monotone automate stdio overhauled [Update]

Yesterday my “automate-out-of-band” branch finally made it into monotone’s trunk. This is a prerequisite for the support of netsync commands in guitone I’ve blogged about earlier, as it makes in-stream informational, error and ticker messages possible, even for remote connections!

While I was at it, several other small things have been changed in stdio – f.e. the error code is now only issued once as payload of the ‘l’ stream-, which mean unfortunately that monotone 0.46 will break compatibility with clients which only understand the pre-0.46 output format. To avoid another hard break like this in the future, a new header section has been added to both stdio’s and the first header which is issued there is the “format-version” header:

$ mtn au stdio
format-version: 2

[...actual output...]

`stdio-version` is promised to stay constant as long as the output format doesn’t change and will be incremented by ‘1’ if there is any other major dealbreaker in the future. This is actually different from the `interface_version` number we also have in the automate interface, whose major number will raise everytime an incompatible change is made to any automate command. We’ll possibly change this behaviour to something more client-friendly in the future, but there is no ETA on this yet, as the current system is still good enough.

All changes for (remote) stdio will be clearly documented in the manual once 0.46 is out. Before this release happens though, I plan to finish the “automate-netsync” branch as well… Holiday time is hacking time 🙂

[Update: It was decided to name the version header “format-version” instead of “stdio-version”; I’ve updated my example accordingly]