Remove error utils function (not used anymore) (zarr-developers#614)

* Remove error utils function (not used anymore)

Convert also one more err_ function into a proper exception that derives
from ValueError.

* turn more function into errors

* use VindexInvalidSelectionError

docs/release.rst

@@ -24,8 +24,8 @@ Next release
   By :user:`Elliott Sales de Andrade <QuLogic>`; :issue:`442`
 
 * Many of the convenience functions to emit errors (``err_*`` from
-  ``zarr.errors``  have been replaced by ``ValueError`` subclasses. The
-  functions are deprecated and will be removed in the future. :issue:`590` )
+  ``zarr.errors``  have been replaced by ``ValueError`` subclasses. The corresponding
+  ``err_*`` function have been removed. :issue:`590`, :issue:`614`)
 
 * Improve consistency of terminology regarding arrays and datasets in the 
   documentation.

zarr/errors.py

@@ -15,49 +15,35 @@ def __init__(self, *args):
         super().__init__(self._msg.format(*args))
 
 
-class ContainsGroupError(_BaseZarrError):
-    _msg = "path {0!r} contains a group"
+class _BaseZarrIndexError(IndexError):
+    _msg = ""
+
+    def __init__(self, *args):
+        super().__init__(self._msg.format(*args))
 
 
-def err_contains_group(path):
-    raise ContainsGroupError(path)  # pragma: no cover
+class ContainsGroupError(_BaseZarrError):
+    _msg = "path {0!r} contains a group"
 
 
 class ContainsArrayError(_BaseZarrError):
     _msg = "path {0!r} contains an array"
 
 
-def err_contains_array(path):
-    raise ContainsArrayError(path)  # pragma: no cover
-
-
 class ArrayNotFoundError(_BaseZarrError):
     _msg = "array not found at path %r' {0!r}"
 
 
-def err_array_not_found(path):
-    raise ArrayNotFoundError(path)  # pragma: no cover
-
-
 class GroupNotFoundError(_BaseZarrError):
     _msg = "group not found at path {0!r}"
 
 
-def err_group_not_found(path):
-    raise GroupNotFoundError(path)  # pragma: no cover
-
-
 class PathNotFoundError(_BaseZarrError):
     _msg = "nothing found at path {0!r}"
 
 
-def err_path_not_found(path):
-    raise PathNotFoundError(path)  # pragma: no cover
-
-
-def err_bad_compressor(compressor):
-    raise ValueError('bad compressor; expected Codec object, found %r' %
-                     compressor)
+class BadCompressorError(_BaseZarrError):
+    _msg = "bad compressor; expected Codec object, found {0!r}"
 
 
 class FSPathExistNotDir(GroupNotFoundError):
@@ -69,25 +55,23 @@ def __init__(self):
         super().__init__("object is read-only")
 
 
-def err_read_only():
-    raise ReadOnlyError()  # pragma: no cover
-
+class BoundsCheckError(_BaseZarrIndexError):
+    _msg = "index out of bounds for dimension with length {0}"
 
-def err_boundscheck(dim_len):
-    raise IndexError('index out of bounds for dimension with length {}'
-                     .format(dim_len))
 
-
-def err_negative_step():
-    raise IndexError('only slices with step >= 1 are supported')
+class NegativeStepError(IndexError):
+    def __init__(self):
+        super().__init__("only slices with step >= 1 are supported")
 
 
 def err_too_many_indices(selection, shape):
     raise IndexError('too many indices for array; expected {}, got {}'
                      .format(len(shape), len(selection)))
 
 
-def err_vindex_invalid_selection(selection):
-    raise IndexError('unsupported selection type for vectorized indexing; only '
-                     'coordinate selection (tuple of integer arrays) and mask selection '
-                     '(single Boolean array) are supported; got {!r}'.format(selection))
+class VindexInvalidSelectionError(_BaseZarrIndexError):
+    _msg = (
+        "unsupported selection type for vectorized indexing; only "
+        "coordinate selection (tuple of integer arrays) and mask selection "
+        "(single Boolean array) are supported; got {0!r}"
+    )

zarr/indexing.py

@@ -5,8 +5,12 @@
 
 import numpy as np
 
-from zarr.errors import (err_boundscheck, err_negative_step,
-                         err_too_many_indices, err_vindex_invalid_selection)
+from zarr.errors import (
+    NegativeStepError,
+    err_too_many_indices,
+    VindexInvalidSelectionError,
+    BoundsCheckError,
+)
 
 
 def is_integer(x):
@@ -46,7 +50,7 @@ def normalize_integer_selection(dim_sel, dim_len):
 
     # handle out of bounds
     if dim_sel >= dim_len or dim_sel < 0:
-        err_boundscheck(dim_len)
+        raise BoundsCheckError(dim_len)
 
     return dim_sel
 
@@ -101,7 +105,7 @@ def __init__(self, dim_sel, dim_len, dim_chunk_len):
         # normalize
         self.start, self.stop, self.step = dim_sel.indices(dim_len)
         if self.step < 1:
-            err_negative_step()
+            raise NegativeStepError()
 
         # store attributes
         self.dim_len = dim_len
@@ -385,7 +389,7 @@ def wraparound_indices(x, dim_len):
 
 def boundscheck_indices(x, dim_len):
     if np.any(x < 0) or np.any(x >= dim_len):
-        err_boundscheck(dim_len)
+        raise BoundsCheckError(dim_len)
 
 
 class IntArrayDimIndexer(object):
@@ -756,7 +760,7 @@ def __getitem__(self, selection):
         elif is_mask_selection(selection, self.array):
             return self.array.get_mask_selection(selection, fields=fields)
         else:
-            err_vindex_invalid_selection(selection)
+            raise VindexInvalidSelectionError(selection)
 
     def __setitem__(self, selection, value):
         fields, selection = pop_fields(selection)
@@ -767,7 +771,7 @@ def __setitem__(self, selection, value):
         elif is_mask_selection(selection, self.array):
             self.array.set_mask_selection(selection, value, fields=fields)
         else:
-            err_vindex_invalid_selection(selection)
+            raise VindexInvalidSelectionError(selection)
 
 
 def check_fields(fields, dtype):

zarr/storage.py

@@ -40,7 +40,7 @@
 
 from zarr.errors import (
     MetadataError,
-    err_bad_compressor,
+    BadCompressorError,
     ContainsArrayError,
     ContainsGroupError,
     FSPathExistNotDir,
@@ -397,8 +397,8 @@ def _init_array_metadata(
     if compressor:
         try:
             compressor_config = compressor.get_config()
-        except AttributeError:
-            err_bad_compressor(compressor)
+        except AttributeError as e:
+            raise BadCompressorError(compressor) from e
 
     # obtain filters config
     if filters: