[release-branch.r60] template: indirect or dereference function arguments if necessary to match the type of the formal.
««« CL 4967056 / a163a464ef59
template: indirect or dereference function arguments if necessary to match the type of the formal.
Fixes #2235
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/4967056
»»»
R=dsymonds
CC=golang-dev
https://golang.org/cl/4992043
diff --git a/src/pkg/template/exec.go b/src/pkg/template/exec.go
index dbe6541..f1590b3 100644
--- a/src/pkg/template/exec.go
+++ b/src/pkg/template/exec.go
@@ -506,7 +506,18 @@
s.errorf("invalid value; expected %s", typ)
}
if !value.Type().AssignableTo(typ) {
- s.errorf("wrong type for value; expected %s; got %s", typ, value.Type())
+ // Does one dereference or indirection work? We could do more, as we
+ // do with method receivers, but that gets messy and method receivers
+ // are much more constrained, so it makes more sense there than here.
+ // Besides, one is almost always all you need.
+ switch {
+ case value.Kind() == reflect.Ptr && value.Elem().Type().AssignableTo(typ):
+ value = value.Elem()
+ case reflect.PtrTo(value.Type()).AssignableTo(typ) && value.CanAddr():
+ value = value.Addr()
+ default:
+ s.errorf("wrong type for value; expected %s; got %s", typ, value.Type())
+ }
}
return value
}
diff --git a/src/pkg/template/exec_test.go b/src/pkg/template/exec_test.go
index 7e07e8c..8e1894e 100644
--- a/src/pkg/template/exec_test.go
+++ b/src/pkg/template/exec_test.go
@@ -416,6 +416,11 @@
{"bug4", "{{if .Empty0}}non-nil{{else}}nil{{end}}", "nil", tVal, true},
// Stringer.
{"bug5", "{{.Str}}", "foozle", tVal, true},
+ // Args need to be indirected and dereferenced sometimes.
+ {"bug6a", "{{vfunc .V0 .V1}}", "vfunc", tVal, true},
+ {"bug6b", "{{vfunc .V0 .V0}}", "vfunc", tVal, true},
+ {"bug6c", "{{vfunc .V1 .V0}}", "vfunc", tVal, true},
+ {"bug6d", "{{vfunc .V1 .V1}}", "vfunc", tVal, true},
}
func zeroArgs() string {
@@ -441,12 +446,18 @@
return c
}
+// vfunc takes a *V and a V
+func vfunc(V, *V) string {
+ return "vfunc"
+}
+
func testExecute(execTests []execTest, set *Set, t *testing.T) {
b := new(bytes.Buffer)
funcs := FuncMap{
"count": count,
"oneArg": oneArg,
"typeOf": typeOf,
+ "vfunc": vfunc,
"zeroArgs": zeroArgs,
}
for _, test := range execTests {
