Update {_py,}decimal.py from 3.13.5 (#6034)

2026-06-02 19:39:49 +09:00 · 2025-07-25 12:04:49 +02:00
parent fb9147736d
commit ae03bacb39
14 changed files with 314 additions and 224 deletions
--- a/Lib/_pydecimal.py
+++ b/Lib/_pydecimal.py
@@ -13,104 +13,7 @@
 # bug) and will be backported.  At this point the spec is stabilizing
 # and the updates are becoming fewer, smaller, and less significant.

-"""
-This is an implementation of decimal floating point arithmetic based on
-the General Decimal Arithmetic Specification:
-
-    http://speleotrove.com/decimal/decarith.html
-
-and IEEE standard 854-1987:
-
-    http://en.wikipedia.org/wiki/IEEE_854-1987
-
-Decimal floating point has finite precision with arbitrarily large bounds.
-
-The purpose of this module is to support arithmetic using familiar
-"schoolhouse" rules and to avoid some of the tricky representation
-issues associated with binary floating point.  The package is especially
-useful for financial applications or for contexts where users have
-expectations that are at odds with binary floating point (for instance,
-in binary floating point, 1.00 % 0.1 gives 0.09999999999999995 instead
-of 0.0; Decimal('1.00') % Decimal('0.1') returns the expected
-Decimal('0.00')).
-
-Here are some examples of using the decimal module:
-
->>> from decimal import *
->>> setcontext(ExtendedContext)
->>> Decimal(0)
-Decimal('0')
->>> Decimal('1')
-Decimal('1')
->>> Decimal('-.0123')
-Decimal('-0.0123')
->>> Decimal(123456)
-Decimal('123456')
->>> Decimal('123.45e12345678')
-Decimal('1.2345E+12345680')
->>> Decimal('1.33') + Decimal('1.27')
-Decimal('2.60')
->>> Decimal('12.34') + Decimal('3.87') - Decimal('18.41')
-Decimal('-2.20')
->>> dig = Decimal(1)
->>> print(dig / Decimal(3))
-0.333333333
->>> getcontext().prec = 18
->>> print(dig / Decimal(3))
-0.333333333333333333
->>> print(dig.sqrt())
-1
->>> print(Decimal(3).sqrt())
-1.73205080756887729
->>> print(Decimal(3) ** 123)
-4.85192780976896427E+58
->>> inf = Decimal(1) / Decimal(0)
->>> print(inf)
-Infinity
->>> neginf = Decimal(-1) / Decimal(0)
->>> print(neginf)
-Infinity
->>> print(neginf + inf)
-NaN
->>> print(neginf * inf)
-Infinity
->>> print(dig / 0)
-Infinity
->>> getcontext().traps[DivisionByZero] = 1
->>> print(dig / 0)
-Traceback (most recent call last):
-  ...
-  ...
-  ...
-decimal.DivisionByZero: x / 0
->>> c = Context()
->>> c.traps[InvalidOperation] = 0
->>> print(c.flags[InvalidOperation])
-0
->>> c.divide(Decimal(0), Decimal(0))
-Decimal('NaN')
->>> c.traps[InvalidOperation] = 1
->>> print(c.flags[InvalidOperation])
-1
->>> c.flags[InvalidOperation] = 0
->>> print(c.flags[InvalidOperation])
-0
->>> print(c.divide(Decimal(0), Decimal(0)))
-Traceback (most recent call last):
-  ...
-  ...
-  ...
-decimal.InvalidOperation: 0 / 0
->>> print(c.flags[InvalidOperation])
-1
->>> c.flags[InvalidOperation] = 0
->>> c.traps[InvalidOperation] = 0
->>> print(c.divide(Decimal(0), Decimal(0)))
-NaN
->>> print(c.flags[InvalidOperation])
-1
->>>
-"""
+"""Python decimal arithmetic module"""

 __all__ = [
    # Two major classes
@@ -140,8 +43,11 @@ __all__ = [
    # Limits for the C version for compatibility
    'MAX_PREC',  'MAX_EMAX', 'MIN_EMIN', 'MIN_ETINY',

-    # C version: compile time choice that enables the thread local context
-    'HAVE_THREADS'
+    # C version: compile time choice that enables the thread local context (deprecated, now always true)
+    'HAVE_THREADS',
+
+    # C version: compile time choice that enables the coroutine local context
+    'HAVE_CONTEXTVAR'
 ]

 __xname__ = __name__    # sys.modules lookup (--without-threads)
@@ -156,7 +62,7 @@ import sys

 try:
    from collections import namedtuple as _namedtuple
-    DecimalTuple = _namedtuple('DecimalTuple', 'sign digits exponent')
+    DecimalTuple = _namedtuple('DecimalTuple', 'sign digits exponent', module='decimal')
 except ImportError:
    DecimalTuple = lambda *args: args

@@ -172,6 +78,7 @@ ROUND_05UP = 'ROUND_05UP'

 # Compatibility with the C version
 HAVE_THREADS = True
+HAVE_CONTEXTVAR = True
 if sys.maxsize == 2**63-1:
    MAX_PREC = 999999999999999999
    MAX_EMAX = 999999999999999999
@@ -190,7 +97,7 @@ class DecimalException(ArithmeticError):

    Used exceptions derive from this.
    If an exception derives from another exception besides this (such as
-    Underflow (Inexact, Rounded, Subnormal) that indicates that it is only
+    Underflow (Inexact, Rounded, Subnormal)) that indicates that it is only
    called if the others are present.  This isn't actually used for
    anything, though.

@@ -238,7 +145,7 @@ class InvalidOperation(DecimalException):
    x ** (+-)INF
    An operand is invalid

-    The result of the operation after these is a quiet positive NaN,
+    The result of the operation after this is a quiet positive NaN,
    except when the cause is a signaling NaN, in which case the result is
    also a quiet NaN, but with the original sign, and an optional
    diagnostic information.
@@ -431,82 +338,40 @@ _rounding_modes = (ROUND_DOWN, ROUND_HALF_UP, ROUND_HALF_EVEN, ROUND_CEILING,
 ##### Context Functions ##################################################

 # The getcontext() and setcontext() function manage access to a thread-local
-# current context.  Py2.4 offers direct support for thread locals.  If that
-# is not available, use threading.current_thread() which is slower but will
-# work for older Pythons.  If threads are not part of the build, create a
-# mock threading object with threading.local() returning the module namespace.
+# current context.

-try:
-    import threading
-except ImportError:
-    # Python was compiled without threads; create a mock object instead
-    class MockThreading(object):
-        def local(self, sys=sys):
-            return sys.modules[__xname__]
-    threading = MockThreading()
-    del MockThreading
+import contextvars

-try:
-    threading.local
+_current_context_var = contextvars.ContextVar('decimal_context')

-except AttributeError:
+_context_attributes = frozenset(
+    ['prec', 'Emin', 'Emax', 'capitals', 'clamp', 'rounding', 'flags', 'traps']
+)

-    # To fix reloading, force it to create a new context
-    # Old contexts have different exceptions in their dicts, making problems.
-    if hasattr(threading.current_thread(), '__decimal_context__'):
-        del threading.current_thread().__decimal_context__
+def getcontext():
+    """Returns this thread's context.

-    def setcontext(context):
-        """Set this thread's context to context."""
-        if context in (DefaultContext, BasicContext, ExtendedContext):
-            context = context.copy()
-            context.clear_flags()
-        threading.current_thread().__decimal_context__ = context
+    If this thread does not yet have a context, returns
+    a new context and sets this thread's context.
+    New contexts are copies of DefaultContext.
+    """
+    try:
+        return _current_context_var.get()
+    except LookupError:
+        context = Context()
+        _current_context_var.set(context)
+        return context

-    def getcontext():
-        """Returns this thread's context.
+def setcontext(context):
+    """Set this thread's context to context."""
+    if context in (DefaultContext, BasicContext, ExtendedContext):
+        context = context.copy()
+        context.clear_flags()
+    _current_context_var.set(context)

-        If this thread does not yet have a context, returns
-        a new context and sets this thread's context.
-        New contexts are copies of DefaultContext.
-        """
-        try:
-            return threading.current_thread().__decimal_context__
-        except AttributeError:
-            context = Context()
-            threading.current_thread().__decimal_context__ = context
-            return context
+del contextvars        # Don't contaminate the namespace

-else:
-
-    local = threading.local()
-    if hasattr(local, '__decimal_context__'):
-        del local.__decimal_context__
-
-    def getcontext(_local=local):
-        """Returns this thread's context.
-
-        If this thread does not yet have a context, returns
-        a new context and sets this thread's context.
-        New contexts are copies of DefaultContext.
-        """
-        try:
-            return _local.__decimal_context__
-        except AttributeError:
-            context = Context()
-            _local.__decimal_context__ = context
-            return context
-
-    def setcontext(context, _local=local):
-        """Set this thread's context to context."""
-        if context in (DefaultContext, BasicContext, ExtendedContext):
-            context = context.copy()
-            context.clear_flags()
-        _local.__decimal_context__ = context
-
-    del threading, local        # Don't contaminate the namespace
-
-def localcontext(ctx=None):
+def localcontext(ctx=None, **kwargs):
    """Return a context manager for a copy of the supplied context

    Uses a copy of the current context if no context is specified
@@ -542,8 +407,14 @@ def localcontext(ctx=None):
    >>> print(getcontext().prec)
    28
    """
-    if ctx is None: ctx = getcontext()
-    return _ContextManager(ctx)
+    if ctx is None:
+        ctx = getcontext()
+    ctx_manager = _ContextManager(ctx)
+    for key, value in kwargs.items():
+        if key not in _context_attributes:
+            raise TypeError(f"'{key}' is an invalid keyword argument for this function")
+        setattr(ctx_manager.new_context, key, value)
+    return ctx_manager


 ##### Decimal class #######################################################
@@ -553,7 +424,7 @@ def localcontext(ctx=None):
 # numbers.py for more detail.

 class Decimal(object):
-    """Floating point class for decimal arithmetic."""
+    """Floating-point class for decimal arithmetic."""

    __slots__ = ('_exp','_int','_sign', '_is_special')
    # Generally, the value of the Decimal instance is given by
@@ -993,7 +864,7 @@ class Decimal(object):
            if self.is_snan():
                raise TypeError('Cannot hash a signaling NaN value.')
            elif self.is_nan():
-                return _PyHASH_NAN
+                return object.__hash__(self)
            else:
                if self._sign:
                    return -_PyHASH_INF
@@ -1674,13 +1545,13 @@ class Decimal(object):

    __trunc__ = __int__

+    @property
    def real(self):
        return self
-    real = property(real)

+    @property
    def imag(self):
        return Decimal(0)
-    imag = property(imag)

    def conjugate(self):
        return self
@@ -2260,10 +2131,16 @@ class Decimal(object):
            else:
                return None

-            if xc >= 10**p:
+            # An exact power of 10 is representable, but can convert to a
+            # string of any length. But an exact power of 10 shouldn't be
+            # possible at this point.
+            assert xc > 1, self
+            assert xc % 10 != 0, self
+            strxc = str(xc)
+            if len(strxc) > p:
                return None
            xe = -e-xe
-            return _dec_from_triple(0, str(xc), xe)
+            return _dec_from_triple(0, strxc, xe)

        # now y is positive; find m and n such that y = m/n
        if ye >= 0:
@@ -2272,7 +2149,7 @@ class Decimal(object):
            if xe != 0 and len(str(abs(yc*xe))) <= -ye:
                return None
            xc_bits = _nbits(xc)
-            if xc != 1 and len(str(abs(yc)*xc_bits)) <= -ye:
+            if len(str(abs(yc)*xc_bits)) <= -ye:
                return None
            m, n = yc, 10**(-ye)
            while m % 2 == n % 2 == 0:
@@ -2285,7 +2162,7 @@ class Decimal(object):
        # compute nth root of xc*10**xe
        if n > 1:
            # if 1 < xc < 2**n then xc isn't an nth power
-            if xc != 1 and xc_bits <= n:
+            if xc_bits <= n:
                return None

            xe, rem = divmod(xe, n)
@@ -2313,13 +2190,18 @@ class Decimal(object):
            return None
        xc = xc**m
        xe *= m
-        if xc > 10**p:
+        # An exact power of 10 is representable, but can convert to a string
+        # of any length. But an exact power of 10 shouldn't be possible at
+        # this point.
+        assert xc > 1, self
+        assert xc % 10 != 0, self
+        str_xc = str(xc)
+        if len(str_xc) > p:
            return None

        # by this point the result *is* exactly representable
        # adjust the exponent to get as close as possible to the ideal
        # exponent, if necessary
-        str_xc = str(xc)
        if other._isinteger() and other._sign == 0:
            ideal_exponent = self._exp*int(other)
            zeros = min(xe-ideal_exponent, p-len(str_xc))
@@ -3837,6 +3719,10 @@ class Decimal(object):
        # represented in fixed point; rescale them to 0e0.
        if not self and self._exp > 0 and spec['type'] in 'fF%':
            self = self._rescale(0, rounding)
+        if not self and spec['no_neg_0'] and self._sign:
+            adjusted_sign = 0
+        else:
+            adjusted_sign = self._sign

        # figure out placement of the decimal point
        leftdigits = self._exp + len(self._int)
@@ -3867,7 +3753,7 @@ class Decimal(object):

        # done with the decimal-specific stuff;  hand over the rest
        # of the formatting to the _format_number function
-        return _format_number(self._sign, intpart, fracpart, exp, spec)
+        return _format_number(adjusted_sign, intpart, fracpart, exp, spec)

 def _dec_from_triple(sign, coefficient, exponent, special=False):
    """Create a decimal instance directly, without any validation,
@@ -5677,8 +5563,6 @@ class _WorkRep(object):
    def __repr__(self):
        return "(%r, %r, %r)" % (self.sign, self.int, self.exp)

-    __str__ = __repr__
-


 def _normalize(op1, op2, prec = 0):
@@ -6187,7 +6071,7 @@ _exact_half = re.compile('50*$').match
 #
 # A format specifier for Decimal looks like:
 #
-#   [[fill]align][sign][#][0][minimumwidth][,][.precision][type]
+#   [[fill]align][sign][z][#][0][minimumwidth][,][.precision][type]

 _parse_format_specifier_regex = re.compile(r"""\A
 (?:
@@ -6195,6 +6079,7 @@ _parse_format_specifier_regex = re.compile(r"""\A
   (?P<align>[<>=^])
 )?
 (?P<sign>[-+ ])?
+(?P<no_neg_0>z)?
 (?P<alt>\#)?
 (?P<zeropad>0)?
 (?P<minimumwidth>(?!0)\d+)?
--- a/Lib/decimal.py
+++ b/Lib/decimal.py
@@ -1,11 +1,109 @@
+"""Decimal fixed-point and floating-point arithmetic.
+
+This is an implementation of decimal floating-point arithmetic based on
+the General Decimal Arithmetic Specification:
+
+    http://speleotrove.com/decimal/decarith.html
+
+and IEEE standard 854-1987:
+
+    http://en.wikipedia.org/wiki/IEEE_854-1987
+
+Decimal floating point has finite precision with arbitrarily large bounds.
+
+The purpose of this module is to support arithmetic using familiar
+"schoolhouse" rules and to avoid some of the tricky representation
+issues associated with binary floating point.  The package is especially
+useful for financial applications or for contexts where users have
+expectations that are at odds with binary floating point (for instance,
+in binary floating point, 1.00 % 0.1 gives 0.09999999999999995 instead
+of 0.0; Decimal('1.00') % Decimal('0.1') returns the expected
+Decimal('0.00')).
+
+Here are some examples of using the decimal module:
+
+>>> from decimal import *
+>>> setcontext(ExtendedContext)
+>>> Decimal(0)
+Decimal('0')
+>>> Decimal('1')
+Decimal('1')
+>>> Decimal('-.0123')
+Decimal('-0.0123')
+>>> Decimal(123456)
+Decimal('123456')
+>>> Decimal('123.45e12345678')
+Decimal('1.2345E+12345680')
+>>> Decimal('1.33') + Decimal('1.27')
+Decimal('2.60')
+>>> Decimal('12.34') + Decimal('3.87') - Decimal('18.41')
+Decimal('-2.20')
+>>> dig = Decimal(1)
+>>> print(dig / Decimal(3))
+0.333333333
+>>> getcontext().prec = 18
+>>> print(dig / Decimal(3))
+0.333333333333333333
+>>> print(dig.sqrt())
+1
+>>> print(Decimal(3).sqrt())
+1.73205080756887729
+>>> print(Decimal(3) ** 123)
+4.85192780976896427E+58
+>>> inf = Decimal(1) / Decimal(0)
+>>> print(inf)
+Infinity
+>>> neginf = Decimal(-1) / Decimal(0)
+>>> print(neginf)
+-Infinity
+>>> print(neginf + inf)
+NaN
+>>> print(neginf * inf)
+-Infinity
+>>> print(dig / 0)
+Infinity
+>>> getcontext().traps[DivisionByZero] = 1
+>>> print(dig / 0)
+Traceback (most recent call last):
+  ...
+  ...
+  ...
+decimal.DivisionByZero: x / 0
+>>> c = Context()
+>>> c.traps[InvalidOperation] = 0
+>>> print(c.flags[InvalidOperation])
+0
+>>> c.divide(Decimal(0), Decimal(0))
+Decimal('NaN')
+>>> c.traps[InvalidOperation] = 1
+>>> print(c.flags[InvalidOperation])
+1
+>>> c.flags[InvalidOperation] = 0
+>>> print(c.flags[InvalidOperation])
+0
+>>> print(c.divide(Decimal(0), Decimal(0)))
+Traceback (most recent call last):
+  ...
+  ...
+  ...
+decimal.InvalidOperation: 0 / 0
+>>> print(c.flags[InvalidOperation])
+1
+>>> c.flags[InvalidOperation] = 0
+>>> c.traps[InvalidOperation] = 0
+>>> print(c.divide(Decimal(0), Decimal(0)))
+NaN
+>>> print(c.flags[InvalidOperation])
+1
+>>>
+"""

 try:
    from _decimal import *
-    from _decimal import __doc__
    from _decimal import __version__
    from _decimal import __libmpdec_version__
 except ImportError:
-    from _pydecimal import *
-    from _pydecimal import __doc__
-    from _pydecimal import __version__
-    from _pydecimal import __libmpdec_version__
+    import _pydecimal
+    import sys
+    _pydecimal.__doc__ = __doc__
+    sys.modules[__name__] = _pydecimal
--- a/Lib/test/decimaltestdata/abs.decTest
+++ b/Lib/test/decimaltestdata/abs.decTest
@@ -20,7 +20,7 @@
 version: 2.59

 -- This set of tests primarily tests the existence of the operator.
-- Additon, subtraction, rounding, and more overflows are tested
+-- Addition, subtraction, rounding, and more overflows are tested
 -- elsewhere.

 precision:   9
--- a/Lib/test/decimaltestdata/ddFMA.decTest
+++ b/Lib/test/decimaltestdata/ddFMA.decTest
@@ -1663,7 +1663,7 @@ ddfma375087 fma  1  12345678 1E-33                   -> 12345678.00000001 Inexac
 ddfma375088 fma  1  12345678 1E-34                   -> 12345678.00000001 Inexact Rounded
 ddfma375089 fma  1  12345678 1E-35                   -> 12345678.00000001 Inexact Rounded

-- desctructive subtraction (from remainder tests)
+-- destructive subtraction (from remainder tests)

 -- +++ some of these will be off-by-one remainder vs remainderNear

--- a/Lib/test/decimaltestdata/ddQuantize.decTest
+++ b/Lib/test/decimaltestdata/ddQuantize.decTest
@@ -462,7 +462,7 @@ ddqua520 quantize   1.234    1e359 -> 0E+359 Inexact Rounded
 ddqua521 quantize 123.456    1e359 -> 0E+359 Inexact Rounded
 ddqua522 quantize   1.234    1e359 -> 0E+359 Inexact Rounded
 ddqua523 quantize 123.456    1e359 -> 0E+359 Inexact Rounded
-- next four are "won't fit" overfl
+-- next four are "won't fit" overflow
 ddqua526 quantize   1.234   1e-299 -> NaN Invalid_operation
 ddqua527 quantize 123.456   1e-299 -> NaN Invalid_operation
 ddqua528 quantize   1.234   1e-299 -> NaN Invalid_operation
--- a/Lib/test/decimaltestdata/ddRemainder.decTest
+++ b/Lib/test/decimaltestdata/ddRemainder.decTest
@@ -422,7 +422,7 @@ ddrem757 remainder  1    sNaN   ->  NaN  Invalid_operation
 ddrem758 remainder  1000 sNaN   ->  NaN  Invalid_operation
 ddrem759 remainder  Inf -sNaN   -> -NaN  Invalid_operation

-- propaging NaNs
+-- propagating NaNs
 ddrem760 remainder  NaN1   NaN7   ->  NaN1
 ddrem761 remainder sNaN2   NaN8   ->  NaN2 Invalid_operation
 ddrem762 remainder  NaN3  sNaN9   ->  NaN9 Invalid_operation
--- a/Lib/test/decimaltestdata/ddRemainderNear.decTest
+++ b/Lib/test/decimaltestdata/ddRemainderNear.decTest
@@ -450,7 +450,7 @@ ddrmn757 remaindernear  1    sNaN   ->  NaN  Invalid_operation
 ddrmn758 remaindernear  1000 sNaN   ->  NaN  Invalid_operation
 ddrmn759 remaindernear  Inf -sNaN   -> -NaN  Invalid_operation

-- propaging NaNs
+-- propagating NaNs
 ddrmn760 remaindernear  NaN1   NaN7   ->  NaN1
 ddrmn761 remaindernear sNaN2   NaN8   ->  NaN2 Invalid_operation
 ddrmn762 remaindernear  NaN3  sNaN9   ->  NaN9 Invalid_operation
--- a/Lib/test/decimaltestdata/dqRemainder.decTest
+++ b/Lib/test/decimaltestdata/dqRemainder.decTest
@@ -418,7 +418,7 @@ dqrem757 remainder  1    sNaN   ->  NaN  Invalid_operation
 dqrem758 remainder  1000 sNaN   ->  NaN  Invalid_operation
 dqrem759 remainder  Inf -sNaN   -> -NaN  Invalid_operation

-- propaging NaNs
+-- propagating NaNs
 dqrem760 remainder  NaN1   NaN7   ->  NaN1
 dqrem761 remainder sNaN2   NaN8   ->  NaN2 Invalid_operation
 dqrem762 remainder  NaN3  sNaN9   ->  NaN9 Invalid_operation
--- a/Lib/test/decimaltestdata/dqRemainderNear.decTest
+++ b/Lib/test/decimaltestdata/dqRemainderNear.decTest
@@ -450,7 +450,7 @@ dqrmn757 remaindernear  1    sNaN   ->  NaN  Invalid_operation
 dqrmn758 remaindernear  1000 sNaN   ->  NaN  Invalid_operation
 dqrmn759 remaindernear  Inf -sNaN   -> -NaN  Invalid_operation

-- propaging NaNs
+-- propagating NaNs
 dqrmn760 remaindernear  NaN1   NaN7   ->  NaN1
 dqrmn761 remaindernear sNaN2   NaN8   ->  NaN2 Invalid_operation
 dqrmn762 remaindernear  NaN3  sNaN9   ->  NaN9 Invalid_operation
--- a/Lib/test/decimaltestdata/exp.decTest
+++ b/Lib/test/decimaltestdata/exp.decTest
@@ -28,7 +28,7 @@ rounding:    half_even
 maxExponent: 384
 minexponent: -383

-- basics (examples in specificiation, etc.)
+-- basics (examples in specification, etc.)
 expx001 exp  -Infinity     -> 0
 expx002 exp  -10           -> 0.0000453999298 Inexact Rounded
 expx003 exp  -1            -> 0.367879441 Inexact Rounded
--- a/Lib/test/decimaltestdata/extra.decTest
+++ b/Lib/test/decimaltestdata/extra.decTest
@@ -156,7 +156,7 @@ extr1302 fma -Inf 0E-456 sNaN148 -> NaN Invalid_operation

 -- max/min/max_mag/min_mag bug in 2.5.2/2.6/3.0: max(NaN, finite) gave
 -- incorrect answers when the finite number required rounding; similarly
-- for the other thre functions
+-- for the other three functions
 maxexponent: 999
 minexponent: -999
 precision: 6
--- a/Lib/test/decimaltestdata/remainder.decTest
+++ b/Lib/test/decimaltestdata/remainder.decTest
@@ -435,7 +435,7 @@ remx757 remainder  1    sNaN   ->  NaN  Invalid_operation
 remx758 remainder  1000 sNaN   ->  NaN  Invalid_operation
 remx759 remainder  Inf -sNaN   -> -NaN  Invalid_operation

-- propaging NaNs
+-- propagating NaNs
 remx760 remainder  NaN1   NaN7   ->  NaN1
 remx761 remainder sNaN2   NaN8   ->  NaN2 Invalid_operation
 remx762 remainder  NaN3  sNaN9   ->  NaN9 Invalid_operation
--- a/Lib/test/decimaltestdata/remainderNear.decTest
+++ b/Lib/test/decimaltestdata/remainderNear.decTest
@@ -498,7 +498,7 @@ rmnx758 remaindernear  1000 sNaN   ->  NaN  Invalid_operation
 rmnx759 remaindernear  Inf  sNaN   ->  NaN  Invalid_operation
 rmnx760 remaindernear  NaN  sNaN   ->  NaN  Invalid_operation

-- propaging NaNs
+-- propagating NaNs
 rmnx761 remaindernear  NaN1   NaN7   ->  NaN1
 rmnx762 remaindernear sNaN2   NaN8   ->  NaN2 Invalid_operation
 rmnx763 remaindernear  NaN3 -sNaN9   -> -NaN9 Invalid_operation
--- a/Lib/test/test_decimal.py
+++ b/Lib/test/test_decimal.py
@@ -24,6 +24,7 @@ you're working through IDLE, you can import this test module and call test()
 with the corresponding argument.
 """

+import logging
 import math
 import os, sys
 import operator
@@ -812,8 +813,6 @@ class ExplicitConstructionTest:
            x = random.expovariate(0.01) * (random.random() * 2.0 - 1.0)
            self.assertEqual(x, float(nc.create_decimal(x))) # roundtrip

-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
    def test_unicode_digits(self):
        Decimal = self.decimal.Decimal

@@ -831,6 +830,11 @@ class CExplicitConstructionTest(ExplicitConstructionTest, unittest.TestCase):
 class PyExplicitConstructionTest(ExplicitConstructionTest, unittest.TestCase):
    decimal = P

+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_unicode_digits(self): # TODO(RUSTPYTHON): Remove this test when it pass
+        return super().test_unicode_digits()
+
 class ImplicitConstructionTest:
    '''Unit tests for Implicit Construction cases of Decimal.'''

@@ -916,8 +920,6 @@ class PyImplicitConstructionTest(ImplicitConstructionTest, unittest.TestCase):

 class FormatTest:
    '''Unit tests for the format function.'''
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
    def test_formatting(self):
        Decimal = self.decimal.Decimal

@@ -1113,6 +1115,13 @@ class FormatTest:
            ('z>z6.1f', '-0.', 'zzz0.0'),
            ('x>z6.1f', '-0.', 'xxx0.0'),
            ('🖤>z6.1f', '-0.', '🖤🖤🖤0.0'),  # multi-byte fill char
+            ('\x00>z6.1f', '-0.', '\x00\x00\x000.0'),  # null fill char
+
+            # issue 114563 ('z' format on F type in cdecimal)
+            ('z3,.10F', '-6.24E-323', '0.0000000000'),
+
+            # issue 91060 ('#' format in cdecimal)
+            ('#', '0', '0.'),

            # issue 6850
            ('a=-7.0', '0.12345', 'aaaa0.1'),
@@ -1128,8 +1137,6 @@ class FormatTest:
        # bytes format argument
        self.assertRaises(TypeError, Decimal(1).__format__, b'-020')

-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
    def test_negative_zero_format_directed_rounding(self):
        with self.decimal.localcontext() as ctx:
            ctx.rounding = ROUND_CEILING
@@ -1228,7 +1235,31 @@ class FormatTest:
        self.assertEqual(get_fmt(Decimal('-1.5'), dotsep_wide, '020n'),
                         '-0\u00b4000\u00b4000\u00b4000\u00b4001\u00bf5')

-    @run_with_locale('LC_ALL', 'ps_AF')
+    def test_deprecated_N_format(self):
+        Decimal = self.decimal.Decimal
+        h = Decimal('6.62607015e-34')
+        if self.decimal == C:
+            with self.assertWarns(DeprecationWarning) as cm:
+                r = format(h, 'N')
+            self.assertEqual(cm.filename, __file__)
+            self.assertEqual(r, format(h, 'n').upper())
+            with self.assertWarns(DeprecationWarning) as cm:
+                r = format(h, '010.3N')
+            self.assertEqual(cm.filename, __file__)
+            self.assertEqual(r, format(h, '010.3n').upper())
+        else:
+            self.assertRaises(ValueError, format, h, 'N')
+            self.assertRaises(ValueError, format, h, '010.3N')
+        with warnings_helper.check_no_warnings(self):
+            self.assertEqual(format(h, 'N>10.3'), 'NN6.63E-34')
+            self.assertEqual(format(h, 'N>10.3n'), 'NN6.63e-34')
+            self.assertEqual(format(h, 'N>10.3e'), 'N6.626e-34')
+            self.assertEqual(format(h, 'N>10.3f'), 'NNNNN0.000')
+            self.assertRaises(ValueError, format, h, '>Nf')
+            self.assertRaises(ValueError, format, h, '10Nf')
+            self.assertRaises(ValueError, format, h, 'Nx')
+
+    @run_with_locale('LC_ALL', 'ps_AF', '')
    def test_wide_char_separator_decimal_point(self):
        # locale with wide char separator and decimal point
        Decimal = self.decimal.Decimal
@@ -1911,8 +1942,6 @@ class UsabilityTest:
            x = 1100 ** 1248
            self.assertEqual(hashit(Decimal(x)), hashit(x))

-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
    def test_hash_method_nan(self):
        Decimal = self.decimal.Decimal
        self.assertRaises(TypeError, hash, Decimal('sNaN'))
@@ -2048,7 +2077,9 @@ class UsabilityTest:
        #to quantize, which is already extensively tested
        test_triples = [
            ('123.456', -4, '0E+4'),
+            ('-123.456', -4, '-0E+4'),
            ('123.456', -3, '0E+3'),
+            ('-123.456', -3, '-0E+3'),
            ('123.456', -2, '1E+2'),
            ('123.456', -1, '1.2E+2'),
            ('123.456', 0, '123'),
@@ -2718,8 +2749,6 @@ class PythonAPItests:
        x = d.quantize(context=c, exp=Decimal("1e797"), rounding=ROUND_DOWN)
        self.assertEqual(x, Decimal('8.71E+799'))

-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
    def test_complex(self):
        Decimal = self.decimal.Decimal

@@ -2894,6 +2923,11 @@ class CPythonAPItests(PythonAPItests, unittest.TestCase):
 class PyPythonAPItests(PythonAPItests, unittest.TestCase):
    decimal = P

+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_complex(self): # TODO(RUSTPYTHON): Remove this test when it pass
+        return super().test_complex()
+
 class ContextAPItests:

    def test_none_args(self):
@@ -3663,8 +3697,6 @@ class ContextWithStatement:
        self.assertIsNot(new_ctx, set_ctx, 'did not copy the context')
        self.assertIs(set_ctx, enter_ctx, '__enter__ returned wrong context')

-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
    def test_localcontext_kwargs(self):
        with self.decimal.localcontext(
            prec=10, rounding=ROUND_HALF_DOWN,
@@ -3693,8 +3725,6 @@ class ContextWithStatement:
        self.assertRaises(TypeError, self.decimal.localcontext, Emin="")
        self.assertRaises(TypeError, self.decimal.localcontext, Emax="")

-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
    def test_local_context_kwargs_does_not_overwrite_existing_argument(self):
        ctx = self.decimal.getcontext()
        orig_prec = ctx.prec
@@ -4362,7 +4392,8 @@ class CheckAttributes(unittest.TestCase):

        self.assertEqual(C.__version__, P.__version__)

-        self.assertEqual(dir(C), dir(P))
+        self.assertLessEqual(set(dir(C)), set(dir(P)))
+        self.assertEqual([n for n in dir(C) if n[:2] != '__'], sorted(P.__all__))

    def test_context_attributes(self):

@@ -4438,6 +4469,15 @@ class Coverage:
            self.assertIs(Decimal("NaN").fma(7, 1).is_nan(), True)
            # three arg power
            self.assertEqual(pow(Decimal(10), 2, 7), 2)
+            if self.decimal == C:
+                self.assertEqual(pow(10, Decimal(2), 7), 2)
+                self.assertEqual(pow(10, 2, Decimal(7)), 2)
+            else:
+                # XXX: Three-arg power doesn't use __rpow__.
+                self.assertRaises(TypeError, pow, 10, Decimal(2), 7)
+                # XXX: There is no special method to dispatch on the
+                # third arg of three-arg power.
+                self.assertRaises(TypeError, pow, 10, 2, Decimal(7))
            # exp
            self.assertEqual(Decimal("1.01").exp(), 3)
            # is_normal
@@ -4648,6 +4688,11 @@ class PyCoverage(Coverage, unittest.TestCase):
        sys.set_int_max_str_digits(self._previous_int_limit)
        super().tearDown()

+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_implicit_context(self): # TODO(RUSTPYTHON): Remove this test when it pass
+        return super().test_implicit_context()
+
 class PyFunctionality(unittest.TestCase):
    """Extra functionality in decimal.py"""

@@ -4699,9 +4744,33 @@ class PyWhitebox(unittest.TestCase):

            c.prec = 1
            x = Decimal("152587890625") ** Decimal('-0.5')
+            self.assertEqual(x, Decimal('3e-6'))
+            c.prec = 2
+            x = Decimal("152587890625") ** Decimal('-0.5')
+            self.assertEqual(x, Decimal('2.6e-6'))
+            c.prec = 3
+            x = Decimal("152587890625") ** Decimal('-0.5')
+            self.assertEqual(x, Decimal('2.56e-6'))
+            c.prec = 28
+            x = Decimal("152587890625") ** Decimal('-0.5')
+            self.assertEqual(x, Decimal('2.56e-6'))
+
            c.prec = 201
            x = Decimal(2**578) ** Decimal("-0.5")

+            # See https://github.com/python/cpython/issues/118027
+            # Testing for an exact power could appear to hang, in the Python
+            # version, as it attempted to compute 10**(MAX_EMAX + 1).
+            # Fixed via https://github.com/python/cpython/pull/118503.
+            c.prec = P.MAX_PREC
+            c.Emax = P.MAX_EMAX
+            c.Emin = P.MIN_EMIN
+            c.traps[P.Inexact] = 1
+            D2 = Decimal(2)
+            # If the bug is still present, the next statement won't complete.
+            res = D2 ** 117
+            self.assertEqual(res, 1 << 117)
+
    def test_py_immutability_operations(self):
        # Do operations and check that it didn't change internal objects.
        Decimal = P.Decimal
@@ -5625,6 +5694,25 @@ class CWhitebox(unittest.TestCase):
            self.assertEqual(Decimal.from_float(cls(101.1)),
                             Decimal.from_float(101.1))

+    def test_c_immutable_types(self):
+        SignalDict = type(C.Context().flags)
+        SignalDictMixin = SignalDict.__bases__[0]
+        ContextManager = type(C.localcontext())
+        types = (
+            SignalDictMixin,
+            ContextManager,
+            C.Decimal,
+            C.Context,
+        )
+        for tp in types:
+            with self.subTest(tp=tp):
+                with self.assertRaisesRegex(TypeError, "immutable"):
+                    tp.foo = 1
+
+    def test_c_disallow_instantiation(self):
+        ContextManager = type(C.localcontext())
+        check_disallow_instantiation(self, ContextManager)
+
    def test_c_signaldict_segfault(self):
        # See gh-106263 for details.
        SignalDict = type(C.Context().flags)
@@ -5655,6 +5743,20 @@ class CWhitebox(unittest.TestCase):
        with self.assertRaisesRegex(ValueError, err_msg):
            sd.copy()

+    def test_format_fallback_capitals(self):
+        # Fallback to _pydecimal formatting (triggered by `#` format which
+        # is unsupported by mpdecimal) should honor the current context.
+        x = C.Decimal('6.09e+23')
+        self.assertEqual(format(x, '#'), '6.09E+23')
+        with C.localcontext(capitals=0):
+            self.assertEqual(format(x, '#'), '6.09e+23')
+
+    def test_format_fallback_rounding(self):
+        y = C.Decimal('6.09')
+        self.assertEqual(format(y, '#.1f'), '6.1')
+        with C.localcontext(rounding=C.ROUND_DOWN):
+            self.assertEqual(format(y, '#.1f'), '6.0')
+
@requires_docstrings
@requires_cdecimal
 class SignatureTest(unittest.TestCase):
@@ -5818,13 +5920,17 @@ def load_tests(loader, tests, pattern):

    if TODO_TESTS is None:
        from doctest import DocTestSuite, IGNORE_EXCEPTION_DETAIL
+        orig_context = orig_sys_decimal.getcontext().copy()
        for mod in C, P:
            if not mod:
                continue
            def setUp(slf, mod=mod):
                sys.modules['decimal'] = mod
-            def tearDown(slf):
+                init(mod)
+            def tearDown(slf, mod=mod):
                sys.modules['decimal'] = orig_sys_decimal
+                mod.setcontext(ORIGINAL_CONTEXT[mod].copy())
+                orig_sys_decimal.setcontext(orig_context.copy())
            optionflags = IGNORE_EXCEPTION_DETAIL if mod is C else 0
            sys.modules['decimal'] = mod
            tests.addTest(DocTestSuite(mod, setUp=setUp, tearDown=tearDown,
@@ -5839,11 +5945,12 @@ def setUpModule():
    TEST_ALL = ARITH if ARITH is not None else is_resource_enabled('decimal')

 def tearDownModule():
-    if C: C.setcontext(ORIGINAL_CONTEXT[C])
-    P.setcontext(ORIGINAL_CONTEXT[P])
+    if C: C.setcontext(ORIGINAL_CONTEXT[C].copy())
+    P.setcontext(ORIGINAL_CONTEXT[P].copy())
    if not C:
-        warnings.warn('C tests skipped: no module named _decimal.',
-                      UserWarning)
+        logging.getLogger(__name__).warning(
+            'C tests skipped: no module named _decimal.'
+        )
    if not orig_sys_decimal is sys.modules['decimal']:
        raise TestFailed("Internal error: unbalanced number of changes to "
                         "sys.modules['decimal'].")