kicad-developers team mailing list archive

[Wayne Stambaugh <stambaughw@xxxxxxxxxxx>]

On 6/4/2014 1:32 PM, Lorenzo Marcantonio wrote:
> On Wed, Jun 04, 2014 at 06:07:18PM +0200, Tomasz Wlostowski wrote:
>> How about modifying the PCB parser to produce warnings for designs that
>> contain layers unsupported by this particular version (same for new object
>> types, such as arcs on copper layers, diff pairs, polygons in footprints,
>> etc.)?
> 
> Also if you don't include the new layers they wouldn't appear anyway in
> the file, so compatibility is kept.
> 
> Junking entities on load when on unsupported layers *could* be done, but
> is that desiderable? what's the 'official' opinion about the 'just do
> make and upgrade' argument popped up a while ago (for similar reasons)?
> 
This is the concept of forward compatibility which seems silly to me.
Maybe proprietary programs need this to prevent obsolescence but open
source software does not suffer from the "buy new software because we
changed the file format" nonsense (think MS office).  Trying to keep
track of unknown sexpr elements to prevent them from being lost in older
versions of Pcbnew would be a nightmare and saving to an older file
format by ignoring unknown sexpr elements would lead to all kinds of
user confusion.  Where would you save them in the old kicad_pcb file
format after you made changes?  If Pcbnew where a read only application,
then this would be less of an issue.