fix: prevent NullPointerException in BackgroundWorker.getDartTask (#636)

* chore(release): publish packages

 - workmanager_apple@0.9.1
 - workmanager@0.9.0+1

* docs: fix incorrect UIBackgroundModes documentation

- Remove invalid 'processing' value from UIBackgroundModes
- Add clarification that BGTaskScheduler doesn't require UIBackgroundModes
- Link to Apple's official UIBackgroundModes documentation
- Update workmanager version to 0.9.0 in installation instructions

Fixes #633

* Revert "docs: fix incorrect UIBackgroundModes documentation"

This reverts commit 7116f5f.

* docs: improve iOS background modes documentation links

- Replace Xcode Help link with Apple's Configuration Guide
- Add link to UIBackgroundModes property list documentation
- Provide both practical configuration and technical reference links

Fixes #633

* fix: prevent NullPointerException in BackgroundWorker.getDartTask

- Remove non-null assertion operator (!!) from dartTask property
- Add null checks in all methods that use dartTask
- Handle null dart task gracefully with proper error reporting
- Fixes crash when DART_TASK_KEY is missing from worker input data

Fixes #635

* Revert "chore(release): publish packages"

This reverts commit aa9e3b6.

Author: ened

docs/quickstart.mdx

@@ -28,7 +28,7 @@ iOS requires a 5-minute setup in Xcode. Choose your approach based on your needs
 #### Option A: Periodic Tasks (Recommended for most use cases)
 For regular data sync, notifications, cleanup - uses iOS Background Fetch:
 
-1. **Enable Background Modes** in Xcode target capabilities ([Xcode Help](https://help.apple.com/xcode/mac/current/#/devbfa1532c4)) and add to Info.plist:
+1. **Enable Background Modes** in Xcode target capabilities ([Configuration Guide](https://developer.apple.com/documentation/xcode/configuring-background-execution-modes)) and add to Info.plist ([UIBackgroundModes reference](https://developer.apple.com/documentation/bundleresources/information-property-list/uibackgroundmodes)):
 ```xml
 <key>UIBackgroundModes</key>
 <array>
@@ -45,7 +45,7 @@ For regular data sync, notifications, cleanup - uses iOS Background Fetch:
 #### Option B: Processing Tasks (For complex operations)
 For file uploads, data processing, longer tasks - uses BGTaskScheduler:
 
-1. **Enable Background Modes** in Xcode target capabilities ([Xcode Help](https://help.apple.com/xcode/mac/current/#/devbfa1532c4)) and add to Info.plist:
+1. **Enable Background Modes** in Xcode target capabilities ([Configuration Guide](https://developer.apple.com/documentation/xcode/configuring-background-execution-modes)) and add to Info.plist ([UIBackgroundModes reference](https://developer.apple.com/documentation/bundleresources/information-property-list/uibackgroundmodes)):
 ```xml
 <key>UIBackgroundModes</key>
 <array>
@@ -75,7 +75,7 @@ WorkmanagerPlugin.registerBGProcessingTask(
 #### Option C: Periodic Tasks with Custom Frequency
 For periodic tasks with more control than Background Fetch - uses BGTaskScheduler with frequency:
 
-1. **Enable Background Modes** in Xcode target capabilities ([Xcode Help](https://help.apple.com/xcode/mac/current/#/devbfa1532c4)) and add to Info.plist:
+1. **Enable Background Modes** in Xcode target capabilities ([Configuration Guide](https://developer.apple.com/documentation/xcode/configuring-background-execution-modes)) and add to Info.plist ([UIBackgroundModes reference](https://developer.apple.com/documentation/bundleresources/information-property-list/uibackgroundmodes)):
 ```xml
 <key>UIBackgroundModes</key>
 <array>

example/ios/Podfile.lock

@@ -1,33 +1,46 @@
 PODS:
   - Flutter (1.0.0)
+  - integration_test (0.0.1):
+    - Flutter
   - path_provider_foundation (0.0.1):
     - Flutter
     - FlutterMacOS
   - permission_handler_apple (9.3.0):
     - Flutter
+  - shared_preferences_foundation (0.0.1):
+    - Flutter
+    - FlutterMacOS
   - workmanager_apple (0.0.1):
     - Flutter
 
 DEPENDENCIES:
   - Flutter (from `Flutter`)
+  - integration_test (from `.symlinks/plugins/integration_test/ios`)
   - path_provider_foundation (from `.symlinks/plugins/path_provider_foundation/darwin`)
   - permission_handler_apple (from `.symlinks/plugins/permission_handler_apple/ios`)
+  - shared_preferences_foundation (from `.symlinks/plugins/shared_preferences_foundation/darwin`)
   - workmanager_apple (from `.symlinks/plugins/workmanager_apple/ios`)
 
 EXTERNAL SOURCES:
   Flutter:
     :path: Flutter
+  integration_test:
+    :path: ".symlinks/plugins/integration_test/ios"
   path_provider_foundation:
     :path: ".symlinks/plugins/path_provider_foundation/darwin"
   permission_handler_apple:
     :path: ".symlinks/plugins/permission_handler_apple/ios"
+  shared_preferences_foundation:
+    :path: ".symlinks/plugins/shared_preferences_foundation/darwin"
   workmanager_apple:
     :path: ".symlinks/plugins/workmanager_apple/ios"
 
 SPEC CHECKSUMS:
   Flutter: e0871f40cf51350855a761d2e70bf5af5b9b5de7
+  integration_test: 4a889634ef21a45d28d50d622cf412dc6d9f586e
   path_provider_foundation: 608fcb11be570ce83519b076ab6a1fffe2474f05
   permission_handler_apple: 4ed2196e43d0651e8ff7ca3483a069d469701f2d
+  shared_preferences_foundation: 9e1978ff2562383bd5676f64ec4e9aa8fa06a6f7
   workmanager_apple: 904529ae31e97fc5be632cf628507652294a0778
 
 PODFILE CHECKSUM: 1959d098c91d8a792531a723c4a9d7e9f6a01e38

example/ios/Runner.xcodeproj/project.pbxproj

@@ -369,12 +369,16 @@
 			);
 			inputPaths = (
 				"${PODS_ROOT}/Target Support Files/Pods-Runner/Pods-Runner-frameworks.sh",
+				"${BUILT_PRODUCTS_DIR}/integration_test/integration_test.framework",
 				"${BUILT_PRODUCTS_DIR}/path_provider_foundation/path_provider_foundation.framework",
+				"${BUILT_PRODUCTS_DIR}/shared_preferences_foundation/shared_preferences_foundation.framework",
 				"${BUILT_PRODUCTS_DIR}/workmanager_apple/workmanager_apple.framework",
 			);
 			name = "[CP] Embed Pods Frameworks";
 			outputPaths = (
+				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/integration_test.framework",
 				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/path_provider_foundation.framework",
+				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/shared_preferences_foundation.framework",
 				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/workmanager_apple.framework",
 			);
 			runOnlyForDeploymentPostprocessing = 0;

workmanager_android/android/src/main/kotlin/dev/fluttercommunity/workmanager/BackgroundWorker.kt

@@ -46,7 +46,7 @@ class BackgroundWorker(
                 }
 
     private val dartTask
-        get() = workerParams.inputData.getString(DART_TASK_KEY)!!
+        get() = workerParams.inputData.getString(DART_TASK_KEY)
 
     private val runAttemptCount = workerParams.runAttemptCount
     private val randomThreadIdentifier = Random().nextInt()
@@ -86,11 +86,20 @@ class BackgroundWorker(
                 return@ensureInitializationCompleteAsync
             }
 
+            val localDartTask = dartTask
+
+            if (localDartTask == null) {
+                val exception = IllegalStateException("Dart task is null")
+                WorkmanagerDebug.onExceptionEncountered(applicationContext, null, exception)
+                completer?.set(Result.failure())
+                return@ensureInitializationCompleteAsync
+            }
+
             val dartBundlePath = flutterLoader.findAppBundlePath()
 
             val taskInfo =
                 TaskDebugInfo(
-                    taskName = dartTask,
+                    taskName = localDartTask,
                     inputData = payload,
                     startTime = startTime,
                     callbackHandle = callbackHandle,
@@ -132,9 +141,18 @@ class BackgroundWorker(
     ) {
         val fetchDuration = System.currentTimeMillis() - startTime
 
+        val localDartTask = dartTask
+
+        if (localDartTask == null) {
+            val exception = IllegalStateException("Dart task is null")
+            WorkmanagerDebug.onExceptionEncountered(applicationContext, null, exception)
+            completer?.set(Result.failure())
+            return
+        }
+
         val taskInfo =
             TaskDebugInfo(
-                taskName = dartTask,
+                taskName = localDartTask,
                 inputData = payload,
                 startTime = startTime,
             )
@@ -175,7 +193,17 @@ class BackgroundWorker(
         // Convert payload to the format expected by Pigeon (Map<String?, Object?>)
         val pigeonPayload = payload.mapKeys { it.key as String? }.mapValues { it.value as Object? }
 
-        flutterApi.executeTask(dartTask, pigeonPayload) { result ->
+        val localDartTask = dartTask
+
+        if (localDartTask == null) {
+            val exception = IllegalStateException("Dart task is null")
+            WorkmanagerDebug.onExceptionEncountered(applicationContext, null, exception)
+
+            stopEngine(Result.failure(), exception.message)
+            return
+        }
+
+        flutterApi.executeTask(localDartTask, pigeonPayload) { result ->
             when {
                 result.isSuccess -> {
                     val wasSuccessful = result.getOrNull() ?: false