_minTime should use math.MinInt64, and test for it

Co-Authored-By: Abhinav Gupta <abg@uber.com>

field.go

@@ -33,7 +33,7 @@ import (
 type Field = zapcore.Field
 
 var (
-	_minTimeInt64 = time.Unix(0, 0)
+	_minTimeInt64 = time.Unix(0, math.MinInt64)
 	_maxTimeInt64 = time.Unix(0, math.MaxInt64)
 )
 

field_test.go

@@ -108,6 +108,7 @@ func TestFieldConstructors(t *testing.T) {
 		{"String", Field{Key: "k", Type: zapcore.StringType, String: "foo"}, String("k", "foo")},
 		{"Time", Field{Key: "k", Type: zapcore.TimeType, Integer: 0, Interface: time.UTC}, Time("k", time.Unix(0, 0).In(time.UTC))},
 		{"Time", Field{Key: "k", Type: zapcore.TimeType, Integer: 1000, Interface: time.UTC}, Time("k", time.Unix(0, 1000).In(time.UTC))},
+		{"Time", Field{Key: "k", Type: zapcore.TimeType, Integer: math.MintInt64, Interface: time.UTC}, Time("k", time.Unix(0, math.MinInt64).In(time.UTC))},
 		{"Time", Field{Key: "k", Type: zapcore.TimeType, Integer: math.MaxInt64, Interface: time.UTC}, Time("k", time.Unix(0, math.MaxInt64).In(time.UTC))},
 		{"Time", Field{Key: "k", Type: zapcore.TimeFullType, Interface: time.Time{}}, Time("k", time.Time{})},
 		{"Time", Field{Key: "k", Type: zapcore.TimeFullType, Interface: time.Unix(math.MaxInt64, 0)}, Time("k", time.Unix(math.MaxInt64, 0))},

zapcore/field_test.go

@@ -165,9 +165,13 @@ func TestFields(t *testing.T) {
 }
 
 func TestEquals(t *testing.T) {
-	timeOutOfRange := time.Unix(0, math.MaxInt64).Add(time.Nanosecond)
-	timeOutOfRangeNano := time.Unix(0, timeOutOfRange.UnixNano())
-	require.NotEqual(t, timeOutOfRange, timeOutOfRangeNano, "should be different as value is out of UnixNano range")
+	// Values outside the UnixNano range were encoded incorrectly (#737, #803).
+	timeOutOfRangeHigh := time.Unix(0, math.MaxInt64).Add(time.Nanosecond)
+	timeOutOfRangeLow := time.Unix(0, math.MinInt64).Add(-time.Nanosecond)
+	timeOutOfRangeHighNano := time.Unix(0, timeOutOfRangeHigh.UnixNano())
+	timeOutOfRangeLowNano := time.Unix(0, timeOutOfRangeLow.UnixNano())
+	require.NotEqual(t, timeOutOfRangeHigh, timeOutOfRangeHighNano, "should be different as value is >  UnixNano range")
+	require.NotEqual(t, timeOutOfRangeHigh, timeOutOfRangeHighNano, "should be different as value is <  UnixNano range")
 
 	tests := []struct {
 		a, b Field
@@ -204,9 +208,13 @@ func TestEquals(t *testing.T) {
 			want: false,
 		},
 		{
-			// Values outside the UnixNano range were encoded incorrectly (#737, #803).
-			a:    zap.Time("k", timeOutOfRange),
-			b:    zap.Time("k", timeOutOfRangeNano),
+			a:    zap.Time("k", timeOutOfRangeLow),
+			b:    zap.Time("k", timeOutOfRangeLowNano),
+			want: false,
+		},
+		{
+			a:    zap.Time("k", timeOutOfRangeHigh),
+			b:    zap.Time("k", timeOutOfRangeHighNano),
 			want: false,
 		},
 		{