Improved error message for missing axes in HIST.fill

src/hist/basehist.py

@@ -292,8 +292,15 @@ def fill(
         }
 
         if set(data_dict) != set(range(len(args), self.ndim)):
+            expected = set(range(len(args), self.ndim))
+            provided = set(data_dict)
+
+            missing = expected - provided
+            missing_values = [self.axes[i].name for i in missing]
+
             raise TypeError(
-                "All axes must be accounted for in fill, you may have used a disallowed name in the axes"
+                f"Missing values for single/multiple axis : {missing_values}."
+                f"Expected axes : {[ax.name for ax in self.axes]}"
             )
 
         data = (data_dict[i] for i in range(len(args), self.ndim))

tests/test_general.py

@@ -1021,3 +1021,13 @@ def test_T_3D():
     assert h_3D.T.axes[0] == h_3D.axes[2]
     assert h_3D.T.axes[1] == h_3D.axes[1]
     assert h_3D.T.axes[2] == h_3D.axes[0]
+
+
+def test_fill_missing_axis_reports_axis_name():
+    h = Hist(
+        axis.Regular(5, 0, 1, name="x"),
+        axis.Regular(5, 0, 1, name="y"),
+    )
+
+    with pytest.raises(TypeError):
+        h.fill(x=[0.1, 0.2])