BUG: Fix duplication of names in 'numpy.__all__'.

Closes numpygh-10198.

Author: WarrenWeckesser

numpy/__init__.py

@@ -233,6 +233,10 @@
     __all__.extend(lib.__all__)
     __all__.extend(['linalg', 'fft', 'random', 'ctypeslib', 'ma'])
 
+    # Remove one of the two occurrences of `issubdtype`, which is exposed as
+    # both `numpy.core.issubdtype` and `numpy.lib.issubdtype`.
+    __all__.remove('issubdtype')
+
     # These are exported by np.core, but are replaced by the builtins below
     # remove them to ensure that we don't end up with `np.long == np.int_`,
     # which would be a breaking change.

numpy/core/__init__.py

@@ -106,7 +106,6 @@
 
 __all__ = ['char', 'rec', 'memmap']
 __all__ += numeric.__all__
-__all__ += fromnumeric.__all__
 __all__ += ['record', 'recarray', 'format_parser']
 __all__ += ['chararray']
 __all__ += function_base.__all__

numpy/tests/test__all__.py

@@ -0,0 +1,9 @@
+
+import collections
+import numpy as np
+
+
+def test_no_duplicates_in_np__all__():
+    # Regression test for gh-10198.
+    dups = {k: v for k, v in collections.Counter(np.__all__).items() if v > 1}
+    assert len(dups) == 0