This PR implements frame caching in the RemoteUnwinder class to significantly reduce memory reads when profiling remote processes with deep call stacks.
When cache_frames=True, the unwinder stores the frame chain from each sample and reuses unchanged portions in subsequent samples. Since most profiling samples capture similar call stacks (especially the parent frames), this optimization avoids repeatedly reading the same frame data from the target process.
The implementation adds a last_profiled_frame field to the thread state that tracks where the previous sample stopped. On the next sample, if the current frame chain reaches this marker, the cached frames from that point onward are reused instead of being re-read from remote memory.
The sampling profiler now enables frame caching by default.
Extend defect handling via policy to a couple of missed defects.
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Co-authored-by: Martin Panter <vadmium@users.noreply.github.com>
Co-authored-by: Ivo Bellin Salarin <ivo@nilleb.com>
The keyword typo suggestion mechanism in traceback would incorrectly
suggest replacements when the extracted source code was merely incomplete
rather than containing an actual typo. For example, when a missing comma
caused a syntax error, the system would suggest replacing 'print' with
'not' because the incomplete code snippet happened to pass validation.
The fix adds a validation step that first checks whether the original
extracted code raises a SyntaxError. If the code compiles successfully
or is simply incomplete (compile_command returns None), the function
returns early since there is no way to verify that a keyword replacement
would actually fix the problem.
RDM: This fixes a subtle folding error that showed up when a token exactly filled a line and was followed by whitespace and a token with no folding whitespace that was longer than a line. In this particular circumstance the whitespace after the first token got pushed on to the next line, and then stolen to go in front of the next unfoldable token...leaving a completely empty line in the line buffer. That line got turned in to a newline, which is RFC illegal, and the newish security check caught it. The fix is to just delete that empty line from the buffer.
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Enhanced the _find_lineno method in doctest to correctly identify and
report line numbers for doctests defined in __test__ dictionaries when
formatted as triple-quoted strings.
Finds a non-blank line in the test string and matches it in the source
file, verifying subsequent lines also match to handle duplicate lines.
Previously, doctest would report "line None" for __test__ dictionary
strings, making it difficult to debug failing tests.
Co-authored-by: Jurjen N.E. Bos <jneb@users.sourceforge.net>
Co-authored-by: R. David Murray <rdmurray@bitdance.com>
Loading a small data which does not even involve arbitrary code execution
could consume arbitrary large amount of memory. There were three issues:
* PUT and LONG_BINPUT with large argument (the C implementation only).
Since the memo is implemented in C as a continuous dynamic array, a single
opcode can cause its resizing to arbitrary size. Now the sparsity of
memo indices is limited.
* BINBYTES, BINBYTES8 and BYTEARRAY8 with large argument. They allocated
the bytes or bytearray object of the specified size before reading into
it. Now they read very large data by chunks.
* BINSTRING, BINUNICODE, LONG4, BINUNICODE8 and FRAME with large
argument. They read the whole data by calling the read() method of
the underlying file object, which usually allocates the bytes object of
the specified size before reading into it. Now they read very large data
by chunks.
Also add comprehensive benchmark suite to measure performance and memory
impact of chunked reading optimization in PR #119204.
Features:
- Normal mode: benchmarks legitimate pickles (time/memory metrics)
- Antagonistic mode: tests malicious pickles (DoS protection)
- Baseline comparison: side-by-side comparison of two Python builds
- Support for truncated data and sparse memo attack vectors
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>
Add readline.get_pre_input_hook() to retrieve the current pre-input
hook. This allows applications to save and restore the hook without
overwriting user settings.
This fixes a regression introduced in gh-140558. The interpreter would
crash if we inserted a non `str` key into a split table that matches an
existing key.
The previous test_spawn_doesnt_hang test had a few problems:
* It would cause ENV CHANGED failures if other tests were running
concurrently due to stty changes
* Typing while the test was running could cause it to fail
* Factor out bodies of the largest uops, to reduce jit code size.
* Factor out common assert, also reducing jit code size.
* Limit size of jitted code for a single executor to 1MB.
* Remove quadratic behavior in node ID cache clearing
Co-authored-by: Jacob Walls <38668450+jacobtylerwalls@users.noreply.github.com>
* Add news fragment
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Co-authored-by: Jacob Walls <38668450+jacobtylerwalls@users.noreply.github.com>
Reading a specially prepared small Plist file could cause OOM because file's
read(n) preallocates a bytes object for reading the specified amount of
data. Now plistlib reads large data by chunks, therefore the upper limit of
consumed memory is proportional to the size of the input file.
Reading the whole body of the HTTP response could cause OOM if
the Content-Length value is too large even if the server does not send
a large amount of data. Now the HTTP client reads large data by chunks,
therefore the amount of consumed memory is proportional to the amount
of sent data.
On Windows, Popen._communicate() previously wrote to stdin synchronously, which could block indefinitely if the subprocess didn't consume input= quickly and the pipe buffer filled up. The timeout= parameter was only checked when joining the reader threads, not during the stdin write.
This change moves the Windows stdin writing to a background thread (similar to how stdout/stderr are read in threads), allowing the timeout to be properly enforced. If timeout expires, TimeoutExpired is raised promptly and the writer thread continues in the background. Subsequent calls to communicate() will join the existing writer thread.
Adds test_communicate_timeout_large_input to verify that TimeoutExpired is raised promptly when communicate() is called with large input and a timeout, even when the subprocess doesn't consume stdin quickly.
This test already passed on POSIX (where select() is used) but failed on Windows where the stdin write blocks without checking the timeout.
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Fix inconsistent subprocess.Popen.communicate() behavior between Windows
and POSIX when using memoryview objects with non-byte elements as input.
On POSIX systems, the code was incorrectly comparing bytes written against
element count instead of byte count, causing data truncation for large
inputs with non-byte element types.
Changes:
- Cast memoryview inputs to byte view when input is already a memoryview
- Fix progress tracking to use len(input_view) instead of len(self._input)
- Add comprehensive test coverage for memoryview inputs
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
* old-man-yells-at-ReST
* Update 2025-05-30-18-37-44.gh-issue-134453.kxkA-o.rst
* assertIsNone review feedback
* fix memoryview_nonbytes test to fail without our fix on main, and have a nicer error.
Thanks to Peter Bierma @ZeroIntensity for the code review.
* gh-141473: Fix subprocess.Popen.communicate to send input to stdin
* Docs: Clarify that `input` is one time only on `communicate()`
* NEWS entry
* Add a regression test.
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Co-authored-by: Gregory P. Smith <greg@krypto.org>
Added atomic operations to `scanner_begin()` and `scanner_end()` to prevent
race conditions on the `executing` flag in free-threaded builds. Also added
tests for concurrent usage of the `re` module.
Without the atomic operations, `test_scanner_concurrent_access()` triggers
`assert(self->executing)` failures, or a thread sanitizer run emits errors.
* Make Py_{SIZE,IS_TYPE,SET_SIZE} regular functions in stable ABI
Group them together with Py_TYPE & Py_SET_TYPE to cut down
on repetitive preprocessor macros.
Format repetitive definitions in object.c more concisely.
Py_SET_TYPE is still left out of the Limited API.
* test_hashlib: better handle support for SHA3
It's possible that the SSL library supports only SHA3 algo and doesn't
have SHAKE one.
The current test wrongly detect this and set both HASH and HASHXOF to
None expecting to have the extra SHA3 attributes present but this should
only be true for SHAKE algo.
To better handle this, move the HASH condition to a dedicated try-expect
condition and check if HASHXOF is None in the relevant code effectively
checking if SHA3 is supported by the SSL library but SHAKE algo needs to
use the sha3module one.
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
* rework the conditional import for all its attrs
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Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>
