done

lib/python3.11/site-packages/numpy/_globals.py

@@ -0,0 +1,96 @@
+"""
+Module defining global singleton classes.
+
+This module raises a RuntimeError if an attempt to reload it is made. In that
+way the identities of the classes defined here are fixed and will remain so
+even if numpy itself is reloaded. In particular, a function like the following
+will still work correctly after numpy is reloaded::
+
+    def foo(arg=np._NoValue):
+        if arg is np._NoValue:
+            ...
+
+That was not the case when the singleton classes were defined in the numpy
+``__init__.py`` file. See gh-7844 for a discussion of the reload problem that
+motivated this module.
+
+"""
+import enum
+
+from ._utils import set_module as _set_module
+
+__all__ = ['_NoValue', '_CopyMode']
+
+
+# Disallow reloading this module so as to preserve the identities of the
+# classes defined here.
+if '_is_loaded' in globals():
+    raise RuntimeError('Reloading numpy._globals is not allowed')
+_is_loaded = True
+
+
+class _NoValueType:
+    """Special keyword value.
+
+    The instance of this class may be used as the default value assigned to a
+    keyword if no other obvious default (e.g., `None`) is suitable,
+
+    Common reasons for using this keyword are:
+
+    - A new keyword is added to a function, and that function forwards its
+      inputs to another function or method which can be defined outside of
+      NumPy. For example, ``np.std(x)`` calls ``x.std``, so when a ``keepdims``
+      keyword was added that could only be forwarded if the user explicitly
+      specified ``keepdims``; downstream array libraries may not have added
+      the same keyword, so adding ``x.std(..., keepdims=keepdims)``
+      unconditionally could have broken previously working code.
+    - A keyword is being deprecated, and a deprecation warning must only be
+      emitted when the keyword is used.
+
+    """
+    __instance = None
+
+    def __new__(cls):
+        # ensure that only one instance exists
+        if not cls.__instance:
+            cls.__instance = super().__new__(cls)
+        return cls.__instance
+
+    def __repr__(self):
+        return "<no value>"
+
+
+_NoValue = _NoValueType()
+
+
+@_set_module("numpy")
+class _CopyMode(enum.Enum):
+    """
+    An enumeration for the copy modes supported
+    by numpy.copy() and numpy.array(). The following three modes are supported,
+
+    - ALWAYS: This means that a deep copy of the input
+              array will always be taken.
+    - IF_NEEDED: This means that a deep copy of the input
+                 array will be taken only if necessary.
+    - NEVER: This means that the deep copy will never be taken.
+             If a copy cannot be avoided then a `ValueError` will be
+             raised.
+
+    Note that the buffer-protocol could in theory do copies.  NumPy currently
+    assumes an object exporting the buffer protocol will never do this.
+    """
+
+    ALWAYS = True
+    NEVER = False
+    IF_NEEDED = 2
+
+    def __bool__(self):
+        # For backwards compatibility
+        if self == _CopyMode.ALWAYS:
+            return True
+
+        if self == _CopyMode.NEVER:
+            return False
+
+        raise ValueError(f"{self} is neither True nor False.")