Rework outgoing message state.

// FREEBIE

src/Devices/OWSRecordTranscriptJob.m

@@ -86,6 +86,7 @@ NS_ASSUME_NONNULL_BEGIN
                                                                         attachmentIds:[NSMutableArray new]
                                                                      expiresInSeconds:transcript.expirationDuration
                                                                       expireStartedAt:transcript.expirationStartedAt];
+        // Since updateWithWasDelivered is a new message, updateWithWasDelivered will save it.
         [textMessage updateWithWasDelivered];
     }
 }

src/Messages/Interactions/TSOutgoingMessage.h

@@ -109,18 +109,30 @@ typedef NS_ENUM(NSInteger, TSOutgoingMessageState) {
                                                                         filename:(nullable NSString *)filename;
 
 // TSOutgoingMessage are updated from many threads. We don't want to save
-// our local copy since it may be out of date.  Instead, we use these
-// "updateWith..." methods to:
+// our local copy (this instance) since it may be out of date.  Instead, we
+// use these "updateWith..." methods to:
 //
-// a) Update a property of the local copy.
+// a) Update a property of this instance.
 // b) Load an up-to-date instance of this model from from the data store.
 // c) Update and save that fresh instance.
+// d) If this message hasn't yet been saved, save this local instance.
+//
+// After "updateWith...":
+//
+// a) An updated copy of this message will always have been saved in the
+//    data store.
+// b) The local property on this instance will always have been updated.
+// c) Other properties on this instance may be out of date.
+//
+// All mutable properties of this class have been made read-only to
+// prevent accidentally modifying them directly.
 //
 // This isn't a perfect arrangement, but in practice this will prevent
-// data loss.
+// data loss and will resolve all known issues.
 - (void)updateWithMessageState:(TSOutgoingMessageState)messageState;
 - (void)updateWithSendingError:(NSError *)error;
 - (void)updateWithHasSyncedTranscript:(BOOL)hasSyncedTranscript;
+- (void)updateWithCustomMessage:(NSString *)customMessage transaction:(YapDatabaseReadWriteTransaction *)transaction;
 - (void)updateWithCustomMessage:(NSString *)customMessage;
 - (void)updateWithWasDeliveredWithTransaction:(YapDatabaseReadWriteTransaction *)transaction;
 - (void)updateWithWasDelivered;

src/Messages/Interactions/TSOutgoingMessage.m

@@ -189,6 +189,8 @@ NSString *const kTSOutgoingMessageSentRecipientAll = @"kTSOutgoingMessageSentRec
 
 - (void)updateWithSendingError:(NSError *)error
 {
+    OWSAssert(error);
+
     [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self applyChangeToSelfAndLatest:transaction
                              changeBlock:^(TSOutgoingMessage *message) {
@@ -218,19 +220,28 @@ NSString *const kTSOutgoingMessageSentRecipientAll = @"kTSOutgoingMessageSentRec
     }];
 }
 
+- (void)updateWithCustomMessage:(NSString *)customMessage transaction:(YapDatabaseReadWriteTransaction *)transaction
+{
+    OWSAssert(customMessage);
+    OWSAssert(transaction);
+
+    [self applyChangeToSelfAndLatest:transaction
+                         changeBlock:^(TSOutgoingMessage *message) {
+                             [message setCustomMessage:customMessage];
+                         }];
+}
+
 - (void)updateWithCustomMessage:(NSString *)customMessage
 {
     [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
-        [self applyChangeToSelfAndLatest:transaction
-                             changeBlock:^(TSOutgoingMessage *message) {
-                                 [message setCustomMessage:customMessage];
-                             }];
+        [self updateWithCustomMessage:customMessage transaction:transaction];
     }];
 }
 
 - (void)updateWithWasDeliveredWithTransaction:(YapDatabaseReadWriteTransaction *)transaction
 {
     OWSAssert(transaction);
+
     [self applyChangeToSelfAndLatest:transaction
                          changeBlock:^(TSOutgoingMessage *message) {
                              [message setWasDelivered:YES];