Merge branch 'master' into randrange-index

python · serhiy-storchaka · Jan 25, 2021 · Jun 22, 2019 · Mar 22, 2020 · Oct 31, 2020
commit fb9382e66d82d5c4986d909f1ec9382547afcec1
diff --git a/Doc/library/random.rst b/Doc/library/random.rst
@@ -135,7 +135,7 @@ Functions for integers
       values.  Formerly it used a style like ``int(random()*n)`` which could produce
       slightly uneven distributions.
 
-   .. deprecated:: 3.9
+   .. deprecated:: 3.10
       Accepting non-integer arguments is deprecated.
 
 

diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
@@ -291,6 +291,9 @@ Deprecated
   as appropriate to help identify code which needs updating during
   this transition.
 
+* Deprecated support of non-integer arguments in :func:`random.randrange`.
+  (Contributed by Serhiy Storchaka in :issue:`37319`.)
+
 
 Removed
 =======

diff --git a/Doc/whatsnew/3.9.rst b/Doc/whatsnew/3.9.rst
@@ -906,9 +906,27 @@ Deprecated
   by :c:func:`Py_Initialize()` since Python 3.7.
   (Contributed by Victor Stinner in :issue:`39877`.)
 
-* Deprecated support of non-integer arguments in :func:`random.randrange`.
-  (Contributed by Serhiy Storchaka in :issue:`37319`.)
+* Passing ``None`` as the first argument to the :func:`shlex.split` function
+  has been deprecated.  (Contributed by Zackery Spytz in :issue:`33262`.)
 
+* :func:`smtpd.MailmanProxy` is now deprecated as it is unusable without
+  an external module, ``mailman``.  (Contributed by Samuel Colvin in :issue:`35800`.)
+
+* The :mod:`lib2to3` module now emits a :exc:`PendingDeprecationWarning`.
+  Python 3.9 switched to a PEG parser (see :pep:`617`), and Python 3.10 may
+  include new language syntax that is not parsable by lib2to3's LL(1) parser.
+  The ``lib2to3`` module may be removed from the standard library in a future
+  Python version. Consider third-party alternatives such as `LibCST`_ or
+  `parso`_.
+  (Contributed by Carl Meyer in :issue:`40360`.)
+
+* The *random* parameter of :func:`random.shuffle` has been deprecated.
+  (Contributed by Raymond Hettinger in :issue:`40465`)
+
+.. _LibCST: https://libcst.readthedocs.io/
+.. _parso: https://parso.readthedocs.io/
+
+.. _removed-in-python-39:
 
 Removed
 =======

diff --git a/Lib/random.py b/Lib/random.py
@@ -95,9 +95,10 @@
 LOG4 = _log(4.0)
 SG_MAGICCONST = 1.0 + _log(4.5)
 BPF = 53        # Number of bits in a float
-RECIP_BPF = 2**-BPF
+RECIP_BPF = 2 ** -BPF
 _ONE = 1
 
+
 class Random(_random.Random):
     """Random number generator base class used by bound module functions.
 
@@ -213,7 +214,82 @@ def __reduce__(self):
         return self.__class__, (), self.getstate()
 
 
-    def randrange(self, start, stop=None, step=_ONE, _index=_index, _int=int):
+    ## ---- internal support method for evenly distributed integers ----
+
+    def __init_subclass__(cls, /, **kwargs):
+        """Control how subclasses generate random integers.
+
+        The algorithm a subclass can use depends on the random() and/or
+        getrandbits() implementation available to it and determines
+        whether it can generate random integers from arbitrarily large
+        ranges.
+        """
+
+        for c in cls.__mro__:
+            if '_randbelow' in c.__dict__:
+                # just inherit it
+                break
+            if 'getrandbits' in c.__dict__:
+                cls._randbelow = cls._randbelow_with_getrandbits
+                break
+            if 'random' in c.__dict__:
+                cls._randbelow = cls._randbelow_without_getrandbits
+                break
+
+    def _randbelow_with_getrandbits(self, n):
+        "Return a random int in the range [0,n).  Returns 0 if n==0."
+
+        if not n:
+            return 0
+        getrandbits = self.getrandbits
+        k = n.bit_length()  # don't use (n-1) here because n can be 1
+        r = getrandbits(k)  # 0 <= r < 2**k
+        while r >= n:
+            r = getrandbits(k)
+        return r
+
+    def _randbelow_without_getrandbits(self, n, maxsize=1<<BPF):
+        """Return a random int in the range [0,n).  Returns 0 if n==0.
+
+        The implementation does not use getrandbits, but only random.
+        """
+
+        random = self.random
+        if n >= maxsize:
+            _warn("Underlying random() generator does not supply \n"
+                "enough bits to choose from a population range this large.\n"
+                "To remove the range limitation, add a getrandbits() method.")
+            return _floor(random() * n)
+        if n == 0:
+            return 0
+        rem = maxsize % n
+        limit = (maxsize - rem) / maxsize   # int(limit * maxsize) % n == 0
+        r = random()
+        while r >= limit:
+            r = random()
+        return _floor(r * maxsize) % n
+
+    _randbelow = _randbelow_with_getrandbits
+
+
+    ## --------------------------------------------------------
+    ## ---- Methods below this point generate custom distributions
+    ## ---- based on the methods defined above.  They do not
+    ## ---- directly touch the underlying generator and only
+    ## ---- access randomness through the methods:  random(),
+    ## ---- getrandbits(), or _randbelow().
+
+
+    ## -------------------- bytes methods ---------------------
+
+    def randbytes(self, n):
+        """Generate n random bytes."""
+        return self.getrandbits(n * 8).to_bytes(n, 'little')
+
+
+    ## -------------------- integer methods  -------------------
+
+    def randrange(self, start, stop=None, step=_ONE):
         """Choose a random item from range(start, stop[, step]).
 
         This fixes the problem with randint() which includes the
@@ -226,7 +302,7 @@ def randrange(self, start, stop=None, step=_ONE, _index=_index, _int=int):
         try:
             istart = _index(start)
         except TypeError:
-            istart = _int(start)
+            istart = int(start)
             if istart != start:
                 raise ValueError("non-integer arg 1 for randrange()")
             _warn('non-integer arg 1 for randrange()',
@@ -240,7 +316,7 @@ def randrange(self, start, stop=None, step=_ONE, _index=_index, _int=int):
         try:
             istop = _index(stop)
         except TypeError:
-            istop = _int(stop)
+            istop = int(stop)
             if istop != stop:
                 raise ValueError("non-integer stop for randrange()")
             _warn('non-integer stop for randrange()',
@@ -256,7 +332,7 @@ def randrange(self, start, stop=None, step=_ONE, _index=_index, _int=int):
         try:
             istep = _index(step)
         except TypeError:
-            istep = _int(step)
+            istep = int(step)
             if istep != step:
                 raise ValueError("non-integer step for randrange()")
             _warn('non-integer step for randrange()',