Merge pull request scipy#12558 from peterbell10/scipy-fft-function

MAINT: Remove hack to allow scipy.fft to act like a function

scipy/__init__.py

@@ -81,14 +81,8 @@
         'use numpy.random.{0} instead')
 rand = _deprecated(_msg.format('rand'))(rand)
 randn = _deprecated(_msg.format('randn'))(randn)
-from numpy.fft import fft, ifft
-# fft is especially problematic, so we deprecate it with a shorter window
-fft_msg = ('Using scipy.fft as a function is deprecated and will be '
-           'removed in SciPy 1.5.0, use scipy.fft.fft instead.')
-# for wrapping in scipy.fft.__call__, so the stacklevel is one off from the
-# usual (2)
-_dep_fft = _deprecated(fft_msg, stacklevel=3)(fft)
-fft = _deprecated(fft_msg)(fft)
+# fft is especially problematic, so was removed in SciPy 1.6.0
+from numpy.fft import ifft
 ifft = _deprecated('scipy.ifft is deprecated and will be removed in SciPy '
                    '2.0.0, use scipy.fft.ifft instead')(ifft)
 import numpy.lib.scimath as _sci
@@ -101,7 +95,7 @@
     globals()[_key] = _fun
 
 __all__ += _num.__all__
-__all__ += ['randn', 'rand', 'fft', 'ifft']
+__all__ += ['randn', 'rand', 'ifft']
 
 del _num
 # Remove the linalg imported from NumPy so that the scipy.linalg package can be
@@ -152,4 +146,3 @@
 
     # This makes "from scipy import fft" return scipy.fft, not np.fft
     del fft
-    from . import fft

scipy/_lib/tests/test__util.py

@@ -141,21 +141,17 @@ def test_mapwrapper_parallel():
 
 # get our custom ones and a few from the "import *" cases
 @pytest.mark.parametrize(
-    'key', ('fft', 'ifft', 'diag', 'arccos',
-            'randn', 'rand', 'array'))
+    'key', ('ifft', 'diag', 'arccos', 'randn', 'rand', 'array'))
 def test_numpy_deprecation(key):
     """Test that 'from numpy import *' functions are deprecated."""
-    if key in ('fft', 'ifft', 'diag', 'arccos'):
+    if key in ('ifft', 'diag', 'arccos'):
         arg = [1.0, 0.]
     elif key == 'finfo':
         arg = float
     else:
         arg = 2
     func = getattr(scipy, key)
-    if key == 'fft':
-        match = r'scipy\.fft.*deprecated.*1.5.0.*'
-    else:
-        match = r'scipy\.%s is deprecated.*2\.0\.0' % key
+    match = r'scipy\.%s is deprecated.*2\.0\.0' % key
     with deprecated_call(match=match) as dep:
         func(arg)  # deprecated
     # in case we catch more than one dep warning
@@ -164,7 +160,7 @@ def test_numpy_deprecation(key):
     assert 'test__util' in basenames
     if key in ('rand', 'randn'):
         root = np.random
-    elif key in ('fft', 'ifft'):
+    elif key == 'ifft':
         root = np.fft
     else:
         root = np

scipy/fft/__init__.py

@@ -96,20 +96,3 @@
 from scipy._lib._testutils import PytestTester
 test = PytestTester(__name__)
 del PytestTester
-
-
-# Hack to allow numpy.fft.fft to be called as scipy.fft
-import sys
-class _FFTModule(sys.modules[__name__].__class__):
-    @staticmethod
-    def __call__(*args, **kwargs):
-        from scipy import _dep_fft
-        return _dep_fft(*args, **kwargs)
-
-
-import os
-if os.environ.get('_SCIPY_BUILDING_DOC') != 'True':
-    sys.modules[__name__].__class__ = _FFTModule
-del os
-del _FFTModule
-del sys

scipy/fft/tests/test_fft_function.py

@@ -1,36 +1,46 @@
+import numpy as np
+import subprocess
+import sys
+
+TEST_BODY = r"""
 import pytest
 import numpy as np
 from numpy.testing import assert_allclose
+import scipy
+import sys
+import pytest
+
+if hasattr(scipy, 'fft'):
+    raise AssertionError("scipy.fft should require an explicit import")
+
+np.random.seed(1234)
+x = np.random.randn(10) + 1j * np.random.randn(10)
+X = np.fft.fft(x)
+# Callable before scipy.fft is imported
+with pytest.deprecated_call(match=r'2\.0\.0'):
+    y = scipy.ifft(X)
+assert_allclose(y, x)
 
+# Callable after scipy.fft is imported
+import scipy.fft
+with pytest.deprecated_call(match=r'2\.0\.0'):
+    y = scipy.ifft(X)
+assert_allclose(y, x)
+
+"""
 
 def test_fft_function():
-    # Many NumPy symbols are imported into the scipy namespace, including
-    # numpy.fft.fft as scipy.fft, conflicting with this module (gh-10253)
-    np.random.seed(1234)
-
-    # Callable before scipy.fft is imported
-    import scipy
-    x = np.random.randn(10) + 1j * np.random.randn(10)
-    with pytest.deprecated_call(match=r'1\.5\.0'):
-        X = scipy.fft(x)
-    with pytest.deprecated_call(match=r'2\.0\.0'):
-        y = scipy.ifft(X)
-    assert_allclose(y, x)
-
-    # Callable after scipy.fft is imported
-    import scipy.fft
-    assert_allclose(X, scipy.fft.fft(x))
-    with pytest.deprecated_call(match=r'1\.5\.0'):
-        X = scipy.fft(x)
-    assert_allclose(X, scipy.fft.fft(x))
-    with pytest.deprecated_call(match=r'2\.0\.0'):
-        y = scipy.ifft(X)
-    assert_allclose(y, x)
-
-    # Callable when imported using from
+    # Historically, scipy.fft was an alias for numpy.fft.fft
+    # Ensure there are no conflicts with the FFT module (gh-10253)
+
+    # Test must run in a subprocess so scipy.fft is not already imported
+    subprocess.check_call([sys.executable, '-c', TEST_BODY])
+
+    # scipy.fft is the correct module
     from scipy import fft
-    with pytest.deprecated_call(match=r'1\.5\.0'):
-        X = fft(x)
-    with pytest.deprecated_call(match=r'2\.0\.0'):
-        y = scipy.ifft(X)
-    assert_allclose(y, x)
+    assert not callable(fft)
+    assert fft.__name__ == 'scipy.fft'
+
+    from scipy import ifft
+    assert ifft.__wrapped__ is np.fft.ifft
+