ds = DataSource('/path/to/your/cities.shp') fails on first try (GDALException Unknown error code: "198770787"), but works on second

[Etiënne Thomassen]

I can not create a DataSource from a gpx file. It returns GDALException Unknown error code: "198770787" with the error code number seemingly random. However on the second try it works. And it does not even need to be the same file.

Python 3.6.0 (default, Dec 24 2016, 08:01:42) 
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from django.contrib.gis.gdal import DataSource
>>> ds = DataSource('gpxfile1.gpx')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/etienne/.virtualenvs/venv1/lib/python3.6/site-packages/django/contrib/gis/gdal/datasource.py", line 64, in __init__
    Driver.ensure_registered()
  File "/Users/etienne/.virtualenvs/venv1/lib/python3.6/site-packages/django/contrib/gis/gdal/driver.py", line 83, in ensure_registered
    rcapi.register_all()
  File "/Users/etienne/.virtualenvs/venv1/lib/python3.6/site-packages/django/contrib/gis/gdal/prototypes/errcheck.py", line 119, in check_errcode
    check_err(result, cpl=cpl)
  File "/Users/etienne/.virtualenvs/venv1/lib/python3.6/site-packages/django/contrib/gis/gdal/error.py", line 74, in check_err
    raise GDALException('Unknown error code: "%s"' % code)
django.contrib.gis.gdal.error.GDALException: Unknown error code: "-1935278031"
>>> ds = DataSource('gpxfile2.gpx')
>>> ds.layer_count
5

This post on StackOverflow pointed me in this direction: ​http://stackoverflow.com/questions/41775536/datasource-gdalexception-unknown-error-code-474873798

Strangely, I can now get it to work doing this in my app:

try:
    datasource = DataSource(target_path)
except:
    datasource = DataSource(target_path)

Btw this part of my app stopped working migrating from Django 1.8 and Python 2.7 to Django 1.9 and Python 3.6. Now on Django 1.10 and Python 3.6

[Tim Graham]

Can you provide the gpx file in question? It would be helpful if you could ​bisect to find the Django commit where the behavior changed.

[Etiënne Thomassen]

Example gpx file (waypoints and tracks do not represent anything in real world). But any valid gpx file triggers the error

[Etiënne Thomassen]

Replying to Tim Graham:

Can you provide the gpx file in question? It would be helpful if you could ​bisect to find the Django commit where the behavior changed.

Added an example gpx file that triggers the error. But any valid gpx file does so. Will look into bisect.

[Sergey Fedoseev]

Replying to Etiënne Thomassen:

I can't reproduce it. I tried both on master and on 1.10.

Could you try to replace

register_all = void_output(std_call('GDALAllRegister'), [])

with

register_all = void_output(std_call('GDALAllRegister'), [], errcheck=False)

in django/contrib/gis/gdal/prototypes/raster.py and say if it works for you?

[Claude Paroz]

I think knowing the GDAL version on tested systems might be a key here.

[Etiënne Thomassen]

Replying to Claude Paroz:

I think knowing the GDAL version on tested systems might be a key here.

I am using GDAL 2.1.2, released 2016/10/24 (with Django 1.10 and Python 3.6)

Previous version was 1.10.1 (with Django 1.8 and Python 2.7)

[Claude Paroz]

I cannot reproduce but suspect the fix proposed by Sergei should work for you. Please try and report.

[Etiënne Thomassen]

Replying to Sergey Fedoseev:

Replying to Etiënne Thomassen:

I can't reproduce it. I tried both on master and on 1.10.

Could you try to replace

register_all = void_output(std_call('GDALAllRegister'), [])

with

register_all = void_output(std_call('GDALAllRegister'), [], errcheck=False)

in django/contrib/gis/gdal/prototypes/raster.py and say if it works for you?

This works!

[Etiënne Thomassen]

Replying to Claude Paroz:

I cannot reproduce but suspect the fix proposed by Sergei should work for you. Please try and report.

Thanks, I somehow missed Sergey's comment. He is right.

[Sergey Fedoseev]

​PR

[Tim Graham <timograham@…>]

In 7063a855:

Fixed #27960 -- Set errcheck=False for GDALAllRegister to prevent crash.

GDALAllRegister returns void so errcheck is not needed.

[Tim Graham <timograham@…>]

In a937785e:

[1.11.x] Fixed #27960 -- Set errcheck=False for GDALAllRegister to prevent crash.

GDALAllRegister returns void so errcheck is not needed.

Backport of 7063a85579f40585f2601ba6e6887b0982e7ce43 from master