use pointer receivers on the IsZero variants for DateTime

closes #106

go.mod

@@ -1,13 +1,20 @@
 module github.com/go-openapi/strfmt
 
 require (
-	github.com/asaskevich/govalidator v0.0.0-20200907205600-7a23bdc65eef
-	github.com/go-openapi/errors v0.20.2
-	github.com/google/uuid v1.1.1
-	github.com/mitchellh/mapstructure v1.3.3
+	github.com/asaskevich/govalidator v0.0.0-20230301143203-a9d515a09cc2
+	github.com/go-openapi/errors v0.20.3
+	github.com/google/uuid v1.3.0
+	github.com/mitchellh/mapstructure v1.5.0
 	github.com/oklog/ulid v1.3.1
-	github.com/stretchr/testify v1.8.0
-	go.mongodb.org/mongo-driver v1.10.0
+	github.com/stretchr/testify v1.8.2
+	go.mongodb.org/mongo-driver v1.11.3
 )
 
-go 1.13
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/stretchr/objx v0.5.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
+
+go 1.19

go.sum

@@ -1,24 +1,24 @@
-github.com/asaskevich/govalidator v0.0.0-20200907205600-7a23bdc65eef h1:46PFijGLmAjMPwCCCo7Jf0W6f9slllCkkv7vyc1yOSg=
-github.com/asaskevich/govalidator v0.0.0-20200907205600-7a23bdc65eef/go.mod h1:WaHUgvxTVq04UNunO+XhnAqY/wQc+bxr74GqbsZ/Jqw=
+github.com/asaskevich/govalidator v0.0.0-20230301143203-a9d515a09cc2 h1:DklsrG3dyBCFEj5IhUbnKptjxatkF07cF2ak3yi77so=
+github.com/asaskevich/govalidator v0.0.0-20230301143203-a9d515a09cc2/go.mod h1:WaHUgvxTVq04UNunO+XhnAqY/wQc+bxr74GqbsZ/Jqw=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/go-openapi/errors v0.20.2 h1:dxy7PGTqEh94zj2E3h1cUmQQWiM1+aeCROfAr02EmK8=
-github.com/go-openapi/errors v0.20.2/go.mod h1:cM//ZKUKyO06HSwqAelJ5NsEMMcpa6VpXe8DOa1Mi1M=
+github.com/go-openapi/errors v0.20.3 h1:rz6kiC84sqNQoqrtulzaL/VERgkoCyB6WdEkc2ujzUc=
+github.com/go-openapi/errors v0.20.3/go.mod h1:Z3FlZ4I8jEGxjUK+bugx3on2mIAk4txuAOhlsB1FSgk=
 github.com/golang/snappy v0.0.1/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
 github.com/google/go-cmp v0.5.2 h1:X2ev0eStA3AbceY54o37/0PQ/UWqKEiiO2dKL5OPaFM=
 github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/uuid v1.1.1 h1:Gkbcsh/GbpXz7lPftLA3P6TYMwjCLYm83jiFQZF/3gY=
-github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/klauspost/compress v1.13.6/go.mod h1:/3/Vjq9QcHkK5uEr5lBEmyoZ1iFhe47etQ6QUkpK6sk=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/mitchellh/mapstructure v1.3.3 h1:SzB1nHZ2Xi+17FP0zVQBHIZqvwRN9408fJO8h+eeNA8=
-github.com/mitchellh/mapstructure v1.3.3/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
+github.com/mitchellh/mapstructure v1.5.0 h1:jeMsZIYE/09sWLaz43PL7Gy6RuMjD2eJVyuac5Z2hdY=
+github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
 github.com/montanaflynn/stats v0.0.0-20171201202039-1bf9dbcd8cbe/go.mod h1:wL8QJuTMNUDYhXwkmfOly8iTdp5TEcJFWZD2D7SIkUc=
 github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs=
 github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
@@ -29,18 +29,20 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
+github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/tidwall/pretty v1.0.0 h1:HsD+QiTn7sK6flMKIvNmpqz1qrpP3Ps6jOKIKMooyg4=
 github.com/tidwall/pretty v1.0.0/go.mod h1:XNkn88O1ChpSDQmQeStsy+sBenx6DDtFZJxhVysOjyk=
 github.com/xdg-go/pbkdf2 v1.0.0/go.mod h1:jrpuAogTd400dnrH08LKmI/xc1MbPOebTwRqcT5RDeI=
 github.com/xdg-go/scram v1.1.1/go.mod h1:RaEWvsqvNKKvBPvcKeFjrG2cJqOkHTiyTpzz23ni57g=
 github.com/xdg-go/stringprep v1.0.3/go.mod h1:W3f5j4i+9rC0kuIEJL0ky1VpHXQU3ocBgklLGvcBnW8=
 github.com/youmark/pkcs8 v0.0.0-20181117223130-1be2e3e5546d/go.mod h1:rHwXgn7JulP+udvsHwJoVG1YGAP6VLg4y9I5dyZdqmA=
-go.mongodb.org/mongo-driver v1.10.0 h1:UtV6N5k14upNp4LTduX0QCufG124fSu25Wz9tu94GLg=
-go.mongodb.org/mongo-driver v1.10.0/go.mod h1:wsihk0Kdgv8Kqu1Anit4sfK+22vSFbUrAVEYRhCXrA8=
+go.mongodb.org/mongo-driver v1.11.3 h1:Ql6K6qYHEzB6xvu4+AU0BoRoqf9vFPcc4o7MUIdPW8Y=
+go.mongodb.org/mongo-driver v1.11.3/go.mod h1:PTSz5yu21bkT/wXpkS7WR5f0ddqw5quethTUn9WM+2g=
 golang.org/x/crypto v0.0.0-20220622213112-05595931fe9d/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
 golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -51,13 +53,11 @@ golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9sn
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f h1:BLraFXnmrev5lT+xlilqcH8XK9/i0At2xKjWk4p6zsU=
 gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gopkg.in/yaml.v3 v3.0.0-20200605160147-a5ece683394c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

time.go

@@ -133,13 +133,19 @@ func (t DateTime) String() string {
 }
 
 // IsZero returns whether the date time is a zero value
-func (t DateTime) IsZero() bool {
-	return time.Time(t).IsZero()
+func (t *DateTime) IsZero() bool {
+	if t == nil {
+		return true
+	}
+	return time.Time(*t).IsZero()
 }
 
 // IsUnixZerom returns whether the date time is equivalent to time.Unix(0, 0).UTC().
-func (t DateTime) IsUnixZero() bool {
-	return time.Time(t) == UnixZero
+func (t *DateTime) IsUnixZero() bool {
+	if t == nil {
+		return true
+	}
+	return time.Time(*t).Equal(UnixZero)
 }
 
 // MarshalText implements the text marshaller interface

time_test.go

@@ -56,11 +56,15 @@ func TestNewDateTime(t *testing.T) {
 func TestIsZero(t *testing.T) {
 	var empty DateTime
 	assert.True(t, empty.IsZero())
-	assert.False(t, DateTime(time.Unix(100, 5)).IsZero())
+	var nilDt *DateTime
+	assert.True(t, nilDt.IsZero())
+	small := DateTime(time.Unix(100, 5))
+	assert.False(t, small.IsZero())
 
 	// time.Unix(0,0) does not produce a true zero value struct,
 	// so this is expected to fail.
-	assert.False(t, NewDateTime().IsZero())
+	dt := NewDateTime()
+	assert.False(t, dt.IsZero())
 }
 
 func TestIsUnixZero(t *testing.T) {
@@ -71,7 +75,9 @@ func TestIsUnixZero(t *testing.T) {
 	estLocation := time.FixedZone("EST", int((-5 * time.Hour).Seconds()))
 	estUnixZero := time.Unix(0, 0).In(estLocation)
 	UnixZero = estUnixZero
-	assert.True(t, DateTime(estUnixZero).IsUnixZero())
+	t.Cleanup(func() { UnixZero = time.Unix(0, 0).UTC() })
+	dtz := DateTime(estUnixZero)
+	assert.True(t, dtz.IsUnixZero())
 }
 
 func TestParseDateTime_errorCases(t *testing.T) {