[GRASS-dev] [GRASS GIS] #2230: 'g.region -p' writes new WIND file, causes race condition for parallel jobs

[GRASS GIS]

#2230: 'g.region -p' writes new WIND file, causes race condition for parallel jobs
----------------------+-----------------------------------------------------
 Reporter:  hamish    |       Owner:  grass-dev@…              
     Type:  defect    |      Status:  new                      
 Priority:  normal    |   Milestone:  6.4.4                    
Component:  Default   |     Version:  svn-develbranch6         
 Keywords:  g.region  |    Platform:  Linux                    
      Cpu:  x86-64    |  
----------------------+-----------------------------------------------------

Comment(by glynn):

 Replying to [comment:3 wenzeslaus]:
 > what is the set of `g.region` flags which should be used by default when
 scripting.

 If you only want to read the region, use the "-u" flag.

 > This is not expected behavior and it is not properly documented.

 Agreed; I overlooked it when writing the grass.script.core Python module.

 > Also I don't understand why it is necessary to write the WIND file in
 `g.region` if the content was not changed.

 It's not simple to tell whether the content was changed, i.e. whether the
 region which is printed will match the contents of the WIND file.

 When the region is changed explicitly (via the -d flag or any option other
 than save=), it's reasonable to assume that the updated region doesn't
 match the WIND file. But the absence of those options doesn't necessarily
 mean that writing to WIND (or $WIND_OVERRIDE) will be a no-op.

 If the behaviour was changed so that WIND was only written when one of
 those options was used, that would technically be a change to the long-
 standing behaviour, but we would probably get away with it. Probably.
 Maybe that's close enough; I have no particular opinion on that.

 However: we'd need to add a -f (force) flag, otherwise there'd be no way
 to copy the $GRASS_REGION value to WIND/$WIND_OVERRIDE, or to perform just
 the adjustment (G_adjust_Cell_head3).

-- 
Ticket URL: <https://trac.osgeo.org/grass/ticket/2230#comment:4>
GRASS GIS <http://grass.osgeo.org>