Raise TypeError if plotting empty data (#7228)

* raise TypeError if plotting empty data

* add to whats-new

* raise TypeError in all DataArray plot methods

* maybe fix tests

* fix test

* fix mypy

Co-authored-by: Deepak Cherian <[email protected]>

Author: headtr1ck

doc/whats-new.rst

@@ -61,6 +61,8 @@ Bug fixes
   now reopens the file from scratch for h5netcdf and scipy netCDF backends,
   rather than reusing a cached version (:issue:`4240`, :issue:`4862`).
   By `Stephan Hoyer <https://github.com/shoyer>`_.
+- Raise a TypeError when trying to plot empty data (:issue:`7156`, :pull:`7228`).
+  By `Michael Niklas <https://github.com/headtr1ck>`_.
 
 Documentation
 ~~~~~~~~~~~~~

xarray/plot/dataarray_plot.py

@@ -280,7 +280,10 @@ def plot(
     ndims = len(plot_dims)
 
     plotfunc: Callable
-    if ndims in [1, 2]:
+
+    if ndims == 0 or darray.size == 0:
+        raise TypeError("No numeric data to plot.")
+    if ndims in (1, 2):
         if row or col:
             kwargs["subplot_kws"] = subplot_kws
             kwargs["row"] = row
@@ -483,6 +486,9 @@ def line(
         return _easy_facetgrid(darray, line, kind="line", **allargs)
 
     ndims = len(darray.dims)
+    if ndims == 0 or darray.size == 0:
+        # TypeError to be consistent with pandas
+        raise TypeError("No numeric data to plot.")
     if ndims > 2:
         raise ValueError(
             "Line plots are for 1- or 2-dimensional DataArrays. "
@@ -699,6 +705,10 @@ def hist(
     """
     assert len(args) == 0
 
+    if darray.ndim == 0 or darray.size == 0:
+        # TypeError to be consistent with pandas
+        raise TypeError("No numeric data to plot.")
+
     ax = get_axis(figsize, size, aspect, ax)
 
     no_nan = np.ravel(darray.to_numpy())
@@ -899,6 +909,10 @@ def newplotfunc(
 
             return _easy_facetgrid(darray, kind="plot1d", **allargs)
 
+        if darray.ndim == 0 or darray.size == 0:
+            # TypeError to be consistent with pandas
+            raise TypeError("No numeric data to plot.")
+
         # The allargs dict passed to _easy_facetgrid above contains args
         if args == ():
             args = kwargs.pop("args", ())
@@ -1496,6 +1510,10 @@ def newplotfunc(
             allargs["plotfunc"] = globals()[plotfunc.__name__]
             return _easy_facetgrid(darray, kind="dataarray", **allargs)
 
+        if darray.ndim == 0 or darray.size == 0:
+            # TypeError to be consistent with pandas
+            raise TypeError("No numeric data to plot.")
+
         plt = import_matplotlib_pyplot()
 
         if (

xarray/tests/test_plot.py

@@ -3180,6 +3180,31 @@ def test_assert_valid_xy() -> None:
         _assert_valid_xy(darray=darray, xy="error_now", name="x")
 
 
+@requires_matplotlib
+@pytest.mark.parametrize(
+    "val", [pytest.param([], id="empty"), pytest.param(0, id="scalar")]
+)
+@pytest.mark.parametrize(
+    "method",
+    [
+        "__call__",
+        "line",
+        "step",
+        "contour",
+        "contourf",
+        "hist",
+        "imshow",
+        "pcolormesh",
+        "scatter",
+        "surface",
+    ],
+)
+def test_plot_empty_raises(val: list | float, method: str) -> None:
+    da = xr.DataArray(val)
+    with pytest.raises(TypeError, match="No numeric data"):
+        getattr(da.plot, method)()
+
+
 @requires_matplotlib
 def test_facetgrid_axes_raises_deprecation_warning():
     with pytest.warns(