* Fix %-formatting of bytes precision, width and %c errors
`format_bytes` subtracted the byte length from the field width without
saturating, so `b'%1s' % (b'abcde',)` aborted with a capacity overflow.
A precision written as a bare dot now truncates to nothing, and `%r`/`%a`
on bytes now honour the precision and width like the other conversions.
`%c` with a bytes, bytearray or str argument that is not one unit long
now names the argument by its length instead of by its type.
Assisted-by: Claude Code:claude-opus-5
* Fix format spec handling of grouping, bool, 'c' and complex
A grouping option next to an unrecognised presentation type now reports
"Cannot specify ',' with 'a'." instead of falling through to the type
check. `format(True, spec)` now validates the spec the way an int does.
The 'c' type now pads and aligns its character, and an integer outside
the C long range raises OverflowError rather than reporting a code point
out of range.
A complex formatted with the 'n'/'g' types or with a precision and no
type now goes through the general format without forcing a fraction.
Assisted-by: Claude Code:claude-opus-5
* Round floats at a negative ndigits from the exact decimal digits
Dividing by a power of ten rounded twice: once when the quotient was
stored and again at the tie, so e.g. `round(2.5e2, -2)` came out as 300.0.
The digits now come from the exact decimal expansion of the value.
Assisted-by: Claude Code:claude-opus-5
* Report the requested base in int literal errors and reject a bare sign
An invalid literal parsed with base 0 named the base that the prefix
turned out to mean rather than 0. A string of nothing but a sign was
taken for the old octal form and returned 0 instead of raising.
Assisted-by: Claude Code:claude-opus-5
* Split, strip and expand tabs over the Py_UNICODE_ISSPACE set
`str.split`, `rsplit`, `strip`, `lstrip` and `rstrip` with no separator
used Rust's whitespace predicate, which differs from the 29 code points
`Py_UNICODE_ISSPACE` names: U+001C-U+001F and U+0085 were skipped and
U+200B was treated as a separator.
`expandtabs` went through `str`, so it dropped the lone surrogates of a
WTF-8 string; it now works on `Wtf8` throughout.
Indexing a str out of range now says "string index out of range".
Assisted-by: Claude Code:claude-opus-5
* Read Unicode numeric values as exact rationals
`DerivedNumericValues.txt` field 1 carries a rounded decimal, so
`unicodedata.numeric('⅐')` and its neighbours came back short of the
value CPython reports. The generator now reads the rational in field 3,
and takes the 3.2 values from field 8 of `UnicodeData-3.2.0.txt`.
Assisted-by: Claude Code:claude-opus-5
* Return a mappingproxy from Pattern.groupindex
`pattern_groupindex` wraps the group index in a dict proxy, and hands
back a plain dict only when the pattern has no named group.
Assisted-by: Claude Code:claude-opus-5
* Fix the utf-16/32/7 codecs' error handling
The utf-32 decoder dropped a code point above U+10FFFF instead of calling
the error handler, and both the utf-16 and utf-32 handlers were told the
encoding was "utf-16"/"utf-32" whichever byte order the data was in.
The encoders now take a bytes replacement from the handler as it stands,
rejecting one that does not fill whole code units, rather than iterating
over it as text; a str replacement from the utf-16 encoder now splits an
astral code point into a surrogate pair.
The utf-7 decoder names its encoding "utf7", as its codec does.
Assisted-by: Claude Code:claude-opus-5
* Rework complex multiplication, division and power
Division now divides by whichever part of the divisor is larger, the way
`_Py_c_quot` does, and both it and multiplication recover the infinities
that the plain formulas turn into nan, following C11 Annex G. An operand
that is a real number is now multiplied and divided component-wise, which
keeps the sign of a zero and the other part of an infinity; a real
numerator has its own quotient so that its zero keeps a sign too.
An integer exponent no greater than 100 in magnitude is now reached by
repeated multiplication rather than through the polar form, so e.g.
`(1+2j) ** 2` is exact. A zero exponent gives 1, and an exponent with no
imaginary part no longer reaches for a logarithm that turns an infinite
magnitude into a nan. A result that came out infinite raises
OverflowError.
`complex() arg is a malformed string` is replaced by `could not convert
string to complex: ...` when the string carries a misplaced underscore,
`complex division by zero` by `division by zero`, and the message for
zero raised to a negative or complex power no longer names the base.
Assisted-by: Claude Code:claude-opus-5
* Intern the string constants that read as names
A code object's string constants were interned by length, so a short
string that is not a name was interned and a long name was not. They are
now picked out the way `all_name_chars` does. The one-character latin-1
strings are interned as well, so that every route to one of them lands on
the same object.
Assisted-by: Claude Code:claude-opus-5
* Honour the marshal version and separate its EOF errors
Versions below 2 now write a float or complex as its digits under
TYPE_FLOAT/TYPE_COMPLEX, versions from 4 on write a tuple of fewer than
256 items under TYPE_SMALL_TUPLE and a long ascii string under
TYPE_ASCII, and a string is marked interned only when it is.
`marshal.loads` now tells apart the three ways its data can run out:
"EOF read where object expected" where an object was to start, "EOF read
where not expected" where a single byte was, and "marshal data too short"
where a run of bytes was cut short.
Assisted-by: Claude Code:claude-opus-5
Jeong, YunWon