fix unnecessary rounding to float64 precision when JSON-marshaling du…

…rations (#453)
golang · Nov 13, 2017 · 1e59b77 · 1e59b77
1 parent 1643683
commit 1e59b77
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/jsonpb/jsonpb.go b/jsonpb/jsonpb.go
@@ -193,8 +193,7 @@ func (m *Marshaler) marshalObject(out *errWriter, v proto.Message, indent, typeU
 			// "Generated output always contains 3, 6, or 9 fractional digits,
 			//  depending on required precision."
 			s, ns := s.Field(0).Int(), s.Field(1).Int()
-			d := time.Duration(s)*time.Second + time.Duration(ns)*time.Nanosecond
-			x := fmt.Sprintf("%.9f", d.Seconds())
+			x := fmt.Sprintf("%d.%09d", s, ns)
 			x = strings.TrimSuffix(x, "000")
 			x = strings.TrimSuffix(x, "000")
 			out.write(`"`)

diff --git a/jsonpb/jsonpb_test.go b/jsonpb/jsonpb_test.go
@@ -407,6 +407,7 @@ var marshalingTests = []struct {
 	{"Any with WKT", marshaler, anyWellKnown, anyWellKnownJSON},
 	{"Any with WKT and indent", marshalerAllOptions, anyWellKnown, anyWellKnownPrettyJSON},
 	{"Duration", marshaler, &pb.KnownTypes{Dur: &durpb.Duration{Seconds: 3}}, `{"dur":"3.000s"}`},
+	{"Duration", marshaler, &pb.KnownTypes{Dur: &durpb.Duration{Seconds: 100000000, Nanos: 1}}, `{"dur":"100000000.000000001s"}`},
 	{"Struct", marshaler, &pb.KnownTypes{St: &stpb.Struct{
 		Fields: map[string]*stpb.Value{
 			"one": {Kind: &stpb.Value_StringValue{"loneliest number"}},