* Optimize tracemalloc_add_trace(): modify hashtable entry data (trace) if the
memory block is already tracked, rather than trying to remove the old trace
and then add a new trace.
* Add _Py_HASHTABLE_ENTRY_WRITE_DATA() macro
Issue #26530:
* Add C functions _PyTraceMalloc_Track() and _PyTraceMalloc_Untrack() to track
memory blocks using the tracemalloc module.
* Add _PyTraceMalloc_GetTraceback() to get the traceback of an object.
Issue #26567:
* Add a new function PyErr_ResourceWarning() function to pass the destroyed
object
* Add a source attribute to warnings.WarningMessage
* Add warnings._showwarnmsg() which uses tracemalloc to get the traceback where
source object was allocated.
Issue #26563:
* Add _PyGILState_GetInterpreterStateUnsafe() function: the single
PyInterpreterState used by this process' GILState implementation.
* Enhance _Py_DumpTracebackThreads() to retrieve the interpreter state from
autoInterpreterState in last resort. The function now accepts NULL for interp
and current_tstate parameters.
* test_faulthandler: fix a ResourceWarning when test is interrupted by CTRL+c
Issue #26564:
* Expose _Py_DumpASCII() and _Py_DumpDecimal() in traceback.h
* Change the type of the second _Py_DumpASCII() parameter from int to unsigned
long
* Rewrite _Py_DumpDecimal() and dump_hexadecimal() to write directly characters
in the expected order, avoid the need of reversing the string.
* dump_hexadecimal() limits width to the size of the buffer
* _Py_DumpASCII() does nothing if the object is not a Unicode string
* dump_frame() wrtites "???" as the line number if the line number is negative
Issue #10915, #15751, #26558:
* PyGILState_Check() now returns 1 (success) before the creation of the GIL and
after the destruction of the GIL. It allows to use the function early in
Python initialization and late in Python finalization.
* Add a flag to disable PyGILState_Check(). Disable PyGILState_Check() when
Py_NewInterpreter() is called
* Add assert(PyGILState_Check()) to: _Py_dup(), _Py_fstat(), _Py_read()
and _Py_write()
Issue #26516:
* Add PYTHONMALLOC environment variable to set the Python memory
allocators and/or install debug hooks.
* PyMem_SetupDebugHooks() can now also be used on Python compiled in release
mode.
* The PYTHONMALLOCSTATS environment variable can now also be used on Python
compiled in release mode. It now has no effect if set to an empty string.
* In debug mode, debug hooks are now also installed on Python memory allocators
when Python is configured without pymalloc.
Issue #26146: Add a new kind of AST node: ast.Constant. It can be used by
external AST optimizers, but the compiler does not emit directly such node.
An optimizer can replace the following AST nodes with ast.Constant:
* ast.NameConstant: None, False, True
* ast.Num: int, float, complex
* ast.Str: str
* ast.Bytes: bytes
* ast.Tuple if items are constants too: tuple
* frozenset
Update code to accept ast.Constant instead of ast.Num and/or ast.Str:
* compiler
* docstrings
* ast.literal_eval()
* Tools/parser/unparse.py
Issue #26161: Use Py_uintptr_t instead of void* for atomic pointers in
pyatomic.h. Use atomic_uintptr_t when <stdatomic.h> is used.
Using void* causes compilation warnings depending on which implementation of
atomic types is used.
Issue #25843: When compiling code, don't merge constants if they are equal but
have a different types. For example, "f1, f2 = lambda: 1, lambda: 1.0" is now
correctly compiled to two different functions: f1() returns 1 (int) and f2()
returns 1.0 (int), even if 1 and 1.0 are equal.
Add a new _PyCode_ConstantKey() private function.
Issue #25843: When compiling code, don't merge constants if they are equal but
have a different types. For example, "f1, f2 = lambda: 1, lambda: 1.0" is now
correctly compiled to two different functions: f1() returns 1 (int) and f2()
returns 1.0 (int), even if 1 and 1.0 are equal.
Add a new _PyCode_ConstantKey() private function.
issue25909 - Correct the documentation of PyMapping_Items, PyMapping_Keys and
PyMapping_Values in Include/abstract.h and Doc/c-api/mapping.rst.
Patch contributed by Sonali Gupta.
Issue #26107: The format of the co_lnotab attribute of code objects changes to
support negative line number delta.
Changes:
* assemble_lnotab(): if line number delta is less than -128 or greater than
127, emit multiple (offset_delta, lineno_delta) in co_lnotab
* update functions decoding co_lnotab to use signed 8-bit integers
- dis.findlinestarts()
- PyCode_Addr2Line()
- _PyCode_CheckLineNumber()
- frame_setlineno()
* update lnotab_notes.txt
* increase importlib MAGIC_NUMBER to 3361
* document the change in What's New in Python 3.6
* cleanup also PyCode_Optimize() to use better variable names
Issue #26154: Add a new private _PyThreadState_UncheckedGet() function which
gets the current thread state, but don't call Py_FatalError() if it is NULL.
Python 3.5.1 removed the _PyThreadState_Current symbol from the Python C API to
no more expose complex and private atomic types. Atomic types depends on the
compiler or can even depend on compiler options. The new function
_PyThreadState_UncheckedGet() allows to get the variable value without having
to care of the exact implementation of atomic types.
Changes:
* Replace direct usage of the _PyThreadState_Current variable with a call to
_PyThreadState_UncheckedGet().
* In pystate.c, replace direct usage of the _PyThreadState_Current variable
with the PyThreadState_GET() macro for readability.
* Document also PyThreadState_Get() in pystate.h
Also document that the separate functions that delete objects are preferred;
using PyObject_SetAttr(), _SetAttrString(), and PySequence_SetItem() to
delete is deprecated.
This changes the main documentation, doc strings, source code comments, and a
couple error messages in the test suite. In some cases the word was removed
or edited some other way to fix the grammar.
* Don't overallocate by 400% when recode is needed: only overallocate on demand
using _PyBytesWriter.
* Use _PyLong_DigitValue to convert hexadecimal digit to int
* Create _PyBytes_DecodeEscapeRecode() subfunction
Issue #25401: Optimize bytes.fromhex() and bytearray.fromhex(): they are now
between 2x and 3.5x faster. Changes:
* Use a fast-path working on a char* string for ASCII string
* Use a slow-path for non-ASCII string
* Replace slow hex_digit_to_int() function with a O(1) lookup in
_PyLong_DigitValue precomputed table
* Use _PyBytesWriter API to handle the buffer
* Add unit tests to check the error position in error messages
Issue #25399: Don't create temporary bytes objects: modify _PyBytes_Format() to
create work directly on bytearray objects.
* Rename _PyBytes_Format() to _PyBytes_FormatEx() just in case if something
outside CPython uses it
* _PyBytes_FormatEx() now uses (char*, Py_ssize_t) for the input string, so
bytearray_format() doesn't need tot create a temporary input bytes object
* Add use_bytearray parameter to _PyBytes_FormatEx() which is passed to
_PyBytesWriter, to create a bytearray buffer instead of a bytes buffer
Most formatting operations are now between 2.5 and 5 times faster.
Issue #25274: sys.setrecursionlimit() now raises a RecursionError if the new
recursion limit is too low depending at the current recursion depth. Modify
also the "lower-water mark" formula to make it monotonic. This mark is used to
decide when the overflowed flag of the thread state is reset.
Don't require _PyBytesWriter pointer to be a "char *". Same change for
_PyBytesWriter_WriteBytes() parameter.
For example, binascii uses "unsigned char*".
Optimize bytes.__mod__(args) for integere formats: %d (%i, %u), %o, %x and %X.
_PyBytesWriter is now used to format directly the integer into the writer
buffer, instead of using a temporary bytes object.
Formatting is between 30% and 50% faster on a microbenchmark.
Add a new private API to optimize Unicode encoders. It uses a small buffer
allocated on the stack and supports overallocation.
Use _PyBytesWriter API for UCS1 (ASCII and Latin1) and UTF-8 encoders. Enable
overallocation for the UTF-8 encoder with error handlers.
unicode_encode_ucs1(): initialize collend to collstart+1 to not check the
current character twice, we already know that it is not ASCII.
Python.h header to fix a compilation error with OpenMP. PyThreadState_GET()
becomes an alias to PyThreadState_Get() to avoid ABI incompatibilies.
It is important that the _PyThreadState_Current variable is always accessed
with the same implementation of pyatomic.h. Use the PyThreadState_Get()
function so extension modules will all reuse the same implementation.
On Windows, the tv_sec field of the timeval structure has the type C long,
whereas it has the type C time_t on all other platforms. A C long has a size of
32 bits (signed inter, 1 bit for the sign, 31 bits for the value) which is not
enough to store an Epoch timestamp after the year 2038.
Add the _PyTime_AsTimevalTime_t() function written for datetime.datetime.now():
convert a _PyTime_t timestamp to a (secs, us) tuple where secs type is time_t.
It allows to support dates after the year 2038 on Windows.
Enhance also _PyTime_AsTimeval_impl() to detect overflow on the number of
seconds when rounding the number of microseconds.
On Windows, the tv_sec field of the timeval structure has the type C long,
whereas it has the type C time_t on all other platforms. A C long has a size of
32 bits (signed inter, 1 bit for the sign, 31 bits for the value) which is not
enough to store an Epoch timestamp after the year 2038.
Add the _PyTime_AsTimevalTime_t() function written for datetime.datetime.now():
convert a _PyTime_t timestamp to a (secs, us) tuple where secs type is time_t.
It allows to support dates after the year 2038 on Windows.
Enhance also _PyTime_AsTimeval_impl() to detect overflow on the number of
seconds when rounding the number of microseconds.
datetime.datetime now round microseconds to nearest with ties going to nearest
even integer (ROUND_HALF_EVEN), as round(float), instead of rounding towards
-Infinity (ROUND_FLOOR).
pytime API: replace _PyTime_ROUND_HALF_UP with _PyTime_ROUND_HALF_EVEN. Fix
also _PyTime_Divide() for negative numbers.
_PyTime_AsTimeval_impl() now reuses _PyTime_Divide() instead of reimplementing
rounding modes.
with ties going away from zero (ROUND_HALF_UP), as Python 2 and Python older
than 3.3, instead of rounding to nearest with ties going to nearest even
integer (ROUND_HALF_EVEN).
Serhiy Storchaka
Martin Panter
Ned Deily
Victor Stinner
Yury Selivanov
Senthil Kumaran
Larry Hastings
Eric V. Smith