[ios, osx] Fixed crash interacting with MGLOfflineTask

Added a missing conditional to the invalidation checking macro that I factored out at the last minute.

1 files changed, 9 insertions, 5 deletions

diff --git a/platform/darwin/src/MGLOfflineTask.mm b/platform/darwin/src/MGLOfflineTask.mm
index f1e8bdb566..d57ae66056 100644
--- a/platform/darwin/src/MGLOfflineTask.mm
+++ b/platform/darwin/src/MGLOfflineTask.mm
@@ -8,11 +8,15 @@
 #include <mbgl/util/string.hpp>
 
 #define MGLAssertOfflineTaskIsValid() \
-    [NSException raise:@"Invalid offline task" \
-                format: \
-     @"-[MGLOfflineStorage removeTask:withCompletionHandler:] has been called " \
-     @"on this instance of MGLOfflineTask, rendering it invalid. It is an " \
-     @"error to send any message to this task."]
+    do { \
+        if (_state == MGLOfflineTaskStateInvalid) { \
+            [NSException raise:@"Invalid offline task" \
+                        format: \
+             @"-[MGLOfflineStorage removeTask:withCompletionHandler:] has been called " \
+             @"on this instance of MGLOfflineTask, rendering it invalid. It is an " \
+             @"error to send any message to this task."]; \
+        } \
+    } while (NO);
 
 class MBGLOfflineRegionObserver;