The tracemalloc_tracebacks hash table has traceback keys and NULL
values, but its destructors do not reflect this -- key_destroy_func is
NULL while value_destroy_func is raw_free. Swap these to free the
traceback keys instead.
gh-120754: Update estimated_size in C truncate (#121357)
Sometimes a large file is truncated (test_largefile). While
estimated_size is used as a estimate (the read will stil get the number
of bytes in the file), that it is much larger than the actual size of
data can result in a significant over allocation and sometimes lead to
a MemoryError / running out of memory.
This brings the C implementation to match the Python _pyio
implementation.
gh-120754: Reduce system calls in full-file FileIO.readall() case (#120755)
This reduces the system call count of a simple program[0] that reads all
the `.rst` files in Doc by over 10% (5706 -> 4734 system calls on my
linux system, 5813 -> 4875 on my macOS)
This reduces the number of `fstat()` calls always and seek calls most
the time. Stat was always called twice, once at open (to error early on
directories), and a second time to get the size of the file to be able
to read the whole file in one read. Now the size is cached with the
first call.
The code keeps an optimization that if the user had previously read a
lot of data, the current position is subtracted from the number of bytes
to read. That is somewhat expensive so only do it on larger files,
otherwise just try and read the extra bytes and resize the PyBytes as
needeed.
I built a little test program to validate the behavior + assumptions
around relative costs and then ran it under `strace` to get a log of the
system calls. Full samples below[1].
After the changes, this is everything in one `filename.read_text()`:
This does make some tradeoffs
1. If the file size changes between open() and readall(), this will
still get all the data but might have more read calls.
2. I experimented with avoiding the stat + cached result for small files
in general, but on my dev workstation at least that tended to reduce
performance compared to using the fstat().
[0]
```python3
from pathlib import Path
nlines = []
for filename in Path("cpython/Doc").glob("**/*.rst"):
nlines.append(len(filename.read_text()))
```
gh-117983: Defer import of threading for lazy module loading (#120233)
As noted in gh-117983, the import importlib.util can be triggered at
interpreter startup under some circumstances, so adding threading makes
it a potentially obligatory load.
Lazy loading is not used in the stdlib, so this removes an unnecessary
load for the majority of users and slightly increases the cost of the
first lazily loaded module.
An obligatory threading load breaks gevent, which monkeypatches the
stdlib. Although unsupported, there doesn't seem to be an offsetting
benefit to breaking their use case.
For reference, here are benchmarks for the current main branch:
```
❯ hyperfine -w 8 './python -c "import importlib.util"'
Benchmark 1: ./python -c "import importlib.util"
Time (mean ± σ): 9.7 ms ± 0.7 ms [User: 7.7 ms, System: 1.8 ms]
Range (min … max): 8.4 ms … 13.1 ms 313 runs
```
And with this patch:
```
❯ hyperfine -w 8 './python -c "import importlib.util"'
Benchmark 1: ./python -c "import importlib.util"
Time (mean ± σ): 8.4 ms ± 0.7 ms [User: 6.8 ms, System: 1.4 ms]
Range (min … max): 7.2 ms … 11.7 ms 352 runs
```
Compare to:
```
❯ hyperfine -w 8 './python -c pass'
Benchmark 1: ./python -c pass
Time (mean ± σ): 7.6 ms ± 0.6 ms [User: 5.9 ms, System: 1.6 ms]
Range (min … max): 6.7 ms … 11.3 ms 390 runs
```
This roughly halves the import time of importlib.util.
gh-61103: Support float and long double complex types in ctypes module (#121248)
This amends 6988ff02a5: memory allocation for
stginfo->ffi_type_pointer.elements in PyCSimpleType_init() should be
more generic (perhaps someday fmt->pffi_type->elements will be not a
two-elements array).
It should finally resolve #61103.
Co-authored-by: Victor Stinner <vstinner@python.org> Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Barney Gale [Wed, 3 Jul 2024 03:30:29 +0000 (04:30 +0100)]
GH-73991: Support copying directory symlinks on older Windows (#120807)
Check for `ERROR_INVALID_PARAMETER` when calling `_winapi.CopyFile2()` and
raise `UnsupportedOperation`. In `Path.copy()`, handle this exception and
fall back to the `PathBase.copy()` implementation.
Victor Stinner [Tue, 2 Jul 2024 08:34:13 +0000 (10:34 +0200)]
Move get_signal_name() to test.support (#121251)
* Move get_signal_name() from test.libregrtest to test.support.
* Use get_signal_name() in support.script_helper.
* support.script_helper now decodes stdout and stderr from UTF-8,
instead of ASCII, if a command failed.
Victor Stinner [Mon, 1 Jul 2024 08:30:33 +0000 (10:30 +0200)]
gh-121188: Sanitize invalid XML characters in regrtest (#121195)
When creating the JUnit XML file, regrtest now escapes characters
which are invalid in XML, such as the chr(27) control character used
in ANSI escape sequences.
gh-113565: Improve and harden detection of curses dependencies (#119816)
1. Use pkg-config to check for ncursesw/panelw. If that fails, use
pkg-config to check for ncurses/panel.
2. Regardless of pkg-config output, search for curses/panel headers, so
we're sure we have all defines in pyconfig.h.
3. Regardless of pkg-config output, check if libncurses or libncursesw
contains the 'initscr' symbol; if it does _and_ pkg-config failed
earlier, add the resulting -llib linker option to CURSES_LIBS.
Ditto for 'update_panels' and PANEL_LIBS.
4. Wrap the rest of the checks with WITH_SAVE_ENV and make sure we're
using updated LIBS and CPPFLAGS for those.
gh-87744: fix waitpid race while calling send_signal in asyncio (#121126)
asyncio earlier relied on subprocess module to send signals to the process, this has some drawbacks one being that subprocess module unnecessarily calls waitpid on child processes and hence it races with asyncio implementation which internally uses child watchers. To mitigate this, now asyncio sends signals directly to the process without going through the subprocess on non windows systems. On Windows it fallbacks to subprocess module handling but on windows there are no child watchers so this issue doesn't exists altogether.
Barney Gale [Sat, 29 Jun 2024 15:09:47 +0000 (16:09 +0100)]
GH-119054: Add "Expanding and resolving paths" section to pathlib docs. (#120970)
Add dedicated subsection for `home()`, `expanduser()`, `cwd()`,
`absolute()`, `resolve()` and `readlink()`. The position of this section
keeps all the `Path` constructors (`Path()`, `Path.from_uri()`,
`Path.home()` and `Path.cwd()`) near the top. Within the section, closely
related methods are kept adjacent. Specifically:
-.`home()` and `expanduser()` (the former calls the latter)
- `cwd()` and `absolute()` (the former calls the latter)
- `absolute()` and `resolve()` (both make paths absolute)
- `resolve()` and `readlink()` (both read symlink targets)
- Ditto `cwd()` and `absolute()`
- Ditto `absolute()` and `resolve()`
gh-119372: Recover inf's and zeros in _Py_c_quot (GH-119457)
In some cases, previously computed as (nan+nanj), we could
recover meaningful component values in the result, see
e.g. the C11, Annex G.5.2, routine _Cdivd().
Serhiy Storchaka [Fri, 28 Jun 2024 14:21:59 +0000 (17:21 +0300)]
gh-121018: Fix more cases of exiting in argparse when exit_on_error=False (GH-121056)
* parse_intermixed_args() now raises ArgumentError instead of calling
error() if exit_on_error is false.
* Internal code now always raises ArgumentError instead of calling
error(). It is then caught at the higher level and error() is called if
exit_on_error is true.
Victor Stinner [Fri, 28 Jun 2024 12:41:37 +0000 (14:41 +0200)]
Check for compiler warnings in test_cext on Windows (#121088)
On Windows, test_cext and test_cppext now pass /WX flag to the MSC
compiler to treat all compiler warnings as errors. In verbose mode,
these tests now log the compiler commands to help debugging.
Change Py_BUILD_ASSERT_EXPR implementation on Windows to avoid a
compiler warning about an unnamed structure.
Craig Robson [Thu, 27 Jun 2024 16:44:40 +0000 (09:44 -0700)]
gh-105623 Fix performance degradation in logging RotatingFileHandler (GH-105887)
The check for whether the log file is a real file is expensive on NFS
filesystems. This commit reorders the rollover condition checking to
not do the file type check if the expected file size is less than the
rotation threshold.
Victor Stinner [Thu, 27 Jun 2024 09:58:44 +0000 (11:58 +0200)]
gh-121040: Use __attribute__((fallthrough)) (#121044)
Fix warnings when using -Wimplicit-fallthrough compiler flag.
Annotate explicitly "fall through" switch cases with a new
_Py_FALLTHROUGH macro which uses __attribute__((fallthrough)) if
available. Replace "fall through" comments with _Py_FALLTHROUGH.
Add _Py__has_attribute() macro. No longer define __has_attribute()
macro if it's not defined. Move also _Py__has_builtin() at the top
of pyport.h.
Eric Snow [Wed, 26 Jun 2024 21:17:26 +0000 (15:17 -0600)]
gh-113433: Automatically Clean Up Subinterpreters in Py_Finalize() (gh-121060)
This change makes things a little less painful for some users. It also fixes a failing assert (gh-120765), by making sure all subinterpreters are destroyed before the main interpreter. As part of that, we make sure Py_Finalize() always runs with the main interpreter active.
Ken Jin [Wed, 26 Jun 2024 19:10:43 +0000 (03:10 +0800)]
gh-117139: Convert the evaluation stack to stack refs (#118450)
This PR sets up tagged pointers for CPython.
The general idea is to create a separate struct _PyStackRef for everything on the evaluation stack to store the bits. This forces the C compiler to warn us if we try to cast things or pull things out of the struct directly.
Only for free threading: We tag the low bit if something is deferred - that means we skip incref and decref operations on it. This behavior may change in the future if Mark's plans to defer all objects in the interpreter loop pans out.
This implies a strict stack reference discipline is required. ALL incref and decref operations on stackrefs must use the stackref variants. It is unsafe to untag something then do normal incref/decref ops on it.
The new incref and decref variants are called dup and close. They mimic a "handle" API operating on these stackrefs.
Please read Include/internal/pycore_stackref.h for more information!
---------
Co-authored-by: Mark Shannon <9448417+markshannon@users.noreply.github.com>
Victor Stinner [Wed, 26 Jun 2024 18:11:21 +0000 (20:11 +0200)]
gh-120593: Fix const qualifier in _PyLong_CompactValue() (#121053)
Remove the const qualifier of the argument of functions:
* _PyLong_IsCompact()
* _PyLong_CompactValue()
Py_TYPE() argument is not const.
Fix the compiler warning:
Include/cpython/longintrepr.h: In function ‘_PyLong_CompactValue’:
Include/pyport.h:19:31: error: cast discards ‘const’ qualifier from
pointer target type [-Werror=cast-qual]
(...)
Include/cpython/longintrepr.h:133:30: note: in expansion of macro
‘Py_TYPE’
assert(PyType_HasFeature(Py_TYPE(op), Py_TPFLAGS_LONG_SUBCLASS));