fix(metrics): Don't crash if there are no diagrams or semantic objects

capellambse/extensions/metrics/composer.py

@@ -145,7 +145,10 @@ def draw_labeled_bar(
 ) -> str:
     """Construct a bar with label and icon (SVG string)."""
     total = sum(segments)
-    normalized_segments = [x / total for x in segments]
+    if total:
+        normalized_segments = [x / total for x in segments]
+    else:
+        normalized_segments = [0 for _ in segments]
     return (
         draw_icon(x, y)
         + draw_text(x + 5, y + 3, f"{total}")

tests/test_aird_parser.py

@@ -10,6 +10,10 @@
 import capellambse
 from capellambse import aird, diagram, loader
 
+EMPTY_MODEL = pathlib.Path(__file__).parent.joinpath(
+    "data/decl/empty_project_52/empty_project_52.aird"
+)
+
 
 class TestAIRDBasicFunctionality:
     test_model = (
@@ -81,6 +85,11 @@ def test_python_code_representation_matches_expected_output(
         actual = repr(diagram_under_test)
         assert actual == expected
 
+    def test_enumerate_diagrams_doesnt_crash_if_there_are_no_diagrams(self):
+        model = loader.MelodyLoader(EMPTY_MODEL)
+        for _ in aird.enumerate_diagrams(model):
+            pass
+
 
 def test_airdparser_msm_produces_valid_json_without_error(
     model: capellambse.MelodyModel,