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Source file src/text/template/exec_test.go

Documentation: text/template

		 1  // Copyright 2011 The Go Authors. All rights reserved.
		 2  // Use of this source code is governed by a BSD-style
		 3  // license that can be found in the LICENSE file.
		 4  
		 5  package template
		 6  
		 7  import (
		 8  	"bytes"
		 9  	"errors"
		10  	"flag"
		11  	"fmt"
		12  	"io"
		13  	"reflect"
		14  	"strings"
		15  	"sync"
		16  	"testing"
		17  )
		18  
		19  var debug = flag.Bool("debug", false, "show the errors produced by the tests")
		20  
		21  // T has lots of interesting pieces to use to test execution.
		22  type T struct {
		23  	// Basics
		24  	True				bool
		25  	I					 int
		26  	U16				 uint16
		27  	X, S				string
		28  	FloatZero	 float64
		29  	ComplexZero complex128
		30  	// Nested structs.
		31  	U *U
		32  	// Struct with String method.
		33  	V0		 V
		34  	V1, V2 *V
		35  	// Struct with Error method.
		36  	W0		 W
		37  	W1, W2 *W
		38  	// Slices
		39  	SI			[]int
		40  	SICap	 []int
		41  	SIEmpty []int
		42  	SB			[]bool
		43  	// Arrays
		44  	AI [3]int
		45  	// Maps
		46  	MSI			map[string]int
		47  	MSIone	 map[string]int // one element, for deterministic output
		48  	MSIEmpty map[string]int
		49  	MXI			map[interface{}]int
		50  	MII			map[int]int
		51  	MI32S		map[int32]string
		52  	MI64S		map[int64]string
		53  	MUI32S	 map[uint32]string
		54  	MUI64S	 map[uint64]string
		55  	MI8S		 map[int8]string
		56  	MUI8S		map[uint8]string
		57  	SMSI		 []map[string]int
		58  	// Empty interfaces; used to see if we can dig inside one.
		59  	Empty0 interface{} // nil
		60  	Empty1 interface{}
		61  	Empty2 interface{}
		62  	Empty3 interface{}
		63  	Empty4 interface{}
		64  	// Non-empty interfaces.
		65  	NonEmptyInterface				 I
		66  	NonEmptyInterfacePtS			*I
		67  	NonEmptyInterfaceNil			I
		68  	NonEmptyInterfaceTypedNil I
		69  	// Stringer.
		70  	Str fmt.Stringer
		71  	Err error
		72  	// Pointers
		73  	PI	*int
		74  	PS	*string
		75  	PSI *[]int
		76  	NIL *int
		77  	// Function (not method)
		78  	BinaryFunc			func(string, string) string
		79  	VariadicFunc		func(...string) string
		80  	VariadicFuncInt func(int, ...string) string
		81  	NilOKFunc			 func(*int) bool
		82  	ErrFunc				 func() (string, error)
		83  	PanicFunc			 func() string
		84  	// Template to test evaluation of templates.
		85  	Tmpl *Template
		86  	// Unexported field; cannot be accessed by template.
		87  	unexported int
		88  }
		89  
		90  type S []string
		91  
		92  func (S) Method0() string {
		93  	return "M0"
		94  }
		95  
		96  type U struct {
		97  	V string
		98  }
		99  
	 100  type V struct {
	 101  	j int
	 102  }
	 103  
	 104  func (v *V) String() string {
	 105  	if v == nil {
	 106  		return "nilV"
	 107  	}
	 108  	return fmt.Sprintf("<%d>", v.j)
	 109  }
	 110  
	 111  type W struct {
	 112  	k int
	 113  }
	 114  
	 115  func (w *W) Error() string {
	 116  	if w == nil {
	 117  		return "nilW"
	 118  	}
	 119  	return fmt.Sprintf("[%d]", w.k)
	 120  }
	 121  
	 122  var siVal = I(S{"a", "b"})
	 123  
	 124  var tVal = &T{
	 125  	True:	 true,
	 126  	I:			17,
	 127  	U16:		16,
	 128  	X:			"x",
	 129  	S:			"xyz",
	 130  	U:			&U{"v"},
	 131  	V0:		 V{6666},
	 132  	V1:		 &V{7777}, // leave V2 as nil
	 133  	W0:		 W{888},
	 134  	W1:		 &W{999}, // leave W2 as nil
	 135  	SI:		 []int{3, 4, 5},
	 136  	SICap:	make([]int, 5, 10),
	 137  	AI:		 [3]int{3, 4, 5},
	 138  	SB:		 []bool{true, false},
	 139  	MSI:		map[string]int{"one": 1, "two": 2, "three": 3},
	 140  	MSIone: map[string]int{"one": 1},
	 141  	MXI:		map[interface{}]int{"one": 1},
	 142  	MII:		map[int]int{1: 1},
	 143  	MI32S:	map[int32]string{1: "one", 2: "two"},
	 144  	MI64S:	map[int64]string{2: "i642", 3: "i643"},
	 145  	MUI32S: map[uint32]string{2: "u322", 3: "u323"},
	 146  	MUI64S: map[uint64]string{2: "ui642", 3: "ui643"},
	 147  	MI8S:	 map[int8]string{2: "i82", 3: "i83"},
	 148  	MUI8S:	map[uint8]string{2: "u82", 3: "u83"},
	 149  	SMSI: []map[string]int{
	 150  		{"one": 1, "two": 2},
	 151  		{"eleven": 11, "twelve": 12},
	 152  	},
	 153  	Empty1:										3,
	 154  	Empty2:										"empty2",
	 155  	Empty3:										[]int{7, 8},
	 156  	Empty4:										&U{"UinEmpty"},
	 157  	NonEmptyInterface:				 &T{X: "x"},
	 158  	NonEmptyInterfacePtS:			&siVal,
	 159  	NonEmptyInterfaceTypedNil: (*T)(nil),
	 160  	Str:											 bytes.NewBuffer([]byte("foozle")),
	 161  	Err:											 errors.New("erroozle"),
	 162  	PI:												newInt(23),
	 163  	PS:												newString("a string"),
	 164  	PSI:											 newIntSlice(21, 22, 23),
	 165  	BinaryFunc:								func(a, b string) string { return fmt.Sprintf("[%s=%s]", a, b) },
	 166  	VariadicFunc:							func(s ...string) string { return fmt.Sprint("<", strings.Join(s, "+"), ">") },
	 167  	VariadicFuncInt:					 func(a int, s ...string) string { return fmt.Sprint(a, "=<", strings.Join(s, "+"), ">") },
	 168  	NilOKFunc:								 func(s *int) bool { return s == nil },
	 169  	ErrFunc:									 func() (string, error) { return "bla", nil },
	 170  	PanicFunc:								 func() string { panic("test panic") },
	 171  	Tmpl:											Must(New("x").Parse("test template")), // "x" is the value of .X
	 172  }
	 173  
	 174  var tSliceOfNil = []*T{nil}
	 175  
	 176  // A non-empty interface.
	 177  type I interface {
	 178  	Method0() string
	 179  }
	 180  
	 181  var iVal I = tVal
	 182  
	 183  // Helpers for creation.
	 184  func newInt(n int) *int {
	 185  	return &n
	 186  }
	 187  
	 188  func newString(s string) *string {
	 189  	return &s
	 190  }
	 191  
	 192  func newIntSlice(n ...int) *[]int {
	 193  	p := new([]int)
	 194  	*p = make([]int, len(n))
	 195  	copy(*p, n)
	 196  	return p
	 197  }
	 198  
	 199  // Simple methods with and without arguments.
	 200  func (t *T) Method0() string {
	 201  	return "M0"
	 202  }
	 203  
	 204  func (t *T) Method1(a int) int {
	 205  	return a
	 206  }
	 207  
	 208  func (t *T) Method2(a uint16, b string) string {
	 209  	return fmt.Sprintf("Method2: %d %s", a, b)
	 210  }
	 211  
	 212  func (t *T) Method3(v interface{}) string {
	 213  	return fmt.Sprintf("Method3: %v", v)
	 214  }
	 215  
	 216  func (t *T) Copy() *T {
	 217  	n := new(T)
	 218  	*n = *t
	 219  	return n
	 220  }
	 221  
	 222  func (t *T) MAdd(a int, b []int) []int {
	 223  	v := make([]int, len(b))
	 224  	for i, x := range b {
	 225  		v[i] = x + a
	 226  	}
	 227  	return v
	 228  }
	 229  
	 230  var myError = errors.New("my error")
	 231  
	 232  // MyError returns a value and an error according to its argument.
	 233  func (t *T) MyError(error bool) (bool, error) {
	 234  	if error {
	 235  		return true, myError
	 236  	}
	 237  	return false, nil
	 238  }
	 239  
	 240  // A few methods to test chaining.
	 241  func (t *T) GetU() *U {
	 242  	return t.U
	 243  }
	 244  
	 245  func (u *U) TrueFalse(b bool) string {
	 246  	if b {
	 247  		return "true"
	 248  	}
	 249  	return ""
	 250  }
	 251  
	 252  func typeOf(arg interface{}) string {
	 253  	return fmt.Sprintf("%T", arg)
	 254  }
	 255  
	 256  type execTest struct {
	 257  	name	 string
	 258  	input	string
	 259  	output string
	 260  	data	 interface{}
	 261  	ok		 bool
	 262  }
	 263  
	 264  // bigInt and bigUint are hex string representing numbers either side
	 265  // of the max int boundary.
	 266  // We do it this way so the test doesn't depend on ints being 32 bits.
	 267  var (
	 268  	bigInt	= fmt.Sprintf("0x%x", int(1<<uint(reflect.TypeOf(0).Bits()-1)-1))
	 269  	bigUint = fmt.Sprintf("0x%x", uint(1<<uint(reflect.TypeOf(0).Bits()-1)))
	 270  )
	 271  
	 272  var execTests = []execTest{
	 273  	// Trivial cases.
	 274  	{"empty", "", "", nil, true},
	 275  	{"text", "some text", "some text", nil, true},
	 276  	{"nil action", "{{nil}}", "", nil, false},
	 277  
	 278  	// Ideal constants.
	 279  	{"ideal int", "{{typeOf 3}}", "int", 0, true},
	 280  	{"ideal float", "{{typeOf 1.0}}", "float64", 0, true},
	 281  	{"ideal exp float", "{{typeOf 1e1}}", "float64", 0, true},
	 282  	{"ideal complex", "{{typeOf 1i}}", "complex128", 0, true},
	 283  	{"ideal int", "{{typeOf " + bigInt + "}}", "int", 0, true},
	 284  	{"ideal too big", "{{typeOf " + bigUint + "}}", "", 0, false},
	 285  	{"ideal nil without type", "{{nil}}", "", 0, false},
	 286  
	 287  	// Fields of structs.
	 288  	{".X", "-{{.X}}-", "-x-", tVal, true},
	 289  	{".U.V", "-{{.U.V}}-", "-v-", tVal, true},
	 290  	{".unexported", "{{.unexported}}", "", tVal, false},
	 291  
	 292  	// Fields on maps.
	 293  	{"map .one", "{{.MSI.one}}", "1", tVal, true},
	 294  	{"map .two", "{{.MSI.two}}", "2", tVal, true},
	 295  	{"map .NO", "{{.MSI.NO}}", "<no value>", tVal, true},
	 296  	{"map .one interface", "{{.MXI.one}}", "1", tVal, true},
	 297  	{"map .WRONG args", "{{.MSI.one 1}}", "", tVal, false},
	 298  	{"map .WRONG type", "{{.MII.one}}", "", tVal, false},
	 299  
	 300  	// Dots of all kinds to test basic evaluation.
	 301  	{"dot int", "<{{.}}>", "<13>", 13, true},
	 302  	{"dot uint", "<{{.}}>", "<14>", uint(14), true},
	 303  	{"dot float", "<{{.}}>", "<15.1>", 15.1, true},
	 304  	{"dot bool", "<{{.}}>", "<true>", true, true},
	 305  	{"dot complex", "<{{.}}>", "<(16.2-17i)>", 16.2 - 17i, true},
	 306  	{"dot string", "<{{.}}>", "<hello>", "hello", true},
	 307  	{"dot slice", "<{{.}}>", "<[-1 -2 -3]>", []int{-1, -2, -3}, true},
	 308  	{"dot map", "<{{.}}>", "<map[two:22]>", map[string]int{"two": 22}, true},
	 309  	{"dot struct", "<{{.}}>", "<{7 seven}>", struct {
	 310  		a int
	 311  		b string
	 312  	}{7, "seven"}, true},
	 313  
	 314  	// Variables.
	 315  	{"$ int", "{{$}}", "123", 123, true},
	 316  	{"$.I", "{{$.I}}", "17", tVal, true},
	 317  	{"$.U.V", "{{$.U.V}}", "v", tVal, true},
	 318  	{"declare in action", "{{$x := $.U.V}}{{$x}}", "v", tVal, true},
	 319  	{"simple assignment", "{{$x := 2}}{{$x = 3}}{{$x}}", "3", tVal, true},
	 320  	{"nested assignment",
	 321  		"{{$x := 2}}{{if true}}{{$x = 3}}{{end}}{{$x}}",
	 322  		"3", tVal, true},
	 323  	{"nested assignment changes the last declaration",
	 324  		"{{$x := 1}}{{if true}}{{$x := 2}}{{if true}}{{$x = 3}}{{end}}{{end}}{{$x}}",
	 325  		"1", tVal, true},
	 326  
	 327  	// Type with String method.
	 328  	{"V{6666}.String()", "-{{.V0}}-", "-<6666>-", tVal, true},
	 329  	{"&V{7777}.String()", "-{{.V1}}-", "-<7777>-", tVal, true},
	 330  	{"(*V)(nil).String()", "-{{.V2}}-", "-nilV-", tVal, true},
	 331  
	 332  	// Type with Error method.
	 333  	{"W{888}.Error()", "-{{.W0}}-", "-[888]-", tVal, true},
	 334  	{"&W{999}.Error()", "-{{.W1}}-", "-[999]-", tVal, true},
	 335  	{"(*W)(nil).Error()", "-{{.W2}}-", "-nilW-", tVal, true},
	 336  
	 337  	// Pointers.
	 338  	{"*int", "{{.PI}}", "23", tVal, true},
	 339  	{"*string", "{{.PS}}", "a string", tVal, true},
	 340  	{"*[]int", "{{.PSI}}", "[21 22 23]", tVal, true},
	 341  	{"*[]int[1]", "{{index .PSI 1}}", "22", tVal, true},
	 342  	{"NIL", "{{.NIL}}", "<nil>", tVal, true},
	 343  
	 344  	// Empty interfaces holding values.
	 345  	{"empty nil", "{{.Empty0}}", "<no value>", tVal, true},
	 346  	{"empty with int", "{{.Empty1}}", "3", tVal, true},
	 347  	{"empty with string", "{{.Empty2}}", "empty2", tVal, true},
	 348  	{"empty with slice", "{{.Empty3}}", "[7 8]", tVal, true},
	 349  	{"empty with struct", "{{.Empty4}}", "{UinEmpty}", tVal, true},
	 350  	{"empty with struct, field", "{{.Empty4.V}}", "UinEmpty", tVal, true},
	 351  
	 352  	// Edge cases with <no value> with an interface value
	 353  	{"field on interface", "{{.foo}}", "<no value>", nil, true},
	 354  	{"field on parenthesized interface", "{{(.).foo}}", "<no value>", nil, true},
	 355  
	 356  	// Issue 31810: Parenthesized first element of pipeline with arguments.
	 357  	// See also TestIssue31810.
	 358  	{"unparenthesized non-function", "{{1 2}}", "", nil, false},
	 359  	{"parenthesized non-function", "{{(1) 2}}", "", nil, false},
	 360  	{"parenthesized non-function with no args", "{{(1)}}", "1", nil, true}, // This is fine.
	 361  
	 362  	// Method calls.
	 363  	{".Method0", "-{{.Method0}}-", "-M0-", tVal, true},
	 364  	{".Method1(1234)", "-{{.Method1 1234}}-", "-1234-", tVal, true},
	 365  	{".Method1(.I)", "-{{.Method1 .I}}-", "-17-", tVal, true},
	 366  	{".Method2(3, .X)", "-{{.Method2 3 .X}}-", "-Method2: 3 x-", tVal, true},
	 367  	{".Method2(.U16, `str`)", "-{{.Method2 .U16 `str`}}-", "-Method2: 16 str-", tVal, true},
	 368  	{".Method2(.U16, $x)", "{{if $x := .X}}-{{.Method2 .U16 $x}}{{end}}-", "-Method2: 16 x-", tVal, true},
	 369  	{".Method3(nil constant)", "-{{.Method3 nil}}-", "-Method3: <nil>-", tVal, true},
	 370  	{".Method3(nil value)", "-{{.Method3 .MXI.unset}}-", "-Method3: <nil>-", tVal, true},
	 371  	{"method on var", "{{if $x := .}}-{{$x.Method2 .U16 $x.X}}{{end}}-", "-Method2: 16 x-", tVal, true},
	 372  	{"method on chained var",
	 373  		"{{range .MSIone}}{{if $.U.TrueFalse $.True}}{{$.U.TrueFalse $.True}}{{else}}WRONG{{end}}{{end}}",
	 374  		"true", tVal, true},
	 375  	{"chained method",
	 376  		"{{range .MSIone}}{{if $.GetU.TrueFalse $.True}}{{$.U.TrueFalse $.True}}{{else}}WRONG{{end}}{{end}}",
	 377  		"true", tVal, true},
	 378  	{"chained method on variable",
	 379  		"{{with $x := .}}{{with .SI}}{{$.GetU.TrueFalse $.True}}{{end}}{{end}}",
	 380  		"true", tVal, true},
	 381  	{".NilOKFunc not nil", "{{call .NilOKFunc .PI}}", "false", tVal, true},
	 382  	{".NilOKFunc nil", "{{call .NilOKFunc nil}}", "true", tVal, true},
	 383  	{"method on nil value from slice", "-{{range .}}{{.Method1 1234}}{{end}}-", "-1234-", tSliceOfNil, true},
	 384  	{"method on typed nil interface value", "{{.NonEmptyInterfaceTypedNil.Method0}}", "M0", tVal, true},
	 385  
	 386  	// Function call builtin.
	 387  	{".BinaryFunc", "{{call .BinaryFunc `1` `2`}}", "[1=2]", tVal, true},
	 388  	{".VariadicFunc0", "{{call .VariadicFunc}}", "<>", tVal, true},
	 389  	{".VariadicFunc2", "{{call .VariadicFunc `he` `llo`}}", "<he+llo>", tVal, true},
	 390  	{".VariadicFuncInt", "{{call .VariadicFuncInt 33 `he` `llo`}}", "33=<he+llo>", tVal, true},
	 391  	{"if .BinaryFunc call", "{{ if .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{end}}", "[1=2]", tVal, true},
	 392  	{"if not .BinaryFunc call", "{{ if not .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{else}}No{{end}}", "No", tVal, true},
	 393  	{"Interface Call", `{{stringer .S}}`, "foozle", map[string]interface{}{"S": bytes.NewBufferString("foozle")}, true},
	 394  	{".ErrFunc", "{{call .ErrFunc}}", "bla", tVal, true},
	 395  	{"call nil", "{{call nil}}", "", tVal, false},
	 396  
	 397  	// Erroneous function calls (check args).
	 398  	{".BinaryFuncTooFew", "{{call .BinaryFunc `1`}}", "", tVal, false},
	 399  	{".BinaryFuncTooMany", "{{call .BinaryFunc `1` `2` `3`}}", "", tVal, false},
	 400  	{".BinaryFuncBad0", "{{call .BinaryFunc 1 3}}", "", tVal, false},
	 401  	{".BinaryFuncBad1", "{{call .BinaryFunc `1` 3}}", "", tVal, false},
	 402  	{".VariadicFuncBad0", "{{call .VariadicFunc 3}}", "", tVal, false},
	 403  	{".VariadicFuncIntBad0", "{{call .VariadicFuncInt}}", "", tVal, false},
	 404  	{".VariadicFuncIntBad`", "{{call .VariadicFuncInt `x`}}", "", tVal, false},
	 405  	{".VariadicFuncNilBad", "{{call .VariadicFunc nil}}", "", tVal, false},
	 406  
	 407  	// Pipelines.
	 408  	{"pipeline", "-{{.Method0 | .Method2 .U16}}-", "-Method2: 16 M0-", tVal, true},
	 409  	{"pipeline func", "-{{call .VariadicFunc `llo` | call .VariadicFunc `he` }}-", "-<he+<llo>>-", tVal, true},
	 410  
	 411  	// Nil values aren't missing arguments.
	 412  	{"nil pipeline", "{{ .Empty0 | call .NilOKFunc }}", "true", tVal, true},
	 413  	{"nil call arg", "{{ call .NilOKFunc .Empty0 }}", "true", tVal, true},
	 414  	{"bad nil pipeline", "{{ .Empty0 | .VariadicFunc }}", "", tVal, false},
	 415  
	 416  	// Parenthesized expressions
	 417  	{"parens in pipeline", "{{printf `%d %d %d` (1) (2 | add 3) (add 4 (add 5 6))}}", "1 5 15", tVal, true},
	 418  
	 419  	// Parenthesized expressions with field accesses
	 420  	{"parens: $ in paren", "{{($).X}}", "x", tVal, true},
	 421  	{"parens: $.GetU in paren", "{{($.GetU).V}}", "v", tVal, true},
	 422  	{"parens: $ in paren in pipe", "{{($ | echo).X}}", "x", tVal, true},
	 423  	{"parens: spaces and args", `{{(makemap "up" "down" "left" "right").left}}`, "right", tVal, true},
	 424  
	 425  	// If.
	 426  	{"if true", "{{if true}}TRUE{{end}}", "TRUE", tVal, true},
	 427  	{"if false", "{{if false}}TRUE{{else}}FALSE{{end}}", "FALSE", tVal, true},
	 428  	{"if nil", "{{if nil}}TRUE{{end}}", "", tVal, false},
	 429  	{"if on typed nil interface value", "{{if .NonEmptyInterfaceTypedNil}}TRUE{{ end }}", "", tVal, true},
	 430  	{"if 1", "{{if 1}}NON-ZERO{{else}}ZERO{{end}}", "NON-ZERO", tVal, true},
	 431  	{"if 0", "{{if 0}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
	 432  	{"if 1.5", "{{if 1.5}}NON-ZERO{{else}}ZERO{{end}}", "NON-ZERO", tVal, true},
	 433  	{"if 0.0", "{{if .FloatZero}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
	 434  	{"if 1.5i", "{{if 1.5i}}NON-ZERO{{else}}ZERO{{end}}", "NON-ZERO", tVal, true},
	 435  	{"if 0.0i", "{{if .ComplexZero}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
	 436  	{"if emptystring", "{{if ``}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
	 437  	{"if string", "{{if `notempty`}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
	 438  	{"if emptyslice", "{{if .SIEmpty}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
	 439  	{"if slice", "{{if .SI}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
	 440  	{"if emptymap", "{{if .MSIEmpty}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
	 441  	{"if map", "{{if .MSI}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
	 442  	{"if map unset", "{{if .MXI.none}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
	 443  	{"if map not unset", "{{if not .MXI.none}}ZERO{{else}}NON-ZERO{{end}}", "ZERO", tVal, true},
	 444  	{"if $x with $y int", "{{if $x := true}}{{with $y := .I}}{{$x}},{{$y}}{{end}}{{end}}", "true,17", tVal, true},
	 445  	{"if $x with $x int", "{{if $x := true}}{{with $x := .I}}{{$x}},{{end}}{{$x}}{{end}}", "17,true", tVal, true},
	 446  	{"if else if", "{{if false}}FALSE{{else if true}}TRUE{{end}}", "TRUE", tVal, true},
	 447  	{"if else chain", "{{if eq 1 3}}1{{else if eq 2 3}}2{{else if eq 3 3}}3{{end}}", "3", tVal, true},
	 448  
	 449  	// Print etc.
	 450  	{"print", `{{print "hello, print"}}`, "hello, print", tVal, true},
	 451  	{"print 123", `{{print 1 2 3}}`, "1 2 3", tVal, true},
	 452  	{"print nil", `{{print nil}}`, "<nil>", tVal, true},
	 453  	{"println", `{{println 1 2 3}}`, "1 2 3\n", tVal, true},
	 454  	{"printf int", `{{printf "%04x" 127}}`, "007f", tVal, true},
	 455  	{"printf float", `{{printf "%g" 3.5}}`, "3.5", tVal, true},
	 456  	{"printf complex", `{{printf "%g" 1+7i}}`, "(1+7i)", tVal, true},
	 457  	{"printf string", `{{printf "%s" "hello"}}`, "hello", tVal, true},
	 458  	{"printf function", `{{printf "%#q" zeroArgs}}`, "`zeroArgs`", tVal, true},
	 459  	{"printf field", `{{printf "%s" .U.V}}`, "v", tVal, true},
	 460  	{"printf method", `{{printf "%s" .Method0}}`, "M0", tVal, true},
	 461  	{"printf dot", `{{with .I}}{{printf "%d" .}}{{end}}`, "17", tVal, true},
	 462  	{"printf var", `{{with $x := .I}}{{printf "%d" $x}}{{end}}`, "17", tVal, true},
	 463  	{"printf lots", `{{printf "%d %s %g %s" 127 "hello" 7-3i .Method0}}`, "127 hello (7-3i) M0", tVal, true},
	 464  
	 465  	// HTML.
	 466  	{"html", `{{html "<script>alert(\"XSS\");</script>"}}`,
	 467  		"&lt;script&gt;alert(&#34;XSS&#34;);&lt;/script&gt;", nil, true},
	 468  	{"html pipeline", `{{printf "<script>alert(\"XSS\");</script>" | html}}`,
	 469  		"&lt;script&gt;alert(&#34;XSS&#34;);&lt;/script&gt;", nil, true},
	 470  	{"html", `{{html .PS}}`, "a string", tVal, true},
	 471  	{"html typed nil", `{{html .NIL}}`, "&lt;nil&gt;", tVal, true},
	 472  	{"html untyped nil", `{{html .Empty0}}`, "&lt;no value&gt;", tVal, true},
	 473  
	 474  	// JavaScript.
	 475  	{"js", `{{js .}}`, `It\'d be nice.`, `It'd be nice.`, true},
	 476  
	 477  	// URL query.
	 478  	{"urlquery", `{{"http://www.example.org/"|urlquery}}`, "http%3A%2F%2Fwww.example.org%2F", nil, true},
	 479  
	 480  	// Booleans
	 481  	{"not", "{{not true}} {{not false}}", "false true", nil, true},
	 482  	{"and", "{{and false 0}} {{and 1 0}} {{and 0 true}} {{and 1 1}}", "false 0 0 1", nil, true},
	 483  	{"or", "{{or 0 0}} {{or 1 0}} {{or 0 true}} {{or 1 1}}", "0 1 true 1", nil, true},
	 484  	{"boolean if", "{{if and true 1 `hi`}}TRUE{{else}}FALSE{{end}}", "TRUE", tVal, true},
	 485  	{"boolean if not", "{{if and true 1 `hi` | not}}TRUE{{else}}FALSE{{end}}", "FALSE", nil, true},
	 486  
	 487  	// Indexing.
	 488  	{"slice[0]", "{{index .SI 0}}", "3", tVal, true},
	 489  	{"slice[1]", "{{index .SI 1}}", "4", tVal, true},
	 490  	{"slice[HUGE]", "{{index .SI 10}}", "", tVal, false},
	 491  	{"slice[WRONG]", "{{index .SI `hello`}}", "", tVal, false},
	 492  	{"slice[nil]", "{{index .SI nil}}", "", tVal, false},
	 493  	{"map[one]", "{{index .MSI `one`}}", "1", tVal, true},
	 494  	{"map[two]", "{{index .MSI `two`}}", "2", tVal, true},
	 495  	{"map[NO]", "{{index .MSI `XXX`}}", "0", tVal, true},
	 496  	{"map[nil]", "{{index .MSI nil}}", "", tVal, false},
	 497  	{"map[``]", "{{index .MSI ``}}", "0", tVal, true},
	 498  	{"map[WRONG]", "{{index .MSI 10}}", "", tVal, false},
	 499  	{"double index", "{{index .SMSI 1 `eleven`}}", "11", tVal, true},
	 500  	{"nil[1]", "{{index nil 1}}", "", tVal, false},
	 501  	{"map MI64S", "{{index .MI64S 2}}", "i642", tVal, true},
	 502  	{"map MI32S", "{{index .MI32S 2}}", "two", tVal, true},
	 503  	{"map MUI64S", "{{index .MUI64S 3}}", "ui643", tVal, true},
	 504  	{"map MI8S", "{{index .MI8S 3}}", "i83", tVal, true},
	 505  	{"map MUI8S", "{{index .MUI8S 2}}", "u82", tVal, true},
	 506  	{"index of an interface field", "{{index .Empty3 0}}", "7", tVal, true},
	 507  
	 508  	// Slicing.
	 509  	{"slice[:]", "{{slice .SI}}", "[3 4 5]", tVal, true},
	 510  	{"slice[1:]", "{{slice .SI 1}}", "[4 5]", tVal, true},
	 511  	{"slice[1:2]", "{{slice .SI 1 2}}", "[4]", tVal, true},
	 512  	{"slice[-1:]", "{{slice .SI -1}}", "", tVal, false},
	 513  	{"slice[1:-2]", "{{slice .SI 1 -2}}", "", tVal, false},
	 514  	{"slice[1:2:-1]", "{{slice .SI 1 2 -1}}", "", tVal, false},
	 515  	{"slice[2:1]", "{{slice .SI 2 1}}", "", tVal, false},
	 516  	{"slice[2:2:1]", "{{slice .SI 2 2 1}}", "", tVal, false},
	 517  	{"out of range", "{{slice .SI 4 5}}", "", tVal, false},
	 518  	{"out of range", "{{slice .SI 2 2 5}}", "", tVal, false},
	 519  	{"len(s) < indexes < cap(s)", "{{slice .SICap 6 10}}", "[0 0 0 0]", tVal, true},
	 520  	{"len(s) < indexes < cap(s)", "{{slice .SICap 6 10 10}}", "[0 0 0 0]", tVal, true},
	 521  	{"indexes > cap(s)", "{{slice .SICap 10 11}}", "", tVal, false},
	 522  	{"indexes > cap(s)", "{{slice .SICap 6 10 11}}", "", tVal, false},
	 523  	{"array[:]", "{{slice .AI}}", "[3 4 5]", tVal, true},
	 524  	{"array[1:]", "{{slice .AI 1}}", "[4 5]", tVal, true},
	 525  	{"array[1:2]", "{{slice .AI 1 2}}", "[4]", tVal, true},
	 526  	{"string[:]", "{{slice .S}}", "xyz", tVal, true},
	 527  	{"string[0:1]", "{{slice .S 0 1}}", "x", tVal, true},
	 528  	{"string[1:]", "{{slice .S 1}}", "yz", tVal, true},
	 529  	{"string[1:2]", "{{slice .S 1 2}}", "y", tVal, true},
	 530  	{"out of range", "{{slice .S 1 5}}", "", tVal, false},
	 531  	{"3-index slice of string", "{{slice .S 1 2 2}}", "", tVal, false},
	 532  	{"slice of an interface field", "{{slice .Empty3 0 1}}", "[7]", tVal, true},
	 533  
	 534  	// Len.
	 535  	{"slice", "{{len .SI}}", "3", tVal, true},
	 536  	{"map", "{{len .MSI }}", "3", tVal, true},
	 537  	{"len of int", "{{len 3}}", "", tVal, false},
	 538  	{"len of nothing", "{{len .Empty0}}", "", tVal, false},
	 539  	{"len of an interface field", "{{len .Empty3}}", "2", tVal, true},
	 540  
	 541  	// With.
	 542  	{"with true", "{{with true}}{{.}}{{end}}", "true", tVal, true},
	 543  	{"with false", "{{with false}}{{.}}{{else}}FALSE{{end}}", "FALSE", tVal, true},
	 544  	{"with 1", "{{with 1}}{{.}}{{else}}ZERO{{end}}", "1", tVal, true},
	 545  	{"with 0", "{{with 0}}{{.}}{{else}}ZERO{{end}}", "ZERO", tVal, true},
	 546  	{"with 1.5", "{{with 1.5}}{{.}}{{else}}ZERO{{end}}", "1.5", tVal, true},
	 547  	{"with 0.0", "{{with .FloatZero}}{{.}}{{else}}ZERO{{end}}", "ZERO", tVal, true},
	 548  	{"with 1.5i", "{{with 1.5i}}{{.}}{{else}}ZERO{{end}}", "(0+1.5i)", tVal, true},
	 549  	{"with 0.0i", "{{with .ComplexZero}}{{.}}{{else}}ZERO{{end}}", "ZERO", tVal, true},
	 550  	{"with emptystring", "{{with ``}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
	 551  	{"with string", "{{with `notempty`}}{{.}}{{else}}EMPTY{{end}}", "notempty", tVal, true},
	 552  	{"with emptyslice", "{{with .SIEmpty}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
	 553  	{"with slice", "{{with .SI}}{{.}}{{else}}EMPTY{{end}}", "[3 4 5]", tVal, true},
	 554  	{"with emptymap", "{{with .MSIEmpty}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
	 555  	{"with map", "{{with .MSIone}}{{.}}{{else}}EMPTY{{end}}", "map[one:1]", tVal, true},
	 556  	{"with empty interface, struct field", "{{with .Empty4}}{{.V}}{{end}}", "UinEmpty", tVal, true},
	 557  	{"with $x int", "{{with $x := .I}}{{$x}}{{end}}", "17", tVal, true},
	 558  	{"with $x struct.U.V", "{{with $x := $}}{{$x.U.V}}{{end}}", "v", tVal, true},
	 559  	{"with variable and action", "{{with $x := $}}{{$y := $.U.V}}{{$y}}{{end}}", "v", tVal, true},
	 560  	{"with on typed nil interface value", "{{with .NonEmptyInterfaceTypedNil}}TRUE{{ end }}", "", tVal, true},
	 561  
	 562  	// Range.
	 563  	{"range []int", "{{range .SI}}-{{.}}-{{end}}", "-3--4--5-", tVal, true},
	 564  	{"range empty no else", "{{range .SIEmpty}}-{{.}}-{{end}}", "", tVal, true},
	 565  	{"range []int else", "{{range .SI}}-{{.}}-{{else}}EMPTY{{end}}", "-3--4--5-", tVal, true},
	 566  	{"range empty else", "{{range .SIEmpty}}-{{.}}-{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
	 567  	{"range []bool", "{{range .SB}}-{{.}}-{{end}}", "-true--false-", tVal, true},
	 568  	{"range []int method", "{{range .SI | .MAdd .I}}-{{.}}-{{end}}", "-20--21--22-", tVal, true},
	 569  	{"range map", "{{range .MSI}}-{{.}}-{{end}}", "-1--3--2-", tVal, true},
	 570  	{"range empty map no else", "{{range .MSIEmpty}}-{{.}}-{{end}}", "", tVal, true},
	 571  	{"range map else", "{{range .MSI}}-{{.}}-{{else}}EMPTY{{end}}", "-1--3--2-", tVal, true},
	 572  	{"range empty map else", "{{range .MSIEmpty}}-{{.}}-{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
	 573  	{"range empty interface", "{{range .Empty3}}-{{.}}-{{else}}EMPTY{{end}}", "-7--8-", tVal, true},
	 574  	{"range empty nil", "{{range .Empty0}}-{{.}}-{{end}}", "", tVal, true},
	 575  	{"range $x SI", "{{range $x := .SI}}<{{$x}}>{{end}}", "<3><4><5>", tVal, true},
	 576  	{"range $x $y SI", "{{range $x, $y := .SI}}<{{$x}}={{$y}}>{{end}}", "<0=3><1=4><2=5>", tVal, true},
	 577  	{"range $x MSIone", "{{range $x := .MSIone}}<{{$x}}>{{end}}", "<1>", tVal, true},
	 578  	{"range $x $y MSIone", "{{range $x, $y := .MSIone}}<{{$x}}={{$y}}>{{end}}", "<one=1>", tVal, true},
	 579  	{"range $x PSI", "{{range $x := .PSI}}<{{$x}}>{{end}}", "<21><22><23>", tVal, true},
	 580  	{"declare in range", "{{range $x := .PSI}}<{{$foo:=$x}}{{$x}}>{{end}}", "<21><22><23>", tVal, true},
	 581  	{"range count", `{{range $i, $x := count 5}}[{{$i}}]{{$x}}{{end}}`, "[0]a[1]b[2]c[3]d[4]e", tVal, true},
	 582  	{"range nil count", `{{range $i, $x := count 0}}{{else}}empty{{end}}`, "empty", tVal, true},
	 583  
	 584  	// Cute examples.
	 585  	{"or as if true", `{{or .SI "slice is empty"}}`, "[3 4 5]", tVal, true},
	 586  	{"or as if false", `{{or .SIEmpty "slice is empty"}}`, "slice is empty", tVal, true},
	 587  
	 588  	// Error handling.
	 589  	{"error method, error", "{{.MyError true}}", "", tVal, false},
	 590  	{"error method, no error", "{{.MyError false}}", "false", tVal, true},
	 591  
	 592  	// Numbers
	 593  	{"decimal", "{{print 1234}}", "1234", tVal, true},
	 594  	{"decimal _", "{{print 12_34}}", "1234", tVal, true},
	 595  	{"binary", "{{print 0b101}}", "5", tVal, true},
	 596  	{"binary _", "{{print 0b_1_0_1}}", "5", tVal, true},
	 597  	{"BINARY", "{{print 0B101}}", "5", tVal, true},
	 598  	{"octal0", "{{print 0377}}", "255", tVal, true},
	 599  	{"octal", "{{print 0o377}}", "255", tVal, true},
	 600  	{"octal _", "{{print 0o_3_7_7}}", "255", tVal, true},
	 601  	{"OCTAL", "{{print 0O377}}", "255", tVal, true},
	 602  	{"hex", "{{print 0x123}}", "291", tVal, true},
	 603  	{"hex _", "{{print 0x1_23}}", "291", tVal, true},
	 604  	{"HEX", "{{print 0X123ABC}}", "1194684", tVal, true},
	 605  	{"float", "{{print 123.4}}", "123.4", tVal, true},
	 606  	{"float _", "{{print 0_0_1_2_3.4}}", "123.4", tVal, true},
	 607  	{"hex float", "{{print +0x1.ep+2}}", "7.5", tVal, true},
	 608  	{"hex float _", "{{print +0x_1.e_0p+0_2}}", "7.5", tVal, true},
	 609  	{"HEX float", "{{print +0X1.EP+2}}", "7.5", tVal, true},
	 610  	{"print multi", "{{print 1_2_3_4 7.5_00_00_00}}", "1234 7.5", tVal, true},
	 611  	{"print multi2", "{{print 1234 0x0_1.e_0p+02}}", "1234 7.5", tVal, true},
	 612  
	 613  	// Fixed bugs.
	 614  	// Must separate dot and receiver; otherwise args are evaluated with dot set to variable.
	 615  	{"bug0", "{{range .MSIone}}{{if $.Method1 .}}X{{end}}{{end}}", "X", tVal, true},
	 616  	// Do not loop endlessly in indirect for non-empty interfaces.
	 617  	// The bug appears with *interface only; looped forever.
	 618  	{"bug1", "{{.Method0}}", "M0", &iVal, true},
	 619  	// Was taking address of interface field, so method set was empty.
	 620  	{"bug2", "{{$.NonEmptyInterface.Method0}}", "M0", tVal, true},
	 621  	// Struct values were not legal in with - mere oversight.
	 622  	{"bug3", "{{with $}}{{.Method0}}{{end}}", "M0", tVal, true},
	 623  	// Nil interface values in if.
	 624  	{"bug4", "{{if .Empty0}}non-nil{{else}}nil{{end}}", "nil", tVal, true},
	 625  	// Stringer.
	 626  	{"bug5", "{{.Str}}", "foozle", tVal, true},
	 627  	{"bug5a", "{{.Err}}", "erroozle", tVal, true},
	 628  	// Args need to be indirected and dereferenced sometimes.
	 629  	{"bug6a", "{{vfunc .V0 .V1}}", "vfunc", tVal, true},
	 630  	{"bug6b", "{{vfunc .V0 .V0}}", "vfunc", tVal, true},
	 631  	{"bug6c", "{{vfunc .V1 .V0}}", "vfunc", tVal, true},
	 632  	{"bug6d", "{{vfunc .V1 .V1}}", "vfunc", tVal, true},
	 633  	// Legal parse but illegal execution: non-function should have no arguments.
	 634  	{"bug7a", "{{3 2}}", "", tVal, false},
	 635  	{"bug7b", "{{$x := 1}}{{$x 2}}", "", tVal, false},
	 636  	{"bug7c", "{{$x := 1}}{{3 | $x}}", "", tVal, false},
	 637  	// Pipelined arg was not being type-checked.
	 638  	{"bug8a", "{{3|oneArg}}", "", tVal, false},
	 639  	{"bug8b", "{{4|dddArg 3}}", "", tVal, false},
	 640  	// A bug was introduced that broke map lookups for lower-case names.
	 641  	{"bug9", "{{.cause}}", "neglect", map[string]string{"cause": "neglect"}, true},
	 642  	// Field chain starting with function did not work.
	 643  	{"bug10", "{{mapOfThree.three}}-{{(mapOfThree).three}}", "3-3", 0, true},
	 644  	// Dereferencing nil pointer while evaluating function arguments should not panic. Issue 7333.
	 645  	{"bug11", "{{valueString .PS}}", "", T{}, false},
	 646  	// 0xef gave constant type float64. Issue 8622.
	 647  	{"bug12xe", "{{printf `%T` 0xef}}", "int", T{}, true},
	 648  	{"bug12xE", "{{printf `%T` 0xEE}}", "int", T{}, true},
	 649  	{"bug12Xe", "{{printf `%T` 0Xef}}", "int", T{}, true},
	 650  	{"bug12XE", "{{printf `%T` 0XEE}}", "int", T{}, true},
	 651  	// Chained nodes did not work as arguments. Issue 8473.
	 652  	{"bug13", "{{print (.Copy).I}}", "17", tVal, true},
	 653  	// Didn't protect against nil or literal values in field chains.
	 654  	{"bug14a", "{{(nil).True}}", "", tVal, false},
	 655  	{"bug14b", "{{$x := nil}}{{$x.anything}}", "", tVal, false},
	 656  	{"bug14c", `{{$x := (1.0)}}{{$y := ("hello")}}{{$x.anything}}{{$y.true}}`, "", tVal, false},
	 657  	// Didn't call validateType on function results. Issue 10800.
	 658  	{"bug15", "{{valueString returnInt}}", "", tVal, false},
	 659  	// Variadic function corner cases. Issue 10946.
	 660  	{"bug16a", "{{true|printf}}", "", tVal, false},
	 661  	{"bug16b", "{{1|printf}}", "", tVal, false},
	 662  	{"bug16c", "{{1.1|printf}}", "", tVal, false},
	 663  	{"bug16d", "{{'x'|printf}}", "", tVal, false},
	 664  	{"bug16e", "{{0i|printf}}", "", tVal, false},
	 665  	{"bug16f", "{{true|twoArgs \"xxx\"}}", "", tVal, false},
	 666  	{"bug16g", "{{\"aaa\" |twoArgs \"bbb\"}}", "twoArgs=bbbaaa", tVal, true},
	 667  	{"bug16h", "{{1|oneArg}}", "", tVal, false},
	 668  	{"bug16i", "{{\"aaa\"|oneArg}}", "oneArg=aaa", tVal, true},
	 669  	{"bug16j", "{{1+2i|printf \"%v\"}}", "(1+2i)", tVal, true},
	 670  	{"bug16k", "{{\"aaa\"|printf }}", "aaa", tVal, true},
	 671  	{"bug17a", "{{.NonEmptyInterface.X}}", "x", tVal, true},
	 672  	{"bug17b", "-{{.NonEmptyInterface.Method1 1234}}-", "-1234-", tVal, true},
	 673  	{"bug17c", "{{len .NonEmptyInterfacePtS}}", "2", tVal, true},
	 674  	{"bug17d", "{{index .NonEmptyInterfacePtS 0}}", "a", tVal, true},
	 675  	{"bug17e", "{{range .NonEmptyInterfacePtS}}-{{.}}-{{end}}", "-a--b-", tVal, true},
	 676  
	 677  	// More variadic function corner cases. Some runes would get evaluated
	 678  	// as constant floats instead of ints. Issue 34483.
	 679  	{"bug18a", "{{eq . '.'}}", "true", '.', true},
	 680  	{"bug18b", "{{eq . 'e'}}", "true", 'e', true},
	 681  	{"bug18c", "{{eq . 'P'}}", "true", 'P', true},
	 682  }
	 683  
	 684  func zeroArgs() string {
	 685  	return "zeroArgs"
	 686  }
	 687  
	 688  func oneArg(a string) string {
	 689  	return "oneArg=" + a
	 690  }
	 691  
	 692  func twoArgs(a, b string) string {
	 693  	return "twoArgs=" + a + b
	 694  }
	 695  
	 696  func dddArg(a int, b ...string) string {
	 697  	return fmt.Sprintln(a, b)
	 698  }
	 699  
	 700  // count returns a channel that will deliver n sequential 1-letter strings starting at "a"
	 701  func count(n int) chan string {
	 702  	if n == 0 {
	 703  		return nil
	 704  	}
	 705  	c := make(chan string)
	 706  	go func() {
	 707  		for i := 0; i < n; i++ {
	 708  			c <- "abcdefghijklmnop"[i : i+1]
	 709  		}
	 710  		close(c)
	 711  	}()
	 712  	return c
	 713  }
	 714  
	 715  // vfunc takes a *V and a V
	 716  func vfunc(V, *V) string {
	 717  	return "vfunc"
	 718  }
	 719  
	 720  // valueString takes a string, not a pointer.
	 721  func valueString(v string) string {
	 722  	return "value is ignored"
	 723  }
	 724  
	 725  // returnInt returns an int
	 726  func returnInt() int {
	 727  	return 7
	 728  }
	 729  
	 730  func add(args ...int) int {
	 731  	sum := 0
	 732  	for _, x := range args {
	 733  		sum += x
	 734  	}
	 735  	return sum
	 736  }
	 737  
	 738  func echo(arg interface{}) interface{} {
	 739  	return arg
	 740  }
	 741  
	 742  func makemap(arg ...string) map[string]string {
	 743  	if len(arg)%2 != 0 {
	 744  		panic("bad makemap")
	 745  	}
	 746  	m := make(map[string]string)
	 747  	for i := 0; i < len(arg); i += 2 {
	 748  		m[arg[i]] = arg[i+1]
	 749  	}
	 750  	return m
	 751  }
	 752  
	 753  func stringer(s fmt.Stringer) string {
	 754  	return s.String()
	 755  }
	 756  
	 757  func mapOfThree() interface{} {
	 758  	return map[string]int{"three": 3}
	 759  }
	 760  
	 761  func testExecute(execTests []execTest, template *Template, t *testing.T) {
	 762  	b := new(bytes.Buffer)
	 763  	funcs := FuncMap{
	 764  		"add":				 add,
	 765  		"count":			 count,
	 766  		"dddArg":			dddArg,
	 767  		"echo":				echo,
	 768  		"makemap":		 makemap,
	 769  		"mapOfThree":	mapOfThree,
	 770  		"oneArg":			oneArg,
	 771  		"returnInt":	 returnInt,
	 772  		"stringer":		stringer,
	 773  		"twoArgs":		 twoArgs,
	 774  		"typeOf":			typeOf,
	 775  		"valueString": valueString,
	 776  		"vfunc":			 vfunc,
	 777  		"zeroArgs":		zeroArgs,
	 778  	}
	 779  	for _, test := range execTests {
	 780  		var tmpl *Template
	 781  		var err error
	 782  		if template == nil {
	 783  			tmpl, err = New(test.name).Funcs(funcs).Parse(test.input)
	 784  		} else {
	 785  			tmpl, err = template.New(test.name).Funcs(funcs).Parse(test.input)
	 786  		}
	 787  		if err != nil {
	 788  			t.Errorf("%s: parse error: %s", test.name, err)
	 789  			continue
	 790  		}
	 791  		b.Reset()
	 792  		err = tmpl.Execute(b, test.data)
	 793  		switch {
	 794  		case !test.ok && err == nil:
	 795  			t.Errorf("%s: expected error; got none", test.name)
	 796  			continue
	 797  		case test.ok && err != nil:
	 798  			t.Errorf("%s: unexpected execute error: %s", test.name, err)
	 799  			continue
	 800  		case !test.ok && err != nil:
	 801  			// expected error, got one
	 802  			if *debug {
	 803  				fmt.Printf("%s: %s\n\t%s\n", test.name, test.input, err)
	 804  			}
	 805  		}
	 806  		result := b.String()
	 807  		if result != test.output {
	 808  			t.Errorf("%s: expected\n\t%q\ngot\n\t%q", test.name, test.output, result)
	 809  		}
	 810  	}
	 811  }
	 812  
	 813  func TestExecute(t *testing.T) {
	 814  	testExecute(execTests, nil, t)
	 815  }
	 816  
	 817  var delimPairs = []string{
	 818  	"", "", // default
	 819  	"{{", "}}", // same as default
	 820  	"<<", ">>", // distinct
	 821  	"|", "|", // same
	 822  	"(日)", "(本)", // peculiar
	 823  }
	 824  
	 825  func TestDelims(t *testing.T) {
	 826  	const hello = "Hello, world"
	 827  	var value = struct{ Str string }{hello}
	 828  	for i := 0; i < len(delimPairs); i += 2 {
	 829  		text := ".Str"
	 830  		left := delimPairs[i+0]
	 831  		trueLeft := left
	 832  		right := delimPairs[i+1]
	 833  		trueRight := right
	 834  		if left == "" { // default case
	 835  			trueLeft = "{{"
	 836  		}
	 837  		if right == "" { // default case
	 838  			trueRight = "}}"
	 839  		}
	 840  		text = trueLeft + text + trueRight
	 841  		// Now add a comment
	 842  		text += trueLeft + "/*comment*/" + trueRight
	 843  		// Now add	an action containing a string.
	 844  		text += trueLeft + `"` + trueLeft + `"` + trueRight
	 845  		// At this point text looks like `{{.Str}}{{/*comment*/}}{{"{{"}}`.
	 846  		tmpl, err := New("delims").Delims(left, right).Parse(text)
	 847  		if err != nil {
	 848  			t.Fatalf("delim %q text %q parse err %s", left, text, err)
	 849  		}
	 850  		var b = new(bytes.Buffer)
	 851  		err = tmpl.Execute(b, value)
	 852  		if err != nil {
	 853  			t.Fatalf("delim %q exec err %s", left, err)
	 854  		}
	 855  		if b.String() != hello+trueLeft {
	 856  			t.Errorf("expected %q got %q", hello+trueLeft, b.String())
	 857  		}
	 858  	}
	 859  }
	 860  
	 861  // Check that an error from a method flows back to the top.
	 862  func TestExecuteError(t *testing.T) {
	 863  	b := new(bytes.Buffer)
	 864  	tmpl := New("error")
	 865  	_, err := tmpl.Parse("{{.MyError true}}")
	 866  	if err != nil {
	 867  		t.Fatalf("parse error: %s", err)
	 868  	}
	 869  	err = tmpl.Execute(b, tVal)
	 870  	if err == nil {
	 871  		t.Errorf("expected error; got none")
	 872  	} else if !strings.Contains(err.Error(), myError.Error()) {
	 873  		if *debug {
	 874  			fmt.Printf("test execute error: %s\n", err)
	 875  		}
	 876  		t.Errorf("expected myError; got %s", err)
	 877  	}
	 878  }
	 879  
	 880  const execErrorText = `line 1
	 881  line 2
	 882  line 3
	 883  {{template "one" .}}
	 884  {{define "one"}}{{template "two" .}}{{end}}
	 885  {{define "two"}}{{template "three" .}}{{end}}
	 886  {{define "three"}}{{index "hi" $}}{{end}}`
	 887  
	 888  // Check that an error from a nested template contains all the relevant information.
	 889  func TestExecError(t *testing.T) {
	 890  	tmpl, err := New("top").Parse(execErrorText)
	 891  	if err != nil {
	 892  		t.Fatal("parse error:", err)
	 893  	}
	 894  	var b bytes.Buffer
	 895  	err = tmpl.Execute(&b, 5) // 5 is out of range indexing "hi"
	 896  	if err == nil {
	 897  		t.Fatal("expected error")
	 898  	}
	 899  	const want = `template: top:7:20: executing "three" at <index "hi" $>: error calling index: index out of range: 5`
	 900  	got := err.Error()
	 901  	if got != want {
	 902  		t.Errorf("expected\n%q\ngot\n%q", want, got)
	 903  	}
	 904  }
	 905  
	 906  type CustomError struct{}
	 907  
	 908  func (*CustomError) Error() string { return "heyo !" }
	 909  
	 910  // Check that a custom error can be returned.
	 911  func TestExecError_CustomError(t *testing.T) {
	 912  	failingFunc := func() (string, error) {
	 913  		return "", &CustomError{}
	 914  	}
	 915  	tmpl := Must(New("top").Funcs(FuncMap{
	 916  		"err": failingFunc,
	 917  	}).Parse("{{ err }}"))
	 918  
	 919  	var b bytes.Buffer
	 920  	err := tmpl.Execute(&b, nil)
	 921  
	 922  	var e *CustomError
	 923  	if !errors.As(err, &e) {
	 924  		t.Fatalf("expected custom error; got %s", err)
	 925  	}
	 926  }
	 927  
	 928  func TestJSEscaping(t *testing.T) {
	 929  	testCases := []struct {
	 930  		in, exp string
	 931  	}{
	 932  		{`a`, `a`},
	 933  		{`'foo`, `\'foo`},
	 934  		{`Go "jump" \`, `Go \"jump\" \\`},
	 935  		{`Yukihiro says "今日は世界"`, `Yukihiro says \"今日は世界\"`},
	 936  		{"unprintable \uFDFF", `unprintable \uFDFF`},
	 937  		{`<html>`, `\u003Chtml\u003E`},
	 938  		{`no = in attributes`, `no \u003D in attributes`},
	 939  		{`&#x27; does not become HTML entity`, `\u0026#x27; does not become HTML entity`},
	 940  	}
	 941  	for _, tc := range testCases {
	 942  		s := JSEscapeString(tc.in)
	 943  		if s != tc.exp {
	 944  			t.Errorf("JS escaping [%s] got [%s] want [%s]", tc.in, s, tc.exp)
	 945  		}
	 946  	}
	 947  }
	 948  
	 949  // A nice example: walk a binary tree.
	 950  
	 951  type Tree struct {
	 952  	Val				 int
	 953  	Left, Right *Tree
	 954  }
	 955  
	 956  // Use different delimiters to test Set.Delims.
	 957  // Also test the trimming of leading and trailing spaces.
	 958  const treeTemplate = `
	 959  	(- define "tree" -)
	 960  	[
	 961  		(- .Val -)
	 962  		(- with .Left -)
	 963  			(template "tree" . -)
	 964  		(- end -)
	 965  		(- with .Right -)
	 966  			(- template "tree" . -)
	 967  		(- end -)
	 968  	]
	 969  	(- end -)
	 970  `
	 971  
	 972  func TestTree(t *testing.T) {
	 973  	var tree = &Tree{
	 974  		1,
	 975  		&Tree{
	 976  			2, &Tree{
	 977  				3,
	 978  				&Tree{
	 979  					4, nil, nil,
	 980  				},
	 981  				nil,
	 982  			},
	 983  			&Tree{
	 984  				5,
	 985  				&Tree{
	 986  					6, nil, nil,
	 987  				},
	 988  				nil,
	 989  			},
	 990  		},
	 991  		&Tree{
	 992  			7,
	 993  			&Tree{
	 994  				8,
	 995  				&Tree{
	 996  					9, nil, nil,
	 997  				},
	 998  				nil,
	 999  			},
	1000  			&Tree{
	1001  				10,
	1002  				&Tree{
	1003  					11, nil, nil,
	1004  				},
	1005  				nil,
	1006  			},
	1007  		},
	1008  	}
	1009  	tmpl, err := New("root").Delims("(", ")").Parse(treeTemplate)
	1010  	if err != nil {
	1011  		t.Fatal("parse error:", err)
	1012  	}
	1013  	var b bytes.Buffer
	1014  	const expect = "[1[2[3[4]][5[6]]][7[8[9]][10[11]]]]"
	1015  	// First by looking up the template.
	1016  	err = tmpl.Lookup("tree").Execute(&b, tree)
	1017  	if err != nil {
	1018  		t.Fatal("exec error:", err)
	1019  	}
	1020  	result := b.String()
	1021  	if result != expect {
	1022  		t.Errorf("expected %q got %q", expect, result)
	1023  	}
	1024  	// Then direct to execution.
	1025  	b.Reset()
	1026  	err = tmpl.ExecuteTemplate(&b, "tree", tree)
	1027  	if err != nil {
	1028  		t.Fatal("exec error:", err)
	1029  	}
	1030  	result = b.String()
	1031  	if result != expect {
	1032  		t.Errorf("expected %q got %q", expect, result)
	1033  	}
	1034  }
	1035  
	1036  func TestExecuteOnNewTemplate(t *testing.T) {
	1037  	// This is issue 3872.
	1038  	New("Name").Templates()
	1039  	// This is issue 11379.
	1040  	new(Template).Templates()
	1041  	new(Template).Parse("")
	1042  	new(Template).New("abc").Parse("")
	1043  	new(Template).Execute(nil, nil)								// returns an error (but does not crash)
	1044  	new(Template).ExecuteTemplate(nil, "XXX", nil) // returns an error (but does not crash)
	1045  }
	1046  
	1047  const testTemplates = `{{define "one"}}one{{end}}{{define "two"}}two{{end}}`
	1048  
	1049  func TestMessageForExecuteEmpty(t *testing.T) {
	1050  	// Test a truly empty template.
	1051  	tmpl := New("empty")
	1052  	var b bytes.Buffer
	1053  	err := tmpl.Execute(&b, 0)
	1054  	if err == nil {
	1055  		t.Fatal("expected initial error")
	1056  	}
	1057  	got := err.Error()
	1058  	want := `template: empty: "empty" is an incomplete or empty template`
	1059  	if got != want {
	1060  		t.Errorf("expected error %s got %s", want, got)
	1061  	}
	1062  	// Add a non-empty template to check that the error is helpful.
	1063  	tests, err := New("").Parse(testTemplates)
	1064  	if err != nil {
	1065  		t.Fatal(err)
	1066  	}
	1067  	tmpl.AddParseTree("secondary", tests.Tree)
	1068  	err = tmpl.Execute(&b, 0)
	1069  	if err == nil {
	1070  		t.Fatal("expected second error")
	1071  	}
	1072  	got = err.Error()
	1073  	want = `template: empty: "empty" is an incomplete or empty template`
	1074  	if got != want {
	1075  		t.Errorf("expected error %s got %s", want, got)
	1076  	}
	1077  	// Make sure we can execute the secondary.
	1078  	err = tmpl.ExecuteTemplate(&b, "secondary", 0)
	1079  	if err != nil {
	1080  		t.Fatal(err)
	1081  	}
	1082  }
	1083  
	1084  func TestFinalForPrintf(t *testing.T) {
	1085  	tmpl, err := New("").Parse(`{{"x" | printf}}`)
	1086  	if err != nil {
	1087  		t.Fatal(err)
	1088  	}
	1089  	var b bytes.Buffer
	1090  	err = tmpl.Execute(&b, 0)
	1091  	if err != nil {
	1092  		t.Fatal(err)
	1093  	}
	1094  }
	1095  
	1096  type cmpTest struct {
	1097  	expr	string
	1098  	truth string
	1099  	ok		bool
	1100  }
	1101  
	1102  var cmpTests = []cmpTest{
	1103  	{"eq true true", "true", true},
	1104  	{"eq true false", "false", true},
	1105  	{"eq 1+2i 1+2i", "true", true},
	1106  	{"eq 1+2i 1+3i", "false", true},
	1107  	{"eq 1.5 1.5", "true", true},
	1108  	{"eq 1.5 2.5", "false", true},
	1109  	{"eq 1 1", "true", true},
	1110  	{"eq 1 2", "false", true},
	1111  	{"eq `xy` `xy`", "true", true},
	1112  	{"eq `xy` `xyz`", "false", true},
	1113  	{"eq .Uthree .Uthree", "true", true},
	1114  	{"eq .Uthree .Ufour", "false", true},
	1115  	{"eq 3 4 5 6 3", "true", true},
	1116  	{"eq 3 4 5 6 7", "false", true},
	1117  	{"ne true true", "false", true},
	1118  	{"ne true false", "true", true},
	1119  	{"ne 1+2i 1+2i", "false", true},
	1120  	{"ne 1+2i 1+3i", "true", true},
	1121  	{"ne 1.5 1.5", "false", true},
	1122  	{"ne 1.5 2.5", "true", true},
	1123  	{"ne 1 1", "false", true},
	1124  	{"ne 1 2", "true", true},
	1125  	{"ne `xy` `xy`", "false", true},
	1126  	{"ne `xy` `xyz`", "true", true},
	1127  	{"ne .Uthree .Uthree", "false", true},
	1128  	{"ne .Uthree .Ufour", "true", true},
	1129  	{"lt 1.5 1.5", "false", true},
	1130  	{"lt 1.5 2.5", "true", true},
	1131  	{"lt 1 1", "false", true},
	1132  	{"lt 1 2", "true", true},
	1133  	{"lt `xy` `xy`", "false", true},
	1134  	{"lt `xy` `xyz`", "true", true},
	1135  	{"lt .Uthree .Uthree", "false", true},
	1136  	{"lt .Uthree .Ufour", "true", true},
	1137  	{"le 1.5 1.5", "true", true},
	1138  	{"le 1.5 2.5", "true", true},
	1139  	{"le 2.5 1.5", "false", true},
	1140  	{"le 1 1", "true", true},
	1141  	{"le 1 2", "true", true},
	1142  	{"le 2 1", "false", true},
	1143  	{"le `xy` `xy`", "true", true},
	1144  	{"le `xy` `xyz`", "true", true},
	1145  	{"le `xyz` `xy`", "false", true},
	1146  	{"le .Uthree .Uthree", "true", true},
	1147  	{"le .Uthree .Ufour", "true", true},
	1148  	{"le .Ufour .Uthree", "false", true},
	1149  	{"gt 1.5 1.5", "false", true},
	1150  	{"gt 1.5 2.5", "false", true},
	1151  	{"gt 1 1", "false", true},
	1152  	{"gt 2 1", "true", true},
	1153  	{"gt 1 2", "false", true},
	1154  	{"gt `xy` `xy`", "false", true},
	1155  	{"gt `xy` `xyz`", "false", true},
	1156  	{"gt .Uthree .Uthree", "false", true},
	1157  	{"gt .Uthree .Ufour", "false", true},
	1158  	{"gt .Ufour .Uthree", "true", true},
	1159  	{"ge 1.5 1.5", "true", true},
	1160  	{"ge 1.5 2.5", "false", true},
	1161  	{"ge 2.5 1.5", "true", true},
	1162  	{"ge 1 1", "true", true},
	1163  	{"ge 1 2", "false", true},
	1164  	{"ge 2 1", "true", true},
	1165  	{"ge `xy` `xy`", "true", true},
	1166  	{"ge `xy` `xyz`", "false", true},
	1167  	{"ge `xyz` `xy`", "true", true},
	1168  	{"ge .Uthree .Uthree", "true", true},
	1169  	{"ge .Uthree .Ufour", "false", true},
	1170  	{"ge .Ufour .Uthree", "true", true},
	1171  	// Mixing signed and unsigned integers.
	1172  	{"eq .Uthree .Three", "true", true},
	1173  	{"eq .Three .Uthree", "true", true},
	1174  	{"le .Uthree .Three", "true", true},
	1175  	{"le .Three .Uthree", "true", true},
	1176  	{"ge .Uthree .Three", "true", true},
	1177  	{"ge .Three .Uthree", "true", true},
	1178  	{"lt .Uthree .Three", "false", true},
	1179  	{"lt .Three .Uthree", "false", true},
	1180  	{"gt .Uthree .Three", "false", true},
	1181  	{"gt .Three .Uthree", "false", true},
	1182  	{"eq .Ufour .Three", "false", true},
	1183  	{"lt .Ufour .Three", "false", true},
	1184  	{"gt .Ufour .Three", "true", true},
	1185  	{"eq .NegOne .Uthree", "false", true},
	1186  	{"eq .Uthree .NegOne", "false", true},
	1187  	{"ne .NegOne .Uthree", "true", true},
	1188  	{"ne .Uthree .NegOne", "true", true},
	1189  	{"lt .NegOne .Uthree", "true", true},
	1190  	{"lt .Uthree .NegOne", "false", true},
	1191  	{"le .NegOne .Uthree", "true", true},
	1192  	{"le .Uthree .NegOne", "false", true},
	1193  	{"gt .NegOne .Uthree", "false", true},
	1194  	{"gt .Uthree .NegOne", "true", true},
	1195  	{"ge .NegOne .Uthree", "false", true},
	1196  	{"ge .Uthree .NegOne", "true", true},
	1197  	{"eq (index `x` 0) 'x'", "true", true}, // The example that triggered this rule.
	1198  	{"eq (index `x` 0) 'y'", "false", true},
	1199  	{"eq .V1 .V2", "true", true},
	1200  	{"eq .Ptr .Ptr", "true", true},
	1201  	{"eq .Ptr .NilPtr", "false", true},
	1202  	{"eq .NilPtr .NilPtr", "true", true},
	1203  	{"eq .Iface1 .Iface1", "true", true},
	1204  	{"eq .Iface1 .NilIface", "false", true},
	1205  	{"eq .NilIface .NilIface", "true", true},
	1206  	{"eq .NilIface .Iface1", "false", true},
	1207  	{"eq .NilIface 0", "false", true},
	1208  	{"eq 0 .NilIface", "false", true},
	1209  	// Errors
	1210  	{"eq `xy` 1", "", false},			 // Different types.
	1211  	{"eq 2 2.0", "", false},				// Different types.
	1212  	{"lt true true", "", false},		// Unordered types.
	1213  	{"lt 1+0i 1+0i", "", false},		// Unordered types.
	1214  	{"eq .Ptr 1", "", false},			 // Incompatible types.
	1215  	{"eq .Ptr .NegOne", "", false}, // Incompatible types.
	1216  	{"eq .Map .Map", "", false},		// Uncomparable types.
	1217  	{"eq .Map .V1", "", false},		 // Uncomparable types.
	1218  }
	1219  
	1220  func TestComparison(t *testing.T) {
	1221  	b := new(bytes.Buffer)
	1222  	var cmpStruct = struct {
	1223  		Uthree, Ufour		uint
	1224  		NegOne, Three		int
	1225  		Ptr, NilPtr			*int
	1226  		Map							map[int]int
	1227  		V1, V2					 V
	1228  		Iface1, NilIface fmt.Stringer
	1229  	}{
	1230  		Uthree: 3,
	1231  		Ufour:	4,
	1232  		NegOne: -1,
	1233  		Three:	3,
	1234  		Ptr:		new(int),
	1235  		Iface1: b,
	1236  	}
	1237  	for _, test := range cmpTests {
	1238  		text := fmt.Sprintf("{{if %s}}true{{else}}false{{end}}", test.expr)
	1239  		tmpl, err := New("empty").Parse(text)
	1240  		if err != nil {
	1241  			t.Fatalf("%q: %s", test.expr, err)
	1242  		}
	1243  		b.Reset()
	1244  		err = tmpl.Execute(b, &cmpStruct)
	1245  		if test.ok && err != nil {
	1246  			t.Errorf("%s errored incorrectly: %s", test.expr, err)
	1247  			continue
	1248  		}
	1249  		if !test.ok && err == nil {
	1250  			t.Errorf("%s did not error", test.expr)
	1251  			continue
	1252  		}
	1253  		if b.String() != test.truth {
	1254  			t.Errorf("%s: want %s; got %s", test.expr, test.truth, b.String())
	1255  		}
	1256  	}
	1257  }
	1258  
	1259  func TestMissingMapKey(t *testing.T) {
	1260  	data := map[string]int{
	1261  		"x": 99,
	1262  	}
	1263  	tmpl, err := New("t1").Parse("{{.x}} {{.y}}")
	1264  	if err != nil {
	1265  		t.Fatal(err)
	1266  	}
	1267  	var b bytes.Buffer
	1268  	// By default, just get "<no value>"
	1269  	err = tmpl.Execute(&b, data)
	1270  	if err != nil {
	1271  		t.Fatal(err)
	1272  	}
	1273  	want := "99 <no value>"
	1274  	got := b.String()
	1275  	if got != want {
	1276  		t.Errorf("got %q; expected %q", got, want)
	1277  	}
	1278  	// Same if we set the option explicitly to the default.
	1279  	tmpl.Option("missingkey=default")
	1280  	b.Reset()
	1281  	err = tmpl.Execute(&b, data)
	1282  	if err != nil {
	1283  		t.Fatal("default:", err)
	1284  	}
	1285  	want = "99 <no value>"
	1286  	got = b.String()
	1287  	if got != want {
	1288  		t.Errorf("got %q; expected %q", got, want)
	1289  	}
	1290  	// Next we ask for a zero value
	1291  	tmpl.Option("missingkey=zero")
	1292  	b.Reset()
	1293  	err = tmpl.Execute(&b, data)
	1294  	if err != nil {
	1295  		t.Fatal("zero:", err)
	1296  	}
	1297  	want = "99 0"
	1298  	got = b.String()
	1299  	if got != want {
	1300  		t.Errorf("got %q; expected %q", got, want)
	1301  	}
	1302  	// Now we ask for an error.
	1303  	tmpl.Option("missingkey=error")
	1304  	err = tmpl.Execute(&b, data)
	1305  	if err == nil {
	1306  		t.Errorf("expected error; got none")
	1307  	}
	1308  	// same Option, but now a nil interface: ask for an error
	1309  	err = tmpl.Execute(&b, nil)
	1310  	t.Log(err)
	1311  	if err == nil {
	1312  		t.Errorf("expected error for nil-interface; got none")
	1313  	}
	1314  }
	1315  
	1316  // Test that the error message for multiline unterminated string
	1317  // refers to the line number of the opening quote.
	1318  func TestUnterminatedStringError(t *testing.T) {
	1319  	_, err := New("X").Parse("hello\n\n{{`unterminated\n\n\n\n}}\n some more\n\n")
	1320  	if err == nil {
	1321  		t.Fatal("expected error")
	1322  	}
	1323  	str := err.Error()
	1324  	if !strings.Contains(str, "X:3: unterminated raw quoted string") {
	1325  		t.Fatalf("unexpected error: %s", str)
	1326  	}
	1327  }
	1328  
	1329  const alwaysErrorText = "always be failing"
	1330  
	1331  var alwaysError = errors.New(alwaysErrorText)
	1332  
	1333  type ErrorWriter int
	1334  
	1335  func (e ErrorWriter) Write(p []byte) (int, error) {
	1336  	return 0, alwaysError
	1337  }
	1338  
	1339  func TestExecuteGivesExecError(t *testing.T) {
	1340  	// First, a non-execution error shouldn't be an ExecError.
	1341  	tmpl, err := New("X").Parse("hello")
	1342  	if err != nil {
	1343  		t.Fatal(err)
	1344  	}
	1345  	err = tmpl.Execute(ErrorWriter(0), 0)
	1346  	if err == nil {
	1347  		t.Fatal("expected error; got none")
	1348  	}
	1349  	if err.Error() != alwaysErrorText {
	1350  		t.Errorf("expected %q error; got %q", alwaysErrorText, err)
	1351  	}
	1352  	// This one should be an ExecError.
	1353  	tmpl, err = New("X").Parse("hello, {{.X.Y}}")
	1354  	if err != nil {
	1355  		t.Fatal(err)
	1356  	}
	1357  	err = tmpl.Execute(io.Discard, 0)
	1358  	if err == nil {
	1359  		t.Fatal("expected error; got none")
	1360  	}
	1361  	eerr, ok := err.(ExecError)
	1362  	if !ok {
	1363  		t.Fatalf("did not expect ExecError %s", eerr)
	1364  	}
	1365  	expect := "field X in type int"
	1366  	if !strings.Contains(err.Error(), expect) {
	1367  		t.Errorf("expected %q; got %q", expect, err)
	1368  	}
	1369  }
	1370  
	1371  func funcNameTestFunc() int {
	1372  	return 0
	1373  }
	1374  
	1375  func TestGoodFuncNames(t *testing.T) {
	1376  	names := []string{
	1377  		"_",
	1378  		"a",
	1379  		"a1",
	1380  		"a1",
	1381  		"Ӵ",
	1382  	}
	1383  	for _, name := range names {
	1384  		tmpl := New("X").Funcs(
	1385  			FuncMap{
	1386  				name: funcNameTestFunc,
	1387  			},
	1388  		)
	1389  		if tmpl == nil {
	1390  			t.Fatalf("nil result for %q", name)
	1391  		}
	1392  	}
	1393  }
	1394  
	1395  func TestBadFuncNames(t *testing.T) {
	1396  	names := []string{
	1397  		"",
	1398  		"2",
	1399  		"a-b",
	1400  	}
	1401  	for _, name := range names {
	1402  		testBadFuncName(name, t)
	1403  	}
	1404  }
	1405  
	1406  func testBadFuncName(name string, t *testing.T) {
	1407  	t.Helper()
	1408  	defer func() {
	1409  		recover()
	1410  	}()
	1411  	New("X").Funcs(
	1412  		FuncMap{
	1413  			name: funcNameTestFunc,
	1414  		},
	1415  	)
	1416  	// If we get here, the name did not cause a panic, which is how Funcs
	1417  	// reports an error.
	1418  	t.Errorf("%q succeeded incorrectly as function name", name)
	1419  }
	1420  
	1421  func TestBlock(t *testing.T) {
	1422  	const (
	1423  		input	 = `a({{block "inner" .}}bar({{.}})baz{{end}})b`
	1424  		want		= `a(bar(hello)baz)b`
	1425  		overlay = `{{define "inner"}}foo({{.}})bar{{end}}`
	1426  		want2	 = `a(foo(goodbye)bar)b`
	1427  	)
	1428  	tmpl, err := New("outer").Parse(input)
	1429  	if err != nil {
	1430  		t.Fatal(err)
	1431  	}
	1432  	tmpl2, err := Must(tmpl.Clone()).Parse(overlay)
	1433  	if err != nil {
	1434  		t.Fatal(err)
	1435  	}
	1436  
	1437  	var buf bytes.Buffer
	1438  	if err := tmpl.Execute(&buf, "hello"); err != nil {
	1439  		t.Fatal(err)
	1440  	}
	1441  	if got := buf.String(); got != want {
	1442  		t.Errorf("got %q, want %q", got, want)
	1443  	}
	1444  
	1445  	buf.Reset()
	1446  	if err := tmpl2.Execute(&buf, "goodbye"); err != nil {
	1447  		t.Fatal(err)
	1448  	}
	1449  	if got := buf.String(); got != want2 {
	1450  		t.Errorf("got %q, want %q", got, want2)
	1451  	}
	1452  }
	1453  
	1454  func TestEvalFieldErrors(t *testing.T) {
	1455  	tests := []struct {
	1456  		name, src string
	1457  		value		 interface{}
	1458  		want			string
	1459  	}{
	1460  		{
	1461  			// Check that calling an invalid field on nil pointer
	1462  			// prints a field error instead of a distracting nil
	1463  			// pointer error. https://golang.org/issue/15125
	1464  			"MissingFieldOnNil",
	1465  			"{{.MissingField}}",
	1466  			(*T)(nil),
	1467  			"can't evaluate field MissingField in type *template.T",
	1468  		},
	1469  		{
	1470  			"MissingFieldOnNonNil",
	1471  			"{{.MissingField}}",
	1472  			&T{},
	1473  			"can't evaluate field MissingField in type *template.T",
	1474  		},
	1475  		{
	1476  			"ExistingFieldOnNil",
	1477  			"{{.X}}",
	1478  			(*T)(nil),
	1479  			"nil pointer evaluating *template.T.X",
	1480  		},
	1481  		{
	1482  			"MissingKeyOnNilMap",
	1483  			"{{.MissingKey}}",
	1484  			(*map[string]string)(nil),
	1485  			"nil pointer evaluating *map[string]string.MissingKey",
	1486  		},
	1487  		{
	1488  			"MissingKeyOnNilMapPtr",
	1489  			"{{.MissingKey}}",
	1490  			(*map[string]string)(nil),
	1491  			"nil pointer evaluating *map[string]string.MissingKey",
	1492  		},
	1493  		{
	1494  			"MissingKeyOnMapPtrToNil",
	1495  			"{{.MissingKey}}",
	1496  			&map[string]string{},
	1497  			"<nil>",
	1498  		},
	1499  	}
	1500  	for _, tc := range tests {
	1501  		t.Run(tc.name, func(t *testing.T) {
	1502  			tmpl := Must(New("tmpl").Parse(tc.src))
	1503  			err := tmpl.Execute(io.Discard, tc.value)
	1504  			got := "<nil>"
	1505  			if err != nil {
	1506  				got = err.Error()
	1507  			}
	1508  			if !strings.HasSuffix(got, tc.want) {
	1509  				t.Fatalf("got error %q, want %q", got, tc.want)
	1510  			}
	1511  		})
	1512  	}
	1513  }
	1514  
	1515  func TestMaxExecDepth(t *testing.T) {
	1516  	if testing.Short() {
	1517  		t.Skip("skipping in -short mode")
	1518  	}
	1519  	tmpl := Must(New("tmpl").Parse(`{{template "tmpl" .}}`))
	1520  	err := tmpl.Execute(io.Discard, nil)
	1521  	got := "<nil>"
	1522  	if err != nil {
	1523  		got = err.Error()
	1524  	}
	1525  	const want = "exceeded maximum template depth"
	1526  	if !strings.Contains(got, want) {
	1527  		t.Errorf("got error %q; want %q", got, want)
	1528  	}
	1529  }
	1530  
	1531  func TestAddrOfIndex(t *testing.T) {
	1532  	// golang.org/issue/14916.
	1533  	// Before index worked on reflect.Values, the .String could not be
	1534  	// found on the (incorrectly unaddressable) V value,
	1535  	// in contrast to range, which worked fine.
	1536  	// Also testing that passing a reflect.Value to tmpl.Execute works.
	1537  	texts := []string{
	1538  		`{{range .}}{{.String}}{{end}}`,
	1539  		`{{with index . 0}}{{.String}}{{end}}`,
	1540  	}
	1541  	for _, text := range texts {
	1542  		tmpl := Must(New("tmpl").Parse(text))
	1543  		var buf bytes.Buffer
	1544  		err := tmpl.Execute(&buf, reflect.ValueOf([]V{{1}}))
	1545  		if err != nil {
	1546  			t.Fatalf("%s: Execute: %v", text, err)
	1547  		}
	1548  		if buf.String() != "<1>" {
	1549  			t.Fatalf("%s: template output = %q, want %q", text, &buf, "<1>")
	1550  		}
	1551  	}
	1552  }
	1553  
	1554  func TestInterfaceValues(t *testing.T) {
	1555  	// golang.org/issue/17714.
	1556  	// Before index worked on reflect.Values, interface values
	1557  	// were always implicitly promoted to the underlying value,
	1558  	// except that nil interfaces were promoted to the zero reflect.Value.
	1559  	// Eliminating a round trip to interface{} and back to reflect.Value
	1560  	// eliminated this promotion, breaking these cases.
	1561  	tests := []struct {
	1562  		text string
	1563  		out	string
	1564  	}{
	1565  		{`{{index .Nil 1}}`, "ERROR: index of untyped nil"},
	1566  		{`{{index .Slice 2}}`, "2"},
	1567  		{`{{index .Slice .Two}}`, "2"},
	1568  		{`{{call .Nil 1}}`, "ERROR: call of nil"},
	1569  		{`{{call .PlusOne 1}}`, "2"},
	1570  		{`{{call .PlusOne .One}}`, "2"},
	1571  		{`{{and (index .Slice 0) true}}`, "0"},
	1572  		{`{{and .Zero true}}`, "0"},
	1573  		{`{{and (index .Slice 1) false}}`, "false"},
	1574  		{`{{and .One false}}`, "false"},
	1575  		{`{{or (index .Slice 0) false}}`, "false"},
	1576  		{`{{or .Zero false}}`, "false"},
	1577  		{`{{or (index .Slice 1) true}}`, "1"},
	1578  		{`{{or .One true}}`, "1"},
	1579  		{`{{not (index .Slice 0)}}`, "true"},
	1580  		{`{{not .Zero}}`, "true"},
	1581  		{`{{not (index .Slice 1)}}`, "false"},
	1582  		{`{{not .One}}`, "false"},
	1583  		{`{{eq (index .Slice 0) .Zero}}`, "true"},
	1584  		{`{{eq (index .Slice 1) .One}}`, "true"},
	1585  		{`{{ne (index .Slice 0) .Zero}}`, "false"},
	1586  		{`{{ne (index .Slice 1) .One}}`, "false"},
	1587  		{`{{ge (index .Slice 0) .One}}`, "false"},
	1588  		{`{{ge (index .Slice 1) .Zero}}`, "true"},
	1589  		{`{{gt (index .Slice 0) .One}}`, "false"},
	1590  		{`{{gt (index .Slice 1) .Zero}}`, "true"},
	1591  		{`{{le (index .Slice 0) .One}}`, "true"},
	1592  		{`{{le (index .Slice 1) .Zero}}`, "false"},
	1593  		{`{{lt (index .Slice 0) .One}}`, "true"},
	1594  		{`{{lt (index .Slice 1) .Zero}}`, "false"},
	1595  	}
	1596  
	1597  	for _, tt := range tests {
	1598  		tmpl := Must(New("tmpl").Parse(tt.text))
	1599  		var buf bytes.Buffer
	1600  		err := tmpl.Execute(&buf, map[string]interface{}{
	1601  			"PlusOne": func(n int) int {
	1602  				return n + 1
	1603  			},
	1604  			"Slice": []int{0, 1, 2, 3},
	1605  			"One":	 1,
	1606  			"Two":	 2,
	1607  			"Nil":	 nil,
	1608  			"Zero":	0,
	1609  		})
	1610  		if strings.HasPrefix(tt.out, "ERROR:") {
	1611  			e := strings.TrimSpace(strings.TrimPrefix(tt.out, "ERROR:"))
	1612  			if err == nil || !strings.Contains(err.Error(), e) {
	1613  				t.Errorf("%s: Execute: %v, want error %q", tt.text, err, e)
	1614  			}
	1615  			continue
	1616  		}
	1617  		if err != nil {
	1618  			t.Errorf("%s: Execute: %v", tt.text, err)
	1619  			continue
	1620  		}
	1621  		if buf.String() != tt.out {
	1622  			t.Errorf("%s: template output = %q, want %q", tt.text, &buf, tt.out)
	1623  		}
	1624  	}
	1625  }
	1626  
	1627  // Check that panics during calls are recovered and returned as errors.
	1628  func TestExecutePanicDuringCall(t *testing.T) {
	1629  	funcs := map[string]interface{}{
	1630  		"doPanic": func() string {
	1631  			panic("custom panic string")
	1632  		},
	1633  	}
	1634  	tests := []struct {
	1635  		name		string
	1636  		input	 string
	1637  		data		interface{}
	1638  		wantErr string
	1639  	}{
	1640  		{
	1641  			"direct func call panics",
	1642  			"{{doPanic}}", (*T)(nil),
	1643  			`template: t:1:2: executing "t" at <doPanic>: error calling doPanic: custom panic string`,
	1644  		},
	1645  		{
	1646  			"indirect func call panics",
	1647  			"{{call doPanic}}", (*T)(nil),
	1648  			`template: t:1:7: executing "t" at <doPanic>: error calling doPanic: custom panic string`,
	1649  		},
	1650  		{
	1651  			"direct method call panics",
	1652  			"{{.GetU}}", (*T)(nil),
	1653  			`template: t:1:2: executing "t" at <.GetU>: error calling GetU: runtime error: invalid memory address or nil pointer dereference`,
	1654  		},
	1655  		{
	1656  			"indirect method call panics",
	1657  			"{{call .GetU}}", (*T)(nil),
	1658  			`template: t:1:7: executing "t" at <.GetU>: error calling GetU: runtime error: invalid memory address or nil pointer dereference`,
	1659  		},
	1660  		{
	1661  			"func field call panics",
	1662  			"{{call .PanicFunc}}", tVal,
	1663  			`template: t:1:2: executing "t" at <call .PanicFunc>: error calling call: test panic`,
	1664  		},
	1665  		{
	1666  			"method call on nil interface",
	1667  			"{{.NonEmptyInterfaceNil.Method0}}", tVal,
	1668  			`template: t:1:23: executing "t" at <.NonEmptyInterfaceNil.Method0>: nil pointer evaluating template.I.Method0`,
	1669  		},
	1670  	}
	1671  	for _, tc := range tests {
	1672  		b := new(bytes.Buffer)
	1673  		tmpl, err := New("t").Funcs(funcs).Parse(tc.input)
	1674  		if err != nil {
	1675  			t.Fatalf("parse error: %s", err)
	1676  		}
	1677  		err = tmpl.Execute(b, tc.data)
	1678  		if err == nil {
	1679  			t.Errorf("%s: expected error; got none", tc.name)
	1680  		} else if !strings.Contains(err.Error(), tc.wantErr) {
	1681  			if *debug {
	1682  				fmt.Printf("%s: test execute error: %s\n", tc.name, err)
	1683  			}
	1684  			t.Errorf("%s: expected error:\n%s\ngot:\n%s", tc.name, tc.wantErr, err)
	1685  		}
	1686  	}
	1687  }
	1688  
	1689  // Issue 31810. Check that a parenthesized first argument behaves properly.
	1690  func TestIssue31810(t *testing.T) {
	1691  	// A simple value with no arguments is fine.
	1692  	var b bytes.Buffer
	1693  	const text = "{{ (.)	}}"
	1694  	tmpl, err := New("").Parse(text)
	1695  	if err != nil {
	1696  		t.Error(err)
	1697  	}
	1698  	err = tmpl.Execute(&b, "result")
	1699  	if err != nil {
	1700  		t.Error(err)
	1701  	}
	1702  	if b.String() != "result" {
	1703  		t.Errorf("%s got %q, expected %q", text, b.String(), "result")
	1704  	}
	1705  
	1706  	// Even a plain function fails - need to use call.
	1707  	f := func() string { return "result" }
	1708  	b.Reset()
	1709  	err = tmpl.Execute(&b, f)
	1710  	if err == nil {
	1711  		t.Error("expected error with no call, got none")
	1712  	}
	1713  
	1714  	// Works if the function is explicitly called.
	1715  	const textCall = "{{ (call .)	}}"
	1716  	tmpl, err = New("").Parse(textCall)
	1717  	b.Reset()
	1718  	err = tmpl.Execute(&b, f)
	1719  	if err != nil {
	1720  		t.Error(err)
	1721  	}
	1722  	if b.String() != "result" {
	1723  		t.Errorf("%s got %q, expected %q", textCall, b.String(), "result")
	1724  	}
	1725  }
	1726  
	1727  // Issue 43065, range over send only channel
	1728  func TestIssue43065(t *testing.T) {
	1729  	var b bytes.Buffer
	1730  	tmp := Must(New("").Parse(`{{range .}}{{end}}`))
	1731  	ch := make(chan<- int)
	1732  	err := tmp.Execute(&b, ch)
	1733  	if err == nil {
	1734  		t.Error("expected err got nil")
	1735  	} else if !strings.Contains(err.Error(), "range over send-only channel") {
	1736  		t.Errorf("%s", err)
	1737  	}
	1738  }
	1739  
	1740  // Issue 39807: data race in html/template & text/template
	1741  func TestIssue39807(t *testing.T) {
	1742  	var wg sync.WaitGroup
	1743  
	1744  	tplFoo, err := New("foo").Parse(`{{ template "bar" . }}`)
	1745  	if err != nil {
	1746  		t.Error(err)
	1747  	}
	1748  
	1749  	tplBar, err := New("bar").Parse("bar")
	1750  	if err != nil {
	1751  		t.Error(err)
	1752  	}
	1753  
	1754  	gofuncs := 10
	1755  	numTemplates := 10
	1756  
	1757  	for i := 1; i <= gofuncs; i++ {
	1758  		wg.Add(1)
	1759  		go func() {
	1760  			defer wg.Done()
	1761  			for j := 0; j < numTemplates; j++ {
	1762  				_, err := tplFoo.AddParseTree(tplBar.Name(), tplBar.Tree)
	1763  				if err != nil {
	1764  					t.Error(err)
	1765  				}
	1766  				err = tplFoo.Execute(io.Discard, nil)
	1767  				if err != nil {
	1768  					t.Error(err)
	1769  				}
	1770  			}
	1771  		}()
	1772  	}
	1773  
	1774  	wg.Wait()
	1775  }
	1776  

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