Fix geojson attr table field order

python/gui/auto_generated/attributetable/qgsattributetablefiltermodel.sip.in

@@ -203,11 +203,13 @@ Returns -1 if none is defined.
     virtual int columnCount( const QModelIndex &parent ) const;
 
 
-    void setAttributeTableConfig( const QgsAttributeTableConfig &config );
+    void setAttributeTableConfig( const QgsAttributeTableConfig &config);
 %Docstring
 Set the attribute table configuration to control which fields are shown,
 in which order they are shown as well as if and where an action column
 is shown.
+
+:param config: attribute table config
 %End
 
     void setFilterExpression( const QgsExpression &expression, const QgsExpressionContext &context );

src/core/providers/ogr/qgsogrprovider.cpp

@@ -3720,7 +3720,7 @@ bool QgsOgrProvider::leaveUpdateMode()
     {
       // Backup fields since if we created new fields, but didn't populate it
       // with any feature yet, it will disappear.
-      QgsFields oldFields = mAttributeFields;
+      const QgsFields oldFields = mAttributeFields;
       reloadData();
       if ( mValid )
       {
@@ -3734,9 +3734,9 @@ bool QgsOgrProvider::leaveUpdateMode()
           {
             bool ignoreErrorOut = false;
             addAttributeOGRLevel( field, ignoreErrorOut );
+            mAttributeFields.append( field );
           }
         }
-        mAttributeFields = oldFields;
       }
     }
     return true;

src/core/providers/ogr/qgsogrprovider.h

@@ -329,6 +329,7 @@ class QgsOgrProvider final: public QgsVectorDataProvider
     * and the new file will be opened.
     */
     void reloadProviderData() override;
+
 };
 
 ///@endcond

src/core/qgsattributetableconfig.cpp

@@ -86,8 +86,14 @@ void QgsAttributeTableConfig::update( const QgsFields &fields )
       newColumn.hidden = false;
       newColumn.type = Field;
       newColumn.name = field.name();
-
-      mColumns.append( newColumn );
+      if ( containsActionColumn )
+      {
+        mColumns.insert( mColumns.size() - 1, newColumn );
+      }
+      else
+      {
+        mColumns.append( newColumn );
+      }
     }
   }
 

src/core/vector/qgsvectorlayer.cpp

@@ -3495,10 +3495,18 @@ bool QgsVectorLayer::commitChanges( bool stopEditing )
   }
 
   updateFields();
-  mDataProvider->updateExtents();
 
+  mDataProvider->updateExtents();
   mDataProvider->leaveUpdateMode();
 
+  // This second call is required because OGR provider with JSON
+  // driver might have changed fields order after the call to
+  // leaveUpdateMode
+  if ( mFields.names() != mDataProvider->fields().names() )
+  {
+    updateFields();
+  }
+
   triggerRepaint();
 
   return success;
@@ -4025,6 +4033,7 @@ void QgsVectorLayer::updateFields()
     emit updatedFields();
     mEditFormConfig.setFields( mFields );
   }
+
 }
 
 

src/gui/attributetable/qgsattributetablefiltermodel.cpp

@@ -143,13 +143,13 @@ int QgsAttributeTableFilterModel::columnCount( const QModelIndex &parent ) const
   return mColumnMapping.count();
 }
 
-void QgsAttributeTableFilterModel::setAttributeTableConfig( const QgsAttributeTableConfig &config )
+void QgsAttributeTableFilterModel::setAttributeTableConfig( const QgsAttributeTableConfig &config, bool force )
 {
   const QgsAttributeTableConfig oldConfig = mConfig;
   mConfig = config;
   mConfig.update( layer()->fields() );
 
-  if ( mConfig.hasSameColumns( oldConfig ) )
+  if ( !force && mConfig.hasSameColumns( oldConfig ) )
   {
     return;
   }

src/gui/attributetable/qgsattributetablefiltermodel.h

@@ -238,8 +238,10 @@ class GUI_EXPORT QgsAttributeTableFilterModel: public QSortFilterProxyModel, pub
      * Set the attribute table configuration to control which fields are shown,
      * in which order they are shown as well as if and where an action column
      * is shown.
+     * \param config attribute table config
+     * \param force default FALSE, if TRUE the attribute table configuration will be reset even if it is not changed.
      */
-    void setAttributeTableConfig( const QgsAttributeTableConfig &config );
+    void setAttributeTableConfig( const QgsAttributeTableConfig &config, bool force SIP_PYARGREMOVE = false );
 
     /**
      * Set the \a expression and the \a context to be stored in case of the features

src/gui/attributetable/qgsdualview.cpp

@@ -128,6 +128,13 @@ void QgsDualView::init( QgsVectorLayer *layer, QgsMapCanvas *mapCanvas, const Qg
   mAttributeForm = nullptr;
 
   mLayer = layer;
+
+  // Keep fields order in sync: force config reset
+  connect( mLayer, &QgsVectorLayer::updatedFields, this, [ = ]
+  {
+    mFilterModel->setAttributeTableConfig( attributeTableConfig(), /* force */ true );
+  } );
+
   mEditorContext = context;
 
   // create an empty form to find out if it needs geometry or not

tests/src/python/test_provider_ogr.py

@@ -2247,6 +2247,72 @@ def test_provider_sidecar_files_for_uri(self):
                          ['/home/me/special.gfs', '/home/me/special.xsd'])
         self.assertEqual(metadata.sidecarFilesForUri('/home/me/special.csv'), ['/home/me/special.csvt'])
 
+    def testGeoJsonFieldOrder(self):
+        """Test issue GH #45139"""
+
+        d = QTemporaryDir()
+        json_path = os.path.join(d.path(), 'test.geojson')
+        with open(json_path, 'w+') as f:
+            f.write("""
+            {
+                "type": "FeatureCollection",
+                "features": [
+                    {
+                        "type": "Feature",
+                        "geometry": {
+                            "type": "Point",
+                            "coordinates": [11.1215698,46.0677293]
+                        },
+                        "properties": {
+                            "A": "A",
+                        }
+                    },
+                    {
+                        "type": "Feature",
+                        "geometry": {
+                            "type": "Point",
+                            "coordinates": [11.1214686,46.0677385]
+                        },
+                        "properties": {
+                            "A": "A",
+                            "B": "B",
+                        }
+                    }
+                ]
+            }
+            """)
+
+        vl = QgsVectorLayer(json_path, 'json')
+        self.assertTrue(vl.isValid())
+        self.assertEqual(vl.featureCount(), 2)
+        self.assertEqual(vl.fields().names(), ['A', 'B'])
+
+        # Append a field
+        self.assertTrue(vl.startEditing())
+        self.assertTrue(vl.addAttribute(QgsField('C', QVariant.String)))
+
+        for f in vl.getFeatures():
+            vl.changeAttributeValue(f.id(), 2, 'C')
+
+        self.assertEqual(vl.fields().names(), ['A', 'B', 'C'])
+
+        features = [f for f in vl.getFeatures()]
+
+        self.assertEqual(features[0].attribute('B'), NULL)
+        self.assertEqual(features[0].attribute('C'), 'C')
+        self.assertEqual(features[1].attribute('B'), 'B')
+        self.assertEqual(features[1].attribute('C'), 'C')
+
+        self.assertTrue(vl.commitChanges())
+        self.assertEqual(vl.fields().names(), ['A', 'C', 'B'])
+
+        features = [f for f in vl.getFeatures()]
+
+        self.assertEqual(features[0].attribute('B'), NULL)
+        self.assertEqual(features[0].attribute('C'), 'C')
+        self.assertEqual(features[1].attribute('B'), 'B')
+        self.assertEqual(features[1].attribute('C'), 'C')
+
 
 if __name__ == '__main__':
     unittest.main()