[WO-855] Fix trying to set a flag when email is deleted

src/js/email/email.js

@@ -492,6 +492,12 @@ Email.prototype.setFlags = function(options) {
         }).then(function(storedMessages) {
             // set the flags
             var storedMessage = storedMessages[0];
+
+            if (!storedMessage) {
+                // the message has been deleted in the meantime
+                return;
+            }
+
             storedMessage.unread = options.message.unread;
             storedMessage.flagged = options.message.flagged;
             storedMessage.answered = options.message.answered;

test/unit/email/email-dao-test.js

@@ -733,6 +733,32 @@ describe('Email DAO unit tests', function() {
             });
         });
 
+        it('should not explode when message has been deleted during imap roundtrip', function(done) {
+            imapMark.withArgs({
+                folder: inboxFolder,
+                uid: message.uid,
+                unread: message.unread,
+                answered: message.answered,
+                flagged: message.flagged
+            }).returns(resolves());
+
+            localListStub.withArgs({
+                folder: inboxFolder,
+                uid: message.uid
+            }).returns(resolves([]));
+
+            dao.setFlags({
+                folder: inboxFolder,
+                message: message
+            }).then(function() {
+                expect(imapMark.calledOnce).to.be.true;
+                expect(localListStub.calledOnce).to.be.true;
+                expect(localStoreStub.called).to.be.false;
+
+                done();
+            });
+        });
+
         it('should set flags for outbox for disk, memory', function(done) {
             localListStub.withArgs({
                 folder: outboxFolder,