[QGIS-Developer] [Qgis-user] QgsBlockingNetworkRequest causes SIGSEGV

Sun May 23 12:23:14 PDT 2021

Hi Frank,

Moving this to dev list as I think that is more appropriate for this question.

I can easily replicate your issue (on Debian Testing, see below the coredump.txt)

BUT: are you sure you want to use it outside of QGIS in a standalone script? Because I think these things will need some kind of Qt-Application to run... (as the Application is responsible for stuff like NetWorkProxies, and has the actual 'NetWorkAccessManager'?). But all just guessing...

Using your code in a minimal HelloWorldPlugin (attached), it just works. (the url I'm using just sents 'ok' as text).

So: I would not try to run it in a standalone script without a QGIS application context, but in a plugin it 'works'?

Regards,

Richard Duivenvoorde

           PID: 18825 (gnome-shell)
           UID: 1000 (richard)
           GID: 1000 (richard)
        Signal: 11 (SEGV)
     Timestamp: Sat 2021-03-06 16:16:12 CET (3min 52s ago)
  Command Line: /usr/bin/gnome-shell
    Executable: /usr/bin/gnome-shell
 Control Group: /user.slice/user-1000.slice/user at 1000.service/session.slice/org.gnome.Shell at wayland.service
          Unit: user at 1000.service
     User Unit: org.gnome.Shell at wayland.service
         Slice: user-1000.slice
     Owner UID: 1000 (richard)
       Boot ID: 4aaa450c98ed47b299254a234e463620
    Machine ID: df76fc45bc594c71b48c4eb87da1774e
      Hostname: oost
       Storage: /var/lib/systemd/coredump/core.gnome-shell.1000.4aaa450c98ed47b299254a234e463620.18825.1615043772000000.zst
       Message: Process 18825 (gnome-shell) of user 1000 dumped core.
················
                Stack trace of thread 18825:
                #0  0x00007fe88cf6003d g_type_check_instance (libgobject-2.0.so.0 + 0x3503d)
                #1  0x00007fe88cf50883 g_signal_handler_disconnect (libgobject-2.0.so.0 + 0x25883)
                #2  0x00007fe88cf42eef n/a (libgobject-2.0.so.0 + 0x17eef)
                #3  0x00007fe88ce2dfae n/a (libglib-2.0.so.0 + 0x31fae)
                #4  0x00007fe88cf440a3 g_object_unref (libgobject-2.0.so.0 + 0x190a3)
                #5  0x00007fe88d1c1df8 n/a (libgnome-shell.so + 0x21df8)
                #6  0x00007fe88cf440a3 g_object_unref (libgobject-2.0.so.0 + 0x190a3)
                #7  0x00007fe88c546c7e n/a (libgjs.so.0 + 0x47c7e)
                #8  0x00007fe88c546d5a n/a (libgjs.so.0 + 0x47d5a)
                #9  0x00007fe88c542588 n/a (libgjs.so.0 + 0x43588)
                #10 0x00007fe88c542673 n/a (libgjs.so.0 + 0x43673)
                #11 0x00007fe88aa3681c n/a (libmozjs-78.so.0 + 0x65381c)
                #12 0x00007fe88aa073be n/a (libmozjs-78.so.0 + 0x6243be)
                #13 0x00007fe88aa10c02 n/a (libmozjs-78.so.0 + 0x62dc02)
                #14 0x00007fe88aa18ac5 n/a (libmozjs-78.so.0 + 0x635ac5)
                #15 0x00007fe88aa330b6 n/a (libmozjs-78.so.0 + 0x6500b6)
                #16 0x00007fe88aa337dc n/a (libmozjs-78.so.0 + 0x6507dc)
                #17 0x00007fe88aa33a6c n/a (libmozjs-78.so.0 + 0x650a6c)
                #18 0x00007fe88aa33d25 n/a (libmozjs-78.so.0 + 0x650d25)
                #19 0x00007fe88c55dc1f n/a (libgjs.so.0 + 0x5ec1f)
                #20 0x00007fe88ce4e8f4 n/a (libglib-2.0.so.0 + 0x528f4)
                #21 0x00007fe88ce4dd6f g_main_context_dispatch (libglib-2.0.so.0 + 0x51d6f)
                #22 0x00007fe88ce4e118 n/a (libglib-2.0.so.0 + 0x52118)
                #23 0x00007fe88ce4e40b g_main_loop_run (libglib-2.0.so.0 + 0x5240b)
                #24 0x00007fe88c27627e meta_init (libmutter-7.so.0 + 0xc529e)
                #25 0x00007ffd8eec1f9c n/a (n/a + 0x0)
                #26 0x455059545f4e4f49 n/a (n/a + 0x0)

On 5/22/21 3:32 PM, Frank Broniewski wrote:
> Hi all,
> 
> I am trying to replace the `requests` module with QgsBlockingNetworkRequest to 
> remove a potentially unnecessary dependency from my QGIS plugin. But I am 
> having trouble using it so far as Python crashes on the command line with a 
> SIGSEGV all the time. First of all, things work from within the QGIS Python 
> shell. But not from the command line outside of QGIS.
> 
> I am running Fedora 34 KDE spin, but I also tested on Ubuntu 20.04 with the 
> same failure. It is rather simple to reproduce on my end:
> 
> 1) open a Python3 shell
> 2) >>> import qgis
>>>> from qgis.core import QgsBlockingNetworkRequest as bnr
>>>> r = bnr()
> fish: Job 1, 'python' terminated by signal SIGSEGV (Adressbereichsfehler)
> 
> I did look at the unittest Testcases  [1] for the class, e.g the 
> testFetchEmptyUrl class method and do not see anything that I could have 
> changed to avoid the SIGSEGV.
> 
> So, can I not use QgsBlockingNetworkRequest outside of QGIS or am I just 
> missing something?
> 
> Any tips are greatly appreciated,
> Frank
> 
> 
> [1] https://github.com/qgis/QGIS/blob/master/tests/src/python/
> test_qgsblockingnetworkrequest.py
> 
> 
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