tpl/time: Handle nil values in time.AsTime

Closes #8865

tpl/time/time.go

@@ -19,6 +19,8 @@ import (
 	"time"
 	_time "time"
 
+	"github.com/gohugoio/hugo/common/hreflect"
+
 	"github.com/gohugoio/hugo/common/htime"
 
 	"github.com/gohugoio/locales"
@@ -43,6 +45,9 @@ type Namespace struct {
 // AsTime converts the textual representation of the datetime string into
 // a time.Time interface.
 func (ns *Namespace) AsTime(v interface{}, args ...interface{}) (interface{}, error) {
+	if !hreflect.IsTruthful(v) {
+		return time.Time{}, nil
+	}
 	loc := ns.location
 	if len(args) > 0 {
 		locStr, err := cast.ToStringE(args[0])

tpl/time/time_test.go

@@ -29,7 +29,7 @@ func TestTimeLocation(t *testing.T) {
 
 	for i, test := range []struct {
 		name     string
-		value    string
+		value    interface{}
 		location interface{}
 		expect   interface{}
 	}{
@@ -39,6 +39,9 @@ func TestTimeLocation(t *testing.T) {
 		{"New York EST", "2020-01-20", "America/New_York", "2020-01-20 00:00:00 -0500 EST"},
 		{"Empty location, time", "2020-10-20 20:33:59", "", "2020-10-20 20:33:59 +0000 UTC"},
 		{"New York, time", "2020-10-20 20:33:59", "America/New_York", "2020-10-20 20:33:59 -0400 EDT"},
+		{"Nil value", nil, "", "0001-01-01 00:00:00 +0000"},
+		{"Empty value", "", "", "0001-01-01 00:00:00 +0000"},
+
 		// The following have an explicit offset specified. In this case, it overrides timezone
 		{"Offset minus 0700, empty location", "2020-09-23T20:33:44-0700", "", "2020-09-23 20:33:44 -0700 -0700"},
 		{"Offset plus 0200, empty location", "2020-09-23T20:33:44+0200", "", "2020-09-23 20:33:44 +0200 +0200"},