qgis_process with algorithms using a CRS: error and a faulty message

[florisvdh]

What is the bug or the crash?

An error is reported while requesting help or while running an algorithm with a crs type argument.

• For qgis_process help, the ERRORs only occur when the argument has a default value.
• In qgis_process run:
  • the ERRORs come up
  • however the process does execute successfully
  • there's also a faulty message Using non-preferred coordinate operation between and EPSG:4326 (see example below). Note the irrelevant EPSG:4326 (it's probably taking that from the default value), since in the example the source and target CRS just use the OSGB_1936 datum.

Steps to reproduce the issue

$ qgis_process help native:reprojectlayer 1> /dev/null 
ERROR: Status 2: File EPSG:4326 could not be found
ERROR: Status 2: File EPSG:4326 could not be found
$ 
$ qgis_process help native:creategrid 1> /dev/null
ERROR: Status 2: File ProjectCrs could not be found
ERROR: Status 2: File ProjectCrs could not be found
$
$ # no default value here:
$ qgis_process help grass:v.proj 1> /dev/null

$ wget -q https://github.com/r-spatial/sf/raw/main/inst/gpkg/b_pump.gpkg
$ 
$ gdalsrsinfo b_pump.gpkg -o wkt2_2019 | head -3

PROJCRS["Transverse_Mercator",
    BASEGEOGCRS["GCS_OSGB 1936",
$ 
$ qgis_process run native:reprojectlayer --INPUT=b_pump.gpkg --TARGET_CRS='EPSG:4277' --OUTPUT=out.gpkg                

----------------
Inputs
----------------

INPUT:	b_pump.gpkg
OUTPUT:	out.gpkg
TARGET_CRS:	EPSG:4277


Using non-preferred coordinate operation between  and EPSG:4326. Using +proj=pipeline +step +inv +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.999601 +x_0=400000 +y_0=-100000 +ellps=airy +step +proj=push +v_3 +step +proj=cart +ellps=airy +step +proj=helmert +x=446.448 +y=-125.157 +z=542.06 +rx=0.15 +ry=0.247 +rz=0.842 +s=-20.489 +convention=position_vector +step +inv +proj=cart +ellps=WGS84 +step +proj=pop +v_3 +step +proj=unitconvert +xy_in=rad +xy_out=deg, preferred +proj=pipeline +step +inv +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.999601 +x_0=400000 +y_0=-100000 +ellps=airy +step +proj=hgridshift +grids=uk_os_OSTN15_NTv2_OSGBtoETRS.tif +step +proj=unitconvert +xy_in=rad +xy_out=deg.
ERROR: Status 2: File EPSG:4277 could not be found
ERROR: Status 2: File EPSG:4277 could not be found

----------------
Results
----------------

OUTPUT:	out.gpkg
$ 
$ ls out.gpkg
out.gpkg
$ 
$ gdalsrsinfo out.gpkg -o wkt2_2019 | head -3

GEOGCRS["OSGB36",
    DATUM["Ordnance Survey of Great Britain 1936",

Versions

$ qgis_process --version
QGIS 3.36.3-Maidenhead 'Maidenhead' (2df9655469b)
QGIS code revision 2df9655469b
Qt version 5.15.3
Python version 3.10.12
GDAL/OGR version 3.8.4
PROJ version 9.3.1
EPSG Registry database version v10.098 (2023-11-24)
GEOS version 3.12.1-CAPI-1.18.1
SQLite version 3.37.2
OS Linux Mint 21.3

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

No response

[agiudiceandrea]

At least the "ERROR: Status 2: File ... could not be found " issue didn't occur using QGIS 3.28.

It seems to me the error message is caused by p->valueAsString( p->defaultValue(), context, ok ) when the following line in QgsProcessingExec::showAlgorithmHelp is executed:

QGIS/src/process/qgsprocess.cpp

Line 910 in 040e231

std::cout << QStringLiteral( "\tDefault value:\t%1\n" ).arg( p->valueAsString( p->defaultValue(), context, ok ) ).toLocal8Bit().constData();

In fact, when the following code is executed in the Python console of QGIS 3.34 or QGIS 3.36:

context = QgsProcessingContext()
alg = QgsApplication.processingRegistry().algorithmById( "native:reprojectlayer" )
defs = alg.parameterDefinitions()
p = defs[1]
p.valueAsString( p.defaultValue(), context)

the output is ('EPSG:4326', True) and the following error is displayed in the OGR tab of the Log Messages Panel:
WARNING Cannot open EPSG:4326 ().()
The same warning is displayed even just opening the algorithm dialog window.

[nyalldawson]

Hmm, this sounds a little like the issue addressed by #56292

Maybe a similar cause for this one..