feat(push): Checks if client compiles leanplum-gcm and leanplum-fcm at… (#150)

* feat(push): Checks if client compiles leanplum-gcm and leanplum-fcm at the same time.

Author: Enuviel

AndroidSDKPush/src/main/java/com/leanplum/LeanplumPushService.java

@@ -154,7 +154,6 @@ public static void setGcmSenderIds(String... senderIds) {
    *  with each module separately.
    *
    *  For example:
-   *    implementation 'com.leanplum:leanplum-core:+'
    *    implementation 'com.leanplum:leanplum-fcm:+'
    *    implementation 'com.leanplum:leanplum-location:+'
    */
@@ -733,21 +732,36 @@ public static void setGcmRegistrationId(String token) {
    * Call this when Leanplum starts. This method will call by reflection from AndroidSDKCore.
    */
   static void onStart() {
-    boolean callFcmOnStart = isFirebaseEnabled();
-    if (!callFcmOnStart) {
+    Class leanplumGcmPushServiceClass = null;
+    Class leanplumFcmPushServiceClass = null;
+
+    try {
+      leanplumGcmPushServiceClass = Class.forName(LEANPLUM_PUSH_SERVICE_GCM);
+    } catch (Throwable ignored) {
+    }
+
+    try {
+      leanplumFcmPushServiceClass = Class.forName(LEANPLUM_PUSH_SERVICE_FCM);
+    } catch (Throwable ignored) {
+    }
+
+    if (leanplumGcmPushServiceClass != null && leanplumFcmPushServiceClass != null) {
+      Log.e("Leanplum does not support leanplum-gcm and leanplum-fcm library at the " +
+          "same time. To support Leanplum GCM and Location services modify your build.gradle by " +
+          "including only implementation 'com.leanplum:leanplum:+' " +
+          "To support only GCM services, use implementation 'com.leanplum:leanplum-gcm:+' " +
+          "For FCM services include implementation 'com.leanplum:leanplum-fcm:+'" +
+          " If you wish to use Leanplum FCM and Location services you also need to include " +
+          "implementation 'com.leanplum:leanplum-location:+'.");
+
+    } else if (leanplumGcmPushServiceClass != null) {
       try {
-        Class.forName(LEANPLUM_PUSH_SERVICE_GCM).getDeclaredMethod("onStart")
-            .invoke(null);
+        leanplumGcmPushServiceClass.getDeclaredMethod("onStart").invoke(null);
       } catch (Throwable ignored) {
-        callFcmOnStart = true;
       }
-    }
-
-    // Try starting FCM if GCM module is not included.
-    if (callFcmOnStart) {
+    } else if (leanplumFcmPushServiceClass != null) {
       try {
-        Class.forName(LEANPLUM_PUSH_SERVICE_FCM).getDeclaredMethod("onStart")
-            .invoke(null);
+        leanplumFcmPushServiceClass.getDeclaredMethod("onStart").invoke(null);
       } catch (Throwable ignored) {
       }
     }

AndroidSDKTests/src/test/java/com/leanplum/LeanplumPushServiceTest.java

@@ -212,21 +212,13 @@ public void testOnStart() throws Exception {
     mockStatic(LeanplumPushServiceGcm.class);
     mockStatic(LeanplumPushServiceFcm.class);
 
-    // Don't call GCM onStart when FCM is enabled.
-    when(LeanplumPushService.isFirebaseEnabled()).thenReturn(true);
+    // Don't call GCM onStart or FCM onStart if both FCM and GCM enabled.
     onStartMethod.invoke(pushService);
     assertNotNull(onStartMethod);
     verifyStatic(times(0));
     LeanplumPushServiceGcm.class.getDeclaredMethod("onStart");
-    verifyStatic(times(1));
+    verifyStatic(times(0));
     LeanplumPushServiceFcm.class.getDeclaredMethod("onStart");
-
-    // Call GCM onStart when FCM is not enabled.
-    when(LeanplumPushService.isFirebaseEnabled()).thenReturn(false);
-    onStartMethod.invoke(pushService);
-    assertNotNull(onStartMethod);
-    verifyStatic(times(1));
-    LeanplumPushServiceGcm.class.getDeclaredMethod("onStart");
   }
 
   /**