text/template: undo reflect.Value wrapping for short-circuit and/or

For #31103

Change-Id: I9c0aa64f95f564de31a4c178e3930584d41316bb
Reviewed-on: https://go-review.googlesource.com/c/go/+/353610
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

src/text/template/exec.go

@@ -714,20 +714,27 @@ func (s *state) evalCall(dot, fun reflect.Value, isBuiltin bool, node parse.Node
 		s.errorf("can't call method/function %q with %d results", name, typ.NumOut())
 	}
 
+	unwrap := func(v reflect.Value) reflect.Value {
+		if v.Type() == reflectValueType {
+			v = v.Interface().(reflect.Value)
+		}
+		return v
+	}
+
 	// Special case for builtin and/or, which short-circuit.
 	if isBuiltin && (name == "and" || name == "or") {
 		argType := typ.In(0)
 		var v reflect.Value
 		for _, arg := range args {
 			v = s.evalArg(dot, argType, arg).Interface().(reflect.Value)
 			if truth(v) == (name == "or") {
-				return v
+				return unwrap(v)
 			}
 		}
 		if final != missingVal {
 			v = s.validateType(final, argType)
 		}
-		return v
+		return unwrap(v)
 	}
 
 	// Build the arg list.
@@ -767,10 +774,7 @@ func (s *state) evalCall(dot, fun reflect.Value, isBuiltin bool, node parse.Node
 		s.at(node)
 		s.errorf("error calling %s: %w", name, err)
 	}
-	if v.Type() == reflectValueType {
-		v = v.Interface().(reflect.Value)
-	}
-	return v
+	return unwrap(v)
 }
 
 // canBeNil reports whether an untyped nil can be assigned to the type. See reflect.Zero.

src/text/template/exec_test.go

@@ -491,6 +491,7 @@ var execTests = []execTest{
 	{"or pipe-false", "{{0 | or 0}}", "0", nil, true},
 	{"boolean if", "{{if and true 1 `hi`}}TRUE{{else}}FALSE{{end}}", "TRUE", tVal, true},
 	{"boolean if not", "{{if and true 1 `hi` | not}}TRUE{{else}}FALSE{{end}}", "FALSE", nil, true},
+	{"boolean if pipe", "{{if true | not | and 1}}TRUE{{else}}FALSE{{end}}", "FALSE", nil, true},
 
 	// Indexing.
 	{"slice[0]", "{{index .SI 0}}", "3", tVal, true},