}}&quot;), url('{{"/**/'\";:// \\"}}'), 'http://www.example.com/?q={{"/**/'\";:// \\"}}''">`,
   421  			`<a style="border-image: url(/**/%27%22;://%20%5c), url(&quot;/**/%27%22;://%20%5c&quot;), url('/**/%27%22;://%20%5c'), 'http://www.example.com/?q=%2f%2a%2a%2f%27%22%3b%3a%2f%2f%20%5c''">`,
   422  		},
   423  		{
   424  			"HTML comment",
   425  			"<b>Hello, <!-- name of world -->{{.C}}</b>",
   426  			"<b>Hello, &lt;Cincinnati&gt;</b>",
   427  		},
   428  		{
   429  			"HTML comment not first < in text node.",
   430  			"<<!-- -->!--",
   431  			"&lt;!--",
   432  		},
   433  		{
   434  			"HTML normalization 1",
   435  			"a < b",
   436  			"a &lt; b",
   437  		},
   438  		{
   439  			"HTML normalization 2",
   440  			"a << b",
   441  			"a &lt;&lt; b",
   442  		},
   443  		{
   444  			"HTML normalization 3",
   445  			"a<<!-- --><!-- -->b",
   446  			"a&lt;b",
   447  		},
   448  		{
   449  			"HTML doctype not normalized",
   450  			"<!DOCTYPE html>Hello, World!",
   451  			"<!DOCTYPE html>Hello, World!",
   452  		},
   453  		{
   454  			"HTML doctype not case-insensitive",
   455  			"<!doCtYPE htMl>Hello, World!",
   456  			"<!doCtYPE htMl>Hello, World!",
   457  		},
   458  		{
   459  			"No doctype injection",
   460  			`<!{{"DOCTYPE"}}`,
   461  			"&lt;!DOCTYPE",
   462  		},
   463  		{
   464  			"Split HTML comment",
   465  			"<b>Hello, <!-- name of {{if .T}}city -->{{.C}}{{else}}world -->{{.W}}{{end}}</b>",
   466  			"<b>Hello, &lt;Cincinnati&gt;</b>",
   467  		},
   468  		{
   469  			"JS line comment",
   470  			"<script>for (;;) { if (c()) break// foo not a label\n" +
   471  				"foo({{.T}});}</script>",
   472  			"<script>for (;;) { if (c()) break\n" +
   473  				"foo( true );}</script>",
   474  		},
   475  		{
   476  			"JS multiline block comment",
   477  			"<script>for (;;) { if (c()) break/* foo not a label\n" +
   478  				" */foo({{.T}});}</script>",
   479  			// Newline separates break from call. If newline
   480  			// removed, then break will consume label leaving
   481  			// code invalid.
   482  			"<script>for (;;) { if (c()) break\n" +
   483  				"foo( true );}</script>",
   484  		},
   485  		{
   486  			"JS single-line block comment",
   487  			"<script>for (;;) {\n" +
   488  				"if (c()) break/* foo a label */foo;" +
   489  				"x({{.T}});}</script>",
   490  			// Newline separates break from call. If newline
   491  			// removed, then break will consume label leaving
   492  			// code invalid.
   493  			"<script>for (;;) {\n" +
   494  				"if (c()) break foo;" +
   495  				"x( true );}</script>",
   496  		},
   497  		{
   498  			"JS block comment flush with mathematical division",
   499  			"<script>var a/*b*//c\nd</script>",
   500  			"<script>var a /c\nd</script>",
   501  		},
   502  		{
   503  			"JS mixed comments",
   504  			"<script>var a/*b*///c\nd</script>",
   505  			"<script>var a \nd</script>",
   506  		},
   507  		{
   508  			"JS HTML-like comments",
   509  			"<script>before <!-- beep\nbetween\nbefore-->boop\n</script>",
   510  			"<script>before \nbetween\nbefore\n</script>",
   511  		},
   512  		{
   513  			"JS hashbang comment",
   514  			"<script>#! beep\n</script>",
   515  			"<script>\n</script>",
   516  		},
   517  		{
   518  			"Special tags in <script> string literals",
   519  			`<script>var a = "asd < 123 <!-- 456 < fgh <script jkl < 789 </script"</script>`,
   520  			`<script>var a = "asd < 123 \x3C!-- 456 < fgh \x3Cscript jkl < 789 \x3C/script"</script>`,
   521  		},
   522  		{
   523  			"Special tags in <script> string literals (mixed case)",
   524  			`<script>var a = "<!-- <ScripT </ScripT"</script>`,
   525  			`<script>var a = "\x3C!-- \x3CScripT \x3C/ScripT"</script>`,
   526  		},
   527  		{
   528  			"Special tags in <script> regex literals (mixed case)",
   529  			`<script>var a = /<!-- <ScripT </ScripT/</script>`,
   530  			`<script>var a = /\x3C!-- \x3CScripT \x3C/ScripT/</script>`,
   531  		},
   532  		{
   533  			"CSS comments",
   534  			"<style>p// paragraph\n" +
   535  				`{border: 1px/* color */{{"#00f"}}}</style>`,
   536  			"<style>p\n" +
   537  				"{border: 1px #00f}</style>",
   538  		},
   539  		{
   540  			"JS attr block comment",
   541  			`<a onclick="f(&quot;&quot;); /* alert({{.H}}) */">`,
   542  			// Attribute comment tests should pass if the comments
   543  			// are successfully elided.
   544  			`<a onclick="f(&quot;&quot;); /* alert() */">`,
   545  		},
   546  		{
   547  			"JS attr line comment",
   548  			`<a onclick="// alert({{.G}})">`,
   549  			`<a onclick="// alert()">`,
   550  		},
   551  		{
   552  			"CSS attr block comment",
   553  			`<a style="/* color: {{.H}} */">`,
   554  			`<a style="/* color:  */">`,
   555  		},
   556  		{
   557  			"CSS attr line comment",
   558  			`<a style="// color: {{.G}}">`,
   559  			`<a style="// color: ">`,
   560  		},
   561  		{
   562  			"HTML substitution commented out",
   563  			"<p><!-- {{.H}} --></p>",
   564  			"<p></p>",
   565  		},
   566  		{
   567  			"Comment ends flush with start",
   568  			"<!--{{.}}--><script>/*{{.}}*///{{.}}\n</script><style>/*{{.}}*///{{.}}\n</style><a onclick='/*{{.}}*///{{.}}' style='/*{{.}}*///{{.}}'>",
   569  			"<script> \n</script><style> \n</style><a onclick='/**///' style='/**///'>",
   570  		},
   571  		{
   572  			"typed HTML in text",
   573  			`{{.W}}`,
   574  			`&iexcl;<b class="foo">Hello</b>, <textarea>O'World</textarea>!`,
   575  		},
   576  		{
   577  			"typed HTML in attribute",
   578  			`<div title="{{.W}}">`,
   579  			`<div title="&iexcl;Hello, O&#39;World!">`,
   580  		},
   581  		{
   582  			"typed HTML in script",
   583  			`<button onclick="alert({{.W}})">`,
   584  			`<button onclick="alert(&#34;\u0026iexcl;\u003cb class=\&#34;foo\&#34;\u003eHello\u003c/b\u003e, \u003ctextarea\u003eO&#39;World\u003c/textarea\u003e!&#34;)">`,
   585  		},
   586  		{
   587  			"typed HTML in RCDATA",
   588  			`<textarea>{{.W}}</textarea>`,
   589  			`<textarea>&iexcl;&lt;b class=&#34;foo&#34;&gt;Hello&lt;/b&gt;, &lt;textarea&gt;O&#39;World&lt;/textarea&gt;!</textarea>`,
   590  		},
   591  		{
   592  			"range in textarea",
   593  			"<textarea>{{range .A}}{{.}}{{end}}</textarea>",
   594  			"<textarea>&lt;a&gt;&lt;b&gt;</textarea>",
   595  		},
   596  		{
   597  			"No tag injection",
   598  			`{{"10$"}}<{{"script src,evil.org/pwnd.js"}}...`,
   599  			`10$&lt;script src,evil.org/pwnd.js...`,
   600  		},
   601  		{
   602  			"No comment injection",
   603  			`<{{"!--"}}`,
   604  			`&lt;!--`,
   605  		},
   606  		{
   607  			"No RCDATA end tag injection",
   608  			`<textarea><{{"/textarea "}}...</textarea>`,
   609  			`<textarea>&lt;/textarea ...</textarea>`,
   610  		},
   611  		{
   612  			"optional attrs",
   613  			`<img class="{{"iconClass"}}"` +
   614  				`{{if .T}} id="{{"<iconId>"}}"{{end}}` +
   615  				// Double quotes inside if/else.
   616  				` src=` +
   617  				`{{if .T}}"?{{"<iconPath>"}}"` +
   618  				`{{else}}"images/cleardot.gif"{{end}}` +
   619  				// Missing space before title, but it is not a
   620  				// part of the src attribute.
   621  				`{{if .T}}title="{{"<title>"}}"{{end}}` +
   622  				// Quotes outside if/else.
   623  				` alt="` +
   624  				`{{if .T}}{{"<alt>"}}` +
   625  				`{{else}}{{if .F}}{{"<title>"}}{{end}}` +
   626  				`{{end}}"` +
   627  				`>`,
   628  			`<img class="iconClass" id="&lt;iconId&gt;" src="?%3ciconPath%3e"title="&lt;title&gt;" alt="&lt;alt&gt;">`,
   629  		},
   630  		{
   631  			"conditional valueless attr name",
   632  			`<input{{if .T}} checked{{end}} name=n>`,
   633  			`<input checked name=n>`,
   634  		},
   635  		{
   636  			"conditional dynamic valueless attr name 1",
   637  			`<input{{if .T}} {{"checked"}}{{end}} name=n>`,
   638  			`<input checked name=n>`,
   639  		},
   640  		{
   641  			"conditional dynamic valueless attr name 2",
   642  			`<input {{if .T}}{{"checked"}} {{end}}name=n>`,
   643  			`<input checked name=n>`,
   644  		},
   645  		{
   646  			"dynamic attribute name",
   647  			`<img on{{"load"}}="alert({{"loaded"}})">`,
   648  			// Treated as JS since quotes are inserted.
   649  			`<img onload="alert(&#34;loaded&#34;)">`,
   650  		},
   651  		{
   652  			"bad dynamic attribute name 1",
   653  			// Allow checked, selected, disabled, but not JS or
   654  			// CSS attributes.
   655  			`<input {{"onchange"}}="{{"doEvil()"}}">`,
   656  			`<input ZgotmplZ="doEvil()">`,
   657  		},
   658  		{
   659  			"bad dynamic attribute name 2",
   660  			`<div {{"sTyle"}}="{{"color: expression(alert(1337))"}}">`,
   661  			`<div ZgotmplZ="color: expression(alert(1337))">`,
   662  		},
   663  		{
   664  			"bad dynamic attribute name 3",
   665  			// Allow title or alt, but not a URL.
   666  			`<img {{"src"}}="{{"javascript:doEvil()"}}">`,
   667  			`<img ZgotmplZ="javascript:doEvil()">`,
   668  		},
   669  		{
   670  			"bad dynamic attribute name 4",
   671  			// Structure preservation requires values to associate
   672  			// with a consistent attribute.
   673  			`<input checked {{""}}="Whose value am I?">`,
   674  			`<input checked ZgotmplZ="Whose value am I?">`,
   675  		},
   676  		{
   677  			"dynamic element name",
   678  			`<h{{3}}><table><t{{"head"}}>...</h{{3}}>`,
   679  			`<h3><table><thead>...</h3>`,
   680  		},
   681  		{
   682  			"bad dynamic element name",
   683  			// Dynamic element names are typically used to switch
   684  			// between (thead, tfoot, tbody), (ul, ol), (th, td),
   685  			// and other replaceable sets.
   686  			// We do not currently easily support (ul, ol).
   687  			// If we do change to support that, this test should
   688  			// catch failures to filter out special tag names which
   689  			// would violate the structure preservation property --
   690  			// if any special tag name could be substituted, then
   691  			// the content could be raw text/RCDATA for some inputs
   692  			// and regular HTML content for others.
   693  			`<{{"script"}}>{{"doEvil()"}}</{{"script"}}>`,
   694  			`&lt;script>doEvil()&lt;/script>`,
   695  		},
   696  		{
   697  			"srcset bad URL in second position",
   698  			`<img srcset="{{"/not-an-image#,javascript:alert(1)"}}">`,
   699  			// The second URL is also filtered.
   700  			`<img srcset="/not-an-image#,#ZgotmplZ">`,
   701  		},
   702  		{
   703  			"srcset buffer growth",
   704  			`<img srcset={{",,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,"}}>`,
   705  			`<img srcset=,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,>`,
   706  		},
   707  		{
   708  			"unquoted empty attribute value (plaintext)",
   709  			"<p name={{.U}}>",
   710  			"<p name=ZgotmplZ>",
   711  		},
   712  		{
   713  			"unquoted empty attribute value (url)",
   714  			"<p href={{.U}}>",
   715  			"<p href=ZgotmplZ>",
   716  		},
   717  		{
   718  			"quoted empty attribute value",
   719  			"<p name=\"{{.U}}\">",
   720  			"<p name=\"\">",
   721  		},
   722  		{
   723  			"JS template lit special characters",
   724  			"<script>var a = `{{.I}}`</script>",
   725  			"<script>var a = `\\u0024\\u007b asd \\u0060\\u0060 \\u007d`</script>",
   726  		},
   727  		{
   728  			"JS template lit special characters, nested lit",
   729  			"<script>var a = `${ `{{.I}}` }`</script>",
   730  			"<script>var a = `${ `\\u0024\\u007b asd \\u0060\\u0060 \\u007d` }`</script>",
   731  		},
   732  		{
   733  			"JS template lit, nested JS",
   734  			"<script>var a = `${ var a = \"{{\"a \\\" d\"}}\" }`</script>",
   735  			"<script>var a = `${ var a = \"a \\u0022 d\" }`</script>",
   736  		},
   737  		{
   738  			"meta content attribute url",
   739  			`<meta http-equiv="refresh" content="asd; url={{"javascript:alert(1)"}}; asd; url={{"vbscript:alert(1)"}}; asd">`,
   740  			`<meta http-equiv="refresh" content="asd; url=#ZgotmplZ; asd; url=#ZgotmplZ; asd">`,
   741  		},
   742  		{
   743  			"meta content string",
   744  			`<meta http-equiv="refresh" content="{{"asd: 123"}}">`,
   745  			`<meta http-equiv="refresh" content="asd: 123">`,
   746  		},
   747  	}
   748  
   749  	for _, test := range tests {
   750  		t.Run(test.name, func(t *testing.T) {
   751  			tmpl := New(test.name)
   752  			tmpl = Must(tmpl.Parse(test.input))
   753  			// Check for bug 6459: Tree field was not set in Parse.
   754  			if tmpl.Tree != tmpl.text.Tree {
   755  				t.Fatalf("%s: tree not set properly", test.name)
   756  			}
   757  			b := new(strings.Builder)
   758  			if err := tmpl.Execute(b, data); err != nil {
   759  				t.Fatalf("%s: template execution failed: %s", test.name, err)
   760  			}
   761  			if w, g := test.output, b.String(); w != g {
   762  				t.Fatalf("%s: escaped output: want\n\t%q\ngot\n\t%q", test.name, w, g)
   763  			}
   764  			b.Reset()
   765  			if err := tmpl.Execute(b, pdata); err != nil {
   766  				t.Fatalf("%s: template execution failed for pointer: %s", test.name, err)
   767  			}
   768  			if w, g := test.output, b.String(); w != g {
   769  				t.Fatalf("%s: escaped output for pointer: want\n\t%q\ngot\n\t%q", test.name, w, g)
   770  			}
   771  			if tmpl.Tree != tmpl.text.Tree {
   772  				t.Fatalf("%s: tree mismatch", test.name)
   773  			}
   774  		})
   775  	}
   776  }
   777  
   778  func TestEscapeMap(t *testing.T) {
   779  	data := map[string]string{
   780  		"html":     `<h1>Hi!</h1>`,
   781  		"urlquery": `http://www.foo.com/index.html?title=main`,
   782  	}
   783  	for _, test := range [...]struct {
   784  		desc, input, output string
   785  	}{
   786  		// covering issue 20323
   787  		{
   788  			"field with predefined escaper name 1",
   789  			`{{.html | print}}`,
   790  			`&lt;h1&gt;Hi!&lt;/h1&gt;`,
   791  		},
   792  		// covering issue 20323
   793  		{
   794  			"field with predefined escaper name 2",
   795  			`{{.urlquery | print}}`,
   796  			`http://www.foo.com/index.html?title=main`,
   797  		},
   798  	} {
   799  		tmpl := Must(New("").Parse(test.input))
   800  		b := new(strings.Builder)
   801  		if err := tmpl.Execute(b, data); err != nil {
   802  			t.Errorf("%s: template execution failed: %s", test.desc, err)
   803  			continue
   804  		}
   805  		if w, g := test.output, b.String(); w != g {
   806  			t.Errorf("%s: escaped output: want\n\t%q\ngot\n\t%q", test.desc, w, g)
   807  			continue
   808  		}
   809  	}
   810  }
   811  
   812  func TestEscapeSet(t *testing.T) {
   813  	type dataItem struct {
   814  		Children []*dataItem
   815  		X        string
   816  	}
   817  
   818  	data := dataItem{
   819  		Children: []*dataItem{
   820  			{X: "foo"},
   821  			{X: "<bar>"},
   822  			{
   823  				Children: []*dataItem{
   824  					{X: "baz"},
   825  				},
   826  			},
   827  		},
   828  	}
   829  
   830  	tests := []struct {
   831  		inputs map[string]string
   832  		want   string
   833  	}{
   834  		// The trivial set.
   835  		{
   836  			map[string]string{
   837  				"main": ``,
   838  			},
   839  			``,
   840  		},
   841  		// A template called in the start context.
   842  		{
   843  			map[string]string{
   844  				"main": `Hello, {{template "helper"}}!`,
   845  				// Not a valid top level HTML template.
   846  				// "<b" is not a full tag.
   847  				"helper": `{{"<World>"}}`,
   848  			},
   849  			`Hello, &lt;World&gt;!`,
   850  		},
   851  		// A template called in a context other than the start.
   852  		{
   853  			map[string]string{
   854  				"main": `<a onclick='a = {{template "helper"}};'>`,
   855  				// Not a valid top level HTML template.
   856  				// "<b" is not a full tag.
   857  				"helper": `{{"<a>"}}<b`,
   858  			},
   859  			`<a onclick='a = &#34;\u003ca\u003e&#34;<b;'>`,
   860  		},
   861  		// A recursive template that ends in its start context.
   862  		{
   863  			map[string]string{
   864  				"main": `{{range .Children}}{{template "main" .}}{{else}}{{.X}} {{end}}`,
   865  			},
   866  			`foo &lt;bar&gt; baz `,
   867  		},
   868  		// A recursive helper template that ends in its start context.
   869  		{
   870  			map[string]string{
   871  				"main":   `{{template "helper" .}}`,
   872  				"helper": `{{if .Children}}<ul>{{range .Children}}<li>{{template "main" .}}</li>{{end}}</ul>{{else}}{{.X}}{{end}}`,
   873  			},
   874  			`<ul><li>foo</li><li>&lt;bar&gt;</li><li><ul><li>baz</li></ul></li></ul>`,
   875  		},
   876  		// Co-recursive templates that end in its start context.
   877  		{
   878  			map[string]string{
   879  				"main":   `<blockquote>{{range .Children}}{{template "helper" .}}{{end}}</blockquote>`,
   880  				"helper": `{{if .Children}}{{template "main" .}}{{else}}{{.X}}<br>{{end}}`,
   881  			},
   882  			`<blockquote>foo<br>&lt;bar&gt;<br><blockquote>baz<br></blockquote></blockquote>`,
   883  		},
   884  		// A template that is called in two different contexts.
   885  		{
   886  			map[string]string{
   887  				"main":   `<button onclick="title='{{template "helper"}}'; ...">{{template "helper"}}</button>`,
   888  				"helper": `{{11}} of {{"<100>"}}`,
   889  			},
   890  			`<button onclick="title='11 of \u003c100\u003e'; ...">11 of &lt;100&gt;</button>`,
   891  		},
   892  		// A non-recursive template that ends in a different context.
   893  		// helper starts in jsCtxRegexp and ends in jsCtxDivOp.
   894  		{
   895  			map[string]string{
   896  				"main":   `<script>var x={{template "helper"}}/{{"42"}};</script>`,
   897  				"helper": "{{126}}",
   898  			},
   899  			`<script>var x= 126 /"42";</script>`,
   900  		},
   901  		// A recursive template that ends in a similar context.
   902  		{
   903  			map[string]string{
   904  				"main":      `<script>var x=[{{template "countdown" 4}}];</script>`,
   905  				"countdown": `{{.}}{{if .}},{{template "countdown" . | pred}}{{end}}`,
   906  			},
   907  			`<script>var x=[ 4 , 3 , 2 , 1 , 0 ];</script>`,
   908  		},
   909  		// A recursive template that ends in a different context.
   910  		/*
   911  			{
   912  				map[string]string{
   913  					"main":   `<a href="/foo{{template "helper" .}}">`,
   914  					"helper": `{{if .Children}}{{range .Children}}{{template "helper" .}}{{end}}{{else}}?x={{.X}}{{end}}`,
   915  				},
   916  				`<a href="/foo?x=foo?x=%3cbar%3e?x=baz">`,
   917  			},
   918  		*/
   919  	}
   920  
   921  	// pred is a template function that returns the predecessor of a
   922  	// natural number for testing recursive templates.
   923  	fns := FuncMap{"pred": func(a ...any) (any, error) {
   924  		if len(a) == 1 {
   925  			if i, _ := a[0].(int); i > 0 {
   926  				return i - 1, nil
   927  			}
   928  		}
   929  		return nil, fmt.Errorf("undefined pred(%v)", a)
   930  	}}
   931  
   932  	for _, test := range tests {
   933  		source := ""
   934  		for name, body := range test.inputs {
   935  			source += fmt.Sprintf("{{define %q}}%s{{end}} ", name, body)
   936  		}
   937  		tmpl, err := New("root").Funcs(fns).Parse(source)
   938  		if err != nil {
   939  			t.Errorf("error parsing %q: %v", source, err)
   940  			continue
   941  		}
   942  		var b strings.Builder
   943  
   944  		if err := tmpl.ExecuteTemplate(&b, "main", data); err != nil {
   945  			t.Errorf("%q executing %v", err.Error(), tmpl.Lookup("main"))
   946  			continue
   947  		}
   948  		if got := b.String(); test.want != got {
   949  			t.Errorf("want\n\t%q\ngot\n\t%q", test.want, got)
   950  		}
   951  	}
   952  
   953  }
   954  
   955  func TestErrors(t *testing.T) {
   956  	tests := []struct {
   957  		input string
   958  		err   string
   959  	}{
   960  		// Non-error cases.
   961  		{
   962  			"{{if .Cond}}<a>{{else}}<b>{{end}}",
   963  			"",
   964  		},
   965  		{
   966  			"{{if .Cond}}<a>{{end}}",
   967  			"",
   968  		},
   969  		{
   970  			"{{if .Cond}}{{else}}<b>{{end}}",
   971  			"",
   972  		},
   973  		{
   974  			"{{with .Cond}}<div>{{end}}",
   975  			"",
   976  		},
   977  		{
   978  			"{{range .Items}}<a>{{end}}",
   979  			"",
   980  		},
   981  		{
   982  			"<a href='/foo?{{range .Items}}&{{.K}}={{.V}}{{end}}'>",
   983  			"",
   984  		},
   985  		{
   986  			"{{range .Items}}<a{{if .X}}{{end}}>{{end}}",
   987  			"",
   988  		},
   989  		{
   990  			"{{range .Items}}<a{{if .X}}{{end}}>{{continue}}{{end}}",
   991  			"",
   992  		},
   993  		{
   994  			"{{range .Items}}<a{{if .X}}{{end}}>{{break}}{{end}}",
   995  			"",
   996  		},
   997  		{
   998  			"{{range .Items}}<a{{if .X}}{{end}}>{{if .X}}{{break}}{{end}}{{end}}",
   999  			"",
  1000  		},
  1001  		{
  1002  			"<script>var a = `${a+b}`</script>`",
  1003  			"",
  1004  		},
  1005  		{
  1006  			"<script>var tmpl = `asd`;</script>",
  1007  			``,
  1008  		},
  1009  		{
  1010  			"<script>var tmpl = `${1}`;</script>",
  1011  			``,
  1012  		},
  1013  		{
  1014  			"<script>var tmpl = `${return ``}`;</script>",
  1015  			``,
  1016  		},
  1017  		{
  1018  			"<script>var tmpl = `${return {{.}} }`;</script>",
  1019  			``,
  1020  		},
  1021  		{
  1022  			"<script>var tmpl = `${ let a = {1:1} {{.}} }`;</script>",
  1023  			``,
  1024  		},
  1025  		{
  1026  			"<script>var tmpl = `asd ${return \"{\"}`;</script>",
  1027  			``,
  1028  		},
  1029  		{
  1030  			`{{if eq "" ""}}<meta>{{end}}`,
  1031  			``,
  1032  		},
  1033  		{
  1034  			`{{if eq "" ""}}<meta content="url={{"asd"}}">{{end}}`,
  1035  			``,
  1036  		},
  1037  
  1038  		// Error cases.
  1039  		{
  1040  			"{{if .Cond}}<a{{end}}",
  1041  			"z:1:5: {{if}} branches",
  1042  		},
  1043  		{
  1044  			"{{if .Cond}}\n{{else}}\n<a{{end}}",
  1045  			"z:1:5: {{if}} branches",
  1046  		},
  1047  		{
  1048  			// Missing quote in the else branch.
  1049  			`{{if .Cond}}<a href="foo">{{else}}<a href="bar>{{end}}`,
  1050  			"z:1:5: {{if}} branches",
  1051  		},
  1052  		{
  1053  			// Different kind of attribute: href implies a URL.
  1054  			"<a {{if .Cond}}href='{{else}}title='{{end}}{{.X}}'>",
  1055  			"z:1:8: {{if}} branches",
  1056  		},
  1057  		{
  1058  			"\n{{with .X}}<a{{end}}",
  1059  			"z:2:7: {{with}} branches",
  1060  		},
  1061  		{
  1062  			"\n{{with .X}}<a>{{else}}<a{{end}}",
  1063  			"z:2:7: {{with}} branches",
  1064  		},
  1065  		{
  1066  			"{{range .Items}}<a{{end}}",
  1067  			`z:1: on range loop re-entry: "<" in attribute name: "<a"`,
  1068  		},
  1069  		{
  1070  			"\n{{range .Items}} x='<a{{end}}",
  1071  			"z:2:8: on range loop re-entry: {{range}} branches",
  1072  		},
  1073  		{
  1074  			"{{range .Items}}<a{{if .X}}{{break}}{{end}}>{{end}}",
  1075  			"z:1:29: at range loop break: {{range}} branches end in different contexts",
  1076  		},
  1077  		{
  1078  			"{{range .Items}}<a{{if .X}}{{continue}}{{end}}>{{end}}",
  1079  			"z:1:29: at range loop continue: {{range}} branches end in different contexts",
  1080  		},
  1081  		{
  1082  			"{{range .Items}}{{if .X}}{{break}}{{end}}<a{{if .Y}}{{continue}}{{end}}>{{if .Z}}{{continue}}{{end}}{{end}}",
  1083  			"z:1:54: at range loop continue: {{range}} branches end in different contexts",
  1084  		},
  1085  		{
  1086  			"<a b=1 c={{.H}}",
  1087  			"z: ends in a non-text context: {stateAttr delimSpaceOrTagEnd",
  1088  		},
  1089  		{
  1090  			"<script>foo();",
  1091  			"z: ends in a non-text context: {stateJS",
  1092  		},
  1093  		{
  1094  			`<a href="{{if .F}}/foo?a={{else}}/bar/{{end}}{{.H}}">`,
  1095  			"z:1:47: {{.H}} appears in an ambiguous context within a URL",
  1096  		},
  1097  		{
  1098  			`<a onclick="alert('Hello \`,
  1099  			`unfinished escape sequence in JS string: "Hello \\"`,
  1100  		},
  1101  		{
  1102  			`<a onclick='alert("Hello\, World\`,
  1103  			`unfinished escape sequence in JS string: "Hello\\, World\\"`,
  1104  		},
  1105  		{
  1106  			`<a onclick='alert(/x+\`,
  1107  			`unfinished escape sequence in JS string: "x+\\"`,
  1108  		},
  1109  		{
  1110  			`<a onclick="/foo[\]/`,
  1111  			`unfinished JS regexp charset: "foo[\\]/"`,
  1112  		},
  1113  		{
  1114  			// It is ambiguous whether 1.5 should be 1\.5 or 1.5.
  1115  			// Either `var x = 1/- 1.5 /i.test(x)`
  1116  			// where `i.test(x)` is a method call of reference i,
  1117  			// or `/-1\.5/i.test(x)` which is a method call on a
  1118  			// case insensitive regular expression.
  1119  			`<script>{{if false}}var x = 1{{end}}/-{{"1.5"}}/i.test(x)</script>`,
  1120  			`'/' could start a division or regexp: "/-"`,
  1121  		},
  1122  		{
  1123  			`{{template "foo"}}`,
  1124  			"z:1:11: no such template \"foo\"",
  1125  		},
  1126  		{
  1127  			`<div{{template "y"}}>` +
  1128  				// Illegal starting in stateTag but not in stateText.
  1129  				`{{define "y"}} foo<b{{end}}`,
  1130  			`"<" in attribute name: " foo<b"`,
  1131  		},
  1132  		{
  1133  			`<script>reverseList = [{{template "t"}}]</script>` +
  1134  				// Missing " after recursive call.
  1135  				`{{define "t"}}{{if .Tail}}{{template "t" .Tail}}{{end}}{{.Head}}",{{end}}`,
  1136  			`: cannot compute output context for template t$htmltemplate_stateJS_elementScript`,
  1137  		},
  1138  		{
  1139  			`<input type=button value=onclick=>`,
  1140  			`html/template:z: "=" in unquoted attr: "onclick="`,
  1141  		},
  1142  		{
  1143  			`<input type=button value= onclick=>`,
  1144  			`html/template:z: "=" in unquoted attr: "onclick="`,
  1145  		},
  1146  		{
  1147  			`<input type=button value= 1+1=2>`,
  1148  			`html/template:z: "=" in unquoted attr: "1+1=2"`,
  1149  		},
  1150  		{
  1151  			"<a class=`foo>",
  1152  			"html/template:z: \"`\" in unquoted attr: \"`foo\"",
  1153  		},
  1154  		{
  1155  			`<a style=font:'Arial'>`,
  1156  			`html/template:z: "'" in unquoted attr: "font:'Arial'"`,
  1157  		},
  1158  		{
  1159  			`<a=foo>`,
  1160  			`: expected space, attr name, or end of tag, but got "=foo>"`,
  1161  		},
  1162  		{
  1163  			`Hello, {{. | urlquery | print}}!`,
  1164  			// urlquery is disallowed if it is not the last command in the pipeline.
  1165  			`predefined escaper "urlquery" disallowed in template`,
  1166  		},
  1167  		{
  1168  			`Hello, {{. | html | print}}!`,
  1169  			// html is disallowed if it is not the last command in the pipeline.
  1170  			`predefined escaper "html" disallowed in template`,
  1171  		},
  1172  		{
  1173  			`Hello, {{html . | print}}!`,
  1174  			// A direct call to html is disallowed if it is not the last command in the pipeline.
  1175  			`predefined escaper "html" disallowed in template`,
  1176  		},
  1177  		{
  1178  			`<div class={{. | html}}>Hello<div>`,
  1179  			// html is disallowed in a pipeline that is in an unquoted attribute context,
  1180  			// even if it is the last command in the pipeline.
  1181  			`predefined escaper "html" disallowed in template`,
  1182  		},
  1183  		{
  1184  			`Hello, {{. | urlquery | html}}!`,
  1185  			// html is allowed since it is the last command in the pipeline, but urlquery is not.
  1186  			`predefined escaper "urlquery" disallowed in template`,
  1187  		},
  1188  		{
  1189  			"<script>var a = `{{if .X}}`{{end}}",
  1190  			`{{if}} branches end in different contexts`,
  1191  		},
  1192  		{
  1193  			"<script>var a = `{{if .X}}a{{else}}`{{end}}",
  1194  			`{{if}} branches end in different contexts`,
  1195  		},
  1196  		{
  1197  			"<script>var a = `{{if .X}}a{{else}}b{{end}}`</script>",
  1198  			``,
  1199  		},
  1200  	}
  1201  	for _, test := range tests {
  1202  		buf := new(bytes.Buffer)
  1203  		tmpl, err := New("z").Parse(test.input)
  1204  		if err != nil {
  1205  			t.Errorf("input=%q: unexpected parse error %s\n", test.input, err)
  1206  			continue
  1207  		}
  1208  		err = tmpl.Execute(buf, nil)
  1209  		var got string
  1210  		if err != nil {
  1211  			got = err.Error()
  1212  		}
  1213  		if test.err == "" {
  1214  			if got != "" {
  1215  				t.Errorf("input=%q: unexpected error %q", test.input, got)
  1216  			}
  1217  			continue
  1218  		}
  1219  		if !strings.Contains(got, test.err) {
  1220  			t.Errorf("input=%q: error\n\t%q\ndoes not contain expected string\n\t%q", test.input, got, test.err)
  1221  			continue
  1222  		}
  1223  		// Check that we get the same error if we call Execute again.
  1224  		if err := tmpl.Execute(buf, nil); err == nil || err.Error() != got {
  1225  			t.Errorf("input=%q: unexpected error on second call %q", test.input, err)
  1226  
  1227  		}
  1228  	}
  1229  }
  1230  
  1231  func TestEscapeText(t *testing.T) {
  1232  	tests := []struct {
  1233  		input  string
  1234  		output context
  1235  	}{
  1236  		{
  1237  			``,
  1238  			context{},
  1239  		},
  1240  		{
  1241  			`Hello, World!`,
  1242  			context{},
  1243  		},
  1244  		{
  1245  			// An orphaned "<" is OK.
  1246  			`I <3 Ponies!`,
  1247  			context{},
  1248  		},
  1249  		{
  1250  			`<a`,
  1251  			context{state: stateTag},
  1252  		},
  1253  		{
  1254  			`<a `,
  1255  			context{state: stateTag},
  1256  		},
  1257  		{
  1258  			`<a>`,
  1259  			context{state: stateText},
  1260  		},
  1261  		{
  1262  			`<a href`,
  1263  			context{state: stateAttrName, attr: attrURL},
  1264  		},
  1265  		{
  1266  			`<a on`,
  1267  			context{state: stateAttrName, attr: attrScript},
  1268  		},
  1269  		{
  1270  			`<a href `,
  1271  			context{state: stateAfterName, attr: attrURL},
  1272  		},
  1273  		{
  1274  			`<a style  =  `,
  1275  			context{state: stateBeforeValue, attr: attrStyle},
  1276  		},
  1277  		{
  1278  			`<a href=`,
  1279  			context{state: stateBeforeValue, attr: attrURL},
  1280  		},
  1281  		{
  1282  			`<a href=x`,
  1283  			context{state: stateURL, delim: delimSpaceOrTagEnd, urlPart: urlPartPreQuery, attr: attrURL},
  1284  		},
  1285  		{
  1286  			`<a href=x `,
  1287  			context{state: stateTag},
  1288  		},
  1289  		{
  1290  			`<a href=>`,
  1291  			context{state: stateText},
  1292  		},
  1293  		{
  1294  			`<a href=x>`,
  1295  			context{state: stateText},
  1296  		},
  1297  		{
  1298  			`<a href ='`,
  1299  			context{state: stateURL, delim: delimSingleQuote, attr: attrURL},
  1300  		},
  1301  		{
  1302  			`<a href=''`,
  1303  			context{state: stateTag},
  1304  		},
  1305  		{
  1306  			`<a href= "`,
  1307  			context{state: stateURL, delim: delimDoubleQuote, attr: attrURL},
  1308  		},
  1309  		{
  1310  			`<a href=""`,
  1311  			context{state: stateTag},
  1312  		},
  1313  		{
  1314  			`<a title="`,
  1315  			context{state: stateAttr, delim: delimDoubleQuote},
  1316  		},
  1317  		{
  1318  			`<a HREF='http:`,
  1319  			context{state: stateURL, delim: delimSingleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  1320  		},
  1321  		{
  1322  			`<a Href='/`,
  1323  			context{state: stateURL, delim: delimSingleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  1324  		},
  1325  		{
  1326  			`<a href='"`,
  1327  			context{state: stateURL, delim: delimSingleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  1328  		},
  1329  		{
  1330  			`<a href="'`,
  1331  			context{state: stateURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  1332  		},
  1333  		{
  1334  			`<a href='&apos;`,
  1335  			context{state: stateURL, delim: delimSingleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  1336  		},
  1337  		{
  1338  			`<a href="&quot;`,
  1339  			context{state: stateURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  1340  		},
  1341  		{
  1342  			`<a href="&#34;`,
  1343  			context{state: stateURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  1344  		},
  1345  		{
  1346  			`<a href=&quot;`,
  1347  			context{state: stateURL, delim: delimSpaceOrTagEnd, urlPart: urlPartPreQuery, attr: attrURL},
  1348  		},
  1349  		{
  1350  			`<img alt="1">`,
  1351  			context{state: stateText},
  1352  		},
  1353  		{
  1354  			`<img alt="1>"`,
  1355  			context{state: stateTag},
  1356  		},
  1357  		{
  1358  			`<img alt="1>">`,
  1359  			context{state: stateText},
  1360  		},
  1361  		{
  1362  			`<input checked type="checkbox"`,
  1363  			context{state: stateTag},
  1364  		},
  1365  		{
  1366  			`<a onclick="`,
  1367  			context{state: stateJS, delim: delimDoubleQuote, attr: attrScript},
  1368  		},
  1369  		{
  1370  			`<a onclick="//foo`,
  1371  			context{state: stateJSLineCmt, delim: delimDoubleQuote, attr: attrScript},
  1372  		},
  1373  		{
  1374  			"<a onclick='//\n",
  1375  			context{state: stateJS, delim: delimSingleQuote, attr: attrScript},
  1376  		},
  1377  		{
  1378  			"<a onclick='//\r\n",
  1379  			context{state: stateJS, delim: delimSingleQuote, attr: attrScript},
  1380  		},
  1381  		{
  1382  			"<a onclick='//\u2028",
  1383  			context{state: stateJS, delim: delimSingleQuote, attr: attrScript},
  1384  		},
  1385  		{
  1386  			`<a onclick="/*`,
  1387  			context{state: stateJSBlockCmt, delim: delimDoubleQuote, attr: attrScript},
  1388  		},
  1389  		{
  1390  			`<a onclick="/*/`,
  1391  			context{state: stateJSBlockCmt, delim: delimDoubleQuote, attr: attrScript},
  1392  		},
  1393  		{
  1394  			`<a onclick="/**/`,
  1395  			context{state: stateJS, delim: delimDoubleQuote, attr: attrScript},
  1396  		},
  1397  		{
  1398  			`<a onkeypress="&quot;`,
  1399  			context{state: stateJSDqStr, delim: delimDoubleQuote, attr: attrScript},
  1400  		},
  1401  		{
  1402  			`<a onclick='&quot;foo&quot;`,
  1403  			context{state: stateJS, delim: delimSingleQuote, jsCtx: jsCtxDivOp, attr: attrScript},
  1404  		},
  1405  		{
  1406  			`<a onclick=&#39;foo&#39;`,
  1407  			context{state: stateJS, delim: delimSpaceOrTagEnd, jsCtx: jsCtxDivOp, attr: attrScript},
  1408  		},
  1409  		{
  1410  			`<a onclick=&#39;foo`,
  1411  			context{state: stateJSSqStr, delim: delimSpaceOrTagEnd, attr: attrScript},
  1412  		},
  1413  		{
  1414  			`<a onclick="&quot;foo'`,
  1415  			context{state: stateJSDqStr, delim: delimDoubleQuote, attr: attrScript},
  1416  		},
  1417  		{
  1418  			`<a onclick="'foo&quot;`,
  1419  			context{state: stateJSSqStr, delim: delimDoubleQuote, attr: attrScript},
  1420  		},
  1421  		{
  1422  			"<a onclick=\"`foo",
  1423  			context{state: stateJSTmplLit, delim: delimDoubleQuote, attr: attrScript},
  1424  		},
  1425  		{
  1426  			`<A ONCLICK="'`,
  1427  			context{state: stateJSSqStr, delim: delimDoubleQuote, attr: attrScript},
  1428  		},
  1429  		{
  1430  			`<a onclick="/`,
  1431  			context{state: stateJSRegexp, delim: delimDoubleQuote, attr: attrScript},
  1432  		},
  1433  		{
  1434  			`<a onclick="'foo'`,
  1435  			context{state: stateJS, delim: delimDoubleQuote, jsCtx: jsCtxDivOp, attr: attrScript},
  1436  		},
  1437  		{
  1438  			`<a onclick="'foo\'`,
  1439  			context{state: stateJSSqStr, delim: delimDoubleQuote, attr: attrScript},
  1440  		},
  1441  		{
  1442  			`<a onclick="'foo\'`,
  1443  			context{state: stateJSSqStr, delim: delimDoubleQuote, attr: attrScript},
  1444  		},
  1445  		{
  1446  			`<a onclick="/foo/`,
  1447  			context{state: stateJS, delim: delimDoubleQuote, jsCtx: jsCtxDivOp, attr: attrScript},
  1448  		},
  1449  		{
  1450  			`<script>/foo/ /=`,
  1451  			context{state: stateJS, element: elementScript},
  1452  		},
  1453  		{
  1454  			`<a onclick="1 /foo`,
  1455  			context{state: stateJS, delim: delimDoubleQuote, jsCtx: jsCtxDivOp, attr: attrScript},
  1456  		},
  1457  		{
  1458  			`<a onclick="1 /*c*/ /foo`,
  1459  			context{state: stateJS, delim: delimDoubleQuote, jsCtx: jsCtxDivOp, attr: attrScript},
  1460  		},
  1461  		{
  1462  			`<a onclick="/foo[/]`,
  1463  			context{state: stateJSRegexp, delim: delimDoubleQuote, attr: attrScript},
  1464  		},
  1465  		{
  1466  			`<a onclick="/foo\/`,
  1467  			context{state: stateJSRegexp, delim: delimDoubleQuote, attr: attrScript},
  1468  		},
  1469  		{
  1470  			`<a onclick="/foo/`,
  1471  			context{state: stateJS, delim: delimDoubleQuote, jsCtx: jsCtxDivOp, attr: attrScript},
  1472  		},
  1473  		{
  1474  			`<input checked style="`,
  1475  			context{state: stateCSS, delim: delimDoubleQuote, attr: attrStyle},
  1476  		},
  1477  		{
  1478  			`<a style="//`,
  1479  			context{state: stateCSSLineCmt, delim: delimDoubleQuote, attr: attrStyle},
  1480  		},
  1481  		{
  1482  			`<a style="//</script>`,
  1483  			context{state: stateCSSLineCmt, delim: delimDoubleQuote, attr: attrStyle},
  1484  		},
  1485  		{
  1486  			"<a style='//\n",
  1487  			context{state: stateCSS, delim: delimSingleQuote, attr: attrStyle},
  1488  		},
  1489  		{
  1490  			"<a style='//\r",
  1491  			context{state: stateCSS, delim: delimSingleQuote, attr: attrStyle},
  1492  		},
  1493  		{
  1494  			`<a style="/*`,
  1495  			context{state: stateCSSBlockCmt, delim: delimDoubleQuote, attr: attrStyle},
  1496  		},
  1497  		{
  1498  			`<a style="/*/`,
  1499  			context{state: stateCSSBlockCmt, delim: delimDoubleQuote, attr: attrStyle},
  1500  		},
  1501  		{
  1502  			`<a style="/**/`,
  1503  			context{state: stateCSS, delim: delimDoubleQuote, attr: attrStyle},
  1504  		},
  1505  		{
  1506  			`<a style="background: '`,
  1507  			context{state: stateCSSSqStr, delim: delimDoubleQuote, attr: attrStyle},
  1508  		},
  1509  		{
  1510  			`<a style="background: &quot;`,
  1511  			context{state: stateCSSDqStr, delim: delimDoubleQuote, attr: attrStyle},
  1512  		},
  1513  		{
  1514  			`<a style="background: '/foo?img=`,
  1515  			context{state: stateCSSSqStr, delim: delimDoubleQuote, urlPart: urlPartQueryOrFrag, attr: attrStyle},
  1516  		},
  1517  		{
  1518  			`<a style="background: '/`,
  1519  			context{state: stateCSSSqStr, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrStyle},
  1520  		},
  1521  		{
  1522  			`<a style="background: url(&#x22;/`,
  1523  			context{state: stateCSSDqURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrStyle},
  1524  		},
  1525  		{
  1526  			`<a style="background: url('/`,
  1527  			context{state: stateCSSSqURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrStyle},
  1528  		},
  1529  		{
  1530  			`<a style="background: url('/)`,
  1531  			context{state: stateCSSSqURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrStyle},
  1532  		},
  1533  		{
  1534  			`<a style="background: url('/ `,
  1535  			context{state: stateCSSSqURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrStyle},
  1536  		},
  1537  		{
  1538  			`<a style="background: url(/`,
  1539  			context{state: stateCSSURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrStyle},
  1540  		},
  1541  		{
  1542  			`<a style="background: url( `,
  1543  			context{state: stateCSSURL, delim: delimDoubleQuote, attr: attrStyle},
  1544  		},
  1545  		{
  1546  			`<a style="background: url( /image?name=`,
  1547  			context{state: stateCSSURL, delim: delimDoubleQuote, urlPart: urlPartQueryOrFrag, attr: attrStyle},
  1548  		},
  1549  		{
  1550  			`<a style="background: url(x)`,
  1551  			context{state: stateCSS, delim: delimDoubleQuote, attr: attrStyle},
  1552  		},
  1553  		{
  1554  			`<a style="background: url('x'`,
  1555  			context{state: stateCSS, delim: delimDoubleQuote, attr: attrStyle},
  1556  		},
  1557  		{
  1558  			`<a style="background: url( x `,
  1559  			context{state: stateCSS, delim: delimDoubleQuote, attr: attrStyle},
  1560  		},
  1561  		{
  1562  			`<!-- foo`,
  1563  			context{state: stateHTMLCmt},
  1564  		},
  1565  		{
  1566  			`<!-->`,
  1567  			context{state: stateHTMLCmt},
  1568  		},
  1569  		{
  1570  			`<!--->`,
  1571  			context{state: stateHTMLCmt},
  1572  		},
  1573  		{
  1574  			`<!-- foo -->`,
  1575  			context{state: stateText},
  1576  		},
  1577  		{
  1578  			`<script`,
  1579  			context{state: stateTag, element: elementScript},
  1580  		},
  1581  		{
  1582  			`<script `,
  1583  			context{state: stateTag, element: elementScript},
  1584  		},
  1585  		{
  1586  			`<script src="foo.js" `,
  1587  			context{state: stateTag, element: elementScript},
  1588  		},
  1589  		{
  1590  			`<script src='foo.js' `,
  1591  			context{state: stateTag, element: elementScript},
  1592  		},
  1593  		{
  1594  			`<script type=text/javascript `,
  1595  			context{state: stateTag, element: elementScript},
  1596  		},
  1597  		{
  1598  			`<script>`,
  1599  			context{state: stateJS, jsCtx: jsCtxRegexp, element: elementScript},
  1600  		},
  1601  		{
  1602  			`<script>foo`,
  1603  			context{state: stateJS, jsCtx: jsCtxDivOp, element: elementScript},
  1604  		},
  1605  		{
  1606  			`<script>foo</script>`,
  1607  			context{state: stateText},
  1608  		},
  1609  		{
  1610  			`<script>foo</script><!--`,
  1611  			context{state: stateHTMLCmt},
  1612  		},
  1613  		{
  1614  			`<script>document.write("<p>foo</p>");`,
  1615  			context{state: stateJS, element: elementScript},
  1616  		},
  1617  		{
  1618  			`<script>document.write("<p>foo<\/script>");`,
  1619  			context{state: stateJS, element: elementScript},
  1620  		},
  1621  		{
  1622  			// <script and </script tags are escaped, so </script> should not
  1623  			// cause us to exit the JS state.
  1624  			`<script>document.write("<script>alert(1)</script>");`,
  1625  			context{state: stateJS, element: elementScript},
  1626  		},
  1627  		{
  1628  			`<script>document.write("<script>`,
  1629  			context{state: stateJSDqStr, element: elementScript},
  1630  		},
  1631  		{
  1632  			`<script>document.write("<script>alert(1)</script>`,
  1633  			context{state: stateJSDqStr, element: elementScript},
  1634  		},
  1635  		{
  1636  			`<script>document.write("<script>alert(1)<!--`,
  1637  			context{state: stateJSDqStr, element: elementScript},
  1638  		},
  1639  		{
  1640  			`<script>document.write("<script>alert(1)</Script>");`,
  1641  			context{state: stateJS, element: elementScript},
  1642  		},
  1643  		{
  1644  			`<script>document.write("<!--");`,
  1645  			context{state: stateJS, element: elementScript},
  1646  		},
  1647  		{
  1648  			`<script>let a = /</script`,
  1649  			context{state: stateJSRegexp, element: elementScript},
  1650  		},
  1651  		{
  1652  			`<script>let a = /</script/`,
  1653  			context{state: stateJS, element: elementScript, jsCtx: jsCtxDivOp},
  1654  		},
  1655  		{
  1656  			`<script type="text/template">`,
  1657  			context{state: stateText},
  1658  		},
  1659  		// covering issue 19968
  1660  		{
  1661  			`<script type="TEXT/JAVASCRIPT">`,
  1662  			context{state: stateJS, element: elementScript},
  1663  		},
  1664  		// covering issue 19965
  1665  		{
  1666  			`<script TYPE="text/template">`,
  1667  			context{state: stateText},
  1668  		},
  1669  		{
  1670  			`<script type="notjs">`,
  1671  			context{state: stateText},
  1672  		},
  1673  		{
  1674  			`<Script>`,
  1675  			context{state: stateJS, element: elementScript},
  1676  		},
  1677  		{
  1678  			`<SCRIPT>foo`,
  1679  			context{state: stateJS, jsCtx: jsCtxDivOp, element: elementScript},
  1680  		},
  1681  		{
  1682  			`<textarea>value`,
  1683  			context{state: stateRCDATA, element: elementTextarea},
  1684  		},
  1685  		{
  1686  			`<textarea>value</TEXTAREA>`,
  1687  			context{state: stateText},
  1688  		},
  1689  		{
  1690  			`<textarea name=html><b`,
  1691  			context{state: stateRCDATA, element: elementTextarea},
  1692  		},
  1693  		{
  1694  			`<title>value`,
  1695  			context{state: stateRCDATA, element: elementTitle},
  1696  		},
  1697  		{
  1698  			`<style>value`,
  1699  			context{state: stateCSS, element: elementStyle},
  1700  		},
  1701  		{
  1702  			`<a xlink:href`,
  1703  			context{state: stateAttrName, attr: attrURL},
  1704  		},
  1705  		{
  1706  			`<a xmlns`,
  1707  			context{state: stateAttrName, attr: attrURL},
  1708  		},
  1709  		{
  1710  			`<a xmlns:foo`,
  1711  			context{state: stateAttrName, attr: attrURL},
  1712  		},
  1713  		{
  1714  			`<a xmlnsxyz`,
  1715  			context{state: stateAttrName},
  1716  		},
  1717  		{
  1718  			`<a data-url`,
  1719  			context{state: stateAttrName, attr: attrURL},
  1720  		},
  1721  		{
  1722  			`<a data-iconUri`,
  1723  			context{state: stateAttrName, attr: attrURL},
  1724  		},
  1725  		{
  1726  			`<a data-urlItem`,
  1727  			context{state: stateAttrName, attr: attrURL},
  1728  		},
  1729  		{
  1730  			`<a g:`,
  1731  			context{state: stateAttrName},
  1732  		},
  1733  		{
  1734  			`<a g:url`,
  1735  			context{state: stateAttrName, attr: attrURL},
  1736  		},
  1737  		{
  1738  			`<a g:iconUri`,
  1739  			context{state: stateAttrName, attr: attrURL},
  1740  		},
  1741  		{
  1742  			`<a g:urlItem`,
  1743  			context{state: stateAttrName, attr: attrURL},
  1744  		},
  1745  		{
  1746  			`<a g:value`,
  1747  			context{state: stateAttrName},
  1748  		},
  1749  		{
  1750  			`<a svg:style='`,
  1751  			context{state: stateCSS, delim: delimSingleQuote, attr: attrStyle},
  1752  		},
  1753  		{
  1754  			`<svg:font-face`,
  1755  			context{state: stateTag},
  1756  		},
  1757  		{
  1758  			`<svg:a svg:onclick="`,
  1759  			context{state: stateJS, delim: delimDoubleQuote, attr: attrScript},
  1760  		},
  1761  		{
  1762  			`<svg:a svg:onclick="x()">`,
  1763  			context{},
  1764  		},
  1765  		{
  1766  			"<script>var a = `",
  1767  			context{state: stateJSTmplLit, element: elementScript},
  1768  		},
  1769  		{
  1770  			"<script>var a = `${",
  1771  			context{state: stateJS, element: elementScript, jsBraceDepth: []int{0}},
  1772  		},
  1773  		{
  1774  			"<script>var a = `${}",
  1775  			context{state: stateJSTmplLit, element: elementScript},
  1776  		},
  1777  		{
  1778  			"<script>var a = `${`",
  1779  			context{state: stateJSTmplLit, element: elementScript, jsBraceDepth: []int{0}},
  1780  		},
  1781  		{
  1782  			"<script>var a = `${var a = \"",
  1783  			context{state: stateJSDqStr, element: elementScript, jsBraceDepth: []int{0}},
  1784  		},
  1785  		{
  1786  			"<script>var a = `${var a = \"`",
  1787  			context{state: stateJSDqStr, element: elementScript, jsBraceDepth: []int{0}},
  1788  		},
  1789  		{
  1790  			"<script>var a = `${var a = \"}",
  1791  			context{state: stateJSDqStr, element: elementScript, jsBraceDepth: []int{0}},
  1792  		},
  1793  		{
  1794  			"<script>var a = `${``",
  1795  			context{state: stateJS, element: elementScript, jsBraceDepth: []int{0}},
  1796  		},
  1797  		{
  1798  			"<script>var a = `${`}",
  1799  			context{state: stateJSTmplLit, element: elementScript, jsBraceDepth: []int{0}},
  1800  		},
  1801  		{
  1802  			"<script>`${ {} } asd`</script><script>`${ {} }",
  1803  			context{state: stateJSTmplLit, element: elementScript},
  1804  		},
  1805  		{
  1806  			"<script>var foo = `${ (_ => { return \"x\" })() + \"${",
  1807  			context{state: stateJSDqStr, element: elementScript, jsBraceDepth: []int{0}},
  1808  		},
  1809  		{
  1810  			"<script>var a = `${ {</script><script>var b = `${ x }",
  1811  			context{state: stateJSTmplLit, element: elementScript, jsCtx: jsCtxDivOp},
  1812  		},
  1813  		{
  1814  			"<script>var foo = `x` + \"${",
  1815  			context{state: stateJSDqStr, element: elementScript},
  1816  		},
  1817  		{
  1818  			"<script>function f() { var a = `${}`; }",
  1819  			context{state: stateJS, element: elementScript},
  1820  		},
  1821  		{
  1822  			"<script>{`${}`}",
  1823  			context{state: stateJS, element: elementScript},
  1824  		},
  1825  		{
  1826  			"<script>`${ function f() { return `${1}` }() }`",
  1827  			context{state: stateJS, element: elementScript, jsCtx: jsCtxDivOp},
  1828  		},
  1829  		{
  1830  			"<script>function f() {`${ function f() { `${1}` } }`}",
  1831  			context{state: stateJS, element: elementScript, jsCtx: jsCtxDivOp},
  1832  		},
  1833  		{
  1834  			"<script>`${ { `` }",
  1835  			context{state: stateJS, element: elementScript, jsBraceDepth: []int{0}},
  1836  		},
  1837  		{
  1838  			"<script>`${ { }`",
  1839  			context{state: stateJSTmplLit, element: elementScript, jsBraceDepth: []int{0}},
  1840  		},
  1841  		{
  1842  			"<script>var foo = `${ foo({ a: { c: `${",
  1843  			context{state: stateJS, element: elementScript, jsBraceDepth: []int{2, 0}},
  1844  		},
  1845  		{
  1846  			"<script>var foo = `${ foo({ a: { c: `${ {{.}} }` }, b: ",
  1847  			context{state: stateJS, element: elementScript, jsBraceDepth: []int{1}},
  1848  		},
  1849  		{
  1850  			"<script>`${ `}",
  1851  			context{state: stateJSTmplLit, element: elementScript, jsBraceDepth: []int{0}},
  1852  		},
  1853  	}
  1854  
  1855  	for _, test := range tests {
  1856  		b, e := []byte(test.input), makeEscaper(nil)
  1857  		c := e.escapeText(context{}, &parse.TextNode{NodeType: parse.NodeText, Text: b})
  1858  		if !test.output.eq(c) {
  1859  			t.Errorf("input %q: want context\n\t%v\ngot\n\t%v", test.input, test.output, c)
  1860  			continue
  1861  		}
  1862  		if test.input != string(b) {
  1863  			t.Errorf("input %q: text node was modified: want %q got %q", test.input, test.input, b)
  1864  			continue
  1865  		}
  1866  	}
  1867  }
  1868  
  1869  func TestEnsurePipelineContains(t *testing.T) {
  1870  	tests := []struct {
  1871  		input, output string
  1872  		ids           []string
  1873  	}{
  1874  		{
  1875  			"{{.X}}",
  1876  			".X",
  1877  			[]string{},
  1878  		},
  1879  		{
  1880  			"{{.X | html}}",
  1881  			".X | html",
  1882  			[]string{},
  1883  		},
  1884  		{
  1885  			"{{.X}}",
  1886  			".X | html",
  1887  			[]string{"html"},
  1888  		},
  1889  		{
  1890  			"{{html .X}}",
  1891  			"_eval_args_ .X | html | urlquery",
  1892  			[]string{"html", "urlquery"},
  1893  		},
  1894  		{
  1895  			"{{html .X .Y .Z}}",
  1896  			"_eval_args_ .X .Y .Z | html | urlquery",
  1897  			[]string{"html", "urlquery"},
  1898  		},
  1899  		{
  1900  			"{{.X | print}}",
  1901  			".X | print | urlquery",
  1902  			[]string{"urlquery"},
  1903  		},
  1904  		{
  1905  			"{{.X | print | urlquery}}",
  1906  			".X | print | urlquery",
  1907  			[]string{"urlquery"},
  1908  		},
  1909  		{
  1910  			"{{.X | urlquery}}",
  1911  			".X | html | urlquery",
  1912  			[]string{"html", "urlquery"},
  1913  		},
  1914  		{
  1915  			"{{.X | print 2 | .f 3}}",
  1916  			".X | print 2 | .f 3 | urlquery | html",
  1917  			[]string{"urlquery", "html"},
  1918  		},
  1919  		{
  1920  			// covering issue 10801
  1921  			"{{.X | println.x }}",
  1922  			".X | println.x | urlquery | html",
  1923  			[]string{"urlquery", "html"},
  1924  		},
  1925  		{
  1926  			// covering issue 10801
  1927  			"{{.X | (print 12 | println).x }}",
  1928  			".X | (print 12 | println).x | urlquery | html",
  1929  			[]string{"urlquery", "html"},
  1930  		},
  1931  		// The following test cases ensure that the merging of internal escapers
  1932  		// with the predefined "html" and "urlquery" escapers is correct.
  1933  		{
  1934  			"{{.X | urlquery}}",
  1935  			".X | _html_template_urlfilter | urlquery",
  1936  			[]string{"_html_template_urlfilter", "_html_template_urlnormalizer"},
  1937  		},
  1938  		{
  1939  			"{{.X | urlquery}}",
  1940  			".X | urlquery | _html_template_urlfilter | _html_template_cssescaper",
  1941  			[]string{"_html_template_urlfilter", "_html_template_cssescaper"},
  1942  		},
  1943  		{
  1944  			"{{.X | urlquery}}",
  1945  			".X | urlquery",
  1946  			[]string{"_html_template_urlnormalizer"},
  1947  		},
  1948  		{
  1949  			"{{.X | urlquery}}",
  1950  			".X | urlquery",
  1951  			[]string{"_html_template_urlescaper"},
  1952  		},
  1953  		{
  1954  			"{{.X | html}}",
  1955  			".X | html",
  1956  			[]string{"_html_template_htmlescaper"},
  1957  		},
  1958  		{
  1959  			"{{.X | html}}",
  1960  			".X | html",
  1961  			[]string{"_html_template_rcdataescaper"},
  1962  		},
  1963  	}
  1964  	for i, test := range tests {
  1965  		tmpl := template.Must(template.New("test").Parse(test.input))
  1966  		action, ok := (tmpl.Tree.Root.Nodes[0].(*parse.ActionNode))
  1967  		if !ok {
  1968  			t.Errorf("First node is not an action: %s", test.input)
  1969  			continue
  1970  		}
  1971  		pipe := action.Pipe
  1972  		originalIDs := make([]string, len(test.ids))
  1973  		copy(originalIDs, test.ids)
  1974  		ensurePipelineContains(pipe, test.ids)
  1975  		got := pipe.String()
  1976  		if got != test.output {
  1977  			t.Errorf("#%d: %s, %v: want\n\t%s\ngot\n\t%s", i, test.input, originalIDs, test.output, got)
  1978  		}
  1979  	}
  1980  }
  1981  
  1982  func TestEscapeMalformedPipelines(t *testing.T) {
  1983  	tests := []string{
  1984  		"{{ 0 | $ }}",
  1985  		"{{ 0 | $ | urlquery }}",
  1986  		"{{ 0 | (nil) }}",
  1987  		"{{ 0 | (nil) | html }}",
  1988  	}
  1989  	for _, test := range tests {
  1990  		var b bytes.Buffer
  1991  		tmpl, err := New("test").Parse(test)
  1992  		if err != nil {
  1993  			t.Errorf("failed to parse set: %q", err)
  1994  		}
  1995  		err = tmpl.Execute(&b, nil)
  1996  		if err == nil {
  1997  			t.Errorf("Expected error for %q", test)
  1998  		}
  1999  	}
  2000  }
  2001  
  2002  func TestEscapeErrorsNotIgnorable(t *testing.T) {
  2003  	var b bytes.Buffer
  2004  	tmpl, _ := New("dangerous").Parse("<a")
  2005  	err := tmpl.Execute(&b, nil)
  2006  	if err == nil {
  2007  		t.Errorf("Expected error")
  2008  	} else if b.Len() != 0 {
  2009  		t.Errorf("Emitted output despite escaping failure")
  2010  	}
  2011  }
  2012  
  2013  func TestEscapeSetErrorsNotIgnorable(t *testing.T) {
  2014  	var b bytes.Buffer
  2015  	tmpl, err := New("root").Parse(`{{define "t"}}<a{{end}}`)
  2016  	if err != nil {
  2017  		t.Errorf("failed to parse set: %q", err)
  2018  	}
  2019  	err = tmpl.ExecuteTemplate(&b, "t", nil)
  2020  	if err == nil {
  2021  		t.Errorf("Expected error")
  2022  	} else if b.Len() != 0 {
  2023  		t.Errorf("Emitted output despite escaping failure")
  2024  	}
  2025  }
  2026  
  2027  func TestRedundantFuncs(t *testing.T) {
  2028  	inputs := []any{
  2029  		"\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f" +
  2030  			"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" +
  2031  			` !"#$%&'()*+,-./` +
  2032  			`0123456789:;<=>?` +
  2033  			`@ABCDEFGHIJKLMNO` +
  2034  			`PQRSTUVWXYZ[\]^_` +
  2035  			"`abcdefghijklmno" +
  2036  			"pqrstuvwxyz{|}~\x7f" +
  2037  			"\u00A0\u0100\u2028\u2029\ufeff\ufdec\ufffd\uffff\U0001D11E" +
  2038  			"&amp;%22\\",
  2039  		CSS(`a[href =~ "//example.com"]#foo`),
  2040  		HTML(`Hello, <b>World</b> &amp;tc!`),
  2041  		HTMLAttr(` dir="ltr"`),
  2042  		JS(`c && alert("Hello, World!");`),
  2043  		JSStr(`Hello, World & O'Reilly\x21`),
  2044  		URL(`greeting=H%69&addressee=(World)`),
  2045  	}
  2046  
  2047  	for n0, m := range redundantFuncs {
  2048  		f0 := funcMap[n0].(func(...any) string)
  2049  		for n1 := range m {
  2050  			f1 := funcMap[n1].(func(...any) string)
  2051  			for _, input := range inputs {
  2052  				want := f0(input)
  2053  				if got := f1(want); want != got {
  2054  					t.Errorf("%s %s with %T %q: want\n\t%q,\ngot\n\t%q", n0, n1, input, input, want, got)
  2055  				}
  2056  			}
  2057  		}
  2058  	}
  2059  }
  2060  
  2061  func TestIndirectPrint(t *testing.T) {
  2062  	a := 3
  2063  	ap := &a
  2064  	b := "hello"
  2065  	bp := &b
  2066  	bpp := &bp
  2067  	tmpl := Must(New("t").Parse(`{{.}}`))
  2068  	var buf strings.Builder
  2069  	err := tmpl.Execute(&buf, ap)
  2070  	if err != nil {
  2071  		t.Errorf("Unexpected error: %s", err)
  2072  	} else if buf.String() != "3" {
  2073  		t.Errorf(`Expected "3"; got %q`, buf.String())
  2074  	}
  2075  	buf.Reset()
  2076  	err = tmpl.Execute(&buf, bpp)
  2077  	if err != nil {
  2078  		t.Errorf("Unexpected error: %s", err)
  2079  	} else if buf.String() != "hello" {
  2080  		t.Errorf(`Expected "hello"; got %q`, buf.String())
  2081  	}
  2082  }
  2083  
  2084  // This is a test for issue 3272.
  2085  func TestEmptyTemplateHTML(t *testing.T) {
  2086  	page := Must(New("page").ParseFiles(os.DevNull))
  2087  	if err := page.ExecuteTemplate(os.Stdout, "page", "nothing"); err == nil {
  2088  		t.Fatal("expected error")
  2089  	}
  2090  }
  2091  
  2092  type Issue7379 int
  2093  
  2094  func (Issue7379) SomeMethod(x int) string {
  2095  	return fmt.Sprintf("<%d>", x)
  2096  }
  2097  
  2098  // This is a test for issue 7379: type assertion error caused panic, and then
  2099  // the code to handle the panic breaks escaping. It's hard to see the second
  2100  // problem once the first is fixed, but its fix is trivial so we let that go. See
  2101  // the discussion for issue 7379.
  2102  func TestPipeToMethodIsEscaped(t *testing.T) {
  2103  	tmpl := Must(New("x").Parse("<html>{{0 | .SomeMethod}}</html>\n"))
  2104  	tryExec := func() string {
  2105  		defer func() {
  2106  			panicValue := recover()
  2107  			if panicValue != nil {
  2108  				t.Errorf("panicked: %v\n", panicValue)
  2109  			}
  2110  		}()
  2111  		var b strings.Builder
  2112  		tmpl.Execute(&b, Issue7379(0))
  2113  		return b.String()
  2114  	}
  2115  	for i := 0; i < 3; i++ {
  2116  		str := tryExec()
  2117  		const expect = "<html>&lt;0&gt;</html>\n"
  2118  		if str != expect {
  2119  			t.Errorf("expected %q got %q", expect, str)
  2120  		}
  2121  	}
  2122  }
  2123  
  2124  // Unlike text/template, html/template crashed if given an incomplete
  2125  // template, that is, a template that had been named but not given any content.
  2126  // This is issue #10204.
  2127  func TestErrorOnUndefined(t *testing.T) {
  2128  	tmpl := New("undefined")
  2129  
  2130  	err := tmpl.Execute(nil, nil)
  2131  	if err == nil {
  2132  		t.Error("expected error")
  2133  	} else if !strings.Contains(err.Error(), "incomplete") {
  2134  		t.Errorf("expected error about incomplete template; got %s", err)
  2135  	}
  2136  }
  2137  
  2138  // This covers issue #20842.
  2139  func TestIdempotentExecute(t *testing.T) {
  2140  	tmpl := Must(New("").
  2141  		Parse(`{{define "main"}}<body>{{template "hello"}}</body>{{end}}`))
  2142  	Must(tmpl.
  2143  		Parse(`{{define "hello"}}Hello, {{"Ladies & Gentlemen!"}}{{end}}`))
  2144  	got := new(strings.Builder)
  2145  	var err error
  2146  	// Ensure that "hello" produces the same output when executed twice.
  2147  	want := "Hello, Ladies &amp; Gentlemen!"
  2148  	for i := 0; i < 2; i++ {
  2149  		err = tmpl.ExecuteTemplate(got, "hello", nil)
  2150  		if err != nil {
  2151  			t.Errorf("unexpected error: %s", err)
  2152  		}
  2153  		if got.String() != want {
  2154  			t.Errorf("after executing template \"hello\", got:\n\t%q\nwant:\n\t%q\n", got.String(), want)
  2155  		}
  2156  		got.Reset()
  2157  	}
  2158  	// Ensure that the implicit re-execution of "hello" during the execution of
  2159  	// "main" does not cause the output of "hello" to change.
  2160  	err = tmpl.ExecuteTemplate(got, "main", nil)
  2161  	if err != nil {
  2162  		t.Errorf("unexpected error: %s", err)
  2163  	}
  2164  	// If the HTML escaper is added again to the action {{"Ladies & Gentlemen!"}},
  2165  	// we would expected to see the ampersand overescaped to "&amp;amp;".
  2166  	want = "<body>Hello, Ladies &amp; Gentlemen!</body>"
  2167  	if got.String() != want {
  2168  		t.Errorf("after executing template \"main\", got:\n\t%q\nwant:\n\t%q\n", got.String(), want)
  2169  	}
  2170  }
  2171  
  2172  func BenchmarkEscapedExecute(b *testing.B) {
  2173  	tmpl := Must(New("t").Parse(`<a onclick="alert('{{.}}')">{{.}}</a>`))
  2174  	var buf bytes.Buffer
  2175  	b.ResetTimer()
  2176  	for i := 0; i < b.N; i++ {
  2177  		tmpl.Execute(&buf, "foo & 'bar' & baz")
  2178  		buf.Reset()
  2179  	}
  2180  }
  2181  
  2182  // Covers issue 22780.
  2183  func TestOrphanedTemplate(t *testing.T) {
  2184  	t1 := Must(New("foo").Parse(`<a href="{{.}}">link1</a>`))
  2185  	t2 := Must(t1.New("foo").Parse(`bar`))
  2186  
  2187  	var b strings.Builder
  2188  	const wantError = `template: "foo" is an incomplete or empty template`
  2189  	if err := t1.Execute(&b, "javascript:alert(1)"); err == nil {
  2190  		t.Fatal("expected error executing t1")
  2191  	} else if gotError := err.Error(); gotError != wantError {
  2192  		t.Fatalf("got t1 execution error:\n\t%s\nwant:\n\t%s", gotError, wantError)
  2193  	}
  2194  	b.Reset()
  2195  	if err := t2.Execute(&b, nil); err != nil {
  2196  		t.Fatalf("error executing t2: %s", err)
  2197  	}
  2198  	const want = "bar"
  2199  	if got := b.String(); got != want {
  2200  		t.Fatalf("t2 rendered %q, want %q", got, want)
  2201  	}
  2202  }
  2203  
  2204  // Covers issue 21844.
  2205  func TestAliasedParseTreeDoesNotOverescape(t *testing.T) {
  2206  	const (
  2207  		tmplText = `{{.}}`
  2208  		data     = `<baz>`
  2209  		want     = `&lt;baz&gt;`
  2210  	)
  2211  	// Templates "foo" and "bar" both alias the same underlying parse tree.
  2212  	tpl := Must(New("foo").Parse(tmplText))
  2213  	if _, err := tpl.AddParseTree("bar", tpl.Tree); err != nil {
  2214  		t.Fatalf("AddParseTree error: %v", err)
  2215  	}
  2216  	var b1, b2 strings.Builder
  2217  	if err := tpl.ExecuteTemplate(&b1, "foo", data); err != nil {
  2218  		t.Fatalf(`ExecuteTemplate failed for "foo": %v`, err)
  2219  	}
  2220  	if err := tpl.ExecuteTemplate(&b2, "bar", data); err != nil {
  2221  		t.Fatalf(`ExecuteTemplate failed for "foo": %v`, err)
  2222  	}
  2223  	got1, got2 := b1.String(), b2.String()
  2224  	if got1 != want {
  2225  		t.Fatalf(`Template "foo" rendered %q, want %q`, got1, want)
  2226  	}
  2227  	if got1 != got2 {
  2228  		t.Fatalf(`Template "foo" and "bar" rendered %q and %q respectively, expected equal values`, got1, got2)
  2229  	}
  2230  }
  2231  
  2232  func TestMetaContentEscapeGODEBUG(t *testing.T) {
  2233  	savedGODEBUG := os.Getenv("GODEBUG")
  2234  	os.Setenv("GODEBUG", savedGODEBUG+",htmlmetacontenturlescape=0")
  2235  	defer func() { os.Setenv("GODEBUG", savedGODEBUG) }()
  2236  
  2237  	tmpl := Must(New("").Parse(`<meta http-equiv="refresh" content="asd; url={{"javascript:alert(1)"}}; asd; url={{"vbscript:alert(1)"}}; asd">`))
  2238  	var b strings.Builder
  2239  	if err := tmpl.Execute(&b, nil); err != nil {
  2240  		t.Fatalf("unexpected error: %s", err)
  2241  	}
  2242  	want := `<meta http-equiv="refresh" content="asd; url=javascript:alert(1); asd; url=vbscript:alert(1); asd">`
  2243  	if got := b.String(); got != want {
  2244  		t.Fatalf("got %q, want %q", got, want)
  2245  	}
  2246  }
  2247  

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