DRY up the debounce of db extension version increment.

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -4904,11 +4904,9 @@ typedef enum : NSUInteger {
     }];
 
     // Flag to ensure that we only increment once per launch.
-    static BOOL hasIncrementedDatabaseView = NO;
+    if (hasError) {
-    if (hasError && !hasIncrementedDatabaseView) {
         OWSLogWarn(@"incrementing version of: %@", TSMessageDatabaseViewExtensionName);
         [OWSPrimaryStorage incrementVersionOfDatabaseExtension:TSMessageDatabaseViewExtensionName];
-        hasIncrementedDatabaseView = YES;
     }
 
     // Update the "break" properties (shouldShowDate and unreadIndicator) of the view items.

Signal/src/ViewControllers/HomeView/HomeViewController.m

@@ -880,11 +880,9 @@ NSString *const kArchivedConversationsReuseIdentifier = @"kArchivedConversations
                                                                                  withMappings:self.threadMappings];
     }];
 
-    static BOOL hasIncrementedDatabaseView = NO;
+    if (![thread isKindOfClass:[TSThread class]]) {
-    if (![thread isKindOfClass:[TSThread class]] && !hasIncrementedDatabaseView) {
         OWSLogError(@"Invalid object in thread view: %@", [thread class]);
         [OWSStorage incrementVersionOfDatabaseExtension:TSThreadDatabaseViewExtensionName];
-        hasIncrementedDatabaseView = YES;
     }
 
     return thread;

SignalServiceKit/src/Storage/OWSStorage.m

@@ -515,6 +515,20 @@ NSString *const kNSUserDefaults_DatabaseExtensionVersionMap = @"kNSUserDefaults_
 {
     OWSLogError(@"%@", extensionName);
 
+    // Don't increment version of a given extension more than once
+    // per launch.
+    static NSMutableSet<NSString *> *incrementedViewSet = nil;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        incrementedViewSet = [NSMutableSet new];
+    });
+    @synchronized(incrementedViewSet) {
+        if ([incrementedViewSet containsObject:extensionName]) {
+            OWSLogInfo(@"Ignoring redundant increment: %@", extensionName);
+        }
+        [incrementedViewSet addObject:extensionName];
+    }
+
     NSUserDefaults *appUserDefaults = [NSUserDefaults appUserDefaults];
     OWSAssertDebug(appUserDefaults);
     NSMutableDictionary<NSString *, NSNumber *> *_Nullable versionMap =