Add new Field Domain merge policy

python/PyQt6/core/auto_additions/qgis.py

@@ -6928,6 +6928,7 @@ Qgis.FieldDomainSplitPolicy.baseClass = Qgis
 Qgis.FieldDomainMergePolicy.DefaultValue.__doc__ = "Use default field value"
 Qgis.FieldDomainMergePolicy.Sum.__doc__ = "Sum of values"
 Qgis.FieldDomainMergePolicy.GeometryWeighted.__doc__ = "New values are computed as the weighted average of the source values"
+Qgis.FieldDomainMergePolicy.UnsetField.__doc__ = "Clears the field value so that the data provider backend will populate using any backend triggers or similar logic \n.. versionadded:: 3.44"
 Qgis.FieldDomainMergePolicy.__doc__ = """Merge policy for field domains.
 
 When a feature is built by merging multiple features, defines how the value of
@@ -6938,6 +6939,10 @@ attributes following the domain are computed.
 * ``DefaultValue``: Use default field value
 * ``Sum``: Sum of values
 * ``GeometryWeighted``: New values are computed as the weighted average of the source values
+* ``UnsetField``: Clears the field value so that the data provider backend will populate using any backend triggers or similar logic
+
+  .. versionadded:: 3.44
+
 
 """
 # --

python/PyQt6/core/auto_generated/qgis.sip.in

@@ -2112,6 +2112,7 @@ The development version
       DefaultValue,
       Sum,
       GeometryWeighted,
+      UnsetField,
     };
 
     enum class FieldDuplicatePolicy /BaseType=IntEnum/

python/core/auto_additions/qgis.py

@@ -6862,6 +6862,7 @@ Qgis.FieldDomainSplitPolicy.baseClass = Qgis
 Qgis.FieldDomainMergePolicy.DefaultValue.__doc__ = "Use default field value"
 Qgis.FieldDomainMergePolicy.Sum.__doc__ = "Sum of values"
 Qgis.FieldDomainMergePolicy.GeometryWeighted.__doc__ = "New values are computed as the weighted average of the source values"
+Qgis.FieldDomainMergePolicy.UnsetField.__doc__ = "Clears the field value so that the data provider backend will populate using any backend triggers or similar logic \n.. versionadded:: 3.44"
 Qgis.FieldDomainMergePolicy.__doc__ = """Merge policy for field domains.
 
 When a feature is built by merging multiple features, defines how the value of
@@ -6872,6 +6873,10 @@ attributes following the domain are computed.
 * ``DefaultValue``: Use default field value
 * ``Sum``: Sum of values
 * ``GeometryWeighted``: New values are computed as the weighted average of the source values
+* ``UnsetField``: Clears the field value so that the data provider backend will populate using any backend triggers or similar logic
+
+  .. versionadded:: 3.44
+
 
 """
 # --

python/core/auto_generated/qgis.sip.in

@@ -2112,6 +2112,7 @@ The development version
       DefaultValue,
       Sum,
       GeometryWeighted,
+      UnsetField,
     };
 
     enum class FieldDuplicatePolicy

src/app/browser/qgsinbuiltdataitemproviders.cpp

@@ -2244,6 +2244,9 @@ QString QgsFieldDomainDetailsWidget::htmlMetadata( QgsFieldDomain *domain, const
     case Qgis::FieldDomainMergePolicy::GeometryWeighted:
       metadata += tr( "Use geometry weighted value" );
       break;
+    case Qgis::FieldDomainMergePolicy::UnsetField:
+      metadata += tr( "Unset field" );
+      break;
   }
 
   metadata += QLatin1String( "</table>\n<br><br>" );

src/core/qgis.h

@@ -3729,6 +3729,7 @@ class CORE_EXPORT Qgis
       DefaultValue, //!< Use default field value
       Sum, //!< Sum of values
       GeometryWeighted, //!< New values are computed as the weighted average of the source values
+      UnsetField, //!< Clears the field value so that the data provider backend will populate using any backend triggers or similar logic \since QGIS 3.44
     };
     Q_ENUM( FieldDomainMergePolicy )
 

src/core/qgsogrutils.cpp

@@ -2298,6 +2298,10 @@ OGRFieldDomainH QgsOgrUtils::convertFieldDomain( const QgsFieldDomain *domain )
     case Qgis::FieldDomainMergePolicy::Sum:
       OGR_FldDomain_SetMergePolicy( res, OFDMP_SUM );
       break;
+
+    case Qgis::FieldDomainMergePolicy::UnsetField:
+      // not supported
+      break;
   }
 
   switch ( domain->splitPolicy() )