Duplicate policy on QgsFields when duplicate features

python/PyQt6/core/auto_additions/qgis.py

@@ -3204,6 +3204,13 @@
 # --
 Qgis.FieldDomainMergePolicy.baseClass = Qgis
 # monkey patching scoped based enum
+Qgis.FieldDomainDuplicatePolicy.DefaultValue.__doc__ = "Use default field value"
+Qgis.FieldDomainDuplicatePolicy.Duplicate.__doc__ = "Duplicate original value"
+Qgis.FieldDomainDuplicatePolicy.UnsetField.__doc__ = "Clears the field value so that the data provider backend will populate using any backend triggers or similar logic (since QGIS 3.30)"
+Qgis.FieldDomainDuplicatePolicy.__doc__ = "Duplicate policy for field domains.\n\nWhen a feature is duplicated, defines how the value of attributes\nfollowing the domain are computed.\n\n.. versionadded:: 3.38\n\n" + '* ``DefaultValue``: ' + Qgis.FieldDomainDuplicatePolicy.DefaultValue.__doc__ + '\n' + '* ``Duplicate``: ' + Qgis.FieldDomainDuplicatePolicy.Duplicate.__doc__ + '\n' + '* ``UnsetField``: ' + Qgis.FieldDomainDuplicatePolicy.UnsetField.__doc__
+# --
+Qgis.FieldDomainDuplicatePolicy.baseClass = Qgis
+# monkey patching scoped based enum
 Qgis.FieldDomainType.Coded.__doc__ = "Coded field domain"
 Qgis.FieldDomainType.Range.__doc__ = "Numeric range field domain (min/max)"
 Qgis.FieldDomainType.Glob.__doc__ = "Glob string pattern field domain"

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

@@ -1817,6 +1817,13 @@ The development version
       GeometryWeighted,
     };
 
+    enum class FieldDomainDuplicatePolicy /BaseType=IntEnum/
+    {
+      DefaultValue,
+      Duplicate,
+      UnsetField,
+    };
+
     enum class FieldDomainType /BaseType=IntEnum/
     {
       Coded,

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

@@ -466,6 +466,26 @@ be handled during a split operation.
 .. seealso:: :py:func:`splitPolicy`
 
 .. versionadded:: 3.30
+%End
+
+    Qgis::FieldDomainDuplicatePolicy duplicatePolicy() const;
+%Docstring
+Returns the field's duplicate policy, which indicates how field values should
+be handled during a duplicate operation.
+
+.. seealso:: :py:func:`setDuplicatePolicy`
+
+.. versionadded:: 3.38
+%End
+
+    void setDuplicatePolicy( Qgis::FieldDomainDuplicatePolicy policy );
+%Docstring
+Sets the field's duplicate ``policy``, which indicates how field values should
+be handled during a duplicate operation.
+
+.. seealso:: :py:func:`duplicatePolicy`
+
+.. versionadded:: 3.38
 %End
 
     SIP_PYOBJECT __repr__();

python/PyQt6/core/auto_generated/vector/qgsvectorlayer.sip.in

@@ -1935,6 +1935,27 @@ Sets a split ``policy`` for the field with the specified index.
     }
 %End
 
+    void setFieldDuplicatePolicy( int index, Qgis::FieldDomainDuplicatePolicy policy );
+%Docstring
+Sets a duplicate ``policy`` for the field with the specified index.
+
+:raises KeyError: if no field with the specified index exists
+
+.. versionadded:: 3.38
+%End
+
+%MethodCode
+    if ( a0 < 0 || a0 >= sipCpp->fields().count() )
+    {
+      PyErr_SetString( PyExc_KeyError, QByteArray::number( a0 ) );
+      sipIsErr = 1;
+    }
+    else
+    {
+      sipCpp->setFieldDuplicatePolicy( a0, a1 );
+    }
+%End
+
  QSet<QString> excludeAttributesWms() const /Deprecated/;
 %Docstring
 A set of attributes that are not advertised in WMS requests with QGIS server.

python/core/auto_additions/qgis.py

@@ -3149,6 +3149,13 @@
 # --
 Qgis.FieldDomainMergePolicy.baseClass = Qgis
 # monkey patching scoped based enum
+Qgis.FieldDomainDuplicatePolicy.DefaultValue.__doc__ = "Use default field value"
+Qgis.FieldDomainDuplicatePolicy.Duplicate.__doc__ = "Duplicate original value"
+Qgis.FieldDomainDuplicatePolicy.UnsetField.__doc__ = "Clears the field value so that the data provider backend will populate using any backend triggers or similar logic (since QGIS 3.30)"
+Qgis.FieldDomainDuplicatePolicy.__doc__ = "Duplicate policy for field domains.\n\nWhen a feature is duplicated, defines how the value of attributes\nfollowing the domain are computed.\n\n.. versionadded:: 3.38\n\n" + '* ``DefaultValue``: ' + Qgis.FieldDomainDuplicatePolicy.DefaultValue.__doc__ + '\n' + '* ``Duplicate``: ' + Qgis.FieldDomainDuplicatePolicy.Duplicate.__doc__ + '\n' + '* ``UnsetField``: ' + Qgis.FieldDomainDuplicatePolicy.UnsetField.__doc__
+# --
+Qgis.FieldDomainDuplicatePolicy.baseClass = Qgis
+# monkey patching scoped based enum
 Qgis.FieldDomainType.Coded.__doc__ = "Coded field domain"
 Qgis.FieldDomainType.Range.__doc__ = "Numeric range field domain (min/max)"
 Qgis.FieldDomainType.Glob.__doc__ = "Glob string pattern field domain"

python/core/auto_generated/qgis.sip.in

@@ -1817,6 +1817,13 @@ The development version
       GeometryWeighted,
     };
 
+    enum class FieldDomainDuplicatePolicy
+    {
+      DefaultValue,
+      Duplicate,
+      UnsetField,
+    };
+
     enum class FieldDomainType
     {
       Coded,

python/core/auto_generated/qgsfield.sip.in

@@ -466,6 +466,26 @@ be handled during a split operation.
 .. seealso:: :py:func:`splitPolicy`
 
 .. versionadded:: 3.30
+%End
+
+    Qgis::FieldDomainDuplicatePolicy duplicatePolicy() const;
+%Docstring
+Returns the field's duplicate policy, which indicates how field values should
+be handled during a duplicate operation.
+
+.. seealso:: :py:func:`setDuplicatePolicy`
+
+.. versionadded:: 3.38
+%End
+
+    void setDuplicatePolicy( Qgis::FieldDomainDuplicatePolicy policy );
+%Docstring
+Sets the field's duplicate ``policy``, which indicates how field values should
+be handled during a duplicate operation.
+
+.. seealso:: :py:func:`duplicatePolicy`
+
+.. versionadded:: 3.38
 %End
 
     SIP_PYOBJECT __repr__();

python/core/auto_generated/vector/qgsvectorlayer.sip.in

@@ -1935,6 +1935,27 @@ Sets a split ``policy`` for the field with the specified index.
     }
 %End
 
+    void setFieldDuplicatePolicy( int index, Qgis::FieldDomainDuplicatePolicy policy );
+%Docstring
+Sets a duplicate ``policy`` for the field with the specified index.
+
+:raises KeyError: if no field with the specified index exists
+
+.. versionadded:: 3.38
+%End
+
+%MethodCode
+    if ( a0 < 0 || a0 >= sipCpp->fields().count() )
+    {
+      PyErr_SetString( PyExc_KeyError, QByteArray::number( a0 ) );
+      sipIsErr = 1;
+    }
+    else
+    {
+      sipCpp->setFieldDuplicatePolicy( a0, a1 );
+    }
+%End
+
  QSet<QString> excludeAttributesWms() const /Deprecated/;
 %Docstring
 A set of attributes that are not advertised in WMS requests with QGIS server.

src/core/qgis.h

@@ -3203,6 +3203,22 @@ class CORE_EXPORT Qgis
     };
     Q_ENUM( FieldDomainMergePolicy )
 
+    /**
+     * Duplicate policy for field domains.
+     *
+     * When a feature is duplicated, defines how the value of attributes
+     * following the domain are computed.
+     *
+     * \since QGIS 3.38
+     */
+    enum class FieldDomainDuplicatePolicy : int
+    {
+      DefaultValue, //!< Use default field value
+      Duplicate, //!< Duplicate original value
+      UnsetField, //!< Clears the field value so that the data provider backend will populate using any backend triggers or similar logic (since QGIS 3.30)
+    };
+    Q_ENUM( FieldDomainDuplicatePolicy )
+
     /**
      * Types of field domain
      *

src/core/qgsfield.cpp

@@ -706,6 +706,11 @@ bool QgsField::convertCompatible( QVariant &v, QString *errorMessage ) const
   return true;
 }
 
+QgsField::operator QVariant() const
+{
+  return QVariant::fromValue( *this );
+}
+
 void QgsField::setEditorWidgetSetup( const QgsEditorWidgetSetup &v )
 {
   d->editorWidgetSetup = v;
@@ -736,6 +741,16 @@ void QgsField::setSplitPolicy( Qgis::FieldDomainSplitPolicy policy )
   d->splitPolicy = policy;
 }
 
+Qgis::FieldDomainDuplicatePolicy QgsField::duplicatePolicy() const
+{
+  return d->duplicatePolicy;
+}
+
+void QgsField::setDuplicatePolicy( Qgis::FieldDomainDuplicatePolicy policy )
+{
+  d->duplicatePolicy = policy;
+}
+
 /***************************************************************************
  * This class is considered CRITICAL and any change MUST be accompanied with
  * full unit tests in testqgsfield.cpp.
@@ -782,6 +797,7 @@ QDataStream &operator>>( QDataStream &in, QgsField &field )
   quint32 strengthUnique;
   quint32 strengthExpression;
   int splitPolicy;
+  int duplicatePolicy;
 
   bool applyOnUpdate;
 
@@ -796,7 +812,7 @@ QDataStream &operator>>( QDataStream &in, QgsField &field )
 
   in >> name >> type >> typeName >> length >> precision >> comment >> alias
      >> defaultValueExpression >> applyOnUpdate >> constraints >> originNotNull >> originUnique >> originExpression >> strengthNotNull >> strengthUnique >> strengthExpression >>
-     constraintExpression >> constraintDescription >> subType >> splitPolicy >> metadata;
+     constraintExpression >> constraintDescription >> subType >> splitPolicy >> duplicatePolicy >> metadata;
   field.setName( name );
   field.setType( static_cast< QVariant::Type >( type ) );
   field.setTypeName( typeName );
@@ -806,6 +822,7 @@ QDataStream &operator>>( QDataStream &in, QgsField &field )
   field.setAlias( alias );
   field.setDefaultValueDefinition( QgsDefaultValue( defaultValueExpression, applyOnUpdate ) );
   field.setSplitPolicy( static_cast< Qgis::FieldDomainSplitPolicy >( splitPolicy ) );
+  field.setDuplicatePolicy( static_cast< Qgis::FieldDomainDuplicatePolicy >( duplicatePolicy ) );
   QgsFieldConstraints fieldConstraints;
   if ( constraints & QgsFieldConstraints::ConstraintNotNull )
   {

src/core/qgsfield.h

@@ -441,10 +441,7 @@ class CORE_EXPORT QgsField
 #endif
 
     //! Allows direct construction of QVariants from fields.
-    operator QVariant() const
-    {
-      return QVariant::fromValue( *this );
-    }
+    operator QVariant() const;
 
     /**
      * Set the editor widget setup for the field.
@@ -497,6 +494,26 @@ class CORE_EXPORT QgsField
      */
     void setSplitPolicy( Qgis::FieldDomainSplitPolicy policy );
 
+    /**
+     * Returns the field's duplicate policy, which indicates how field values should
+     * be handled during a duplicate operation.
+     *
+     * \see setDuplicatePolicy()
+     *
+     * \since QGIS 3.38
+     */
+    Qgis::FieldDomainDuplicatePolicy duplicatePolicy() const;
+
+    /**
+     * Sets the field's duplicate \a policy, which indicates how field values should
+     * be handled during a duplicate operation.
+     *
+     * \see duplicatePolicy()
+     *
+     * \since QGIS 3.38
+     */
+    void setDuplicatePolicy( Qgis::FieldDomainDuplicatePolicy policy );
+
 #ifdef SIP_RUN
     SIP_PYOBJECT __repr__();
     % MethodCode

src/core/qgsfield_p.h

@@ -84,6 +84,7 @@ class QgsFieldPrivate : public QSharedData
       , constraints( other.constraints )
       , editorWidgetSetup( other.editorWidgetSetup )
       , splitPolicy( other.splitPolicy )
+      , duplicatePolicy( other.duplicatePolicy )
       , isReadOnly( other.isReadOnly )
     {
     }
@@ -99,6 +100,7 @@ class QgsFieldPrivate : public QSharedData
                && ( alias == other.alias ) && ( defaultValueDefinition == other.defaultValueDefinition )
                && ( constraints == other.constraints )  && ( flags == other.flags )
                && ( splitPolicy == other.splitPolicy )
+               && ( duplicatePolicy == other.duplicatePolicy )
                && ( isReadOnly == other.isReadOnly )
                && ( editorWidgetSetup == other.editorWidgetSetup ) );
     }
@@ -144,6 +146,9 @@ class QgsFieldPrivate : public QSharedData
     //! Split policy
     Qgis::FieldDomainSplitPolicy splitPolicy = Qgis::FieldDomainSplitPolicy::Duplicate;
 
+    //! Duplicate policy
+    Qgis::FieldDomainDuplicatePolicy duplicatePolicy = Qgis::FieldDomainDuplicatePolicy::Duplicate;
+
     //! Read-only
     bool isReadOnly = false;
 

src/core/vector/qgsvectorlayer.cpp

@@ -2243,6 +2243,10 @@ bool QgsVectorLayer::setDataProvider( QString const &provider, const QgsDataProv
     {
       mAttributeSplitPolicy[ field.name() ] = field.splitPolicy();
     }
+    if ( !mAttributeDuplicatePolicy.contains( field.name() ) )
+    {
+      mAttributeDuplicatePolicy[ field.name() ] = field.duplicatePolicy();
+    }
   }
 
   if ( profile )
@@ -2573,6 +2577,21 @@ bool QgsVectorLayer::readSymbology( const QDomNode &layerNode, QString &errorMes
       }
     }
 
+    // The duplicate policy is - unlike alias and split policy - never defined by the data provider, so we clear the map
+    mAttributeDuplicatePolicy.clear();
+    const QDomNode duplicatePoliciesNode = layerNode.namedItem( QStringLiteral( "duplicatePolicies" ) );
+    if ( !duplicatePoliciesNode.isNull() )
+    {
+      const QDomNodeList duplicatePolicyNodeList = duplicatePoliciesNode.toElement().elementsByTagName( QStringLiteral( "policy" ) );
+      for ( int i = 0; i < duplicatePolicyNodeList.size(); ++i )
+      {
+        const QDomElement duplicatePolicyElem = duplicatePolicyNodeList.at( i ).toElement();
+        const QString field = duplicatePolicyElem.attribute( QStringLiteral( "field" ) );
+        const Qgis::FieldDomainDuplicatePolicy policy = qgsEnumKeyToValue( duplicatePolicyElem.attribute( QStringLiteral( "policy" ) ), Qgis::FieldDomainDuplicatePolicy::Duplicate );
+        mAttributeDuplicatePolicy.insert( field, policy );
+      }
+    }
+
     // default expressions
     mDefaultExpressionMap.clear();
     QDomNode defaultsNode = layerNode.namedItem( QStringLiteral( "defaults" ) );
@@ -3085,6 +3104,19 @@ bool QgsVectorLayer::writeSymbology( QDomNode &node, QDomDocument &doc, QString
       node.appendChild( splitPoliciesElement );
     }
 
+    //duplicate policies
+    {
+      QDomElement duplicatePoliciesElement = doc.createElement( QStringLiteral( "duplicatePolicies" ) );
+      for ( const QgsField &field : std::as_const( mFields ) )
+      {
+        QDomElement duplicatePolicyElem = doc.createElement( QStringLiteral( "policy" ) );
+        duplicatePolicyElem.setAttribute( QStringLiteral( "field" ), field.name() );
+        duplicatePolicyElem.setAttribute( QStringLiteral( "policy" ), qgsEnumValueToKey( field.duplicatePolicy() ) );
+        duplicatePoliciesElement.appendChild( duplicatePolicyElem );
+      }
+      node.appendChild( duplicatePoliciesElement );
+    }
+
     //default expressions
     QDomElement defaultsElem = doc.createElement( QStringLiteral( "defaults" ) );
     for ( const QgsField &field : std::as_const( mFields ) )
@@ -3588,6 +3620,22 @@ void QgsVectorLayer::setFieldSplitPolicy( int index, Qgis::FieldDomainSplitPolic
   emit layerModified(); // TODO[MD]: should have a different signal?
 }
 
+void QgsVectorLayer::setFieldDuplicatePolicy( int index, Qgis::FieldDomainDuplicatePolicy policy )
+{
+  QGIS_PROTECT_QOBJECT_THREAD_ACCESS
+
+  if ( index < 0 || index >= fields().count() )
+    return;
+
+  const QString name = fields().at( index ).name();
+
+  mAttributeDuplicatePolicy.insert( name, policy );
+  mFields[ index ].setDuplicatePolicy( policy );
+  mEditFormConfig.setFields( mFields );
+  emit layerModified(); // TODO[MD]: should have a different signal?
+}
+
+
 QSet<QString> QgsVectorLayer::excludeAttributesWms() const
 {
   QGIS_PROTECT_QOBJECT_THREAD_ACCESS
@@ -4463,6 +4511,15 @@ void QgsVectorLayer::updateFields()
     mFields[ index ].setSplitPolicy( splitPolicyIt.value() );
   }
 
+  for ( auto duplicatePolicyIt = mAttributeDuplicatePolicy.constBegin(); duplicatePolicyIt != mAttributeDuplicatePolicy.constEnd(); ++duplicatePolicyIt )
+  {
+    int index = mFields.lookupField( duplicatePolicyIt.key() );
+    if ( index < 0 )
+      continue;
+
+    mFields[ index ].setDuplicatePolicy( duplicatePolicyIt.value() );
+  }
+
   // Update configuration flags
   QMap< QString, Qgis::FieldConfigurationFlags >::const_iterator flagsIt = mFieldConfigurationFlags.constBegin();
   for ( ; flagsIt != mFieldConfigurationFlags.constEnd(); ++flagsIt )