Enable Bugbear 904 - Within an except clause, raise exceptions with…

… `from err` or `from None` (#5992)

.pre-commit-config.yaml

@@ -41,6 +41,6 @@ repos:
       - id: rst-directive-colons
       - id: rst-inline-touching-normal
   - repo: https://github.com/shellcheck-py/shellcheck-py
-    rev: "v0.9.0.6"
+    rev: v0.9.0.6
     hooks:
       - id: shellcheck

holoviews/core/dimension.py

@@ -998,7 +998,7 @@ def get_dimension_index(self, dimension):
             dimensions = self.kdims+self.vdims
             return next(i for i, d in enumerate(dimensions) if d == dim)
         except StopIteration:
-            raise Exception(f"Dimension {dim} not found in {self.__class__.__name__}.")
+            raise Exception(f"Dimension {dim} not found in {self.__class__.__name__}.") from None
 
 
     def get_dimension_type(self, dim):

holoviews/core/io.py

@@ -634,8 +634,8 @@ def parse_fields(cls, formatter):
         try:
             parse = list(string.Formatter().parse(formatter))
             return {f for f in list(zip(*parse))[1] if f is not None}
-        except Exception:
-            raise SyntaxError(f"Could not parse formatter {formatter!r}")
+        except Exception as e:
+            raise SyntaxError(f"Could not parse formatter {formatter!r}") from e
 
     def __init__(self, **params):
         super().__init__(**params)
@@ -673,8 +673,8 @@ def _validate_formatters(self):
             raise Exception(f"Valid export fields are: {','.join(sorted(self.efields))}")
         try:
             time.strftime(self.timestamp_format, tuple(time.localtime()))
-        except Exception:
-            raise Exception("Timestamp format invalid")
+        except Exception as e:
+            raise Exception("Timestamp format invalid") from e
 
 
     def add(self, obj=None, filename=None, data=None, info=None, **kwargs):

holoviews/core/options.py

@@ -78,7 +78,7 @@ def cleanup_custom_options(id, weakref=None):
             f"Cleanup of custom options tree with id '{id}' failed "
             f"with the following exception: {e}, an unreferenced "
             "orphan tree may persist in memory."
-        )
+        ) from e
 
 
 def lookup_options(obj, group, backend):
@@ -660,7 +660,7 @@ def _merge_options(self, identifier, group_name, options):
             raise OptionError(e.invalid_keyword,
                               e.allowed_keywords,
                               group_name=group_name,
-                              path = self.path)
+                              path = self.path) from e
 
     def __getitem__(self, item):
         if item in self.groups:

holoviews/element/comparison.py

@@ -241,8 +241,8 @@ def compare_lists(cls, l1, l2, msg=None):
             cls.assertEqual(len(l1), len(l2))
             for v1, v2 in zip(l1, l2):
                 cls.assertEqual(v1, v2)
-        except AssertionError:
-            raise AssertionError(msg or f'{l1!r} != {l2!r}')
+        except AssertionError as e:
+            raise AssertionError(msg or f'{l1!r} != {l2!r}') from e
 
 
     @classmethod
@@ -251,8 +251,8 @@ def compare_tuples(cls, t1, t2, msg=None):
             cls.assertEqual(len(t1), len(t2))
             for i1, i2 in zip(t1, t2):
                 cls.assertEqual(i1, i2)
-        except AssertionError:
-            raise AssertionError(msg or f'{t1!r} != {t2!r}')
+        except AssertionError as e:
+            raise AssertionError(msg or f'{t1!r} != {t2!r}') from e
 
 
     #=====================#
@@ -275,7 +275,7 @@ def compare_arrays(cls, arr1, arr2, msg='Arrays'):
             try:
                 cls.assert_array_almost_equal_fn(arr1, arr2)
             except AssertionError as e:
-                raise cls.failureException(msg + str(e)[11:])
+                raise cls.failureException(msg + str(e)[11:]) from e
 
     @classmethod
     def bounds_check(cls, el1, el2, msg=None):
@@ -288,8 +288,8 @@ def bounds_check(cls, el1, el2, msg=None):
                 if isinstance(v2, datetime_types):
                     v2 = dt_to_int(v2)
                 cls.assert_array_almost_equal_fn(v1, v2)
-        except AssertionError:
-            raise cls.failureException(f"BoundingBoxes are mismatched: {el1.bounds.lbrt()} != {el2.bounds.lbrt()}.")
+        except AssertionError as e:
+            raise cls.failureException(f"BoundingBoxes are mismatched: {el1.bounds.lbrt()} != {el2.bounds.lbrt()}.") from e
 
 
     #=======================================#
@@ -321,7 +321,7 @@ def compare_dimensions(cls, dim1, dim2, msg=None):
                 cls.assertEqual(dim1_params[k], dim2_params[k], msg=None)
             except AssertionError as e:
                 msg = f'Dimension parameter {k!r} mismatched: '
-                raise cls.failureException(f"{msg}{e!s}")
+                raise cls.failureException(f"{msg}{e!s}") from e
 
     @classmethod
     def compare_labelled_data(cls, obj1, obj2, msg=None):
@@ -712,7 +712,7 @@ def compare_dataframe(cls, df1, df2, msg='DFrame'):
         try:
             assert_frame_equal(df1, df2)
         except AssertionError as e:
-            raise cls.failureException(msg+': '+str(e))
+            raise cls.failureException(f'{msg}: {e}') from e
 
     #============#
     # Statistics #

holoviews/element/graphs.py

@@ -528,11 +528,11 @@ def __init__(self, data, kdims=None, vdims=None, **params):
                     points = self.point_type(nodes)
                     ds = Dataset(points).add_dimension('index', 2, np.arange(len(points)))
                     nodes = self.node_type(ds)
-                except Exception:
+                except Exception as e:
                     raise ValueError(
                         "Nodes argument could not be interpreted, expected "
                         "data with two or three columns representing the "
-                        "x/y positions and optionally the node indices.")
+                        "x/y positions and optionally the node indices.") from e
         if edgepaths is not None and not isinstance(edgepaths, self.edge_type):
             edgepaths = self.edge_type(edgepaths)
 
@@ -549,7 +549,7 @@ def from_vertices(cls, data):
             from scipy.spatial import Delaunay
         except ImportError:
             raise ImportError("Generating triangles from points requires "
-                              "SciPy to be installed.")
+                              "SciPy to be installed.") from None
         if not isinstance(data, Points):
             data = Points(data)
         if not len(data):

holoviews/element/raster.py

@@ -648,7 +648,7 @@ def load_image(cls, filename, height=1, array=False, bounds=None, bare=False, **
         try:
             from PIL import Image
         except ImportError:
-            raise ImportError("RGB.load_image requires PIL (or Pillow).")
+            raise ImportError("RGB.load_image requires PIL (or Pillow).") from None
 
         with open(filename, 'rb') as f:
             data = np.array(Image.open(f))

holoviews/element/selection.py

@@ -69,7 +69,7 @@ def spatial_select_gridded(xvals, yvals, geometry):
             from ..operation.datashader import rasterize
         except ImportError:
             raise ImportError("Lasso selection on gridded data requires "
-                              "datashader to be available.")
+                              "datashader to be available.") from None
         xs, ys = xvals[0], yvals[:, 0]
         target = Image((xs, ys, np.empty(ys.shape+xs.shape)))
         poly = Polygons([geometry])
@@ -132,7 +132,7 @@ def spatial_select_columnar(xvals, yvals, geometry):
             geom_mask = np.array([poly.contains(p) for p in points])
         except ImportError:
             raise ImportError("Lasso selection on tabular data requires "
-                              "either spatialpandas or shapely to be available.")
+                              "either spatialpandas or shapely to be available.") from None
     if isinstance(xvals, pd.Series):
         sel_mask[sel_mask.index[np.where(sel_mask)[0]]] = geom_mask
     else:
@@ -155,7 +155,7 @@ def spatial_geom_select(x0vals, y0vals, x1vals, y1vals, geometry):
         return np.array([poly.contains(p) for p in boxes])
     except ImportError:
         raise ImportError("Lasso selection on geometry data requires "
-                          "shapely to be available.")
+                          "shapely to be available.") from None
 
 def spatial_poly_select(xvals, yvals, geometry):
     try:
@@ -165,7 +165,7 @@ def spatial_poly_select(xvals, yvals, geometry):
         return np.array([poly.contains(p) for p in boxes])
     except ImportError:
         raise ImportError("Lasso selection on geometry data requires "
-                          "shapely to be available.")
+                          "shapely to be available.") from None
 
 def spatial_bounds_select(xvals, yvals, bounds):
     x0, y0, x1, y1 = bounds

holoviews/ipython/__init__.py

@@ -41,8 +41,8 @@ def setUp(self):
             self.ip = IPython.InteractiveShell()
             if self.ip is None:
                 raise TypeError()
-        except Exception:
-                raise SkipTest("IPython could not be started")
+        except Exception as e:
+            raise SkipTest("IPython could not be started") from e
 
         self.addTypeEqualityFunc(HTML, self.skip_comparison)
         self.addTypeEqualityFunc(SVG,  self.skip_comparison)

holoviews/operation/datashader.py

@@ -1570,9 +1570,9 @@ def _process(self, overlay, key=None):
 
         try:
             imgs = xr.align(*imgs, join='exact')
-        except ValueError:
+        except ValueError as e:
             raise ValueError('RGB inputs to the stack operation could not be aligned; '
-                             'ensure they share the same grid sampling.')
+                             'ensure they share the same grid sampling.') from e
 
         stacked = tf.stack(*imgs, how=self.p.compositor)
         arr = shade.uint32_to_uint8(stacked.data)[::-1]

holoviews/operation/element.py

@@ -568,7 +568,7 @@ def _process(self, element, key=None):
                 contour_generator,
             )
         except ImportError:
-            raise ImportError("contours operation requires contourpy.")
+            raise ImportError("contours operation requires contourpy.") from None
 
         xs = element.dimension_values(0, True, flat=False)
         ys = element.dimension_values(1, True, flat=False)

holoviews/operation/normalization.py

@@ -117,7 +117,7 @@ def get_ranges(self, element, key):
                 index = keys.index(key)
                 specs = ranges[index]
             except Exception:
-                raise KeyError("Could not match element key to defined keys")
+                raise KeyError("Could not match element key to defined keys") from None
         else:
             raise ValueError("Key list length must match length of supplied ranges")
 

holoviews/operation/stats.py

@@ -68,7 +68,7 @@ def _process(self, element, key=None):
             from scipy import stats
             from scipy.linalg import LinAlgError
         except ImportError:
-            raise ImportError(f'{type(self).__name__} operation requires SciPy to be installed.')
+            raise ImportError(f'{type(self).__name__} operation requires SciPy to be installed.') from None
 
         params = {}
         if isinstance(element, Distribution):
@@ -172,7 +172,7 @@ def _process(self, element, key=None):
         try:
             from scipy import stats
         except ImportError:
-            raise ImportError(f'{type(self).__name__} operation requires SciPy to be installed.')
+            raise ImportError(f'{type(self).__name__} operation requires SciPy to be installed.') from None
 
         if len(element.dimensions()) < 2:
             raise ValueError("bivariate_kde can only be computed on elements "

holoviews/plotting/plot.py

@@ -348,9 +348,9 @@ def get_plot_class(self, obj):
     def __setattr__(self, label, value):
         try:
             return super().__setattr__(label, value)
-        except Exception:
+        except Exception as e:
             raise Exception("Please set class parameters directly on classes %s"
-                            % ', '.join(str(cls) for cls in self.__dict__['plot_classes'].values()))
+                            % ', '.join(str(cls) for cls in self.__dict__['plot_classes'].values())) from e
 
     def params(self):
         return self.plot_options

holoviews/plotting/plotly/chart3d.py

@@ -102,7 +102,7 @@ def get_data(self, element, ranges, style, **kwargs):
         try:
             from scipy.spatial import Delaunay
         except ImportError:
-            raise SkipRendering("SciPy not available, cannot plot TriSurface")
+            raise SkipRendering("SciPy not available, cannot plot TriSurface") from None
         x, y, z = (element.dimension_values(i) for i in range(3))
         points2D = np.vstack([x, y]).T
         tri = Delaunay(points2D)

holoviews/plotting/plotly/images.py

@@ -55,7 +55,7 @@ def get_data(self, element, ranges, style, is_geo=False, **kwargs):
             import PIL.Image
         except ImportError:
             raise VersionError("""\
-Rendering RGB elements with the plotly backend requires the Pillow package""")
+Rendering RGB elements with the plotly backend requires the Pillow package""") from None
 
         img = np.flip(
             np.dstack([element.dimension_values(d, flat=False)

holoviews/plotting/renderer.py

@@ -541,7 +541,7 @@ class needed to render it with the current renderer.
         try:
             plotclass = Store.registry[cls.backend][element_type]
         except KeyError:
-            raise SkipRendering(f"No plotting class for {element_type.__name__} found.")
+            raise SkipRendering(f"No plotting class for {element_type.__name__} found.") from None
         return plotclass
 
     @classmethod

holoviews/plotting/util.py

@@ -104,8 +104,8 @@ def collate(obj):
                     collated_layout = Layout(el.collate())
                     expanded.extend(collated_layout.values())
             return Layout(expanded)
-        except Exception:
-            raise Exception(undisplayable_info(obj))
+        except Exception as e:
+            raise Exception(undisplayable_info(obj)) from e
     else:
         raise Exception(undisplayable_info(obj))
 

holoviews/selection.py

@@ -520,10 +520,10 @@ def _select(element, selection_expr, cache=None):
             except KeyError as e:
                 key_error = str(e).replace('"', '').replace('.', '')
                 raise CallbackError("linked_selection aborted because it could not "
-                                    f"display selection for all elements: {key_error} on '{element!r}'.")
+                                    f"display selection for all elements: {key_error} on '{element!r}'.") from e
             except Exception as e:
                 raise CallbackError("linked_selection aborted because it could not "
-                                    "display selection for all elements: %s." % e)
+                                    "display selection for all elements: %s." % e) from e
             ds_cache[selection_expr] = mask
         else:
             selection = element

holoviews/util/__init__.py

@@ -341,7 +341,7 @@ def _expand_options(cls, options, backend=None):
         try:
             backend_options = Store.options(backend=backend or current_backend)
         except KeyError as e:
-            raise Exception(f'The {e} backend is not loaded. Please load the backend using hv.extension.')
+            raise Exception(f'The {e} backend is not loaded. Please load the backend using hv.extension.') from None
         expanded = {}
         if isinstance(options, list):
             options = merge_options_to_dict(options)
@@ -645,10 +645,10 @@ def renderer(name):
             if prev_backend:
                 Store.set_current_backend(prev_backend)
         return Store.renderers[name]
-    except ImportError:
+    except ImportError as e:
         msg = ('Could not find a {name!r} renderer, available renderers are: {available}.')
         available = ', '.join(repr(k) for k in Store.renderers)
-        raise ImportError(msg.format(name=name, available=available))
+        raise ImportError(msg.format(name=name, available=available)) from e
 
 
 class extension(_pyviz_extension):

holoviews/util/parser.py

@@ -115,7 +115,7 @@ def todict(cls, parseresult, mode='parens', ns=None):
                                    dict(cls.namespace, **ns)))
             except Exception:
                 if cls.abort_on_eval_failure:
-                    raise SyntaxError(f"Could not evaluate keyword: {keyword!r}")
+                    raise SyntaxError(f"Could not evaluate keyword: {keyword!r}") from None
                 msg = "Ignoring keyword pair that fails to evaluate: '%s'"
                 parsewarning.warning(msg % keyword)
 

holoviews/util/settings.py

@@ -95,7 +95,7 @@ def extract_keywords(cls, line, items):
             try:
                 items.update(eval(f'dict({keyword})'))
             except Exception:
-                raise SyntaxError(f"Could not evaluate keyword: {keyword}")
+                raise SyntaxError(f"Could not evaluate keyword: {keyword}") from None
         return items
 
 
@@ -321,7 +321,7 @@ def output(cls, line=None, cell=None, cell_runner=None,
                 raise ValueError(f"The selected plotting extension {backend!r} "
                                  "has not been loaded, ensure you load it "
                                  f"with hv.extension({backend!r}) before using "
-                                 "hv.output.")
+                                 "hv.output.") from e
             print(f'Error: {e}')
             if help_prompt:
                 print(help_prompt)

holoviews/util/transform.py

@@ -930,7 +930,7 @@ def __init__(self, obj, *args, **kwargs):
             import xarray as xr
         except ImportError:
             raise ImportError("XArray could not be imported, dim().xr "
-                              "requires the xarray to be available.")
+                              "requires the xarray to be available.") from None
         super().__init__(obj, *args, **kwargs)
         self._ns = xr.DataArray
 

pyproject.toml

@@ -73,7 +73,6 @@ select = [
 ]
 
 ignore = [
-    "B904",     # Within an `except` clause, raise exceptions with from err or None
     "E402",     # Module level import not at top of file
     "E501",     # Line too long
     "E701",     # Multiple statements on one line
@@ -99,6 +98,7 @@ unfixable = [
 "holoviews/tests/*" = [
     "RUF001", "RUF002", "RUF003",  # Ambiguous unicode character
     "NPY002",  # Replace legacy `np.random.rand` call with Generator
+    "B904",  # Within an `except` clause, raise exceptions with from err or None
 ]
 
 [tool.ruff.lint.isort]