"Duplicate Layer" does not copy some custom properties #60884

Alex-Kent · 2025-03-06T23:41:56Z

What is the bug or the crash?

Observed behavior
When "Duplicate Layer" is used any custom properties set for the original layer via the layer tree interface are not copied to the new layer.

Expected behavior
All custom properties set for the original layer should also be set in the duplicate layer.

Additional notes
If "Copy Layer" or "Copy Group" followed by "Paste Layer/Group" is used then all custom properties are preserved in the new layers/groups.

It appears that there are two sets of custom properties for each layer/group: those set via the layer tree (in QgsProject.instance().layerTreeRoot()) and those set via the set of map layers (in QgsProject.instance().mapLayers()). For copy/paste custom properties for both are carried over; for duplicate only those in the latter are.

Steps to reproduce the issue

Create a new empty project
Create a new Temporary Scratch Layer (of any geometry type)
Open the Python console (Plugins→Python Console) and run:

def ShowValues():
    print("Via QgsProject.instance().mapLayers().values():")
    for layer in QgsProject.instance().mapLayers().values():
        name = layer.id()
        print(f"{name}: map-layers-key = { layer.customProperty('map-layers-key') }")
        print(f"{name}: layer-tree-key = { layer.customProperty('layer-tree-key') }")
    print()
    print("Via QgsProject.instance().layerTreeRoot().children():")
    for layer in QgsProject.instance().layerTreeRoot().children():
        name = layer.layerId()
        print(f"{name}: map-layers-key = { layer.customProperty('map-layers-key') }")
        print(f"{name}: layer-tree-key = { layer.customProperty('layer-tree-key') }")

Show the values:

ShowValues()

Via QgsProject.instance().mapLayers().values(): New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: map-layers-key = None New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: layer-tree-key = None

Via QgsProject.instance().layerTreeRoot().children(): New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: map-layers-key = None New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: layer-tree-key = None

[The specific layer IDs shown will be different from those in this example.]

Set a custom property via the map layers interface:

for layer in QgsProject.instance().mapLayers().values():
    layer.setCustomProperty("map-layers-key", "map layers value")

ShowValues()

Via QgsProject.instance().mapLayers().values(): New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: map-layers-key = map layers value New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: layer-tree-key = None

Via QgsProject.instance().layerTreeRoot().children(): New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: map-layers-key = None New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: layer-tree-key = None

Set a custom property via the layer tree interface:

for layer in QgsProject.instance().layerTreeRoot().children():
    layer.setCustomProperty("layer-tree-key", "layer tree value")

ShowValues()

Via QgsProject.instance().mapLayers().values(): New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: map-layers-key = map layers value New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: layer-tree-key = None

Via QgsProject.instance().layerTreeRoot().children(): New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: map-layers-key = None New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: layer-tree-key = layer tree value

Copy and paste the layer:

Select the layer in the Layers panel
In the top menu select Layer→Copy Layer
In the top menu select Layer→Paste Layer/Group

Show the values:

ShowValues()

Via QgsProject.instance().mapLayers().values(): New_scratch_layer_e7cb95fb_f982_48d1_86b2_a3a23d9c184c: map-layers-key = map layers value New_scratch_layer_e7cb95fb_f982_48d1_86b2_a3a23d9c184c: layer-tree-key = None New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: map-layers-key = map layers value New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: layer-tree-key = None

Via QgsProject.instance().layerTreeRoot().children(): New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: map-layers-key = None New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: layer-tree-key = layer tree value New_scratch_layer_e7cb95fb_f982_48d1_86b2_a3a23d9c184c: map-layers-key = None New_scratch_layer_e7cb95fb_f982_48d1_86b2_a3a23d9c184c: layer-tree-key = layer tree value

All custom properties are present in the copied layer (this is the expected behavior).

Delete the newly-created layer (the second layer in the Layers list)
Duplicate the original layer:

Right-click on the layer in the Layers panel and select Duplicate Layer

Show the values:

ShowValues()

Via QgsProject.instance().mapLayers().values(): New_scratch_layer_1225a646_ca6e_4b7e_b346_3875b76e034d: map-layers-key = map layers value New_scratch_layer_1225a646_ca6e_4b7e_b346_3875b76e034d: layer-tree-key = None New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: map-layers-key = map layers value New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: layer-tree-key = None

Via QgsProject.instance().layerTreeRoot().children(): New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: map-layers-key = None New_scratch_layer_f5cae7b8_e1a0_4a04_803c_476d3baebdb6: layer-tree-key = layer tree value New_scratch_layer_1225a646_ca6e_4b7e_b346_3875b76e034d: map-layers-key = None New_scratch_layer_1225a646_ca6e_4b7e_b346_3875b76e034d: layer-tree-key = None

Only the value set via the map layers interface is present in the duplicate layer.

The value set via the layer tree interface is not present in the duplicate layer (but it should be present).

Versions

QGIS version	3.22.4-Białowieża	QGIS code branch	Release 3.22
Qt version	5.15.3
Python version	3.10.3
…
OS version	Ubuntu 22.04.5 LTS

This version of QGIS is the latest version for this [actively-supported] Ubuntu LTS release.

Edit: I also built QGIS from source, behavior is the same.

QGIS version	3.43.0-Master
QGIS code revision	`9a1d453`

Libraries
Qt version	5.15.3
Python version	3.10.12
…
OS version	Ubuntu 22.04.5 LTS

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

I encountered this while working on improvements to the Layer Color Plugin. That plugin uses custom properties (via the layer tree interface) to store layer colors.

The text was updated successfully, but these errors were encountered:

Alex-Kent · 2025-03-07T19:30:22Z

I've found the calls that handle this (and a potential fix, see the end of the comment).

For copy/paste (correct behavior):

In method void QgisApp::copyLayer():

QGIS/src/app/qgisapp.cpp

Line 10369 in 9a1d453

    
           bool saved = QgsLayerDefinition::exportLayerDefinition( doc, mLayerTreeView->selectedNodes(), errorMessage, readWriteContext );

In method void QgisApp::pasteLayer():

QGIS/src/app/qgisapp.cpp

Line 10405 in 9a1d453

    
           bool loaded = QgsLayerDefinition::loadLayerDefinition( doc, QgsProject::instance(), root, errorMessage, readWriteContext, insertionMethod, &insertionPoint );

For duplicate layer (incorrect behavior):

In method void QgisApp::duplicateLayers( const QList<QgsMapLayer *> &lyrList ):

For Vector layers:

QGIS/src/app/qgisapp.cpp

Line 11709 in 9a1d453

dupLayer = vlayer->clone();

For PointCloud, Raster, VectorTile, Mesh, Annotation, and TiledScene layers:

QGIS/src/app/qgisapp.cpp

Line 11721 in 9a1d453

dupLayer = selectedLyr->clone();

The actual code that copies the custom properties appears to be:

In method void QgsMapLayer::clone( QgsMapLayer *layer ) const:

QGIS/src/core/qgsmaplayer.cpp

Line 160 in 9a1d453

layer->setCustomProperties( mCustomProperties );

However this only copies the properties for the QgsMapLayer; it does not copy those of the associated QgsLayerTreeLayer.

After the QgsMapLayer has been cloned it is manually added to the layer tree as a QgsLayerTreeLayer. Next any necessary additional layer-specific tasks are performed:

QGIS/src/app/qgisapp.cpp

Lines 11766 to 11779 in 9a1d453

    
           // always set duplicated layers to not visible so layer can be configured before being turned on 
        
           nodeDupLayer->setItemVisibilityChecked( false ); 
        
           // duplicate the layer style 
        
           QString errMsg; 
        
           QDomDocument style; 
        
           QgsReadWriteContext context; 
        
           selectedLyr->exportNamedStyle( style, errMsg, context ); 
        
           if ( errMsg.isEmpty() ) 
        
             dupLayer->importNamedStyle( style, errMsg ); 
        
           if ( !errMsg.isEmpty() ) 
        
             visibleMessageBar()->pushMessage( errMsg, tr( "Cannot copy style to duplicated layer." ), Qgis::MessageLevel::Critical ); 
        
           else if ( qobject_cast<QgsVectorLayer *>( dupLayer ) ) 
        
             visibleMessageBar()->pushMessage( tr( "Layer duplication complete" ), dupLayer->providerType() != QLatin1String( "memory" ) ? tr( "Note that it's using the same data source." ) : QString(), Qgis::MessageLevel::Info );

Perhaps the custom properties for the new QgsLayerTreeLayer could be set here [line 11768], maybe something like:

    // duplicate the layer tree layer's custom properties
    for ( const QString &key : nodeSelectedLyr->customProperties() )
    {
        nodeDupLayer->setCustomProperty(key, nodeSelectedLyr->customProperty(key));
    }

[The above code has not been tested.]

Thoughts?

…ixes qgis#60884]

Alex-Kent · 2025-03-07T22:05:52Z

I downloaded the current QGIS source (9a1d453) and tested the fix I suggested above. The fix worked properly and resolves this issue. The linked PR (#60897) contains this fix.

…ixes #60884]

Alex-Kent added the Bug Either a bug report, or a bug fix. Let's hope for the latter! label Mar 6, 2025

This was referenced Mar 7, 2025

Colors are tied to the displayed layer/group labels, not to the individual layers/groups [with fix] Spartacus1/LayerColorPlugin#2

Open

Highlight colors are now applied to specific layers or groups [fixes #2] Spartacus1/LayerColorPlugin#3

Open

Alex-Kent added a commit to Alex-Kent/QGIS that referenced this issue Mar 7, 2025

When duplicating a layer copy layer tree layer's custom properties [f…

58affe4

…ixes qgis#60884]

Alex-Kent mentioned this issue Mar 7, 2025

When duplicating a layer copy layer tree layer's custom properties [fixes #60884] #60897

Merged

nyalldawson closed this as completed in #60897 Mar 11, 2025

nyalldawson closed this as completed in d6f93cb Mar 11, 2025

qgis-bot pushed a commit that referenced this issue Mar 11, 2025

When duplicating a layer copy layer tree layer's custom properties [f…

e10d5ad

…ixes #60884]

qgis-bot pushed a commit that referenced this issue Mar 11, 2025

When duplicating a layer copy layer tree layer's custom properties [f…

4e33a8a

…ixes #60884]

nyalldawson pushed a commit that referenced this issue Mar 11, 2025

When duplicating a layer copy layer tree layer's custom properties [f…

12539e7

…ixes #60884]

nyalldawson pushed a commit that referenced this issue Mar 11, 2025

When duplicating a layer copy layer tree layer's custom properties [f…

530471a

…ixes #60884]

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"Duplicate Layer" does not copy some custom properties #60884

"Duplicate Layer" does not copy some custom properties #60884

Alex-Kent commented Mar 6, 2025 •

edited

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Alex-Kent commented Mar 7, 2025

Alex-Kent commented Mar 7, 2025

"Duplicate Layer" does not copy some custom properties #60884

"Duplicate Layer" does not copy some custom properties #60884

Comments

Alex-Kent commented Mar 6, 2025 • edited Loading

What is the bug or the crash?

Steps to reproduce the issue

Versions

Supported QGIS version

New profile

Additional context

Alex-Kent commented Mar 7, 2025

For copy/paste (correct behavior):

For duplicate layer (incorrect behavior):

Alex-Kent commented Mar 7, 2025

Alex-Kent commented Mar 6, 2025 •

edited

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