fix: preserve service layer state on SDK initialization failure

State is now only reset after Approov.initialize() confirms success.
When the SDK throws (e.g. different config), all prior operating state
(isInitialized, configString, pinningInterceptor, OkHttp builder) is preserved.

Per TESTING_REQUIREMENTS §17-18 (core-service-layers-testing).

Author: ivol

approov-service/src/main/java/io/approov/service/retrofit/ApproovService.java

@@ -163,7 +163,25 @@ private ApproovService() {
     public static synchronized void initialize(Context context, String config, String comment) {
         if (config == null)
             throw new IllegalArgumentException("config must not be null; pass \"\" for bypass mode");
-        // Reset service layer state
+
+        // Initialize the platform SDK if not in bypass mode (empty config).
+        // State is only modified after the SDK confirms success, preserving the current
+        // operating mode (protected or bypass) if the call fails.
+        if (!config.isEmpty()) {
+            try {
+                boolean sdkInitialized = Approov.initialize(context.getApplicationContext(), config, "auto", comment);
+                if (!sdkInitialized) {
+                    Log.d(TAG, "Approov SDK already initialized");
+                }
+            } catch (IllegalArgumentException e) {
+                Log.e(TAG, "Approov initialization failed: " + e.getMessage());
+                throw e; // service-layer state NOT modified — prior operating mode preserved
+            } catch (IllegalStateException e) {
+                Log.e(TAG, "Approov initialization failed: " + e.getMessage());
+                throw e; // service-layer state NOT modified — prior operating mode preserved
+            }
+        }
+        // SDK succeeded (or bypass) — now reset and commit new service-layer state.
         isInitialized = false;
         proceedOnNetworkFail = false;
         useApproovStatusIfNoToken = false;
@@ -181,26 +199,6 @@ public static synchronized void initialize(Context context, String config, Strin
             cachedFailureResult = null;
             cachedFailureTimeMs = 0;
         }
-
-        // Initialize the platform SDK if not in bypass mode (empty config).
-        // The SDK returns true if initialization succeeded, false if already
-        // initialized
-        // with the same config even by another service layer instance. Any other
-        // failure (e.g. different config) throws.
-        if (!config.isEmpty()) {
-            try {
-                boolean sdkInitialized = Approov.initialize(context.getApplicationContext(), config, "auto", comment);
-                if (!sdkInitialized) {
-                    Log.d(TAG, "Approov SDK already initialized");
-                }
-            } catch (IllegalArgumentException e) {
-                Log.e(TAG, "Approov initialization failed: " + e.getMessage());
-                throw e;
-            } catch (IllegalStateException e) {
-                Log.e(TAG, "Approov initialization failed: " + e.getMessage());
-                throw e;
-            }
-        }
         if (!config.isEmpty())
             pinningInterceptor = new ApproovPinningInterceptor();
         else

approov-service/src/test/java/io/approov/service/retrofit/ApproovServiceContractTest.java

@@ -85,11 +85,10 @@ public void initializeWithEmptyConfigCanLaterBuildProtectedClients() {
     }
 
     @Test
-    public void initializeWithNullConfigAndCommentSucceedsAsBypass() {
+    public void initializeWithNullConfigThrowsIllegalArgument() {
         Context context = mock(Context.class);
-        ApproovService.initialize(context, null, null);
-        assertTrue(ApproovService.isInitialized());
-        assertFalse(ApproovService.isApproovEnabled());
+        assertThrows(IllegalArgumentException.class, () -> ApproovService.initialize(context, null, null));
+        assertFalse(ApproovService.isInitialized());
     }
 
     @Test