Running model freezes QGIS

[gioman]

What is the bug or the crash?

While testing for https://github.com/qgis/QGIS/issues/45676

I discovered that (at least) with the attached project/data

https://github.com/qgis/QGIS/files/7419765/contourtest.zip

and the attached model

https://github.com/qgis/QGIS/files/7424186/contours_from_text_dem.zip

running the model on QGIS 3.22/master (on Windows) leads to a complete freeze. The model runs fine on 3.16.12.

Not sure if is related or not but on a new QGIS profile on 3.22/master, "add model to toolbox" won't result in the model being added to Processing, not even after a restart (works fine on 3.16.12).

Steps to reproduce the issue

See above.

Versions

3.22 and master from osgeo4w on Windows 10.

Supported QGIS version

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

New profile

• [X] I tried with a new QGIS profile

Additional context

Due to the seriousness of this bug (if confirmed) I would appreciate if others can check so to exclude a local issue.

[nicogodet]

I can confirm both issues on 3.22 windows

[ulmi]

I can confirm the issue on windows, with 3.22 from osgeo4w on Windows 10. The model freezes upon running it.

On linux (mint 20.2) with 3.22, the model runs with no issue.

Not sure if is related or not but on a new QGIS profile on 3.22/master, "add model to toolbox" won't result in the model being added to Processing, not even after a restart (works fine on 3.16.12).

Also there is a bug, not sure if reported already, related with adding models to the processing toolbox, on Windows and on Linux.

[gioman]

Thanks @ulmi @nicogodet Let's wait and see if the two issues are related before splitting the ticket.

[nicogodet]

Opening the model, convert it to python script and it runs smoothly.

[gioman]

Opening the model, convert it to python script and it runs smoothly.

Confirmed here too.

[nicogodet]

I can crash Linux with a model invoking a gdal alg too.

[alexbruy]

IMHO, there are two different issues here. First is one is about QGIS freezes/crash when executing a model containing GDAL algorithms. This happens only with GDAL algorithms and only on Windows. Most likely this is because of the changes in the way how GDAL algorithms are called (via QgsBlockingProcess).

Issue with adding a model to toolbox is not related. Moreover, I can't confirm it completely, in my tests I can't see a new model immediately after adding it, but restarting QGIS helps.

[nicogodet]

@alexbruy I successfully crashed QGIS on Debian. I will retry

AFAIK QgsBlockingProcess is used in 3.20 too

[nyalldawson]

@alexbruy

Most likely this is because of the changes in the way how GDAL algorithms are called (via QgsBlockingProcess).

I think that's unlikely -- we switched to QgsBlockingProcess in 3.18 and there's been no related bug reports in the meantime

[nicogodet]

@nyalldawson

there's been no related bug reports in the meantime

I think it's not true -> https://github.com/qgis/QGIS/issues/42724

[alexbruy]

@nyalldawson I have made such assumption because models with algorithms which use subprocess to run external tools work without any issues, while models with GDAL algorithms cause freeze.

[gioman]

Issue with adding a model to toolbox is not related.

@alexbruy I'm splitting the issue then.

[gioman]

IMHO, there are two different issues here. First is one is about QGIS freezes/crash when executing a model containing GDAL algorithms. This happens only with GDAL algorithms and only on Windows. Most likely this is because of the changes in the way how GDAL algorithms are called (via QgsBlockingProcess).

Issue with adding a model to toolbox is not related. Moreover, I can't confirm it completely, in my tests I can't see a new model immediately after adding it, but restarting QGIS helps.

@alexbruy I split the ticket here https://github.com/qgis/QGIS/issues/45730

[nyalldawson]

see https://github.com/qgis/QGIS/pull/45128#issuecomment-958529173 -- caused by the update to the sip library

[nicogodet]

Fixed in OSGeo4W v2 3.22.0-4 and 3.16.12-4