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Source file src/html/template/escape_test.go

Documentation: html/template

  // Copyright 2011 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  package template
  
  import (
  	"bytes"
  	"encoding/json"
  	"fmt"
  	"os"
  	"strings"
  	"testing"
  	"text/template"
  	"text/template/parse"
  )
  
  type badMarshaler struct{}
  
  func (x *badMarshaler) MarshalJSON() ([]byte, error) {
  	// Keys in valid JSON must be double quoted as must all strings.
  	return []byte("{ foo: 'not quite valid JSON' }"), nil
  }
  
  type goodMarshaler struct{}
  
  func (x *goodMarshaler) MarshalJSON() ([]byte, error) {
  	return []byte(`{ "<foo>": "O'Reilly" }`), nil
  }
  
  func TestEscape(t *testing.T) {
  	data := struct {
  		F, T    bool
  		C, G, H string
  		A, E    []string
  		B, M    json.Marshaler
  		N       int
  		Z       *int
  		W       HTML
  	}{
  		F: false,
  		T: true,
  		C: "<Cincinatti>",
  		G: "<Goodbye>",
  		H: "<Hello>",
  		A: []string{"<a>", "<b>"},
  		E: []string{},
  		N: 42,
  		B: &badMarshaler{},
  		M: &goodMarshaler{},
  		Z: nil,
  		W: HTML(`&iexcl;<b class="foo">Hello</b>, <textarea>O'World</textarea>!`),
  	}
  	pdata := &data
  
  	tests := []struct {
  		name   string
  		input  string
  		output string
  	}{
  		{
  			"if",
  			"{{if .T}}Hello{{end}}, {{.C}}!",
  			"Hello, &lt;Cincinatti&gt;!",
  		},
  		{
  			"else",
  			"{{if .F}}{{.H}}{{else}}{{.G}}{{end}}!",
  			"&lt;Goodbye&gt;!",
  		},
  		{
  			"overescaping1",
  			"Hello, {{.C | html}}!",
  			"Hello, &lt;Cincinatti&gt;!",
  		},
  		{
  			"overescaping2",
  			"Hello, {{html .C}}!",
  			"Hello, &lt;Cincinatti&gt;!",
  		},
  		{
  			"overescaping3",
  			"{{with .C}}{{$msg := .}}Hello, {{$msg}}!{{end}}",
  			"Hello, &lt;Cincinatti&gt;!",
  		},
  		{
  			"assignment",
  			"{{if $x := .H}}{{$x}}{{end}}",
  			"&lt;Hello&gt;",
  		},
  		{
  			"withBody",
  			"{{with .H}}{{.}}{{end}}",
  			"&lt;Hello&gt;",
  		},
  		{
  			"withElse",
  			"{{with .E}}{{.}}{{else}}{{.H}}{{end}}",
  			"&lt;Hello&gt;",
  		},
  		{
  			"rangeBody",
  			"{{range .A}}{{.}}{{end}}",
  			"&lt;a&gt;&lt;b&gt;",
  		},
  		{
  			"rangeElse",
  			"{{range .E}}{{.}}{{else}}{{.H}}{{end}}",
  			"&lt;Hello&gt;",
  		},
  		{
  			"nonStringValue",
  			"{{.T}}",
  			"true",
  		},
  		{
  			"constant",
  			`<a href="/search?q={{"'a<b'"}}">`,
  			`<a href="/search?q=%27a%3cb%27">`,
  		},
  		{
  			"multipleAttrs",
  			"<a b=1 c={{.H}}>",
  			"<a b=1 c=&lt;Hello&gt;>",
  		},
  		{
  			"urlStartRel",
  			`<a href='{{"/foo/bar?a=b&c=d"}}'>`,
  			`<a href='/foo/bar?a=b&amp;c=d'>`,
  		},
  		{
  			"urlStartAbsOk",
  			`<a href='{{"http://example.com/foo/bar?a=b&c=d"}}'>`,
  			`<a href='http://example.com/foo/bar?a=b&amp;c=d'>`,
  		},
  		{
  			"protocolRelativeURLStart",
  			`<a href='{{"//example.com:8000/foo/bar?a=b&c=d"}}'>`,
  			`<a href='//example.com:8000/foo/bar?a=b&amp;c=d'>`,
  		},
  		{
  			"pathRelativeURLStart",
  			`<a href="{{"/javascript:80/foo/bar"}}">`,
  			`<a href="/javascript:80/foo/bar">`,
  		},
  		{
  			"dangerousURLStart",
  			`<a href='{{"javascript:alert(%22pwned%22)"}}'>`,
  			`<a href='#ZgotmplZ'>`,
  		},
  		{
  			"dangerousURLStart2",
  			`<a href='  {{"javascript:alert(%22pwned%22)"}}'>`,
  			`<a href='  #ZgotmplZ'>`,
  		},
  		{
  			"nonHierURL",
  			`<a href={{"mailto:Muhammed \"The Greatest\" Ali <m.ali@example.com>"}}>`,
  			`<a href=mailto:Muhammed%20%22The%20Greatest%22%20Ali%20%3cm.ali@example.com%3e>`,
  		},
  		{
  			"urlPath",
  			`<a href='http://{{"javascript:80"}}/foo'>`,
  			`<a href='http://javascript:80/foo'>`,
  		},
  		{
  			"urlQuery",
  			`<a href='/search?q={{.H}}'>`,
  			`<a href='/search?q=%3cHello%3e'>`,
  		},
  		{
  			"urlFragment",
  			`<a href='/faq#{{.H}}'>`,
  			`<a href='/faq#%3cHello%3e'>`,
  		},
  		{
  			"urlBranch",
  			`<a href="{{if .F}}/foo?a=b{{else}}/bar{{end}}">`,
  			`<a href="/bar">`,
  		},
  		{
  			"urlBranchConflictMoot",
  			`<a href="{{if .T}}/foo?a={{else}}/bar#{{end}}{{.C}}">`,
  			`<a href="/foo?a=%3cCincinatti%3e">`,
  		},
  		{
  			"jsStrValue",
  			"<button onclick='alert({{.H}})'>",
  			`<button onclick='alert(&#34;\u003cHello\u003e&#34;)'>`,
  		},
  		{
  			"jsNumericValue",
  			"<button onclick='alert({{.N}})'>",
  			`<button onclick='alert( 42 )'>`,
  		},
  		{
  			"jsBoolValue",
  			"<button onclick='alert({{.T}})'>",
  			`<button onclick='alert( true )'>`,
  		},
  		{
  			"jsNilValue",
  			"<button onclick='alert(typeof{{.Z}})'>",
  			`<button onclick='alert(typeof null )'>`,
  		},
  		{
  			"jsObjValue",
  			"<button onclick='alert({{.A}})'>",
  			`<button onclick='alert([&#34;\u003ca\u003e&#34;,&#34;\u003cb\u003e&#34;])'>`,
  		},
  		{
  			"jsObjValueScript",
  			"<script>alert({{.A}})</script>",
  			`<script>alert(["\u003ca\u003e","\u003cb\u003e"])</script>`,
  		},
  		{
  			"jsObjValueNotOverEscaped",
  			"<button onclick='alert({{.A | html}})'>",
  			`<button onclick='alert([&#34;\u003ca\u003e&#34;,&#34;\u003cb\u003e&#34;])'>`,
  		},
  		{
  			"jsStr",
  			"<button onclick='alert(&quot;{{.H}}&quot;)'>",
  			`<button onclick='alert(&quot;\x3cHello\x3e&quot;)'>`,
  		},
  		{
  			"badMarshaler",
  			`<button onclick='alert(1/{{.B}}in numbers)'>`,
  			`<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)'>`,
  		},
  		{
  			"jsMarshaler",
  			`<button onclick='alert({{.M}})'>`,
  			`<button onclick='alert({&#34;\u003cfoo\u003e&#34;:&#34;O&#39;Reilly&#34;})'>`,
  		},
  		{
  			"jsStrNotUnderEscaped",
  			"<button onclick='alert({{.C | urlquery}})'>",
  			// URL escaped, then quoted for JS.
  			`<button onclick='alert(&#34;%3CCincinatti%3E&#34;)'>`,
  		},
  		{
  			"jsRe",
  			`<button onclick='alert(/{{"foo+bar"}}/.test(""))'>`,
  			`<button onclick='alert(/foo\x2bbar/.test(""))'>`,
  		},
  		{
  			"jsReBlank",
  			`<script>alert(/{{""}}/.test(""));</script>`,
  			`<script>alert(/(?:)/.test(""));</script>`,
  		},
  		{
  			"jsReAmbigOk",
  			`<script>{{if true}}var x = 1{{end}}</script>`,
  			// The {if} ends in an ambiguous jsCtx but there is
  			// no slash following so we shouldn't care.
  			`<script>var x = 1</script>`,
  		},
  		{
  			"styleBidiKeywordPassed",
  			`<p style="dir: {{"ltr"}}">`,
  			`<p style="dir: ltr">`,
  		},
  		{
  			"styleBidiPropNamePassed",
  			`<p style="border-{{"left"}}: 0; border-{{"right"}}: 1in">`,
  			`<p style="border-left: 0; border-right: 1in">`,
  		},
  		{
  			"styleExpressionBlocked",
  			`<p style="width: {{"expression(alert(1337))"}}">`,
  			`<p style="width: ZgotmplZ">`,
  		},
  		{
  			"styleTagSelectorPassed",
  			`<style>{{"p"}} { color: pink }</style>`,
  			`<style>p { color: pink }</style>`,
  		},
  		{
  			"styleIDPassed",
  			`<style>p{{"#my-ID"}} { font: Arial }</style>`,
  			`<style>p#my-ID { font: Arial }</style>`,
  		},
  		{
  			"styleClassPassed",
  			`<style>p{{".my_class"}} { font: Arial }</style>`,
  			`<style>p.my_class { font: Arial }</style>`,
  		},
  		{
  			"styleQuantityPassed",
  			`<a style="left: {{"2em"}}; top: {{0}}">`,
  			`<a style="left: 2em; top: 0">`,
  		},
  		{
  			"stylePctPassed",
  			`<table style=width:{{"100%"}}>`,
  			`<table style=width:100%>`,
  		},
  		{
  			"styleColorPassed",
  			`<p style="color: {{"#8ff"}}; background: {{"#000"}}">`,
  			`<p style="color: #8ff; background: #000">`,
  		},
  		{
  			"styleObfuscatedExpressionBlocked",
  			`<p style="width: {{"  e\\78preS\x00Sio/**/n(alert(1337))"}}">`,
  			`<p style="width: ZgotmplZ">`,
  		},
  		{
  			"styleMozBindingBlocked",
  			`<p style="{{"-moz-binding(alert(1337))"}}: ...">`,
  			`<p style="ZgotmplZ: ...">`,
  		},
  		{
  			"styleObfuscatedMozBindingBlocked",
  			`<p style="{{"  -mo\\7a-B\x00I/**/nding(alert(1337))"}}: ...">`,
  			`<p style="ZgotmplZ: ...">`,
  		},
  		{
  			"styleFontNameString",
  			`<p style='font-family: "{{"Times New Roman"}}"'>`,
  			`<p style='font-family: "Times New Roman"'>`,
  		},
  		{
  			"styleFontNameString",
  			`<p style='font-family: "{{"Times New Roman"}}", "{{"sans-serif"}}"'>`,
  			`<p style='font-family: "Times New Roman", "sans-serif"'>`,
  		},
  		{
  			"styleFontNameUnquoted",
  			`<p style='font-family: {{"Times New Roman"}}'>`,
  			`<p style='font-family: Times New Roman'>`,
  		},
  		{
  			"styleURLQueryEncoded",
  			`<p style="background: url(/img?name={{"O'Reilly Animal(1)<2>.png"}})">`,
  			`<p style="background: url(/img?name=O%27Reilly%20Animal%281%29%3c2%3e.png)">`,
  		},
  		{
  			"styleQuotedURLQueryEncoded",
  			`<p style="background: url('/img?name={{"O'Reilly Animal(1)<2>.png"}}')">`,
  			`<p style="background: url('/img?name=O%27Reilly%20Animal%281%29%3c2%3e.png')">`,
  		},
  		{
  			"styleStrQueryEncoded",
  			`<p style="background: '/img?name={{"O'Reilly Animal(1)<2>.png"}}'">`,
  			`<p style="background: '/img?name=O%27Reilly%20Animal%281%29%3c2%3e.png'">`,
  		},
  		{
  			"styleURLBadProtocolBlocked",
  			`<a style="background: url('{{"javascript:alert(1337)"}}')">`,
  			`<a style="background: url('#ZgotmplZ')">`,
  		},
  		{
  			"styleStrBadProtocolBlocked",
  			`<a style="background: '{{"vbscript:alert(1337)"}}'">`,
  			`<a style="background: '#ZgotmplZ'">`,
  		},
  		{
  			"styleStrEncodedProtocolEncoded",
  			`<a style="background: '{{"javascript\\3a alert(1337)"}}'">`,
  			// The CSS string 'javascript\\3a alert(1337)' does not contain a colon.
  			`<a style="background: 'javascript\\3a alert\28 1337\29 '">`,
  		},
  		{
  			"styleURLGoodProtocolPassed",
  			`<a style="background: url('{{"http://oreilly.com/O'Reilly Animals(1)<2>;{}.html"}}')">`,
  			`<a style="background: url('http://oreilly.com/O%27Reilly%20Animals%281%29%3c2%3e;%7b%7d.html')">`,
  		},
  		{
  			"styleStrGoodProtocolPassed",
  			`<a style="background: '{{"http://oreilly.com/O'Reilly Animals(1)<2>;{}.html"}}'">`,
  			`<a style="background: 'http\3a\2f\2foreilly.com\2fO\27Reilly Animals\28 1\29\3c 2\3e\3b\7b\7d.html'">`,
  		},
  		{
  			"styleURLEncodedForHTMLInAttr",
  			`<a style="background: url('{{"/search?img=foo&size=icon"}}')">`,
  			`<a style="background: url('/search?img=foo&amp;size=icon')">`,
  		},
  		{
  			"styleURLNotEncodedForHTMLInCdata",
  			`<style>body { background: url('{{"/search?img=foo&size=icon"}}') }</style>`,
  			`<style>body { background: url('/search?img=foo&size=icon') }</style>`,
  		},
  		{
  			"styleURLMixedCase",
  			`<p style="background: URL(#{{.H}})">`,
  			`<p style="background: URL(#%3cHello%3e)">`,
  		},
  		{
  			"stylePropertyPairPassed",
  			`<a style='{{"color: red"}}'>`,
  			`<a style='color: red'>`,
  		},
  		{
  			"styleStrSpecialsEncoded",
  			`<a style="font-family: '{{"/**/'\";:// \\"}}', &quot;{{"/**/'\";:// \\"}}&quot;">`,
  			`<a style="font-family: '\2f**\2f\27\22\3b\3a\2f\2f  \\', &quot;\2f**\2f\27\22\3b\3a\2f\2f  \\&quot;">`,
  		},
  		{
  			"styleURLSpecialsEncoded",
  			`<a style="border-image: url({{"/**/'\";:// \\"}}), url(&quot;{{"/**/'\";:// \\"}}&quot;), url('{{"/**/'\";:// \\"}}'), 'http://www.example.com/?q={{"/**/'\";:// \\"}}''">`,
  			`<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''">`,
  		},
  		{
  			"HTML comment",
  			"<b>Hello, <!-- name of world -->{{.C}}</b>",
  			"<b>Hello, &lt;Cincinatti&gt;</b>",
  		},
  		{
  			"HTML comment not first < in text node.",
  			"<<!-- -->!--",
  			"&lt;!--",
  		},
  		{
  			"HTML normalization 1",
  			"a < b",
  			"a &lt; b",
  		},
  		{
  			"HTML normalization 2",
  			"a << b",
  			"a &lt;&lt; b",
  		},
  		{
  			"HTML normalization 3",
  			"a<<!-- --><!-- -->b",
  			"a&lt;b",
  		},
  		{
  			"HTML doctype not normalized",
  			"<!DOCTYPE html>Hello, World!",
  			"<!DOCTYPE html>Hello, World!",
  		},
  		{
  			"HTML doctype not case-insensitive",
  			"<!doCtYPE htMl>Hello, World!",
  			"<!doCtYPE htMl>Hello, World!",
  		},
  		{
  			"No doctype injection",
  			`<!{{"DOCTYPE"}}`,
  			"&lt;!DOCTYPE",
  		},
  		{
  			"Split HTML comment",
  			"<b>Hello, <!-- name of {{if .T}}city -->{{.C}}{{else}}world -->{{.W}}{{end}}</b>",
  			"<b>Hello, &lt;Cincinatti&gt;</b>",
  		},
  		{
  			"JS line comment",
  			"<script>for (;;) { if (c()) break// foo not a label\n" +
  				"foo({{.T}});}</script>",
  			"<script>for (;;) { if (c()) break\n" +
  				"foo( true );}</script>",
  		},
  		{
  			"JS multiline block comment",
  			"<script>for (;;) { if (c()) break/* foo not a label\n" +
  				" */foo({{.T}});}</script>",
  			// Newline separates break from call. If newline
  			// removed, then break will consume label leaving
  			// code invalid.
  			"<script>for (;;) { if (c()) break\n" +
  				"foo( true );}</script>",
  		},
  		{
  			"JS single-line block comment",
  			"<script>for (;;) {\n" +
  				"if (c()) break/* foo a label */foo;" +
  				"x({{.T}});}</script>",
  			// Newline separates break from call. If newline
  			// removed, then break will consume label leaving
  			// code invalid.
  			"<script>for (;;) {\n" +
  				"if (c()) break foo;" +
  				"x( true );}</script>",
  		},
  		{
  			"JS block comment flush with mathematical division",
  			"<script>var a/*b*//c\nd</script>",
  			"<script>var a /c\nd</script>",
  		},
  		{
  			"JS mixed comments",
  			"<script>var a/*b*///c\nd</script>",
  			"<script>var a \nd</script>",
  		},
  		{
  			"CSS comments",
  			"<style>p// paragraph\n" +
  				`{border: 1px/* color */{{"#00f"}}}</style>`,
  			"<style>p\n" +
  				"{border: 1px #00f}</style>",
  		},
  		{
  			"JS attr block comment",
  			`<a onclick="f(&quot;&quot;); /* alert({{.H}}) */">`,
  			// Attribute comment tests should pass if the comments
  			// are successfully elided.
  			`<a onclick="f(&quot;&quot;); /* alert() */">`,
  		},
  		{
  			"JS attr line comment",
  			`<a onclick="// alert({{.G}})">`,
  			`<a onclick="// alert()">`,
  		},
  		{
  			"CSS attr block comment",
  			`<a style="/* color: {{.H}} */">`,
  			`<a style="/* color:  */">`,
  		},
  		{
  			"CSS attr line comment",
  			`<a style="// color: {{.G}}">`,
  			`<a style="// color: ">`,
  		},
  		{
  			"HTML substitution commented out",
  			"<p><!-- {{.H}} --></p>",
  			"<p></p>",
  		},
  		{
  			"Comment ends flush with start",
  			"<!--{{.}}--><script>/*{{.}}*///{{.}}\n</script><style>/*{{.}}*///{{.}}\n</style><a onclick='/*{{.}}*///{{.}}' style='/*{{.}}*///{{.}}'>",
  			"<script> \n</script><style> \n</style><a onclick='/**///' style='/**///'>",
  		},
  		{
  			"typed HTML in text",
  			`{{.W}}`,
  			`&iexcl;<b class="foo">Hello</b>, <textarea>O'World</textarea>!`,
  		},
  		{
  			"typed HTML in attribute",
  			`<div title="{{.W}}">`,
  			`<div title="&iexcl;Hello, O&#39;World!">`,
  		},
  		{
  			"typed HTML in script",
  			`<button onclick="alert({{.W}})">`,
  			`<button onclick="alert(&#34;\u0026iexcl;\u003cb class=\&#34;foo\&#34;\u003eHello\u003c/b\u003e, \u003ctextarea\u003eO&#39;World\u003c/textarea\u003e!&#34;)">`,
  		},
  		{
  			"typed HTML in RCDATA",
  			`<textarea>{{.W}}</textarea>`,
  			`<textarea>&iexcl;&lt;b class=&#34;foo&#34;&gt;Hello&lt;/b&gt;, &lt;textarea&gt;O&#39;World&lt;/textarea&gt;!</textarea>`,
  		},
  		{
  			"range in textarea",
  			"<textarea>{{range .A}}{{.}}{{end}}</textarea>",
  			"<textarea>&lt;a&gt;&lt;b&gt;</textarea>",
  		},
  		{
  			"No tag injection",
  			`{{"10$"}}<{{"script src,evil.org/pwnd.js"}}...`,
  			`10$&lt;script src,evil.org/pwnd.js...`,
  		},
  		{
  			"No comment injection",
  			`<{{"!--"}}`,
  			`&lt;!--`,
  		},
  		{
  			"No RCDATA end tag injection",
  			`<textarea><{{"/textarea "}}...</textarea>`,
  			`<textarea>&lt;/textarea ...</textarea>`,
  		},
  		{
  			"optional attrs",
  			`<img class="{{"iconClass"}}"` +
  				`{{if .T}} id="{{"<iconId>"}}"{{end}}` +
  				// Double quotes inside if/else.
  				` src=` +
  				`{{if .T}}"?{{"<iconPath>"}}"` +
  				`{{else}}"images/cleardot.gif"{{end}}` +
  				// Missing space before title, but it is not a
  				// part of the src attribute.
  				`{{if .T}}title="{{"<title>"}}"{{end}}` +
  				// Quotes outside if/else.
  				` alt="` +
  				`{{if .T}}{{"<alt>"}}` +
  				`{{else}}{{if .F}}{{"<title>"}}{{end}}` +
  				`{{end}}"` +
  				`>`,
  			`<img class="iconClass" id="&lt;iconId&gt;" src="?%3ciconPath%3e"title="&lt;title&gt;" alt="&lt;alt&gt;">`,
  		},
  		{
  			"conditional valueless attr name",
  			`<input{{if .T}} checked{{end}} name=n>`,
  			`<input checked name=n>`,
  		},
  		{
  			"conditional dynamic valueless attr name 1",
  			`<input{{if .T}} {{"checked"}}{{end}} name=n>`,
  			`<input checked name=n>`,
  		},
  		{
  			"conditional dynamic valueless attr name 2",
  			`<input {{if .T}}{{"checked"}} {{end}}name=n>`,
  			`<input checked name=n>`,
  		},
  		{
  			"dynamic attribute name",
  			`<img on{{"load"}}="alert({{"loaded"}})">`,
  			// Treated as JS since quotes are inserted.
  			`<img onload="alert(&#34;loaded&#34;)">`,
  		},
  		{
  			"bad dynamic attribute name 1",
  			// Allow checked, selected, disabled, but not JS or
  			// CSS attributes.
  			`<input {{"onchange"}}="{{"doEvil()"}}">`,
  			`<input ZgotmplZ="doEvil()">`,
  		},
  		{
  			"bad dynamic attribute name 2",
  			`<div {{"sTyle"}}="{{"color: expression(alert(1337))"}}">`,
  			`<div ZgotmplZ="color: expression(alert(1337))">`,
  		},
  		{
  			"bad dynamic attribute name 3",
  			// Allow title or alt, but not a URL.
  			`<img {{"src"}}="{{"javascript:doEvil()"}}">`,
  			`<img ZgotmplZ="javascript:doEvil()">`,
  		},
  		{
  			"bad dynamic attribute name 4",
  			// Structure preservation requires values to associate
  			// with a consistent attribute.
  			`<input checked {{""}}="Whose value am I?">`,
  			`<input checked ZgotmplZ="Whose value am I?">`,
  		},
  		{
  			"dynamic element name",
  			`<h{{3}}><table><t{{"head"}}>...</h{{3}}>`,
  			`<h3><table><thead>...</h3>`,
  		},
  		{
  			"bad dynamic element name",
  			// Dynamic element names are typically used to switch
  			// between (thead, tfoot, tbody), (ul, ol), (th, td),
  			// and other replaceable sets.
  			// We do not currently easily support (ul, ol).
  			// If we do change to support that, this test should
  			// catch failures to filter out special tag names which
  			// would violate the structure preservation property --
  			// if any special tag name could be substituted, then
  			// the content could be raw text/RCDATA for some inputs
  			// and regular HTML content for others.
  			`<{{"script"}}>{{"doEvil()"}}</{{"script"}}>`,
  			`&lt;script>doEvil()&lt;/script>`,
  		},
  	}
  
  	for _, test := range tests {
  		tmpl := New(test.name)
  		tmpl = Must(tmpl.Parse(test.input))
  		// Check for bug 6459: Tree field was not set in Parse.
  		if tmpl.Tree != tmpl.text.Tree {
  			t.Errorf("%s: tree not set properly", test.name)
  			continue
  		}
  		b := new(bytes.Buffer)
  		if err := tmpl.Execute(b, data); err != nil {
  			t.Errorf("%s: template execution failed: %s", test.name, err)
  			continue
  		}
  		if w, g := test.output, b.String(); w != g {
  			t.Errorf("%s: escaped output: want\n\t%q\ngot\n\t%q", test.name, w, g)
  			continue
  		}
  		b.Reset()
  		if err := tmpl.Execute(b, pdata); err != nil {
  			t.Errorf("%s: template execution failed for pointer: %s", test.name, err)
  			continue
  		}
  		if w, g := test.output, b.String(); w != g {
  			t.Errorf("%s: escaped output for pointer: want\n\t%q\ngot\n\t%q", test.name, w, g)
  			continue
  		}
  		if tmpl.Tree != tmpl.text.Tree {
  			t.Errorf("%s: tree mismatch", test.name)
  			continue
  		}
  	}
  }
  
  func TestEscapeMap(t *testing.T) {
  	data := map[string]string{
  		"html":     `<h1>Hi!</h1>`,
  		"urlquery": `http://www.foo.com/index.html?title=main`,
  	}
  	for _, test := range [...]struct {
  		desc, input, output string
  	}{
  		// covering issue 20323
  		{
  			"field with predefined escaper name 1",
  			`{{.html | print}}`,
  			`&lt;h1&gt;Hi!&lt;/h1&gt;`,
  		},
  		// covering issue 20323
  		{
  			"field with predefined escaper name 2",
  			`{{.urlquery | print}}`,
  			`http://www.foo.com/index.html?title=main`,
  		},
  	} {
  		tmpl := Must(New("").Parse(test.input))
  		b := new(bytes.Buffer)
  		if err := tmpl.Execute(b, data); err != nil {
  			t.Errorf("%s: template execution failed: %s", test.desc, err)
  			continue
  		}
  		if w, g := test.output, b.String(); w != g {
  			t.Errorf("%s: escaped output: want\n\t%q\ngot\n\t%q", test.desc, w, g)
  			continue
  		}
  	}
  }
  
  func TestEscapeSet(t *testing.T) {
  	type dataItem struct {
  		Children []*dataItem
  		X        string
  	}
  
  	data := dataItem{
  		Children: []*dataItem{
  			{X: "foo"},
  			{X: "<bar>"},
  			{
  				Children: []*dataItem{
  					{X: "baz"},
  				},
  			},
  		},
  	}
  
  	tests := []struct {
  		inputs map[string]string
  		want   string
  	}{
  		// The trivial set.
  		{
  			map[string]string{
  				"main": ``,
  			},
  			``,
  		},
  		// A template called in the start context.
  		{
  			map[string]string{
  				"main": `Hello, {{template "helper"}}!`,
  				// Not a valid top level HTML template.
  				// "<b" is not a full tag.
  				"helper": `{{"<World>"}}`,
  			},
  			`Hello, &lt;World&gt;!`,
  		},
  		// A template called in a context other than the start.
  		{
  			map[string]string{
  				"main": `<a onclick='a = {{template "helper"}};'>`,
  				// Not a valid top level HTML template.
  				// "<b" is not a full tag.
  				"helper": `{{"<a>"}}<b`,
  			},
  			`<a onclick='a = &#34;\u003ca\u003e&#34;<b;'>`,
  		},
  		// A recursive template that ends in its start context.
  		{
  			map[string]string{
  				"main": `{{range .Children}}{{template "main" .}}{{else}}{{.X}} {{end}}`,
  			},
  			`foo &lt;bar&gt; baz `,
  		},
  		// A recursive helper template that ends in its start context.
  		{
  			map[string]string{
  				"main":   `{{template "helper" .}}`,
  				"helper": `{{if .Children}}<ul>{{range .Children}}<li>{{template "main" .}}</li>{{end}}</ul>{{else}}{{.X}}{{end}}`,
  			},
  			`<ul><li>foo</li><li>&lt;bar&gt;</li><li><ul><li>baz</li></ul></li></ul>`,
  		},
  		// Co-recursive templates that end in its start context.
  		{
  			map[string]string{
  				"main":   `<blockquote>{{range .Children}}{{template "helper" .}}{{end}}</blockquote>`,
  				"helper": `{{if .Children}}{{template "main" .}}{{else}}{{.X}}<br>{{end}}`,
  			},
  			`<blockquote>foo<br>&lt;bar&gt;<br><blockquote>baz<br></blockquote></blockquote>`,
  		},
  		// A template that is called in two different contexts.
  		{
  			map[string]string{
  				"main":   `<button onclick="title='{{template "helper"}}'; ...">{{template "helper"}}</button>`,
  				"helper": `{{11}} of {{"<100>"}}`,
  			},
  			`<button onclick="title='11 of \x3c100\x3e'; ...">11 of &lt;100&gt;</button>`,
  		},
  		// A non-recursive template that ends in a different context.
  		// helper starts in jsCtxRegexp and ends in jsCtxDivOp.
  		{
  			map[string]string{
  				"main":   `<script>var x={{template "helper"}}/{{"42"}};</script>`,
  				"helper": "{{126}}",
  			},
  			`<script>var x= 126 /"42";</script>`,
  		},
  		// A recursive template that ends in a similar context.
  		{
  			map[string]string{
  				"main":      `<script>var x=[{{template "countdown" 4}}];</script>`,
  				"countdown": `{{.}}{{if .}},{{template "countdown" . | pred}}{{end}}`,
  			},
  			`<script>var x=[ 4 , 3 , 2 , 1 , 0 ];</script>`,
  		},
  		// A recursive template that ends in a different context.
  		/*
  			{
  				map[string]string{
  					"main":   `<a href="/foo{{template "helper" .}}">`,
  					"helper": `{{if .Children}}{{range .Children}}{{template "helper" .}}{{end}}{{else}}?x={{.X}}{{end}}`,
  				},
  				`<a href="/foo?x=foo?x=%3cbar%3e?x=baz">`,
  			},
  		*/
  	}
  
  	// pred is a template function that returns the predecessor of a
  	// natural number for testing recursive templates.
  	fns := FuncMap{"pred": func(a ...interface{}) (interface{}, error) {
  		if len(a) == 1 {
  			if i, _ := a[0].(int); i > 0 {
  				return i - 1, nil
  			}
  		}
  		return nil, fmt.Errorf("undefined pred(%v)", a)
  	}}
  
  	for _, test := range tests {
  		source := ""
  		for name, body := range test.inputs {
  			source += fmt.Sprintf("{{define %q}}%s{{end}} ", name, body)
  		}
  		tmpl, err := New("root").Funcs(fns).Parse(source)
  		if err != nil {
  			t.Errorf("error parsing %q: %v", source, err)
  			continue
  		}
  		var b bytes.Buffer
  
  		if err := tmpl.ExecuteTemplate(&b, "main", data); err != nil {
  			t.Errorf("%q executing %v", err.Error(), tmpl.Lookup("main"))
  			continue
  		}
  		if got := b.String(); test.want != got {
  			t.Errorf("want\n\t%q\ngot\n\t%q", test.want, got)
  		}
  	}
  
  }
  
  func TestErrors(t *testing.T) {
  	tests := []struct {
  		input string
  		err   string
  	}{
  		// Non-error cases.
  		{
  			"{{if .Cond}}<a>{{else}}<b>{{end}}",
  			"",
  		},
  		{
  			"{{if .Cond}}<a>{{end}}",
  			"",
  		},
  		{
  			"{{if .Cond}}{{else}}<b>{{end}}",
  			"",
  		},
  		{
  			"{{with .Cond}}<div>{{end}}",
  			"",
  		},
  		{
  			"{{range .Items}}<a>{{end}}",
  			"",
  		},
  		{
  			"<a href='/foo?{{range .Items}}&{{.K}}={{.V}}{{end}}'>",
  			"",
  		},
  		// Error cases.
  		{
  			"{{if .Cond}}<a{{end}}",
  			"z:1:5: {{if}} branches",
  		},
  		{
  			"{{if .Cond}}\n{{else}}\n<a{{end}}",
  			"z:1:5: {{if}} branches",
  		},
  		{
  			// Missing quote in the else branch.
  			`{{if .Cond}}<a href="foo">{{else}}<a href="bar>{{end}}`,
  			"z:1:5: {{if}} branches",
  		},
  		{
  			// Different kind of attribute: href implies a URL.
  			"<a {{if .Cond}}href='{{else}}title='{{end}}{{.X}}'>",
  			"z:1:8: {{if}} branches",
  		},
  		{
  			"\n{{with .X}}<a{{end}}",
  			"z:2:7: {{with}} branches",
  		},
  		{
  			"\n{{with .X}}<a>{{else}}<a{{end}}",
  			"z:2:7: {{with}} branches",
  		},
  		{
  			"{{range .Items}}<a{{end}}",
  			`z:1: on range loop re-entry: "<" in attribute name: "<a"`,
  		},
  		{
  			"\n{{range .Items}} x='<a{{end}}",
  			"z:2:8: on range loop re-entry: {{range}} branches",
  		},
  		{
  			"<a b=1 c={{.H}}",
  			"z: ends in a non-text context: {stateAttr delimSpaceOrTagEnd",
  		},
  		{
  			"<script>foo();",
  			"z: ends in a non-text context: {stateJS",
  		},
  		{
  			`<a href="{{if .F}}/foo?a={{else}}/bar/{{end}}{{.H}}">`,
  			"z:1:47: {{.H}} appears in an ambiguous context within a URL",
  		},
  		{
  			`<a onclick="alert('Hello \`,
  			`unfinished escape sequence in JS string: "Hello \\"`,
  		},
  		{
  			`<a onclick='alert("Hello\, World\`,
  			`unfinished escape sequence in JS string: "Hello\\, World\\"`,
  		},
  		{
  			`<a onclick='alert(/x+\`,
  			`unfinished escape sequence in JS string: "x+\\"`,
  		},
  		{
  			`<a onclick="/foo[\]/`,
  			`unfinished JS regexp charset: "foo[\\]/"`,
  		},
  		{
  			// It is ambiguous whether 1.5 should be 1\.5 or 1.5.
  			// Either `var x = 1/- 1.5 /i.test(x)`
  			// where `i.test(x)` is a method call of reference i,
  			// or `/-1\.5/i.test(x)` which is a method call on a
  			// case insensitive regular expression.
  			`<script>{{if false}}var x = 1{{end}}/-{{"1.5"}}/i.test(x)</script>`,
  			`'/' could start a division or regexp: "/-"`,
  		},
  		{
  			`{{template "foo"}}`,
  			"z:1:11: no such template \"foo\"",
  		},
  		{
  			`<div{{template "y"}}>` +
  				// Illegal starting in stateTag but not in stateText.
  				`{{define "y"}} foo<b{{end}}`,
  			`"<" in attribute name: " foo<b"`,
  		},
  		{
  			`<script>reverseList = [{{template "t"}}]</script>` +
  				// Missing " after recursive call.
  				`{{define "t"}}{{if .Tail}}{{template "t" .Tail}}{{end}}{{.Head}}",{{end}}`,
  			`: cannot compute output context for template t$htmltemplate_stateJS_elementScript`,
  		},
  		{
  			`<input type=button value=onclick=>`,
  			`html/template:z: "=" in unquoted attr: "onclick="`,
  		},
  		{
  			`<input type=button value= onclick=>`,
  			`html/template:z: "=" in unquoted attr: "onclick="`,
  		},
  		{
  			`<input type=button value= 1+1=2>`,
  			`html/template:z: "=" in unquoted attr: "1+1=2"`,
  		},
  		{
  			"<a class=`foo>",
  			"html/template:z: \"`\" in unquoted attr: \"`foo\"",
  		},
  		{
  			`<a style=font:'Arial'>`,
  			`html/template:z: "'" in unquoted attr: "font:'Arial'"`,
  		},
  		{
  			`<a=foo>`,
  			`: expected space, attr name, or end of tag, but got "=foo>"`,
  		},
  		{
  			`Hello, {{. | urlquery | print}}!`,
  			// urlquery is disallowed if it is not the last command in the pipeline.
  			`predefined escaper "urlquery" disallowed in template`,
  		},
  		{
  			`Hello, {{. | html | print}}!`,
  			// html is disallowed if it is not the last command in the pipeline.
  			`predefined escaper "html" disallowed in template`,
  		},
  		{
  			`Hello, {{html . | print}}!`,
  			// A direct call to html is disallowed if it is not the last command in the pipeline.
  			`predefined escaper "html" disallowed in template`,
  		},
  		{
  			`<div class={{. | html}}>Hello<div>`,
  			// html is disallowed in a pipeline that is in an unquoted attribute context,
  			// even if it is the last command in the pipeline.
  			`predefined escaper "html" disallowed in template`,
  		},
  		{
  			`Hello, {{. | urlquery | html}}!`,
  			// html is allowed since it is the last command in the pipeline, but urlquery is not.
  			`predefined escaper "urlquery" disallowed in template`,
  		},
  	}
  	for _, test := range tests {
  		buf := new(bytes.Buffer)
  		tmpl, err := New("z").Parse(test.input)
  		if err != nil {
  			t.Errorf("input=%q: unexpected parse error %s\n", test.input, err)
  			continue
  		}
  		err = tmpl.Execute(buf, nil)
  		var got string
  		if err != nil {
  			got = err.Error()
  		}
  		if test.err == "" {
  			if got != "" {
  				t.Errorf("input=%q: unexpected error %q", test.input, got)
  			}
  			continue
  		}
  		if !strings.Contains(got, test.err) {
  			t.Errorf("input=%q: error\n\t%q\ndoes not contain expected string\n\t%q", test.input, got, test.err)
  			continue
  		}
  		// Check that we get the same error if we call Execute again.
  		if err := tmpl.Execute(buf, nil); err == nil || err.Error() != got {
  			t.Errorf("input=%q: unexpected error on second call %q", test.input, err)
  
  		}
  	}
  }
  
  func TestEscapeText(t *testing.T) {
  	tests := []struct {
  		input  string
  		output context
  	}{
  		{
  			``,
  			context{},
  		},
  		{
  			`Hello, World!`,
  			context{},
  		},
  		{
  			// An orphaned "<" is OK.
  			`I <3 Ponies!`,
  			context{},
  		},
  		{
  			`<a`,
  			context{state: stateTag},
  		},
  		{
  			`<a `,
  			context{state: stateTag},
  		},
  		{
  			`<a>`,
  			context{state: stateText},
  		},
  		{
  			`<a href`,
  			context{state: stateAttrName, attr: attrURL},
  		},
  		{
  			`<a on`,
  			context{state: stateAttrName, attr: attrScript},
  		},
  		{
  			`<a href `,
  			context{state: stateAfterName, attr: attrURL},
  		},
  		{
  			`<a style  =  `,
  			context{state: stateBeforeValue, attr: attrStyle},
  		},
  		{
  			`<a href=`,
  			context{state: stateBeforeValue, attr: attrURL},
  		},
  		{
  			`<a href=x`,
  			context{state: stateURL, delim: delimSpaceOrTagEnd, urlPart: urlPartPreQuery, attr: attrURL},
  		},
  		{
  			`<a href=x `,
  			context{state: stateTag},
  		},
  		{
  			`<a href=>`,
  			context{state: stateText},
  		},
  		{
  			`<a href=x>`,
  			context{state: stateText},
  		},
  		{
  			`<a href ='`,
  			context{state: stateURL, delim: delimSingleQuote, attr: attrURL},
  		},
  		{
  			`<a href=''`,
  			context{state: stateTag},
  		},
  		{
  			`<a href= "`,
  			context{state: stateURL, delim: delimDoubleQuote, attr: attrURL},
  		},
  		{
  			`<a href=""`,
  			context{state: stateTag},
  		},
  		{
  			`<a title="`,
  			context{state: stateAttr, delim: delimDoubleQuote},
  		},
  		{
  			`<a HREF='http:`,
  			context{state: stateURL, delim: delimSingleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  		},
  		{
  			`<a Href='/`,
  			context{state: stateURL, delim: delimSingleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  		},
  		{
  			`<a href='"`,
  			context{state: stateURL, delim: delimSingleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  		},
  		{
  			`<a href="'`,
  			context{state: stateURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  		},
  		{
  			`<a href='&apos;`,
  			context{state: stateURL, delim: delimSingleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  		},
  		{
  			`<a href="&quot;`,
  			context{state: stateURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  		},
  		{
  			`<a href="&#34;`,
  			context{state: stateURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrURL},
  		},
  		{
  			`<a href=&quot;`,
  			context{state: stateURL, delim: delimSpaceOrTagEnd, urlPart: urlPartPreQuery, attr: attrURL},
  		},
  		{
  			`<img alt="1">`,
  			context{state: stateText},
  		},
  		{
  			`<img alt="1>"`,
  			context{state: stateTag},
  		},
  		{
  			`<img alt="1>">`,
  			context{state: stateText},
  		},
  		{
  			`<input checked type="checkbox"`,
  			context{state: stateTag},
  		},
  		{
  			`<a onclick="`,
  			context{state: stateJS, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<a onclick="//foo`,
  			context{state: stateJSLineCmt, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			"<a onclick='//\n",
  			context{state: stateJS, delim: delimSingleQuote, attr: attrScript},
  		},
  		{
  			"<a onclick='//\r\n",
  			context{state: stateJS, delim: delimSingleQuote, attr: attrScript},
  		},
  		{
  			"<a onclick='//\u2028",
  			context{state: stateJS, delim: delimSingleQuote, attr: attrScript},
  		},
  		{
  			`<a onclick="/*`,
  			context{state: stateJSBlockCmt, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<a onclick="/*/`,
  			context{state: stateJSBlockCmt, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<a onclick="/**/`,
  			context{state: stateJS, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<a onkeypress="&quot;`,
  			context{state: stateJSDqStr, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<a onclick='&quot;foo&quot;`,
  			context{state: stateJS, delim: delimSingleQuote, jsCtx: jsCtxDivOp, attr: attrScript},
  		},
  		{
  			`<a onclick=&#39;foo&#39;`,
  			context{state: stateJS, delim: delimSpaceOrTagEnd, jsCtx: jsCtxDivOp, attr: attrScript},
  		},
  		{
  			`<a onclick=&#39;foo`,
  			context{state: stateJSSqStr, delim: delimSpaceOrTagEnd, attr: attrScript},
  		},
  		{
  			`<a onclick="&quot;foo'`,
  			context{state: stateJSDqStr, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<a onclick="'foo&quot;`,
  			context{state: stateJSSqStr, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<A ONCLICK="'`,
  			context{state: stateJSSqStr, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<a onclick="/`,
  			context{state: stateJSRegexp, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<a onclick="'foo'`,
  			context{state: stateJS, delim: delimDoubleQuote, jsCtx: jsCtxDivOp, attr: attrScript},
  		},
  		{
  			`<a onclick="'foo\'`,
  			context{state: stateJSSqStr, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<a onclick="'foo\'`,
  			context{state: stateJSSqStr, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<a onclick="/foo/`,
  			context{state: stateJS, delim: delimDoubleQuote, jsCtx: jsCtxDivOp, attr: attrScript},
  		},
  		{
  			`<script>/foo/ /=`,
  			context{state: stateJS, element: elementScript},
  		},
  		{
  			`<a onclick="1 /foo`,
  			context{state: stateJS, delim: delimDoubleQuote, jsCtx: jsCtxDivOp, attr: attrScript},
  		},
  		{
  			`<a onclick="1 /*c*/ /foo`,
  			context{state: stateJS, delim: delimDoubleQuote, jsCtx: jsCtxDivOp, attr: attrScript},
  		},
  		{
  			`<a onclick="/foo[/]`,
  			context{state: stateJSRegexp, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<a onclick="/foo\/`,
  			context{state: stateJSRegexp, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<a onclick="/foo/`,
  			context{state: stateJS, delim: delimDoubleQuote, jsCtx: jsCtxDivOp, attr: attrScript},
  		},
  		{
  			`<input checked style="`,
  			context{state: stateCSS, delim: delimDoubleQuote, attr: attrStyle},
  		},
  		{
  			`<a style="//`,
  			context{state: stateCSSLineCmt, delim: delimDoubleQuote, attr: attrStyle},
  		},
  		{
  			`<a style="//</script>`,
  			context{state: stateCSSLineCmt, delim: delimDoubleQuote, attr: attrStyle},
  		},
  		{
  			"<a style='//\n",
  			context{state: stateCSS, delim: delimSingleQuote, attr: attrStyle},
  		},
  		{
  			"<a style='//\r",
  			context{state: stateCSS, delim: delimSingleQuote, attr: attrStyle},
  		},
  		{
  			`<a style="/*`,
  			context{state: stateCSSBlockCmt, delim: delimDoubleQuote, attr: attrStyle},
  		},
  		{
  			`<a style="/*/`,
  			context{state: stateCSSBlockCmt, delim: delimDoubleQuote, attr: attrStyle},
  		},
  		{
  			`<a style="/**/`,
  			context{state: stateCSS, delim: delimDoubleQuote, attr: attrStyle},
  		},
  		{
  			`<a style="background: '`,
  			context{state: stateCSSSqStr, delim: delimDoubleQuote, attr: attrStyle},
  		},
  		{
  			`<a style="background: &quot;`,
  			context{state: stateCSSDqStr, delim: delimDoubleQuote, attr: attrStyle},
  		},
  		{
  			`<a style="background: '/foo?img=`,
  			context{state: stateCSSSqStr, delim: delimDoubleQuote, urlPart: urlPartQueryOrFrag, attr: attrStyle},
  		},
  		{
  			`<a style="background: '/`,
  			context{state: stateCSSSqStr, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrStyle},
  		},
  		{
  			`<a style="background: url(&#x22;/`,
  			context{state: stateCSSDqURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrStyle},
  		},
  		{
  			`<a style="background: url('/`,
  			context{state: stateCSSSqURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrStyle},
  		},
  		{
  			`<a style="background: url('/)`,
  			context{state: stateCSSSqURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrStyle},
  		},
  		{
  			`<a style="background: url('/ `,
  			context{state: stateCSSSqURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrStyle},
  		},
  		{
  			`<a style="background: url(/`,
  			context{state: stateCSSURL, delim: delimDoubleQuote, urlPart: urlPartPreQuery, attr: attrStyle},
  		},
  		{
  			`<a style="background: url( `,
  			context{state: stateCSSURL, delim: delimDoubleQuote, attr: attrStyle},
  		},
  		{
  			`<a style="background: url( /image?name=`,
  			context{state: stateCSSURL, delim: delimDoubleQuote, urlPart: urlPartQueryOrFrag, attr: attrStyle},
  		},
  		{
  			`<a style="background: url(x)`,
  			context{state: stateCSS, delim: delimDoubleQuote, attr: attrStyle},
  		},
  		{
  			`<a style="background: url('x'`,
  			context{state: stateCSS, delim: delimDoubleQuote, attr: attrStyle},
  		},
  		{
  			`<a style="background: url( x `,
  			context{state: stateCSS, delim: delimDoubleQuote, attr: attrStyle},
  		},
  		{
  			`<!-- foo`,
  			context{state: stateHTMLCmt},
  		},
  		{
  			`<!-->`,
  			context{state: stateHTMLCmt},
  		},
  		{
  			`<!--->`,
  			context{state: stateHTMLCmt},
  		},
  		{
  			`<!-- foo -->`,
  			context{state: stateText},
  		},
  		{
  			`<script`,
  			context{state: stateTag, element: elementScript},
  		},
  		{
  			`<script `,
  			context{state: stateTag, element: elementScript},
  		},
  		{
  			`<script src="foo.js" `,
  			context{state: stateTag, element: elementScript},
  		},
  		{
  			`<script src='foo.js' `,
  			context{state: stateTag, element: elementScript},
  		},
  		{
  			`<script type=text/javascript `,
  			context{state: stateTag, element: elementScript},
  		},
  		{
  			`<script>`,
  			context{state: stateJS, jsCtx: jsCtxRegexp, element: elementScript},
  		},
  		{
  			`<script>foo`,
  			context{state: stateJS, jsCtx: jsCtxDivOp, element: elementScript},
  		},
  		{
  			`<script>foo</script>`,
  			context{state: stateText},
  		},
  		{
  			`<script>foo</script><!--`,
  			context{state: stateHTMLCmt},
  		},
  		{
  			`<script>document.write("<p>foo</p>");`,
  			context{state: stateJS, element: elementScript},
  		},
  		{
  			`<script>document.write("<p>foo<\/script>");`,
  			context{state: stateJS, element: elementScript},
  		},
  		{
  			`<script>document.write("<script>alert(1)</script>");`,
  			context{state: stateText},
  		},
  		{
  			`<script type="text/template">`,
  			context{state: stateText},
  		},
  		// covering issue 19968
  		{
  			`<script type="TEXT/JAVASCRIPT">`,
  			context{state: stateJS, element: elementScript},
  		},
  		// covering issue 19965
  		{
  			`<script TYPE="text/template">`,
  			context{state: stateText},
  		},
  		{
  			`<script type="notjs">`,
  			context{state: stateText},
  		},
  		{
  			`<Script>`,
  			context{state: stateJS, element: elementScript},
  		},
  		{
  			`<SCRIPT>foo`,
  			context{state: stateJS, jsCtx: jsCtxDivOp, element: elementScript},
  		},
  		{
  			`<textarea>value`,
  			context{state: stateRCDATA, element: elementTextarea},
  		},
  		{
  			`<textarea>value</TEXTAREA>`,
  			context{state: stateText},
  		},
  		{
  			`<textarea name=html><b`,
  			context{state: stateRCDATA, element: elementTextarea},
  		},
  		{
  			`<title>value`,
  			context{state: stateRCDATA, element: elementTitle},
  		},
  		{
  			`<style>value`,
  			context{state: stateCSS, element: elementStyle},
  		},
  		{
  			`<a xlink:href`,
  			context{state: stateAttrName, attr: attrURL},
  		},
  		{
  			`<a xmlns`,
  			context{state: stateAttrName, attr: attrURL},
  		},
  		{
  			`<a xmlns:foo`,
  			context{state: stateAttrName, attr: attrURL},
  		},
  		{
  			`<a xmlnsxyz`,
  			context{state: stateAttrName},
  		},
  		{
  			`<a data-url`,
  			context{state: stateAttrName, attr: attrURL},
  		},
  		{
  			`<a data-iconUri`,
  			context{state: stateAttrName, attr: attrURL},
  		},
  		{
  			`<a data-urlItem`,
  			context{state: stateAttrName, attr: attrURL},
  		},
  		{
  			`<a g:`,
  			context{state: stateAttrName},
  		},
  		{
  			`<a g:url`,
  			context{state: stateAttrName, attr: attrURL},
  		},
  		{
  			`<a g:iconUri`,
  			context{state: stateAttrName, attr: attrURL},
  		},
  		{
  			`<a g:urlItem`,
  			context{state: stateAttrName, attr: attrURL},
  		},
  		{
  			`<a g:value`,
  			context{state: stateAttrName},
  		},
  		{
  			`<a svg:style='`,
  			context{state: stateCSS, delim: delimSingleQuote, attr: attrStyle},
  		},
  		{
  			`<svg:font-face`,
  			context{state: stateTag},
  		},
  		{
  			`<svg:a svg:onclick="`,
  			context{state: stateJS, delim: delimDoubleQuote, attr: attrScript},
  		},
  		{
  			`<svg:a svg:onclick="x()">`,
  			context{},
  		},
  	}
  
  	for _, test := range tests {
  		b, e := []byte(test.input), makeEscaper(nil)
  		c := e.escapeText(context{}, &parse.TextNode{NodeType: parse.NodeText, Text: b})
  		if !test.output.eq(c) {
  			t.Errorf("input %q: want context\n\t%v\ngot\n\t%v", test.input, test.output, c)
  			continue
  		}
  		if test.input != string(b) {
  			t.Errorf("input %q: text node was modified: want %q got %q", test.input, test.input, b)
  			continue
  		}
  	}
  }
  
  func TestEnsurePipelineContains(t *testing.T) {
  	tests := []struct {
  		input, output string
  		ids           []string
  	}{
  		{
  			"{{.X}}",
  			".X",
  			[]string{},
  		},
  		{
  			"{{.X | html}}",
  			".X | html",
  			[]string{},
  		},
  		{
  			"{{.X}}",
  			".X | html",
  			[]string{"html"},
  		},
  		{
  			"{{html .X}}",
  			"_eval_args_ .X | html | urlquery",
  			[]string{"html", "urlquery"},
  		},
  		{
  			"{{html .X .Y .Z}}",
  			"_eval_args_ .X .Y .Z | html | urlquery",
  			[]string{"html", "urlquery"},
  		},
  		{
  			"{{.X | print}}",
  			".X | print | urlquery",
  			[]string{"urlquery"},
  		},
  		{
  			"{{.X | print | urlquery}}",
  			".X | print | urlquery",
  			[]string{"urlquery"},
  		},
  		{
  			"{{.X | urlquery}}",
  			".X | html | urlquery",
  			[]string{"html", "urlquery"},
  		},
  		{
  			"{{.X | print 2 | .f 3}}",
  			".X | print 2 | .f 3 | urlquery | html",
  			[]string{"urlquery", "html"},
  		},
  		{
  			// covering issue 10801
  			"{{.X | println.x }}",
  			".X | println.x | urlquery | html",
  			[]string{"urlquery", "html"},
  		},
  		{
  			// covering issue 10801
  			"{{.X | (print 12 | println).x }}",
  			".X | (print 12 | println).x | urlquery | html",
  			[]string{"urlquery", "html"},
  		},
  		// The following test cases ensure that the merging of internal escapers
  		// with the predefined "html" and "urlquery" escapers is correct.
  		{
  			"{{.X | urlquery}}",
  			".X | _html_template_urlfilter | urlquery",
  			[]string{"_html_template_urlfilter", "_html_template_urlnormalizer"},
  		},
  		{
  			"{{.X | urlquery}}",
  			".X | urlquery | _html_template_urlfilter | _html_template_cssescaper",
  			[]string{"_html_template_urlfilter", "_html_template_cssescaper"},
  		},
  		{
  			"{{.X | urlquery}}",
  			".X | urlquery",
  			[]string{"_html_template_urlnormalizer"},
  		},
  		{
  			"{{.X | urlquery}}",
  			".X | urlquery",
  			[]string{"_html_template_urlescaper"},
  		},
  		{
  			"{{.X | html}}",
  			".X | html",
  			[]string{"_html_template_htmlescaper"},
  		},
  		{
  			"{{.X | html}}",
  			".X | html",
  			[]string{"_html_template_rcdataescaper"},
  		},
  	}
  	for i, test := range tests {
  		tmpl := template.Must(template.New("test").Parse(test.input))
  		action, ok := (tmpl.Tree.Root.Nodes[0].(*parse.ActionNode))
  		if !ok {
  			t.Errorf("First node is not an action: %s", test.input)
  			continue
  		}
  		pipe := action.Pipe
  		originalIDs := make([]string, len(test.ids))
  		copy(originalIDs, test.ids)
  		ensurePipelineContains(pipe, test.ids)
  		got := pipe.String()
  		if got != test.output {
  			t.Errorf("#%d: %s, %v: want\n\t%s\ngot\n\t%s", i, test.input, originalIDs, test.output, got)
  		}
  	}
  }
  
  func TestEscapeMalformedPipelines(t *testing.T) {
  	tests := []string{
  		"{{ 0 | $ }}",
  		"{{ 0 | $ | urlquery }}",
  		"{{ 0 | (nil) }}",
  		"{{ 0 | (nil) | html }}",
  	}
  	for _, test := range tests {
  		var b bytes.Buffer
  		tmpl, err := New("test").Parse(test)
  		if err != nil {
  			t.Errorf("failed to parse set: %q", err)
  		}
  		err = tmpl.Execute(&b, nil)
  		if err == nil {
  			t.Errorf("Expected error for %q", test)
  		}
  	}
  }
  
  func TestEscapeErrorsNotIgnorable(t *testing.T) {
  	var b bytes.Buffer
  	tmpl, _ := New("dangerous").Parse("<a")
  	err := tmpl.Execute(&b, nil)
  	if err == nil {
  		t.Errorf("Expected error")
  	} else if b.Len() != 0 {
  		t.Errorf("Emitted output despite escaping failure")
  	}
  }
  
  func TestEscapeSetErrorsNotIgnorable(t *testing.T) {
  	var b bytes.Buffer
  	tmpl, err := New("root").Parse(`{{define "t"}}<a{{end}}`)
  	if err != nil {
  		t.Errorf("failed to parse set: %q", err)
  	}
  	err = tmpl.ExecuteTemplate(&b, "t", nil)
  	if err == nil {
  		t.Errorf("Expected error")
  	} else if b.Len() != 0 {
  		t.Errorf("Emitted output despite escaping failure")
  	}
  }
  
  func TestRedundantFuncs(t *testing.T) {
  	inputs := []interface{}{
  		"\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f" +
  			"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" +
  			` !"#$%&'()*+,-./` +
  			`0123456789:;<=>?` +
  			`@ABCDEFGHIJKLMNO` +
  			`PQRSTUVWXYZ[\]^_` +
  			"`abcdefghijklmno" +
  			"pqrstuvwxyz{|}~\x7f" +
  			"\u00A0\u0100\u2028\u2029\ufeff\ufdec\ufffd\uffff\U0001D11E" +
  			"&amp;%22\\",
  		CSS(`a[href =~ "//example.com"]#foo`),
  		HTML(`Hello, <b>World</b> &amp;tc!`),
  		HTMLAttr(` dir="ltr"`),
  		JS(`c && alert("Hello, World!");`),
  		JSStr(`Hello, World & O'Reilly\x21`),
  		URL(`greeting=H%69&addressee=(World)`),
  	}
  
  	for n0, m := range redundantFuncs {
  		f0 := funcMap[n0].(func(...interface{}) string)
  		for n1 := range m {
  			f1 := funcMap[n1].(func(...interface{}) string)
  			for _, input := range inputs {
  				want := f0(input)
  				if got := f1(want); want != got {
  					t.Errorf("%s %s with %T %q: want\n\t%q,\ngot\n\t%q", n0, n1, input, input, want, got)
  				}
  			}
  		}
  	}
  }
  
  func TestIndirectPrint(t *testing.T) {
  	a := 3
  	ap := &a
  	b := "hello"
  	bp := &b
  	bpp := &bp
  	tmpl := Must(New("t").Parse(`{{.}}`))
  	var buf bytes.Buffer
  	err := tmpl.Execute(&buf, ap)
  	if err != nil {
  		t.Errorf("Unexpected error: %s", err)
  	} else if buf.String() != "3" {
  		t.Errorf(`Expected "3"; got %q`, buf.String())
  	}
  	buf.Reset()
  	err = tmpl.Execute(&buf, bpp)
  	if err != nil {
  		t.Errorf("Unexpected error: %s", err)
  	} else if buf.String() != "hello" {
  		t.Errorf(`Expected "hello"; got %q`, buf.String())
  	}
  }
  
  // This is a test for issue 3272.
  func TestEmptyTemplate(t *testing.T) {
  	page := Must(New("page").ParseFiles(os.DevNull))
  	if err := page.ExecuteTemplate(os.Stdout, "page", "nothing"); err == nil {
  		t.Fatal("expected error")
  	}
  }
  
  type Issue7379 int
  
  func (Issue7379) SomeMethod(x int) string {
  	return fmt.Sprintf("<%d>", x)
  }
  
  // This is a test for issue 7379: type assertion error caused panic, and then
  // the code to handle the panic breaks escaping. It's hard to see the second
  // problem once the first is fixed, but its fix is trivial so we let that go. See
  // the discussion for issue 7379.
  func TestPipeToMethodIsEscaped(t *testing.T) {
  	tmpl := Must(New("x").Parse("<html>{{0 | .SomeMethod}}</html>\n"))
  	tryExec := func() string {
  		defer func() {
  			panicValue := recover()
  			if panicValue != nil {
  				t.Errorf("panicked: %v\n", panicValue)
  			}
  		}()
  		var b bytes.Buffer
  		tmpl.Execute(&b, Issue7379(0))
  		return b.String()
  	}
  	for i := 0; i < 3; i++ {
  		str := tryExec()
  		const expect = "<html>&lt;0&gt;</html>\n"
  		if str != expect {
  			t.Errorf("expected %q got %q", expect, str)
  		}
  	}
  }
  
  // Unlike text/template, html/template crashed if given an incomplete
  // template, that is, a template that had been named but not given any content.
  // This is issue #10204.
  func TestErrorOnUndefined(t *testing.T) {
  	tmpl := New("undefined")
  
  	err := tmpl.Execute(nil, nil)
  	if err == nil {
  		t.Error("expected error")
  	}
  	if !strings.Contains(err.Error(), "incomplete") {
  		t.Errorf("expected error about incomplete template; got %s", err)
  	}
  }
  
  // This covers issue #20842.
  func TestIdempotentExecute(t *testing.T) {
  	tmpl := Must(New("").
  		Parse(`{{define "main"}}<body>{{template "hello"}}</body>{{end}}`))
  	Must(tmpl.
  		Parse(`{{define "hello"}}Hello, {{"Ladies & Gentlemen!"}}{{end}}`))
  	got := new(bytes.Buffer)
  	var err error
  	// Ensure that "hello" produces the same output when executed twice.
  	want := "Hello, Ladies &amp; Gentlemen!"
  	for i := 0; i < 2; i++ {
  		err = tmpl.ExecuteTemplate(got, "hello", nil)
  		if err != nil {
  			t.Errorf("unexpected error: %s", err)
  		}
  		if got.String() != want {
  			t.Errorf("after executing template \"hello\", got:\n\t%q\nwant:\n\t%q\n", got.String(), want)
  		}
  		got.Reset()
  	}
  	// Ensure that the implicit re-execution of "hello" during the execution of
  	// "main" does not cause the output of "hello" to change.
  	err = tmpl.ExecuteTemplate(got, "main", nil)
  	if err != nil {
  		t.Errorf("unexpected error: %s", err)
  	}
  	// If the HTML escaper is added again to the action {{"Ladies & Gentlemen!"}},
  	// we would expected to see the ampersand overescaped to "&amp;amp;".
  	want = "<body>Hello, Ladies &amp; Gentlemen!</body>"
  	if got.String() != want {
  		t.Errorf("after executing template \"main\", got:\n\t%q\nwant:\n\t%q\n", got.String(), want)
  	}
  }
  
  func BenchmarkEscapedExecute(b *testing.B) {
  	tmpl := Must(New("t").Parse(`<a onclick="alert('{{.}}')">{{.}}</a>`))
  	var buf bytes.Buffer
  	b.ResetTimer()
  	for i := 0; i < b.N; i++ {
  		tmpl.Execute(&buf, "foo & 'bar' & baz")
  		buf.Reset()
  	}
  }
  

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