RE: vc-state always calls heuristic function

[<klaus.berndl@sdm.de>]

Stefan Monnier wrote:
>> You see, that always the heuristic method of a backend is used
>> [(vc-call state-heuristic file)] - even if a backend offers also
>> a "real" statechecker. E.g. vc-cvs.el offers `vc-cvs-state' and
>> `vc-cvs-state-heuristic'... But current implementation of `vc-state'
>> will never use `vc-cvs-state'! Why??
> 
> Why not?
> 
>> IMHO there should be a way so a user can customize if `vc-state'
>> should use the heuristic approach or the real state-check if a
>> backend offers both of them. What do you think?
> 
> It's the responsability of the backend.
> vc.el uses `state-heuristic' when a heuristic is enough (e.g. in
> vc-state) and uses `state' when it really needs fresh data (in
> `vc-recompute-state'). 

ah, i didn't know the function `vc-recompute-state' - my fault..

> 
> The backend is then free to always use fresh data, or to use a
> heuristic when possible.  Backends usually use a config var such as
> vc-cvs-stay-local to decide which to choose.
> 
> What problem are you trying to solve?

The next version of ECB (Emacs Code browser) will display the VC-state
of sourcefiles with image-icons in its special browsable tree-windows.
For this a function is needed to compute the VC-state of a file. Whic one
is used is customizable in an option of ECB - and currently `vc-state' is
used per default for the backend CVS, RCS and SCCS... and i have wondered
if there is a function available which performs real checks not only
heuristic - now i know such a function - thanks Stefan!
I think i will not use vc-recompute-state per default because especially with
remote repositories this can be very expensive - even the state-check is 
performed stealthy and interruptable in the background as with ECB.
But i want to mentionin the docstring of that ECB-option that there
is another function `vc-recompute-state' a user can use if he works
in a fast LAN and with a CVS-server in that LAN for example....

understandable?

Ciao,
Klaus



> 
> 
>         Stefan