Update all attributes in a single transaction

Fixes #17869

python/core/qgsvectorlayer.sip.in

@@ -1502,6 +1502,50 @@ Returns true if the feature's attribute was successfully changed.
 .. seealso:: :py:func:`changeGeometry`
 
 .. seealso:: :py:func:`updateFeature`
+%End
+
+    bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap(), bool skeipDefaultValues = false );
+%Docstring
+Changes attributes' values for a feature (but does not immediately
+commit the changes).
+The ``fid`` argument specifies the ID of the feature to be changed.
+
+The new values to be assigned to the fields are given by ``newValues``.
+
+If a valid QVariant is specified for a field in ``oldValues``, it will be
+used as the field value in the case of an undo operation corresponding
+to this attribute value change. If an invalid QVariant is used (the
+default behavior), then the feature's current value will be
+automatically retrieved and used. Note that this involves a feature
+request to the underlying data provider, so it is more efficient to
+explicitly pass an oldValue if it is already available.
+
+If ``skipDefaultValue`` is set to true, default field values will not
+be updated. This can be used to override default field value
+expressions.
+
+Returns true if feature's attributes was successfully changed.
+
+.. note::
+
+   Calls to changeAttributeValues() are only valid for layers in
+   which edits have been enabled by a call to startEditing(). Changes made
+   to features using this method are not committed to the underlying data
+   provider until a commitChanges() call is made. Any uncommitted changes
+   can be discarded by calling rollBack().
+
+.. seealso:: :py:func:`startEditing`
+
+.. seealso:: :py:func:`commitChanges`
+
+.. seealso:: :py:func:`changeGeometry`
+
+.. seealso:: :py:func:`updateFeature`
+
+.. seealso:: :py:func:`changeAttributeValue`
+
+
+.. versionadded:: 3.0
 %End
 
     bool addAttribute( const QgsField &field );

python/core/qgsvectorlayereditbuffer.sip.in

@@ -58,6 +58,15 @@ Change feature's geometry
     virtual bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant() );
 %Docstring
 Changed an attribute value (but does not commit it)
+%End
+
+    virtual bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues );
+%Docstring
+Changes values of attributes (but does not commit it).
+
+:return: true if attributes are well updated, false otherwise
+
+.. versionadded:: 3.0
 %End
 
     virtual bool addAttribute( const QgsField &field );

python/core/qgsvectorlayereditpassthrough.sip.in

@@ -30,6 +30,17 @@ class QgsVectorLayerEditPassthrough : QgsVectorLayerEditBuffer
 
     virtual bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant() );
 
+
+    virtual bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues );
+
+%Docstring
+Changes values of attributes (but does not commit it).
+
+:return: true if attributes are well updated, false otherwise
+
+.. versionadded:: 3.0
+%End
+
     virtual bool addAttribute( const QgsField &field );
 
     virtual bool deleteAttribute( int attr );

python/core/qgsvectorlayerjoinbuffer.sip.in

@@ -185,6 +185,23 @@ created if its fields are not empty.
 :return: false if an error happened, true otherwise
 
 
+.. versionadded:: 3.0
+%End
+
+    bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap() );
+%Docstring
+Changes attributes' values in joined layers. The feature id given in
+parameter is the one added in target layer. If the corresponding joined
+feature does not exist in a joined layer, then it's automatically
+created if its fields are not empty.
+
+:param fid: The feature id
+:param newValues: The new values for attributes
+:param oldValues: The old values for attributes
+
+:return: false if an error happened, true otherwise
+
+
 .. versionadded:: 3.0
 %End
 

python/core/qgsvectorlayerundopassthroughcommand.sip.in

@@ -202,6 +202,37 @@ Constructor for QgsVectorLayerUndoPassthroughCommandChangeAttribute
 };
 
 
+class QgsVectorLayerUndoPassthroughCommandChangeAttributes: QgsVectorLayerUndoPassthroughCommand
+{
+%Docstring
+ Undo command for changing attributes' values from a vector layer in transaction group.
+
+.. versionadded:: 3.0
+%End
+
+%TypeHeaderCode
+#include "qgsvectorlayerundopassthroughcommand.h"
+%End
+  public:
+
+    QgsVectorLayerUndoPassthroughCommandChangeAttributes( QgsVectorLayerEditBuffer *buffer /Transfer/, QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap() );
+%Docstring
+Constructor for QgsVectorLayerUndoPassthroughCommandChangeAttributes
+
+:param buffer: associated edit buffer
+:param fid: feature ID of feature
+:param newValues: New values for attributes
+:param oldValues: Old values for attributes
+%End
+
+    virtual void undo();
+
+    virtual void redo();
+
+
+};
+
+
 class QgsVectorLayerUndoPassthroughCommandAddAttribute : QgsVectorLayerUndoPassthroughCommand
 {
 %Docstring

src/core/qgsvectorlayer.cpp

@@ -2387,6 +2387,64 @@ bool QgsVectorLayer::changeAttributeValue( QgsFeatureId fid, int field, const QV
   return result;
 }
 
+bool QgsVectorLayer::changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues, bool skipDefaultValues )
+{
+  bool result = true;
+
+  QgsAttributeMap newValuesJoin;
+  QgsAttributeMap oldValuesJoin;
+
+  QgsAttributeMap newValuesNotJoin;
+  QgsAttributeMap oldValuesNotJoin;
+
+  for ( auto it = newValues.constBegin(); it != newValues.constEnd(); ++it )
+  {
+    const int field = it.key();
+    const QVariant newValue = it.value();
+    QVariant oldValue;
+
+    if ( oldValues.contains( field ) )
+      oldValue = oldValues[field];
+
+    switch ( fields().fieldOrigin( field ) )
+    {
+      case QgsFields::OriginJoin:
+        newValuesJoin[field] = newValue;
+        oldValuesJoin[field] = oldValue;
+        break;
+
+      case QgsFields::OriginProvider:
+      case QgsFields::OriginEdit:
+      case QgsFields::OriginExpression:
+      {
+        newValuesNotJoin[field] = newValue;
+        oldValuesNotJoin[field] = oldValue;
+        break;
+      }
+
+      case QgsFields::OriginUnknown:
+        break;
+    }
+  }
+
+  if ( ! newValuesJoin.isEmpty() && mJoinBuffer )
+  {
+    result = mJoinBuffer->changeAttributeValues( fid, newValuesJoin, oldValuesJoin );
+  }
+
+  if ( ! newValuesNotJoin.isEmpty() && mEditBuffer && mDataProvider )
+  {
+    result &= mEditBuffer->changeAttributeValues( fid, newValues, oldValues );
+  }
+
+  if ( result && !skipDefaultValues && !mDefaultValueOnUpdateFields.isEmpty() )
+  {
+    updateDefaultValues( fid );
+  }
+
+  return result;
+}
+
 bool QgsVectorLayer::addAttribute( const QgsField &field )
 {
   if ( !mEditBuffer || !mDataProvider )

src/core/qgsvectorlayer.h

@@ -1395,6 +1395,43 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
      */
     bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant(), bool skipDefaultValues = false );
 
+    /**
+     * Changes attributes' values for a feature (but does not immediately
+     * commit the changes).
+     * The \a fid argument specifies the ID of the feature to be changed.
+     *
+     * The new values to be assigned to the fields are given by \a newValues.
+     *
+     * If a valid QVariant is specified for a field in \a oldValues, it will be
+     * used as the field value in the case of an undo operation corresponding
+     * to this attribute value change. If an invalid QVariant is used (the
+     * default behavior), then the feature's current value will be
+     * automatically retrieved and used. Note that this involves a feature
+     * request to the underlying data provider, so it is more efficient to
+     * explicitly pass an oldValue if it is already available.
+     *
+     * If \a skipDefaultValue is set to true, default field values will not
+     * be updated. This can be used to override default field value
+     * expressions.
+     *
+     * Returns true if feature's attributes was successfully changed.
+     *
+     * \note Calls to changeAttributeValues() are only valid for layers in
+     * which edits have been enabled by a call to startEditing(). Changes made
+     * to features using this method are not committed to the underlying data
+     * provider until a commitChanges() call is made. Any uncommitted changes
+     * can be discarded by calling rollBack().
+     *
+     * \see startEditing()
+     * \see commitChanges()
+     * \see changeGeometry()
+     * \see updateFeature()
+     * \see changeAttributeValue()
+     *
+     * \since QGIS 3.0
+     */
+    bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap(), bool skeipDefaultValues = false );
+
     /**
      * Add an attribute field (but does not commit it)
      * returns true if the field was added
@@ -2376,6 +2413,7 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
     //! stores information about uncommitted changes to layer
     QgsVectorLayerEditBuffer *mEditBuffer = nullptr;
     friend class QgsVectorLayerEditBuffer;
+    friend class QgsVectorLayerEditPassthrough;
 
     //stores information about joined layers
     QgsVectorLayerJoinBuffer *mJoinBuffer = nullptr;

src/core/qgsvectorlayereditbuffer.cpp

@@ -208,6 +208,23 @@ bool QgsVectorLayerEditBuffer::changeGeometry( QgsFeatureId fid, const QgsGeomet
   return true;
 }
 
+bool QgsVectorLayerEditBuffer::changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues )
+{
+  bool success = true;
+  for ( auto it = newValues.constBegin() ; it != newValues.constEnd(); ++it )
+  {
+    const int field = it.key();
+    const QVariant newValue = it.value();
+    QVariant oldValue;
+
+    if ( oldValues.contains( field ) )
+      oldValue = oldValues[field];
+
+    success &= changeAttributeValue( fid, field, newValue, oldValue );
+  }
+
+  return success;
+}
 
 bool QgsVectorLayerEditBuffer::changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue )
 {

src/core/qgsvectorlayereditbuffer.h

@@ -65,6 +65,13 @@ class CORE_EXPORT QgsVectorLayerEditBuffer : public QObject
     //! Changed an attribute value (but does not commit it)
     virtual bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant() );
 
+    /**
+     * Changes values of attributes (but does not commit it).
+     * \returns true if attributes are well updated, false otherwise
+     * \since QGIS 3.0
+     */
+    virtual bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues );
+
     /**
      * Add an attribute field (but does not commit it)
         returns true if the field was added */
@@ -265,6 +272,7 @@ class CORE_EXPORT QgsVectorLayerEditBuffer : public QObject
     friend class QgsVectorLayerUndoPassthroughCommandDeleteFeatures;
     friend class QgsVectorLayerUndoPassthroughCommandChangeGeometry;
     friend class QgsVectorLayerUndoPassthroughCommandChangeAttribute;
+    friend class QgsVectorLayerUndoPassthroughCommandChangeAttributes;
     friend class QgsVectorLayerUndoPassthroughCommandAddAttribute;
     friend class QgsVectorLayerUndoPassthroughCommandDeleteAttribute;
     friend class QgsVectorLayerUndoPassthroughCommandRenameAttribute;

src/core/qgsvectorlayereditpassthrough.cpp

@@ -86,6 +86,11 @@ bool QgsVectorLayerEditPassthrough::changeAttributeValue( QgsFeatureId fid, int
   return modify( new QgsVectorLayerUndoPassthroughCommandChangeAttribute( this, fid, field, newValue ) );
 }
 
+bool QgsVectorLayerEditPassthrough::changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues )
+{
+  return modify( new QgsVectorLayerUndoPassthroughCommandChangeAttributes( this, fid, newValues, oldValues ) );
+}
+
 bool QgsVectorLayerEditPassthrough::addAttribute( const QgsField &field )
 {
   return modify( new QgsVectorLayerUndoPassthroughCommandAddAttribute( this, field ) );

src/core/qgsvectorlayereditpassthrough.h

@@ -38,6 +38,14 @@ class CORE_EXPORT QgsVectorLayerEditPassthrough : public QgsVectorLayerEditBuffe
     bool deleteFeatures( const QgsFeatureIds &fids ) override;
     bool changeGeometry( QgsFeatureId fid, const QgsGeometry &geom ) override;
     bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant() ) override;
+
+    /**
+     * Changes values of attributes (but does not commit it).
+     * \returns true if attributes are well updated, false otherwise
+     * \since QGIS 3.0
+     */
+    bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues ) override;
+
     bool addAttribute( const QgsField &field ) override;
     bool deleteAttribute( int attr ) override;
     bool renameAttribute( int attr, const QString &newName ) override;

src/core/qgsvectorlayerjoinbuffer.cpp

@@ -637,6 +637,25 @@ bool QgsVectorLayerJoinBuffer::changeAttributeValue( QgsFeatureId fid, int field
     return false;
 }
 
+bool QgsVectorLayerJoinBuffer::changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues )
+{
+  bool success = true;
+
+  for ( auto it = newValues.constBegin(); it != newValues.constEnd(); ++it )
+  {
+    const int field = it.key();
+    const QVariant newValue = it.value();
+    QVariant oldValue;
+
+    if ( oldValues.contains( field ) )
+      oldValue = oldValues[field];
+
+    success &= changeAttributeValue( fid, field, newValue, oldValue );
+  }
+
+  return success;
+}
+
 bool QgsVectorLayerJoinBuffer::deleteFeature( QgsFeatureId fid ) const
 {
   return deleteFeatures( QgsFeatureIds() << fid );

src/core/qgsvectorlayerjoinbuffer.h

@@ -171,6 +171,22 @@ class CORE_EXPORT QgsVectorLayerJoinBuffer : public QObject, public QgsFeatureSi
      */
     bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant() );
 
+    /**
+     * Changes attributes' values in joined layers. The feature id given in
+     * parameter is the one added in target layer. If the corresponding joined
+     * feature does not exist in a joined layer, then it's automatically
+     * created if its fields are not empty.
+     *
+     * \param fid The feature id
+     * \param newValues The new values for attributes
+     * \param oldValues The old values for attributes
+     *
+     * \returns false if an error happened, true otherwise
+     *
+     * \since QGIS 3.0
+     */
+    bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap() );
+
     /**
      * Deletes a feature from joined layers. The feature id given in
      * parameter is the one coming from the target layer.

src/core/qgsvectorlayerundopassthroughcommand.cpp

@@ -403,3 +403,35 @@ void QgsVectorLayerUndoPassthroughCommandUpdate::redo()
     }
   }
 }
+
+QgsVectorLayerUndoPassthroughCommandChangeAttributes::QgsVectorLayerUndoPassthroughCommandChangeAttributes( QgsVectorLayerEditBuffer *buffer, QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues )
+  : QgsVectorLayerUndoPassthroughCommand( buffer, QObject::tr( "change attribute value" ) )
+  , mFid( fid )
+  , mNewValues( newValues )
+  , mOldValues( oldValues )
+{
+}
+
+void QgsVectorLayerUndoPassthroughCommandChangeAttributes::undo()
+{
+  if ( rollBackToSavePoint() )
+  {
+    for ( auto it = mNewValues.constBegin(); it != mNewValues.constEnd(); ++it )
+    {
+      emit mBuffer->attributeValueChanged( mFid, it.key(), it.value() );
+    }
+  }
+}
+
+void QgsVectorLayerUndoPassthroughCommandChangeAttributes::redo()
+{
+  QgsChangedAttributesMap attribMap;
+  attribMap.insert( mFid, mNewValues );
+  if ( setSavePoint() && mBuffer->L->dataProvider()->changeAttributeValues( attribMap ) )
+  {
+    for ( auto it = mNewValues.constBegin(); it != mNewValues.constEnd(); ++it )
+    {
+      emit mBuffer->attributeValueChanged( mFid, it.key(), it.value() );
+    }
+  }
+}

src/core/qgsvectorlayerundopassthroughcommand.h

@@ -203,6 +203,35 @@ class CORE_EXPORT QgsVectorLayerUndoPassthroughCommandChangeAttribute: public Qg
     const QVariant mOldValue;
 };
 
+/**
+ * \ingroup core
+ * \class QgsVectorLayerUndoPassthroughCommandChangeAttributes
+ * \brief Undo command for changing attributes' values from a vector layer in transaction group.
+ * \since QGIS 3.0
+ */
+
+class CORE_EXPORT QgsVectorLayerUndoPassthroughCommandChangeAttributes: public QgsVectorLayerUndoPassthroughCommand
+{
+  public:
+
+    /**
+     * Constructor for QgsVectorLayerUndoPassthroughCommandChangeAttributes
+     * \param buffer associated edit buffer
+     * \param fid feature ID of feature
+     * \param newValues New values for attributes
+     * \param oldValues Old values for attributes
+     */
+    QgsVectorLayerUndoPassthroughCommandChangeAttributes( QgsVectorLayerEditBuffer *buffer SIP_TRANSFER, QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap() );
+
+    void undo() override;
+    void redo() override;
+
+  private:
+    QgsFeatureId mFid;
+    const QgsAttributeMap mNewValues;
+    const QgsAttributeMap mOldValues;
+};
+
 /**
  * \ingroup core
  * \class QgsVectorLayerUndoPassthroughCommandAddAttribute

src/gui/qgsattributeform.cpp

@@ -330,6 +330,9 @@ bool QgsAttributeForm::saveEdits()
       {
         mLayer->beginEditCommand( mEditCommandMessage );
 
+        QgsAttributeMap newValues;
+        QgsAttributeMap oldValues;
+
         int n = 0;
         for ( int i = 0; i < dst.count(); ++i )
         {
@@ -346,10 +349,14 @@ bool QgsAttributeForm::saveEdits()
           QgsDebugMsg( QString( "src:'%1' (type:%2, isNull:%3, isValid:%4)" )
                        .arg( src.at( i ).toString(), src.at( i ).typeName() ).arg( src.at( i ).isNull() ).arg( src.at( i ).isValid() ) );
 
-          success &= mLayer->changeAttributeValue( mFeature.id(), i, dst.at( i ), src.at( i ) );
+          newValues[i] = dst.at( i );
+          oldValues[i] = src.at( i );
+
           n++;
         }
 
+        success = mLayer->changeAttributeValues( mFeature.id(), newValues, oldValues );
+
         if ( success && n > 0 )
         {
           mLayer->endEditCommand();