[QGIS-trac] [Quantum GIS] #3572: Handling of symbology load error on project load

[Quantum GIS]

#3572: Handling of symbology load error on project load
---------------------------------------------------------+------------------
   Reporter:  ccrook                                     |              Owner:  nobody       
       Type:  bug                                        |             Status:  new          
   Priority:  critical: causes crash or data corruption  |          Milestone:  Version 1.7.0
  Component:  Build/Install                              |            Version:  Trunk        
   Keywords:  project file load error                    |   Platform_version:               
   Platform:  All                                        |           Must_fix:  No           
Status_info:  0                                          |  
---------------------------------------------------------+------------------
 This is a proposed patch to change the behaviour of QGis if a layer fails
 to load because it cannot process the symbology definition in the project
 file (eg because a renderer plugin is missing).

 The current behaviour is to fail to load the layer.  The attached patch
 changes this to instead use a default symbology.

 Neither is ideal ... I think it would be better to load a default
 symbology and report to the user that the original symbology could not be
 loaded - preferably with a reason why.  However that raises a bigger
 question about how to handle errors when loading the project file.

 At the moment if the symbology doesn't load, the layer fails, and the user
 is presented with the bad layers handler.  This allows them to reselect
 the file used by the layer.  However this is really confusing if the file
 is correct and exists, but the symbology cannot be loaded ... it confused
 me anyway!

 With this patch the layer loads, but the symbology reverts to a default
 definition - not what the user would expect, but the best that can be
 done.

-- 
Ticket URL: <http://trac.osgeo.org/qgis/ticket/3572>
Quantum GIS <http://qgis.org>
Quantum GIS is an Open Source GIS viewer/editor supporting OGR, PostGIS, and GRASS formats