Consistently report all dimensions in error messages if invalid dimen…

…sions are given (#8079)

* Show dims and coords in idxmin/idxmax error message if an invalid dim is given

* Show data dims in error messages of Dataset and update tests

Remove _assert_empty, not used anymore

* Update test for dataarray

* Show data dims in error messages of weighted and update test

* Show dimensions in error message of group_indexers_by_index

* List coordinates in concat error message, update test

* List coordinates in coords __delitem__ error message, update tests

* Show list of names in error message of PandasMultiIndex.sel, update test

* Show list of dimensions in error messages of Rolling and Coarsen, update tests

* Show dims in Variable.concat error message as tuple for consistency

* Change 'dataset' to 'data' in error messages

* Update whats-new

---------

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

doc/whats-new.rst

@@ -67,6 +67,8 @@ Documentation
 Internal Changes
 ~~~~~~~~~~~~~~~~
 
+- Many error messages related to invalid dimensions or coordinates now always show the list of valid dims/coords (:pull:`8079`).
+  By `András Gunyhó <https://github.com/mgunyho>`_.
 
 .. _whats-new.2023.08.0:
 

xarray/core/computation.py

@@ -2046,9 +2046,13 @@ def _calc_idxminmax(
         raise ValueError("Must supply 'dim' argument for multidimensional arrays")
 
     if dim not in array.dims:
-        raise KeyError(f'Dimension "{dim}" not in dimension')
+        raise KeyError(
+            f"Dimension {dim!r} not found in array dimensions {array.dims!r}"
+        )
     if dim not in array.coords:
-        raise KeyError(f'Dimension "{dim}" does not have coordinates')
+        raise KeyError(
+            f"Dimension {dim!r} is not one of the coordinates {tuple(array.coords.keys())}"
+        )
 
     # These are dtypes with NaN values argmin and argmax can handle
     na_dtypes = "cfO"

xarray/core/concat.py

@@ -391,17 +391,20 @@ def process_subset_opt(opt, subset):
             else:
                 raise ValueError(f"unexpected value for {subset}: {opt}")
         else:
-            invalid_vars = [k for k in opt if k not in getattr(datasets[0], subset)]
+            valid_vars = tuple(getattr(datasets[0], subset))
+            invalid_vars = [k for k in opt if k not in valid_vars]
             if invalid_vars:
                 if subset == "coords":
                     raise ValueError(
-                        "some variables in coords are not coordinates on "
-                        f"the first dataset: {invalid_vars}"
+                        f"the variables {invalid_vars} in coords are not "
+                        f"found in the coordinates of the first dataset {valid_vars}"
                     )
                 else:
+                    # note: data_vars are not listed in the error message here,
+                    # because there may be lots of them
                     raise ValueError(
-                        "some variables in data_vars are not data variables "
-                        f"on the first dataset: {invalid_vars}"
+                        f"the variables {invalid_vars} in data_vars are not "
+                        f"found in the data variables of the first dataset"
                     )
             concat_over.update(opt)
 

xarray/core/coordinates.py

@@ -769,7 +769,9 @@ def __delitem__(self, key: Hashable) -> None:
         if key in self:
             del self._data[key]
         else:
-            raise KeyError(f"{key!r} is not a coordinate variable.")
+            raise KeyError(
+                f"{key!r} is not in coordinate variables {tuple(self.keys())}"
+            )
 
     def _ipython_key_completions_(self):
         """Provide method for the key-autocompletions in IPython."""
@@ -855,7 +857,9 @@ def to_dataset(self) -> Dataset:
 
     def __delitem__(self, key: Hashable) -> None:
         if key not in self:
-            raise KeyError(f"{key!r} is not a coordinate variable.")
+            raise KeyError(
+                f"{key!r} is not in coordinate variables {tuple(self.keys())}"
+            )
         assert_no_index_corrupted(self._data.xindexes, {key})
 
         del self._data._coords[key]

xarray/core/dataset.py

@@ -213,11 +213,6 @@ def _get_virtual_variable(
     return ref_name, var_name, virtual_var
 
 
-def _assert_empty(args: tuple, msg: str = "%s") -> None:
-    if args:
-        raise ValueError(msg % args)
-
-
 def _get_chunk(var: Variable, chunks, chunkmanager: ChunkManagerEntrypoint):
     """
     Return map from each dim to chunk sizes, accounting for backend's preferred chunks.
@@ -2640,7 +2635,7 @@ def chunk(
         bad_dims = chunks.keys() - self.dims.keys()
         if bad_dims:
             raise ValueError(
-                f"some chunks keys are not dimensions on this object: {bad_dims}"
+                f"chunks keys {tuple(bad_dims)} not found in data dimensions {tuple(self.dims)}"
             )
 
         chunkmanager = guess_chunkmanager(chunked_array_type)
@@ -4243,8 +4238,8 @@ def rename_dims(
         for k, v in dims_dict.items():
             if k not in self.dims:
                 raise ValueError(
-                    f"cannot rename {k!r} because it is not a "
-                    "dimension in this dataset"
+                    f"cannot rename {k!r} because it is not found "
+                    f"in the dimensions of this dataset {tuple(self.dims)}"
                 )
             if v in self.dims or v in self:
                 raise ValueError(
@@ -4366,7 +4361,7 @@ def swap_dims(
             if k not in self.dims:
                 raise ValueError(
                     f"cannot swap from dimension {k!r} because it is "
-                    "not an existing dimension"
+                    f"not one of the dimensions of this dataset {tuple(self.dims)}"
                 )
             if v in self.variables and self.variables[v].dims != (k,):
                 raise ValueError(
@@ -5448,10 +5443,10 @@ def unstack(
             else:
                 dims = list(dim)
 
-            missing_dims = [d for d in dims if d not in self.dims]
+            missing_dims = set(dims) - set(self.dims)
             if missing_dims:
                 raise ValueError(
-                    f"Dataset does not contain the dimensions: {missing_dims}"
+                    f"Dimensions {tuple(missing_dims)} not found in data dimensions {tuple(self.dims)}"
                 )
 
         # each specified dimension must have exactly one multi-index
@@ -5836,7 +5831,10 @@ def drop_indexes(
         if errors == "raise":
             invalid_coords = coord_names - self._coord_names
             if invalid_coords:
-                raise ValueError(f"those coordinates don't exist: {invalid_coords}")
+                raise ValueError(
+                    f"The coordinates {tuple(invalid_coords)} are not found in the "
+                    f"dataset coordinates {tuple(self.coords.keys())}"
+                )
 
             unindexed_coords = set(coord_names) - set(self._indexes)
             if unindexed_coords:
@@ -6084,7 +6082,7 @@ def drop_dims(
             missing_dims = drop_dims - set(self.dims)
             if missing_dims:
                 raise ValueError(
-                    f"Dataset does not contain the dimensions: {missing_dims}"
+                    f"Dimensions {tuple(missing_dims)} not found in data dimensions {tuple(self.dims)}"
                 )
 
         drop_vars = {k for k, v in self._variables.items() if set(v.dims) & drop_dims}
@@ -6244,7 +6242,9 @@ def dropna(
         # depending on the order of the supplied axes.
 
         if dim not in self.dims:
-            raise ValueError(f"{dim} must be a single dataset dimension")
+            raise ValueError(
+                f"Dimension {dim!r} not found in data dimensions {tuple(self.dims)}"
+            )
 
         if subset is None:
             subset = iter(self.data_vars)
@@ -6725,10 +6725,10 @@ def reduce(
         else:
             dims = set(dim)
 
-        missing_dimensions = [d for d in dims if d not in self.dims]
+        missing_dimensions = tuple(d for d in dims if d not in self.dims)
         if missing_dimensions:
             raise ValueError(
-                f"Dataset does not contain the dimensions: {missing_dimensions}"
+                f"Dimensions {missing_dimensions} not found in data dimensions {tuple(self.dims)}"
             )
 
         if keep_attrs is None:
@@ -7710,9 +7710,11 @@ def shift(
             foo      (x) object nan nan 'a' 'b' 'c'
         """
         shifts = either_dict_or_kwargs(shifts, shifts_kwargs, "shift")
-        invalid = [k for k in shifts if k not in self.dims]
+        invalid = tuple(k for k in shifts if k not in self.dims)
         if invalid:
-            raise ValueError(f"dimensions {invalid!r} do not exist")
+            raise ValueError(
+                f"Dimensions {invalid} not found in data dimensions {tuple(self.dims)}"
+            )
 
         variables = {}
         for name, var in self.variables.items():
@@ -7789,7 +7791,9 @@ def roll(
         shifts = either_dict_or_kwargs(shifts, shifts_kwargs, "roll")
         invalid = [k for k in shifts if k not in self.dims]
         if invalid:
-            raise ValueError(f"dimensions {invalid!r} do not exist")
+            raise ValueError(
+                f"Dimensions {invalid} not found in data dimensions {tuple(self.dims)}"
+            )
 
         unrolled_vars: tuple[Hashable, ...]
 
@@ -8038,10 +8042,11 @@ def quantile(
         else:
             dims = set(dim)
 
-        _assert_empty(
-            tuple(d for d in dims if d not in self.dims),
-            "Dataset does not contain the dimensions: %s",
-        )
+        invalid_dims = set(dims) - set(self.dims)
+        if invalid_dims:
+            raise ValueError(
+                f"Dimensions {tuple(invalid_dims)} not found in data dimensions {tuple(self.dims)}"
+            )
 
         q = np.asarray(q, dtype=np.float64)
 
@@ -8117,7 +8122,9 @@ def rank(
             )
 
         if dim not in self.dims:
-            raise ValueError(f"Dataset does not contain the dimension: {dim}")
+            raise ValueError(
+                f"Dimension {dim!r} not found in data dimensions {tuple(self.dims)}"
+            )
 
         variables = {}
         for name, var in self.variables.items():
@@ -8167,7 +8174,10 @@ def differentiate(
         from xarray.core.variable import Variable
 
         if coord not in self.variables and coord not in self.dims:
-            raise ValueError(f"Coordinate {coord} does not exist.")
+            variables_and_dims = tuple(set(self.variables.keys()).union(self.dims))
+            raise ValueError(
+                f"Coordinate {coord!r} not found in variables or dimensions {variables_and_dims}."
+            )
 
         coord_var = self[coord].variable
         if coord_var.ndim != 1:
@@ -8269,7 +8279,10 @@ def _integrate_one(self, coord, datetime_unit=None, cumulative=False):
         from xarray.core.variable import Variable
 
         if coord not in self.variables and coord not in self.dims:
-            raise ValueError(f"Coordinate {coord} does not exist.")
+            variables_and_dims = tuple(set(self.variables.keys()).union(self.dims))
+            raise ValueError(
+                f"Coordinate {coord!r} not found in variables or dimensions {variables_and_dims}."
+            )
 
         coord_var = self[coord].variable
         if coord_var.ndim != 1:
@@ -9771,7 +9784,9 @@ def drop_duplicates(
 
         missing_dims = set(dims) - set(self.dims)
         if missing_dims:
-            raise ValueError(f"'{missing_dims}' not found in dimensions")
+            raise ValueError(
+                f"Dimensions {tuple(missing_dims)} not found in data dimensions {tuple(self.dims)}"
+            )
 
         indexes = {dim: ~self.get_index(dim).duplicated(keep=keep) for dim in dims}
         return self.isel(indexes)

xarray/core/indexes.py

@@ -1203,12 +1203,12 @@ def sel(self, labels, method=None, tolerance=None) -> IndexSelResult:
             coord_name, label = next(iter(labels.items()))
 
             if is_dict_like(label):
-                invalid_levels = [
+                invalid_levels = tuple(
                     name for name in label if name not in self.index.names
-                ]
+                )
                 if invalid_levels:
                     raise ValueError(
-                        f"invalid multi-index level names {invalid_levels}"
+                        f"multi-index level names {invalid_levels} not found in indexes {tuple(self.index.names)}"
                     )
                 return self.sel(label)
 

xarray/core/indexing.py

@@ -143,7 +143,10 @@ def group_indexers_by_index(
         elif key in obj.coords:
             raise KeyError(f"no index found for coordinate {key!r}")
         elif key not in obj.dims:
-            raise KeyError(f"{key!r} is not a valid dimension or coordinate")
+            raise KeyError(
+                f"{key!r} is not a valid dimension or coordinate for "
+                f"{obj.__class__.__name__} with dimensions {obj.dims!r}"
+            )
         elif len(options):
             raise ValueError(
                 f"cannot supply selection options {options!r} for dimension {key!r}"

xarray/core/rolling.py

@@ -102,6 +102,14 @@ def __init__(
         self.center = self._mapping_to_list(center, default=False)
         self.obj: T_Xarray = obj
 
+        missing_dims = tuple(dim for dim in self.dim if dim not in self.obj.dims)
+        if missing_dims:
+            # NOTE: we raise KeyError here but ValueError in Coarsen.
+            raise KeyError(
+                f"Window dimensions {missing_dims} not found in {self.obj.__class__.__name__} "
+                f"dimensions {tuple(self.obj.dims)}"
+            )
+
         # attributes
         if min_periods is not None and min_periods <= 0:
             raise ValueError("min_periods must be greater than zero or None")
@@ -624,8 +632,7 @@ def __init__(
         xarray.DataArray.groupby
         """
         super().__init__(obj, windows, min_periods, center)
-        if any(d not in self.obj.dims for d in self.dim):
-            raise KeyError(self.dim)
+
         # Keep each Rolling object as a dictionary
         self.rollings = {}
         for key, da in self.obj.data_vars.items():
@@ -839,10 +846,11 @@ def __init__(
         self.side = side
         self.boundary = boundary
 
-        absent_dims = [dim for dim in windows.keys() if dim not in self.obj.dims]
-        if absent_dims:
+        missing_dims = tuple(dim for dim in windows.keys() if dim not in self.obj.dims)
+        if missing_dims:
             raise ValueError(
-                f"Dimensions {absent_dims!r} not found in {self.obj.__class__.__name__}."
+                f"Window dimensions {missing_dims} not found in {self.obj.__class__.__name__} "
+                f"dimensions {tuple(self.obj.dims)}"
             )
         if not utils.is_dict_like(coord_func):
             coord_func = {d: coord_func for d in self.obj.dims}  # type: ignore[misc]

xarray/core/variable.py

@@ -2117,7 +2117,7 @@ def concat(
             for var in variables:
                 if var.dims != first_var_dims:
                     raise ValueError(
-                        f"Variable has dimensions {list(var.dims)} but first Variable has dimensions {list(first_var_dims)}"
+                        f"Variable has dimensions {tuple(var.dims)} but first Variable has dimensions {tuple(first_var_dims)}"
                     )
 
         return cls(dims, data, attrs, encoding, fastpath=True)

xarray/core/weighted.py

@@ -198,10 +198,11 @@ def _check_dim(self, dim: Dims):
             dims = [dim] if dim else []
         else:
             dims = list(dim)
-        missing_dims = set(dims) - set(self.obj.dims) - set(self.weights.dims)
+        all_dims = set(self.obj.dims).union(set(self.weights.dims))
+        missing_dims = set(dims) - all_dims
         if missing_dims:
             raise ValueError(
-                f"{self.__class__.__name__} does not contain the dimensions: {missing_dims}"
+                f"Dimensions {tuple(missing_dims)} not found in {self.__class__.__name__} dimensions {tuple(all_dims)}"
             )
 
     @staticmethod

xarray/tests/test_coarsen.py

@@ -17,7 +17,10 @@
 
 
 def test_coarsen_absent_dims_error(ds: Dataset) -> None:
-    with pytest.raises(ValueError, match=r"not found in Dataset."):
+    with pytest.raises(
+        ValueError,
+        match=r"Window dimensions \('foo',\) not found in Dataset dimensions",
+    ):
         ds.coarsen(foo=2)
 
 

xarray/tests/test_concat.py

@@ -614,9 +614,12 @@ def test_concat_errors(self):
         with pytest.raises(ValueError, match=r"must supply at least one"):
             concat([], "dim1")
 
-        with pytest.raises(ValueError, match=r"are not coordinates"):
+        with pytest.raises(ValueError, match=r"are not found in the coordinates"):
             concat([data, data], "new_dim", coords=["not_found"])
 
+        with pytest.raises(ValueError, match=r"are not found in the data variables"):
+            concat([data, data], "new_dim", data_vars=["not_found"])
+
         with pytest.raises(ValueError, match=r"global attributes not"):
             # call deepcopy seperately to get unique attrs
             data0 = deepcopy(split_data[0])

xarray/tests/test_coordinates.py

@@ -103,6 +103,11 @@ def test_delitem(self) -> None:
         del coords["x"]
         assert "x" not in coords
 
+        with pytest.raises(
+            KeyError, match="'nonexistent' is not in coordinate variables"
+        ):
+            del coords["nonexistent"]
+
     def test_update(self) -> None:
         coords = Coordinates(coords={"x": [0, 1, 2]})