How are new folders announced in the Block Exchange Protocol?

Development
1

Hi. I try to write a Syncthing implementation in rust (just for the fun of it, nothing wrong with the current Syncthing implementation).

Reading Block Exchange Protocol v1 — Syncthing v1 documentation it states that a ClusterConfig must not be repeated. How are new folders handled? Suppose I configure a new folder on one device, or share it with a new device, how would the new folder be announced to the other device?

The only way I can think about reading the current specs is that the connection is torn down and re-established.

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2

We used to disconnect and reconnect to announce new folders, however, I think (not sure, on the phone so hard to verify) that the statement might no longer be true, and we do repeat it on the same connection.

3

Yeah good find, Syncthing is indeed not behaving according to spec there - we do send multiple cluster-configs. Now in general that would probably have to be a BEP v1.1 or something, but given no-one else is using the BEP as far as we know, we might just sneekily remove that “must not” requirement?

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4

Thanks for the quick update. Does a new cluster config completely replace the existing folder list or is it more like an update message?

5

I believe its replace.

6

Going toward a BEP v1.1 would be a good occasion to include other enhancements, for example: