closes #4583

src/notifications.js

@@ -81,6 +81,21 @@ var plugins = require('./plugins');
 		});
 	};
 
+	Notifications.filterExists = function(nids, callback) {
+		// Removes nids that have been pruned
+		db.isSortedSetMembers('notifications', nids, function(err, exists) {
+			if (err) {
+				return callbacK(err);
+			}
+
+			nids = nids.filter(function(notifId, idx) {
+				return exists[idx];
+			});
+
+			callback(null, nids);
+		});
+	};
+
 	Notifications.findRelated = function(mergeIds, set, callback) {
 		// A related notification is one in a zset that has the same mergeId
 		var _nids;

src/posts/flags.js

@@ -67,29 +67,28 @@ module.exports = function(Posts) {
 	}
 
 	Posts.dismissFlag = function(pid, callback) {
+		var uid;
+
 		async.parallel([
 			function(next) {
-				db.getObjectField('post:' + pid, 'uid', function(err, uid) {
+				db.getObjectField('post:' + pid, 'uid', function(err, _uid) {
 					if (err) {
 						return next(err);
 					}
 
+					uid = _uid;
+
 					db.sortedSetsRemove([
 						'posts:flagged',
 						'posts:flags:count',
 						'uid:' + uid + ':flag:pids'
 					], pid, next);
 				});
 			},
-			function(next) {
-				db.deleteObjectField('post:' + pid, 'flags', next);
-			},
-			function(next) {
-				db.delete('pid:' + pid + ':flag:uids', next);
-			},
-			function(next) {
-				db.delete('pid:' + pid + ':flag:uid:reason', next);
-			}
+			async.apply(db.deleteObjectField, 'post:' + pid, 'flags'),
+			async.apply(db.delete, 'pid:' + pid + ':flag:uids'),
+			async.apply(db.delete, 'pid:' + pid + ':flag:uid:reason'),
+			async.apply(db.sortedSetRemove, 'notifications', 'post_flag:' + pid + ':uid:' + uid)
 		], function(err) {
 			callback(err);
 		});

src/upgrade.js

@@ -10,7 +10,7 @@ var db = require('./database'),
 	schemaDate, thisSchemaDate,
 
 	// IMPORTANT: REMEMBER TO UPDATE VALUE OF latestSchema
-	latestSchema = Date.UTC(2016, 3, 18);
+	latestSchema = Date.UTC(2016, 3, 29);
 
 Upgrade.check = function(callback) {
 	db.get('schemaDate', function(err, value) {
@@ -530,6 +530,52 @@ Upgrade.upgrade = function(callback) {
 				winston.info('[2016/04/19] Users post count per tid skipped!');
 				next();
 			}
+		},
+		function(next) {
+			thisSchemaDate = Date.UTC(2016, 3, 29);
+
+			if (schemaDate < thisSchemaDate) {
+				updatesMade = true;
+				winston.info('[2016/04/29] Dismiss flags from deleted topics');
+
+				var posts = require('./posts'),
+					topics = require('./topics');
+
+				var pids, tids;
+
+				async.waterfall([
+					async.apply(db.getSortedSetRange, 'posts:flagged', 0, -1),
+					function(_pids, next) {
+						pids = _pids;
+						posts.getPostsFields(pids, ['tid'], next);
+					},
+					function(_tids, next) {
+						tids = _tids.map(function(a) {
+							return a.tid;
+						});
+
+						topics.getTopicsFields(tids, ['deleted'], next);
+					},
+					function(state, next) {
+						var toDismiss = state.map(function(a, idx) {
+							return parseInt(a.deleted, 10) === 1 ? pids[idx] : null;
+						}).filter(Boolean);
+
+						winston.info('[2016/04/29] ' + toDismiss.length + ' dismissable flags found');
+						async.each(toDismiss, posts.dismissFlag, next);
+					}
+				], function(err) {
+					if (err) {
+						return next(err);
+					}
+
+					winston.info('[2016/04/29] Dismiss flags from deleted topics done');
+					Upgrade.update(thisSchemaDate, next);
+				});
+			} else {
+				winston.info('[2016/04/29] Dismiss flags from deleted topics skipped!');
+				next();
+			}
 		}
 		// Add new schema updates here
 		// IMPORTANT: REMEMBER TO UPDATE VALUE OF latestSchema IN LINE 24!!!

src/user/notifications.js

@@ -211,6 +211,7 @@ var async = require('async'),
 		// Collapse any notifications with identical mergeIds
 		async.waterfall([
 			async.apply(db.getSortedSetRevRange, 'uid:' + uid + ':notifications:unread', 0, 99),
+			async.apply(notifications.filterExists),
 			function(nids, next) {
 				var keys = nids.map(function(nid) {
 					return 'notifications:' + nid;