replaced api version check in webhook/client with isCompatibleApiVers…

…ion, which will test if the release train of the webhook event matches the pinned version, or return false for any event api version that does not have a release train

webhook/client.go

@@ -187,6 +187,20 @@ type signedHeader struct {
 // Private functions
 //
 
+func isCompatibleAPIVersion(eventApiVersion string) bool {
+	// If the event api version is from before we started adding
+	// a release train, there's no way its compatible with this
+	// version
+	if !strings.Contains(eventApiVersion, ".") {
+		return false
+	}
+
+	// versions are yyyy-MM-dd.train
+	var eventReleaseTrain = strings.Split(eventApiVersion, ".")[1]
+	var currentReleaseTrain = strings.Split(stripe.APIVersion, ".")[1]
+	return eventReleaseTrain == currentReleaseTrain
+}
+
 func constructEvent(payload []byte, sigHeader string, secret string, options ConstructEventOptions) (stripe.Event, error) {
 	e := stripe.Event{}
 
@@ -203,7 +217,7 @@ func constructEvent(payload []byte, sigHeader string, secret string, options Con
 		return e, fmt.Errorf("Failed to parse webhook body json: %s", err.Error())
 	}
 
-	if !options.IgnoreAPIVersionMismatch && e.APIVersion != stripe.APIVersion {
+	if !options.IgnoreAPIVersionMismatch && !isCompatibleAPIVersion(e.APIVersion) {
 		return e, fmt.Errorf("Received event with API version %s, but stripe-go %s expects API version %s. We recommend that you create a WebhookEndpoint with this API version. Otherwise, you can disable this error by using `ConstructEventWithOptions(..., ConstructEventOptions{..., ignoreAPIVersionMismatch: true})`  but be wary that objects may be incorrectly deserialized.", e.APIVersion, stripe.ClientVersion, stripe.APIVersion)
 	}
 

webhook/client_test.go

@@ -15,11 +15,25 @@ var testPayload = []byte(fmt.Sprintf(`{
   "object": "event",
   "api_version": "%s"
 }`, stripe.APIVersion))
+
+var testPayloadWithNewVersionInReleaseTrain = []byte(fmt.Sprintf(`{
+	"id": "evt_test_webhook",
+	"object": "event",
+	"api_version": "%s"
+  }`, "2099-10-10."+strings.Split(stripe.APIVersion, ".")[1]))
+
 var testPayloadWithAPIVersionMismatch = []byte(`{
 	"id": "evt_test_webhook",
 	"object": "event",
 	"api_version": "2020-01-01"
   }`)
+
+var testPayloadWithReleaseTrainVersionMismatch = []byte(`{
+	"id": "evt_test_webhook",
+	"object": "event",
+	"api_version": "2099-10-10.the_larch"
+  }`)
+
 var testSecret = "whsec_test_secret"
 
 func newSignedPayload(options ...func(*SignedPayload)) *SignedPayload {
@@ -179,7 +193,39 @@ func TestTokenNew(t *testing.T) {
 	}
 }
 
-func TestConstructEvent_ErrorOnAPIVersionMismatch(t *testing.T) {
+func TestConstructEvent_SuccessOnExpectedAPIVersion(t *testing.T) {
+	p := newSignedPayload(func(p *SignedPayload) {
+		p.Payload = testPayload
+	})
+
+	evt, err := ConstructEvent(p.Payload, p.Header, p.Secret)
+
+	if err != nil {
+		t.Errorf("Unexpected error in ConstructEvent: %v", err)
+	}
+
+	if evt.APIVersion != stripe.APIVersion {
+		t.Errorf("Expected API versions to match")
+	}
+}
+
+func TestConstructEvent_SuccessOnNewAPIVersionInExpectedReleaseTrain(t *testing.T) {
+	p := newSignedPayload(func(p *SignedPayload) {
+		p.Payload = testPayloadWithNewVersionInReleaseTrain
+	})
+
+	evt, err := ConstructEvent(p.Payload, p.Header, p.Secret)
+
+	if err != nil {
+		t.Errorf("Unexpected error in ConstructEvent: %v", err)
+	}
+
+	expectedSuffix := "." + strings.Split(stripe.APIVersion, ".")[1]
+	if !strings.HasSuffix(evt.APIVersion, expectedSuffix) {
+		t.Errorf("Expected API release trains to match")
+	}
+}
+func TestConstructEvent_ErrorOnLegacyAPIVersionMismatch(t *testing.T) {
 	p := newSignedPayload(func(p *SignedPayload) {
 		p.Payload = testPayloadWithAPIVersionMismatch
 	})
@@ -195,6 +241,21 @@ func TestConstructEvent_ErrorOnAPIVersionMismatch(t *testing.T) {
 	}
 }
 
+func TestConstructEvent_ErrorOnReleaseTrainMismatch(t *testing.T) {
+	p := newSignedPayload(func(p *SignedPayload) {
+		p.Payload = testPayloadWithReleaseTrainVersionMismatch
+	})
+
+	_, err := ConstructEvent(p.Payload, p.Header, p.Secret)
+
+	if err == nil {
+		t.Errorf("Expected error due to API version mismatch.")
+	}
+
+	if !strings.Contains(err.Error(), "Received event with API version") {
+		t.Errorf("Expected API version mismatch error but received %v", err)
+	}
+}
 func TestConstructEventWithOptions_IgnoreAPIVersionMismatch(t *testing.T) {
 
 	p := newSignedPayload(func(p *SignedPayload) {