Merge remote-tracking branch 'upstream/main' into fixes

Author: pablogsal

.github/workflows/tail-call.yml

@@ -79,19 +79,17 @@ jobs:
         with:
           python-version: '3.11'
 
-      - name: Native Windows (debug)
+      - name: Native Windows MSVC (release)
         if: runner.os == 'Windows' && matrix.architecture != 'ARM64'
         shell: cmd
         run: |
-          choco install llvm --allow-downgrade --no-progress --version ${{ matrix.llvm }}.1.0
-          set PlatformToolset=clangcl
-          set LLVMToolsVersion=${{ matrix.llvm }}.1.0
-          set LLVMInstallDir=C:\Program Files\LLVM
-          call ./PCbuild/build.bat --tail-call-interp -d -p ${{ matrix.architecture }}
-          call ./PCbuild/rt.bat -d -p ${{ matrix.architecture }} -q --multiprocess 0 --timeout 4500 --verbose2 --verbose3
+          choco install visualstudio2026buildtools --no-progress -y --force --params "--add Microsoft.VisualStudio.Component.VC.Tools.x86.x64  --locale en-US --passive"
+          $env:PATH = "C:\Program Files (x86)\Microsoft Visual Studio\18\BuildTools\MSBuild\Current\bin;$env:PATH"
+          ./PCbuild/build.bat --tail-call-interp -c Release -p ${{ matrix.architecture }} "/p:PlatformToolset=v145"
+          ./PCbuild/rt.bat -p ${{ matrix.architecture }} -q --multiprocess 0 --timeout 4500 --verbose2 --verbose3
 
       # No tests (yet):
-      - name: Emulated Windows (release)
+      - name: Emulated Windows Clang (release)
         if: runner.os == 'Windows' && matrix.architecture == 'ARM64'
         shell: cmd
         run: |

Doc/library/datetime.rst

@@ -2651,9 +2651,42 @@ Broadly speaking, ``d.strftime(fmt)`` acts like the :mod:`time` module's
 ``time.strftime(fmt, d.timetuple())`` although not all objects support a
 :meth:`~date.timetuple` method.
 
-For the :meth:`.datetime.strptime` class method, the default value is
-``1900-01-01T00:00:00.000``: any components not specified in the format string
-will be pulled from the default value. [#]_
+For the :meth:`.datetime.strptime` and :meth:`.date.strptime` class methods,
+the default value is ``1900-01-01T00:00:00.000``: any components not specified
+in the format string will be pulled from the default value.
+
+.. note::
+   When used to parse partial dates lacking a year, :meth:`.datetime.strptime`
+   and :meth:`.date.strptime` will raise when encountering February 29 because
+   the default year of 1900 is *not* a leap year.  Always add a default leap
+   year to partial date strings before parsing.
+
+
+.. testsetup::
+
+    # doctest seems to turn the warning into an error which makes it
+    # show up and require matching and prevents the actual interesting
+    # exception from being raised.
+    # Manually apply the catch_warnings context manager
+    import warnings
+    catch_warnings = warnings.catch_warnings()
+    catch_warnings.__enter__()
+    warnings.simplefilter("ignore")
+
+.. testcleanup::
+
+    catch_warnings.__exit__()
+
+.. doctest::
+
+    >>> from datetime import datetime
+    >>> value = "2/29"
+    >>> datetime.strptime(value, "%m/%d")
+    Traceback (most recent call last):
+    ...
+    ValueError: day 29 must be in range 1..28 for month 2 in year 1900
+    >>> datetime.strptime(f"1904 {value}", "%Y %m/%d")
+    datetime.datetime(1904, 2, 29, 0, 0)
 
 Using ``datetime.strptime(date_string, format)`` is equivalent to::
 
@@ -2790,7 +2823,7 @@ Notes:
    include a year in the format.  If the value you need to parse lacks a year,
    append an explicit dummy leap year.  Otherwise your code will raise an
    exception when it encounters leap day because the default year used by the
-   parser is not a leap year.  Users run into this bug every four years...
+   parser (1900) is not a leap year.  Users run into that bug every leap year.
 
    .. doctest::
 
@@ -2817,5 +2850,3 @@ Notes:
 .. [#] See R. H. van Gent's `guide to the mathematics of the ISO 8601 calendar
        <https://web.archive.org/web/20220531051136/https://webspace.science.uu.nl/~gent0113/calendar/isocalendar.htm>`_
        for a good explanation.
-
-.. [#] Passing ``datetime.strptime('Feb 29', '%b %d')`` will fail since 1900 is not a leap year.

Doc/library/pdb.rst

@@ -520,7 +520,8 @@ can be overridden by the local file.
    To remove all commands from a breakpoint, type ``commands`` and follow it
    immediately with ``end``; that is, give no commands.
 
-   With no *bpnumber* argument, ``commands`` refers to the last breakpoint set.
+   With no *bpnumber* argument, ``commands`` refers to the most recently set
+   breakpoint that still exists.
 
    You can use breakpoint commands to start your program up again.  Simply use
    the :pdbcmd:`continue` command, or :pdbcmd:`step`,

Doc/library/profiling.sampling.rst

@@ -200,6 +200,36 @@ On most systems, attaching to another process requires appropriate permissions.
 See :ref:`profiling-permissions` for platform-specific requirements.
 
 
+.. _replay-command:
+
+The ``replay`` command
+----------------------
+
+The ``replay`` command converts binary profile files to other output formats::
+
+   python -m profiling.sampling replay profile.bin
+   python -m profiling.sampling replay --flamegraph -o profile.html profile.bin
+
+This command is useful when you have captured profiling data in binary format
+and want to analyze it later or convert it to a visualization format. Binary
+profiles can be replayed multiple times to different formats without
+re-profiling.
+
+::
+
+   # Convert binary to pstats (default, prints to stdout)
+   python -m profiling.sampling replay profile.bin
+
+   # Convert binary to flame graph
+   python -m profiling.sampling replay --flamegraph -o output.html profile.bin
+
+   # Convert binary to gecko format for Firefox Profiler
+   python -m profiling.sampling replay --gecko -o profile.json profile.bin
+
+   # Convert binary to heatmap
+   python -m profiling.sampling replay --heatmap -o my_heatmap profile.bin
+
+
 Profiling in production
 -----------------------
 
@@ -1087,6 +1117,59 @@ intuitive view that shows exactly where time is spent without requiring
 interpretation of hierarchical visualizations.
 
 
+Binary format
+-------------
+
+Binary format (:option:`--binary`) produces a compact binary file for efficient
+storage of profiling data::
+
+   python -m profiling.sampling run --binary -o profile.bin script.py
+   python -m profiling.sampling attach --binary -o profile.bin 12345
+
+The :option:`--compression` option controls data compression:
+
+- ``auto`` (default): Use zstd compression if available, otherwise no
+  compression
+- ``zstd``: Force zstd compression (requires :mod:`compression.zstd` support)
+- ``none``: Disable compression
+
+::
+
+   python -m profiling.sampling run --binary --compression=zstd -o profile.bin script.py
+
+To analyze binary profiles, use the :ref:`replay-command` to convert them to
+other formats like flame graphs or pstats output.
+
+
+Record and replay workflow
+==========================
+
+The binary format combined with the replay command enables a record-and-replay
+workflow that separates data capture from analysis. Rather than generating
+visualizations during profiling, you capture raw data to a compact binary file
+and convert it to different formats later.
+
+This approach has three main benefits:
+
+- Sampling runs faster because the work of building data structures for
+  visualization is deferred until replay.
+- A single binary capture can be converted to multiple output formats
+  without re-profiling: pstats for a quick overview, flame graph for visual
+  exploration, heatmap for line-level detail.
+- Binary files are compact and easy to share with colleagues who can convert
+  them to their preferred format.
+
+A typical workflow::
+
+   # Capture profile in production or during tests
+   python -m profiling.sampling attach --binary -o profile.bin 12345
+
+   # Later, analyze with different formats
+   python -m profiling.sampling replay profile.bin
+   python -m profiling.sampling replay --flamegraph -o profile.html profile.bin
+   python -m profiling.sampling replay --heatmap -o heatmap profile.bin
+
+
 Live mode
 =========
 
@@ -1298,6 +1381,10 @@ Global options
 
    Attach to and profile a running process by PID.
 
+.. option:: replay
+
+   Convert a binary profile file to another output format.
+
 
 Sampling options
 ----------------
@@ -1388,12 +1475,22 @@ Output options
 
    Generate HTML heatmap with line-level sample counts.
 
+.. option:: --binary
+
+   Generate high-performance binary format for later conversion with the
+   ``replay`` command.
+
+.. option:: --compression <type>
+
+   Compression for binary format: ``auto`` (use zstd if available, default),
+   ``zstd``, or ``none``.
+
 .. option:: -o <path>, --output <path>
 
    Output file or directory path. Default behavior varies by format:
-   ``--pstats`` writes to stdout, ``--flamegraph`` and ``--gecko`` generate
-   files like ``flamegraph.PID.html``, and ``--heatmap`` creates a directory
-   named ``heatmap_PID``.
+   :option:`--pstats` writes to stdout, while other formats generate a file
+   named ``<format>_<PID>.<ext>`` (for example, ``flamegraph_12345.html``).
+   :option:`--heatmap` creates a directory named ``heatmap_<PID>``.
 
 
 pstats display options

Doc/library/stdtypes.rst

@@ -46,8 +46,10 @@ Any object can be tested for truth value, for use in an :keyword:`if` or
 By default, an object is considered true unless its class defines either a
 :meth:`~object.__bool__` method that returns ``False`` or a
 :meth:`~object.__len__` method that
-returns zero, when called with the object. [1]_  Here are most of the built-in
-objects considered false:
+returns zero, when called with the object. [1]_ If one of the methods raises an
+exception when called, the exception is propagated and the object does
+not have a truth value (for example, :data:`NotImplemented`).
+Here are most of the built-in objects considered false:
 
 .. index::
    single: None (Built-in object)

Doc/whatsnew/3.15.rst

@@ -849,6 +849,16 @@ zlib
 Optimizations
 =============
 
+* Builds using Visual Studio 2026 (MSVC 18) may now use the new
+  :ref:`tail-calling interpreter <whatsnew314-tail-call-interpreter>`.
+  Results on an early experimental MSVC compiler reported roughly 15% speedup
+  on the geometric mean of pyperformance on Windows x86-64 over
+  the switch-case interpreter. We have
+  observed speedups ranging from 15% for large pure-Python libraries
+  to 40% for long-running small pure-Python scripts on Windows.
+  (Contributed by Chris Eibl, Ken Jin, and Brandt Bucher in :gh:`143068`.
+  Special thanks to the MSVC team including Hulon Jenkins.)
+
 csv
 ---
 

Include/internal/pycore_ceval.h

@@ -415,6 +415,17 @@ _Py_VectorCall_StackRefSteal(
     int total_args,
     _PyStackRef kwnames);
 
+PyAPI_FUNC(PyObject*)
+_Py_VectorCallInstrumentation_StackRefSteal(
+    _PyStackRef callable,
+    _PyStackRef* arguments,
+    int total_args,
+    _PyStackRef kwnames,
+    bool call_instrumentation,
+    _PyInterpreterFrame* frame,
+    _Py_CODEUNIT* this_instr,
+    PyThreadState* tstate);
+
 PyAPI_FUNC(PyObject *)
 _Py_BuiltinCallFast_StackRefSteal(
     _PyStackRef callable,
@@ -464,6 +475,11 @@ _Py_assert_within_stack_bounds(
     _PyInterpreterFrame *frame, _PyStackRef *stack_pointer,
     const char *filename, int lineno);
 
+// Like PyMapping_GetOptionalItem, but returns the PyObject* instead of taking
+// it as an out parameter. This helps MSVC's escape analysis when used with
+// tail calling.
+PyAPI_FUNC(PyObject*) _PyMapping_GetOptionalItem2(PyObject* obj, PyObject* key, int* err);
+
 #ifdef __cplusplus
 }
 #endif