fix(items): prevent crashes when clicking empty legends

Author: ThomasMalletCodra

plotpy/items/label.py

@@ -828,7 +828,7 @@ def click_inside(self, locx: float, locy: float) -> tuple[float, float, bool, ty
                 for item in self.plot().get_items()
                 if self.include_item(item) and isinstance(item, CurveItem)
             ]
-            if line < len(items):
+            if 0 <= line < len(items):
                 return 1000.0, None, False, items[line]
         return 2.0, 1, True, None
 

plotpy/tests/items/test_label.py

@@ -0,0 +1,39 @@
+# -*- coding: utf-8 -*-
+
+"""Label and legend item tests."""
+
+import numpy as np
+from guidata.qthelpers import qt_app_context
+
+from plotpy.builder import make
+
+
+def test_legend_click_inside_out_of_range_row() -> None:
+    """Clicking outside a legend row must not index the curve list negatively."""
+    with qt_app_context(exec_loop=False):
+        window = make.dialog(edit=False, type="curve", size=(640, 480))
+        plot = window.manager.get_plot()
+        plot.add_item(make.curve(np.arange(3), np.arange(3), title="Signal"))
+        legend = make.legend("TR")
+        plot.add_item(legend)
+        legend.get_text_rect()
+
+        result = legend.click_inside(6.0, -100.0)
+
+        assert result == (2.0, 1, True, None)
+        window.close()
+
+
+def test_empty_legend_click_inside_does_not_crash() -> None:
+    """Clicking an empty legend must not index an empty curve list."""
+    with qt_app_context(exec_loop=False):
+        window = make.dialog(edit=False, type="curve", size=(640, 480))
+        plot = window.manager.get_plot()
+        legend = make.legend("TR")
+        plot.add_item(legend)
+        legend.get_text_rect()
+
+        result = legend.click_inside(6.0, -100.0)
+
+        assert result == (2.0, 1, True, None)
+        window.close()