Added KVO detection to the revert operation

Author: lukaskubanek

Sources/InterposeKit/Hooks/HookStrategy/ObjectHookStrategy/ObjectHookStrategy.swift

@@ -151,6 +151,10 @@ internal final class ObjectHookStrategy: HookStrategy {
     }
 
     internal func restoreImplementation() throws {
+        if object_isKVOActive(self.object) {
+            throw InterposeError.kvoDetected(object: self.object)
+        }
+        
         guard let hookIMP = self.appliedHookIMP else { return }
         guard let originalIMP = self.storedOriginalIMP else { return }
 

Tests/InterposeKitTests/ObjectHookTests.swift

@@ -166,7 +166,10 @@ final class ObjectHookTests: XCTestCase {
         _ = token
     }
 
-    // KVO works just fine on an object that has already been hooked.
+    // KVO works on an object that was hooked earlier, but reverting the hook while an active
+    // observer is installed fails. While it is technically possible to recover by stopping
+    // the observation before reverting, the hook enters a failed state on error, preventing
+    // it from accepting further operations.
     func testKVO_observationAfterHooking() throws {
         let object = ExampleClass()
 
@@ -199,6 +202,11 @@ final class ObjectHookTests: XCTestCase {
         XCTAssertEqual(object.intValue, 3)
         XCTAssertEqual(didInvokeObserver, true)
 
+        XCTAssertThrowsError(
+            try hook.revert(),
+            expected: InterposeError.kvoDetected(object: object)
+        )
+        
         _ = token
     }