[Qgis-developer] Project file backward compatibility

[Marco Hugentobler]

Hi Radim

I have similar issues regarding the merge of the raster_resampling 
branch (I wrote the project file conversion code in Lyon). The problem 
there is that even with the project file conversion code, the old qmls 
won't load. Maybe I'll try to access the project file conversion methods 
from the qml loading methods.

>What is the project file (PF) backward compatibility policy?


Afaik there is no official policy yet (can be added to the coding 
standards document if there are no objections). My opinion is that if 
2.0 can break the API, it should also be possible that it breaks project 
file compability:

>PF written by a lower major release must be supported? Example:  QGIS
>2.0 must support 1.7 PF?


Is not required but would be nice.

>PF written by a lower minor release in the same major line must be
>supported? Example:  QGIS 1.8 must support 1.7 PF?


Is required

>PF must be readable by a lower major release? Example:  QGIS 2.0 must
>write PF readable by QGIS 1.7?

Forward compatibility not required

>PF must be readable by a lower minor release in the same major line?
>Example:  QGIS 1.8 must write PF readable by QGIS 1.7?

Forward compatibility not required


Regards,
Marco





On 16.04.2012 13:15, Radim Blazek wrote:
> What is the project file (PF) backward compatibility policy?
>
> PF written by a lower major release must be supported? Example:  QGIS
> 2.0 must support 1.7 PF?
>
> PF written by a lower minor release in the same major line must be
> supported? Example:  QGIS 1.8 must support 1.7 PF?
>
> PF must be readable by a lower major release? Example:  QGIS 2.0 must
> write PF readable by QGIS 1.7?
>
> PF must be readable by a lower minor release in the same major line?
> Example:  QGIS 1.8 must write PF readable by QGIS 1.7?
>
> Is it current master considered to be 2.0 in this context?
>
> I have modified WMS to use extended QgsDataSourceURI but the new
> encoded URI would break backward compatibility. I can do conversion
> when saving/reading to/from PF but is it necessary?
>
> Radim
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-- 
Dr. Marco Hugentobler
Sourcepole -  Linux&  Open Source Solutions
Churerstrasse 22, CH-8808 Pfäffikon SZ, Switzerland
marco.hugentobler at sourcepole.ch http://www.sourcepole.ch
Technical Advisor QGIS Project Steering Committee