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exp/template: do not take address of interface variable to find methods.

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Also allow struct values as "with" targets.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/4809086
This commit is contained in:
Rob Pike 2011-08-09 17:07:29 +10:00
parent 7506ee7584
commit 1adda4601a
2 changed files with 21 additions and 12 deletions
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8
src/pkg/exp/template/exec.go
View File

@ -179,6 +179,8 @@ func isTrue(val reflect.Value) (truth, ok bool) {
truth = val.Float() != 0
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
truth = val.Uint() != 0
case reflect.Struct:
truth = true // Struct values are always true.
default:
return
}
@ -377,10 +379,10 @@ func (s *state) evalField(dot reflect.Value, fieldName string, args []parse.Node
}
typ := receiver.Type()
receiver, _ = indirect(receiver)
// Need to get to a value of type *T to guarantee we see all
// methods of T and *T.
// Unless it's an interface, need to get to a value of type *T to guarantee
// we see all methods of T and *T.
ptr := receiver
if ptr.CanAddr() {
if ptr.Kind() != reflect.Interface && ptr.CanAddr() {
ptr = ptr.Addr()
}
if method, ok := methodByName(ptr, fieldName); ok {

11
src/pkg/exp/template/exec_test.go
View File

@ -43,6 +43,8 @@ type T struct {
Empty2 interface{}
Empty3 interface{}
Empty4 interface{}
// Non-empty interface.
NonEmptyInterface I
// Pointers
PI *int
PSI *[]int
@ -73,6 +75,7 @@ var tVal = &T{
Empty2: "empty2",
Empty3: []int{7, 8},
Empty4: &U{"UinEmpty"},
NonEmptyInterface: new(T),
PI: newInt(23),
PSI: newIntSlice(21, 22, 23),
Tmpl: Must(New("x").Parse("test template")), // "x" is the value of .X
@ -358,8 +361,12 @@ var execTests = []execTest{
// Must separate dot and receiver; otherwise args are evaluated with dot set to variable.
{"bug0", "{{range .MSIone}}{{if $.Method1 .}}X{{end}}{{end}}", "X", tVal, true},
// Do not loop endlessly in indirect for non-empty interfaces.
// The bug appears with *interface only; this is supposed to fail (cannot invoke Method0), but terminate.
{"bug1", "{{.Method0}}", "", &iVal, false},
// The bug appears with *interface only; looped forever.
{"bug1", "{{.Method0}}", "M0", &iVal, true},
// Was taking address of interface field, so method set was empty.
{"bug2", "{{$.NonEmptyInterface.Method0}}", "M0", tVal, true},
// Struct values were not legal in with - mere oversight.
{"bug4", "{{with $}}{{.Method0}}{{end}}", "M0", tVal, true},
}
func zeroArgs() string {