Regenerating the registration file breaks M → D silently

[Vyquos]

To Reproduce

1. Setup the bridge
2. Send any number of messages on matrix (in a room that's bridged to discord)
3. Regenerate discord-registration.yaml according to the instructions in the README^1
4. Replace the old discord-registration.yaml with the newly generated one
5. Try sending a message on matrix

Behavior After completing all steps above, the new message isn't bridged to discord.

What goes wrong

• For some reason the TransactionId of new matrix events is reset to 1 (This can be shown by logging the txnId in the bot sdk).
• Meanwhile the table as_txns in discord.db still retains all previous TransactionIds.
• When the appservice receives a new matrix event, it checks^2 whether the TransactionId (e.g. 2) is a member of discord.dbs as_txns table^3 (e.g. 1, 2, 3, 4, ..., 100).
• Since the (old) table already contains the TransactionId from messages that were sent before regenerating discord-registration.yaml, the bot sdk ignores the transaction.
• The message isn't handled any further, thereby making the bridge fail silently.

[Vyquos]

The reason for the TransactionId-reset may be newly generated appservice / homeserver tokens in discord-registration.yaml.

[Vyquos]

This can be manually fixed by clearing the as_txns table in discord.db.

[Vyquos]

Seeing as this seems to be an issue with crashes too i suspect that any restart of the connection between the homeserver and the appservice causes this breakage.