text/template: exec should accept interface value as valid.
Currently, if you pass some data to a template as an interface (e.g. interface{})
and extract that value that value as a parameter for a function, it fails, saying
wrong type.
This is because it is only looking at the interface type, not the interface content.
This CL uses the underlying content as the parameter to the func.
Fixes #3642.
R=golang-dev, r, r
CC=golang-dev
https://golang.org/cl/6218052
diff --git a/src/pkg/text/template/exec.go b/src/pkg/text/template/exec.go
index 0c633e6..5fad5cc 100644
--- a/src/pkg/text/template/exec.go
+++ b/src/pkg/text/template/exec.go
@@ -520,6 +520,13 @@
}
}
if !value.Type().AssignableTo(typ) {
+ if value.Kind() == reflect.Interface && !value.IsNil() {
+ value = value.Elem()
+ if value.Type().AssignableTo(typ) {
+ return value
+ }
+ // fallthrough
+ }
// 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.
diff --git a/src/pkg/text/template/exec_test.go b/src/pkg/text/template/exec_test.go
index 8f6c67b..c8a3013 100644
--- a/src/pkg/text/template/exec_test.go
+++ b/src/pkg/text/template/exec_test.go
@@ -314,6 +314,7 @@
{".VariadicFuncInt", "{{call .VariadicFuncInt 33 `he` `llo`}}", "33=<he+llo>", tVal, true},
{"if .BinaryFunc call", "{{ if .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{end}}", "[1=2]", tVal, true},
{"if not .BinaryFunc call", "{{ if not .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{else}}No{{end}}", "No", tVal, true},
+ {"Interface Call", `{{stringer .S}}`, "foozle", map[string]interface{}{"S": bytes.NewBufferString("foozle")}, true},
// Erroneous function calls (check args).
{".BinaryFuncTooFew", "{{call .BinaryFunc `1`}}", "", tVal, false},
@@ -512,6 +513,10 @@
return "vfunc"
}
+func stringer(s fmt.Stringer) string {
+ return s.String()
+}
+
func testExecute(execTests []execTest, template *Template, t *testing.T) {
b := new(bytes.Buffer)
funcs := FuncMap{
@@ -521,6 +526,7 @@
"typeOf": typeOf,
"vfunc": vfunc,
"zeroArgs": zeroArgs,
+ "stringer": stringer,
}
for _, test := range execTests {
var tmpl *Template
