Don't try to upload empty vector layers

felt/core/layer_exporter.py

@@ -18,7 +18,10 @@
 import zipfile
 from dataclasses import dataclass
 from pathlib import Path
-from typing import Optional
+from typing import (
+    Optional,
+    Tuple
+)
 
 from qgis.PyQt.QtCore import (
     QVariant,
@@ -27,7 +30,6 @@
 from qgis.PyQt.QtXml import (
     QDomDocument
 )
-
 from qgis.core import (
     QgsFeedback,
     QgsMapLayer,
@@ -53,8 +55,8 @@
 )
 
 from .enums import LayerExportResult
-from .layer_style import LayerStyle
 from .exceptions import LayerPackagingException
+from .layer_style import LayerStyle
 from .logger import Logger
 
 
@@ -87,20 +89,32 @@ def __del__(self):
         self.temp_dir.cleanup()
 
     @staticmethod
-    def can_export_layer(layer: QgsMapLayer) -> bool:
+    def can_export_layer(layer: QgsMapLayer) -> Tuple[bool, str]:
         """
-        Returns True if a layer can be exported
+        Returns True if a layer can be exported, and an explanatory
+        string if not
         """
         if isinstance(layer, QgsVectorLayer):
-            return True
+            # Vector layers must have some features
+            if layer.featureCount() == 0:
+                return False, 'Layer is empty'
+
+            return True, ''
 
         if isinstance(layer, QgsRasterLayer):
-            return layer.providerType() in (
-                'gdal',
-                'virtualraster'
+            if layer.providerType() in (
+                    'gdal',
+                    'virtualraster'
+            ):
+                return True, ''
+
+            return False, '{} raster layers are not yet supported'.format(
+                layer.providerType()
             )
 
-        return False
+        return False, '{} layers are not yet supported'.format(
+            layer.__class__.__name__
+        )
 
     @staticmethod
     def representative_layer_style(layer: QgsVectorLayer) -> LayerStyle:
@@ -168,7 +182,8 @@ def generate_file_name(self, suffix: str) -> str:
         Generates a temporary file name with the given suffix
         """
         return (Path(str(self.temp_dir.name)) / ('qgis_export_' +
-                (uuid.uuid4().hex + suffix))).as_posix()
+                                                 (
+                                                             uuid.uuid4().hex + suffix))).as_posix()
 
     def export_layer_for_felt(
             self,
@@ -269,7 +284,7 @@ def export_vector_layer(
                 {
                     'type': Logger.PACKAGING_VECTOR,
                     'error': 'Error packaging layer: {}'.format(error_message)
-                 }
+                }
             )
 
             raise LayerPackagingException(error_message)
@@ -393,7 +408,7 @@ def export_raster_layer(
                 {
                     'type': Logger.PACKAGING_RASTER,
                     'error': 'Error packaging layer: {}'.format(error_message)
-                 }
+                }
             )
             raise LayerPackagingException(error_message)
 

felt/core/map_uploader.py

@@ -18,7 +18,8 @@
 from pathlib import Path
 from typing import (
     Optional,
-    List
+    List,
+    Tuple
 )
 
 from qgis.PyQt.QtCore import (
@@ -71,7 +72,7 @@ def __init__(self,
         )
         project = project or QgsProject.instance()
 
-        self.unsupported_layers = []
+        self.unsupported_layers: List[Tuple[str, str]] = []
         if layers:
             self.current_map_crs = QgsCoordinateReferenceSystem('EPSG:4326')
             self.current_map_extent = QgsMapLayerUtils.combinedExtent(
@@ -101,7 +102,7 @@ def __init__(self,
 
             self.layers = [
                 layer.clone() for layer in visible_layers if
-                LayerExporter.can_export_layer(layer)
+                LayerExporter.can_export_layer(layer)[0]
             ]
 
             self._build_unsupported_layer_details(project, visible_layers)
@@ -149,11 +150,14 @@ def _build_unsupported_layer_details(self,
         these to users and to Felt
         """
         unsupported_layer_type_count = defaultdict(int)
+        unsupported_layer_names = set()
         for layer in layers:
-            if LayerExporter.can_export_layer(layer):
+            can_export, reason = LayerExporter.can_export_layer(layer)
+            if can_export:
                 continue
 
-            self.unsupported_layers.append(layer.name())
+            unsupported_layer_names.add(layer.name())
+            self.unsupported_layers.append((layer.name(), reason))
             if layer.type() == QgsMapLayer.PluginLayer:
                 id_string = layer.pluginLayerType()
             else:
@@ -169,8 +173,8 @@ def _build_unsupported_layer_details(self,
         for layer_tree_layer in project.layerTreeRoot().findLayers():
             if layer_tree_layer.isVisible() and \
                     not layer_tree_layer.layer() and \
-                    not layer_tree_layer.name() in self.unsupported_layers:
-                self.unsupported_layers.append(layer_tree_layer.name())
+                    not layer_tree_layer.name() in unsupported_layer_names:
+                self.unsupported_layers.append((layer_tree_layer.name(), ''))
 
     def default_map_title(self) -> str:
         """
@@ -199,7 +203,13 @@ def warning_message(self) -> Optional[str]:
 
         msg = '<p>' + self.tr('The following layers are not supported '
                               'and won\'t be uploaded:') + '</p><ul><li>'
-        msg += '</li><li>'.join(self.unsupported_layers)
+
+        for layer_name, reason in self.unsupported_layers:
+            if reason:
+                msg += '<li>{}: {}</li>'.format(layer_name, reason)
+            else:
+                msg += '<li>{}</li>'.format(layer_name)
+
         msg += '</ul>'
         return msg
 

felt/plugin.py

@@ -241,7 +241,7 @@ def _layer_tree_view_context_menu_about_to_show(self, menu: QMenu):
         if layer is None:
             return
 
-        if LayerExporter.can_export_layer(layer):
+        if LayerExporter.can_export_layer(layer)[0]:
             menus = [action for action in menu.children() if
                      isinstance(action, QMenu) and
                      action.objectName() == 'exportMenu']
@@ -269,5 +269,7 @@ def _update_action_enabled_states(self):
         has_layers = bool(QgsProject.instance().mapLayers())
         is_authorizing = AUTHORIZATION_MANAGER.status == AuthState.Authorizing
         allowed_to_export = has_layers and not is_authorizing
-        self.share_map_to_felt_action.setEnabled(allowed_to_export)
-        self.create_map_action.setEnabled(allowed_to_export)
+        if self.share_map_to_felt_action:
+            self.share_map_to_felt_action.setEnabled(allowed_to_export)
+        if self.create_map_action:
+            self.create_map_action.setEnabled(allowed_to_export)

felt/test/test_layer_exporter.py

@@ -48,19 +48,21 @@ def test_can_export_layer(self):
         file = str(TEST_DATA_PATH / 'points.gpkg')
         layer = QgsVectorLayer(file, 'test')
         self.assertTrue(layer.isValid())
-        self.assertTrue(LayerExporter.can_export_layer(layer))
+        self.assertTrue(LayerExporter.can_export_layer(layer)[0])
 
         file = str(TEST_DATA_PATH / 'dem.tif')
         layer = QgsRasterLayer(file, 'test')
         self.assertTrue(layer.isValid())
-        self.assertTrue(LayerExporter.can_export_layer(layer))
+        self.assertTrue(LayerExporter.can_export_layer(layer)[0])
 
         layer = QgsRasterLayer(
             'crs=EPSG:3857&format&type=xyz&url='
             'https://tile.openstreetmap.org/%7Bz%7D/%7Bx%7D/%7By%7D.png'
             '&zmax=19&zmin=0',
             'test', 'wms')
-        self.assertFalse(LayerExporter.can_export_layer(layer))
+        can_export, reason = LayerExporter.can_export_layer(layer)
+        self.assertFalse(can_export)
+        self.assertEqual(reason, 'wms raster layers are not yet supported')
 
     def test_file_name(self):
         """