[Qgis-user] removing fields from drag and drop designer (leads to segmentation fault)

[Roland Berger]

Hi

I would like to achieve programmatically the equivalent of removing a 
field from the drag an drop designer of a layers "Attributes Form".
Since there is no method to remove a field, the way to do it, is to 
clearTabs() ( 
https://qgis.org/pyqgis/3.34/core/QgsEditFormConfig.html#qgis.core.QgsEditFormConfig.clearTabs 
) and then to re-add the fields again.
If I do that inside QGIS it crashes. If I do that with standalone 
scripts I get a segmentation fault ([1]    4828 segmentation fault (core 
dumped) ).
Here is the code you can paste into qgis python console editor. It will 
first setup a layer with 2 fields and then try to remove one of the 
fields again. You can comment the last line to set thins up first and 
rerun it with the uncommented line.

So the question is:

 1. Does QGIS crash in our environment too? If not, what is your
    environment and version in use?
 2. Did I miss something in the API?
 3. Do I do it the wrong way?
 4. If yes, how to do it properly?
 5. Is it a bug in QGIS or in the Python API?

Thanks
Roland

Paste this code into a QGIS Python Console Editor and run it:

# =================

# Setup Layer with 2 fields

# =================

# Create a vector layer

layer = QgsVectorLayer("Point?crs=EPSG:4326", "MyLayer", "memory")

if not layer.isValid():

     print("Failed to create the layer!")

     sys.exit(1)

# Add fields to the layer

layer_data_provider = layer.dataProvider()

layer_data_provider.addAttributes([QgsField("field1", QVariant.String), QgsField("field2", QVariant.String)])

layer.updateFields()

# Add a feature to the layer

feature = QgsFeature(layer.fields())

feature.setGeometry(QgsGeometry.fromPointXY(QgsPointXY(0, 0)))

feature.setAttribute("field1", "value1")

feature.setAttribute("field2", "value2")

layer_data_provider.addFeature(feature)

layer.updateExtents()

# Get the current edit form configuration

edit_form_config = layer.editFormConfig()

# Ensure the layout is set to use the tab layout

edit_form_config.setLayout(QgsEditFormConfig.TabLayout)

# Apply the updated edit form configuration to the layer

layer.setEditFormConfig(edit_form_config)

# Add the layer to the project

project = QgsProject.instance()

project.addMapLayer(layer)

# =================

# Remove field2 from tab layout

# =================

# List of fields to retain

fields_to_retain = ['field2']

edit_form_config = layer.editFormConfig()

tabs = edit_form_config.tabs()

edit_form_config.clearTabs()

for tab in tabs:

     if tab.name() in fields_to_retain:

         edit_form_config.addTab(tab)

# layer.setEditFormConfig(edit_form_config) # --> QGIS Crashes after that in my case




The QGIS Version I use:

QGIS version

	

3.34.3-Prizren

	

QGIS code revision

	

47373234acd <https://github.com/qgis/QGIS/commit/47373234acd>

Qt version

	

5.15.3

Python version

	

3.10.12






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