unloading+loading GDAL might cause PROJ 7.0.0 to loose its way to proj.db.

[edzer]

One of the tests in R package sf unloads GDAL, which calls

    OGRCleanupAll();
    OSRCleanup();

and then loads it again, which calls

    GDALAllRegister();
    OGRRegisterAll();

After this test, all GDAL/PROJ calls result in

In CPL_crs_from_input(x) :
  GDAL Error 1: PROJ: proj_create_from_database: Cannot find proj.db

where CPL_crs_from_input(x) calls OGRSpatialReference::SetFromUserInput.

This happens in GDAL 3.0.4/PROJ 7.0.0 combinations, not seen in GDAL 3.0.2/PROJ 6.3.1 versions. Removing the unload/load GDAL test resolved the issue. Can you work with this, or shall I try to put this in a standalone C++ program causing an error?

Cc: @rsbivand

[rouault]

I've tried the following reproducer, but works fine for me with GDAL master/3.0 branch + PROJ master:

#include <gdal_priv.h>
#include <ogr_spatialref.h>

int main(int argc, char* argv[]){
    GDALAllRegister();
    OGRRegisterAll();

    {
        OGRSpatialReference oSRS;
        printf("ok = %d\n", oSRS.importFromEPSG(32631) == OGRERR_NONE);
    }

    OGRCleanupAll();
    OSRCleanup();

    GDALAllRegister();
    OGRRegisterAll();

    {
        OGRSpatialReference oSRS;
        printf("ok = %d\n", oSRS.importFromEPSG(32631) == OGRERR_NONE);
    }

    return 0;
}

[rouault]

@edzer Is this still an issue ?

[edzer]

Thanks for looking at this, Even! I haven't been able to reproduce this outside the R context, and am now somewhat confused whether this has disappeared in the R context or not. If not, I'll get back here to dive into it further.