Add check for empty baselayers group in the legend fix #540

lizmap/plugin.py

@@ -138,7 +138,10 @@
 from lizmap.table_manager.dataviz import TableManagerDataviz
 from lizmap.table_manager.layouts import TableManagerLayouts
 from lizmap.tools import cast_to_group, cast_to_layer
-from lizmap.widgets.project_tools import is_layer_wms_excluded
+from lizmap.widgets.project_tools import (
+    empty_baselayers,
+    is_layer_wms_excluded,
+)
 
 try:
     from lizmap.plugin_manager import QgisPluginManager
@@ -3168,6 +3171,11 @@ def project_config_file(
             self.dlg.check_results.add_error(Error(Path(self.project.fileName()).name, checks.TrustProject))
             self.dlg.enabled_trust_project(True)
 
+        if empty_baselayers(self.project):
+            self.dlg.check_results.add_error(
+                Error(Path(self.project.fileName()).name, checks.EmptyBaseLayersGroup)
+            )
+
         # Not blocking, we change it in the background
         if self.project.readNumEntry("WMSMaxAtlasFeatures", '')[0] <= 0:
             LOGGER.info("The maximum atlas features was less than '1'. We set it to '1' to at least have a value.")

lizmap/widgets/check_project.py

@@ -415,6 +415,23 @@ def __init__(self):
             Severities().blocking if qgis_version() >= 32200 else Severities().important,
             QIcon(':/images/themes/default/mIconQgsProjectFile.svg'),
         )
+        self.EmptyBaseLayersGroup = Check(
+            'empty_baselayers_group',
+            tr('Empty "baselayers" group'),
+            tr('The group "baselayers" cannot be empty.'),
+            (
+                '<ul>'
+                '<li>{}</li>'
+                '<li>{}</li>'
+                '</ul>'.format(
+                    tr("Either add some layers in it"),
+                    tr('Or remove it.'),
+                )
+            ),
+            Levels.Project,
+            Severities().blocking,
+            QIcon(':/images/themes/default/mIconQgsProjectFile.svg'),
+        )
         self.LeadingTrailingSpaceLayerGroupName = Check(
             'leading_trailing_space',
             tr('Leading/trailing space in layer/group name'),

lizmap/widgets/project_tools.py

@@ -2,7 +2,7 @@
 __license__ = 'GPL version 3'
 __email__ = '[email protected]'
 
-from qgis.core import QgsProject
+from qgis.core import QgsLayerTreeGroup, QgsProject
 
 
 def is_layer_wms_excluded(project: QgsProject, name: str) -> bool:
@@ -12,3 +12,14 @@ def is_layer_wms_excluded(project: QgsProject, name: str) -> bool:
     """
     server_wms_excluded_list, server_exclude = project.readListEntry('WMSRestrictedLayers', '')
     return server_exclude and name in server_wms_excluded_list
+
+
+def empty_baselayers(project: QgsProject) -> bool:
+    """ Check if the "baselayers" group is empty or not. """
+    root_group = project.layerTreeRoot()
+    groups = root_group.findGroups()
+    for qgis_group in groups:
+        qgis_group: QgsLayerTreeGroup
+        if qgis_group.name() == 'baselayers':
+            return len(qgis_group.children()) == 0
+    return False