Re: [Monotone-devel] encapsulation branch

[Markus Schiltknecht]

Hi,

Thomas Keller wrote:
> I like the idea. One question though: if we look at certain system
> entities, like a database or a workspace as single entities, and no
> longer in terms of a global, single "app_state" object, would it be
> possible (in general) to make these exchangable easily?
>
> What I was thinking of here is automate stdio, which, once started, runs
> on exactly one single database / workspace, and this is determined
> during initialization. The basic problems here are

Well, automate stdio is the only command I can think of which could make 
use of such a feature. IMO, it's better to check for everything that's 
needed right from the start of the automate command. And let users 
simply start multiple mtn processes if they need to 'change'. Why define 
extra automate commands to switch databases if you can do it in your 
shell ;-)

Regarding the deferred failures: maybe we need to add options like 
'--read-only-db' or '--no-workspace' to automate stdio and make it check 
right from the start. So if a 'mtn -d test.db --read-only-db automate 
stdio' starts up correctly, you can be sure to be successfully connected 
to a read-only database.

Maybe we can spice it up further, by some auto detection stuff, i.e. 
telling the user if a workspace could be found or not. But OTOH, such 
automatisms are more of a foot-gun than explicit options are.

As a side note: there's no meaning in having chosen the AUTOMATE 
commands first. I plan to do something similar to all CMDs, i.e. limit 
them to their contexts. And make the compiler enforce that limitation.

Regards

Markus