gh-158540: Add the profiled script's directory to sys.path by hetaozdh · Pull Request #158548 · python/cpython

hetaozdh · 2026-10-01T05:01:24Z

When a script is executed with python -m profiling.sampling run script.py
from another directory, the script cannot import modules placed next to it:
_sync_coordinator._execute_script() runs it with the working directory
(added by _setup_environment() for the -m case) as sys.path[0]
instead of the script's own directory.

This change adds the script's directory to sys.path in _execute_script(),
matching the behavior of python script.py.

Added a regression test in
Lib/test/test_profiling/test_sampling_profiler/test_sync_coordinator.py
that runs the coordinator on a script importing a sibling module, plus a
Misc/NEWS.d entry.

Tests:

./python -m test test_profiling
./python Tools/patchcheck/patchcheck.py

python-cla-bot · 2026-10-01T05:01:29Z

All commit authors signed the Contributor License Agreement.

When a script is profiled with ``python -m profiling.sampling run script.py`` from another directory, the script cannot import modules placed next to it, because ``_sync_coordinator._execute_script()`` executes it with the working directory (added by ``_setup_environment()`` for the module case) as ``sys.path[0]`` instead of the script's own directory. Make the script's directory importable in ``_execute_script()``, matching the behavior of ``python script.py``. Add a regression test that runs the coordinator on a script importing a sibling module.

Co-authored-by: Eduardo Villalpando Mello <eduardo.villalpando.mello@gmail.com>

maurycy · 2026-10-01T11:00:05Z

+    # Put directory containing the script (not the current working directory) on sys.path so that modules next to it can be imported. Similar to ``python script.py``
+    script_dir = os.path.dirname(script_path)
+    if script_dir not in sys.path:
+        sys.path.insert(0, script_dir)


What do you think about this edge case?

2026-10-01T12:57:30.615506000+0200 maurycy@gimel /Users/maurycy/work/cpython-pr158548 (pr158548 91c5ab3?) % tree w w ├── link.py -> sub/where.py └── sub ├── helper.py └── where.py 2 directories, 3 files 2026-10-01T12:57:32.453682000+0200 maurycy@gimel /Users/maurycy/work/cpython-pr158548 (pr158548 91c5ab3?) % sudo ./python.exe -m profiling.sampling run w/link.py Traceback (most recent call last): File "<frozen runpy>", line 201, in _run_module_as_main File "<frozen runpy>", line 87, in _run_code File "/Users/maurycy/work/cpython-pr158548/Lib/profiling/sampling/_sync_coordinator.py", line 261, in <module> main() ~~~~^^ File "/Users/maurycy/work/cpython-pr158548/Lib/profiling/sampling/_sync_coordinator.py", line 254, in main _execute_script(script_path, script_args, cwd) ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/maurycy/work/cpython-pr158548/Lib/profiling/sampling/_sync_coordinator.py", line 201, in _execute_script exec(code, main_module.__dict__) ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/maurycy/work/cpython-pr158548/w/link.py", line 1, in <module> import helper ModuleNotFoundError: No module named 'helper' 2026-10-01T12:57:43.707720000+0200 maurycy@gimel /Users/maurycy/work/cpython-pr158548 (pr158548 91c5ab3?) % ./python.exe -VV Python 3.16.0a0 (heads/pr158548:91c5ab3e096, Oct 1 2026, 10:22:50) [Clang 21.0.0 (clang-2100.3.34.2)]

I'm wondering if this might be an approach to mimic:

cpython/Lib/pdb.py

Lines 192 to 197 in 763b6ed

self._target = self._safe_realpath(target)

# If PYTHONSAFEPATH (-P) is not set, sys.path[0] is the directory

# of pdb, and we should replace it with the directory of the script

if not sys.flags.safe_path:

sys.path[0] = os.path.dirname(self._target)

Thanks for the comment. Fixed in 264a36c

A note for the reviewer is that there are two approaches in the stdlib.

pdb does not insert but replace:

cpython/Lib/pdb.py

Line 197 in 763b6ed

sys.path[0] = os.path.dirname(self._target)

Same as trace:

cpython/Lib/trace.py

Line 730 in ab01d18

sys.path[0] = os.path.dirname(opts.progname)

While profile does insert:

cpython/Lib/profile.py

Line 600 in ab01d18

sys.path.insert(0, os.path.dirname(progname))

… sys.path ``python script.py`` resolves symlinks when computing ``sys.path[0]``, so a script reached through a symlink (``link.py -> sub/where.py``) imports modules from the real script's directory. Apply ``os.path.realpath()`` before taking the directory name, and make sure the result is placed at the front of ``sys.path`` even if it was already listed. Add a regression test for a symlinked script.

miss-islington-app · 2026-10-05T13:51:43Z

Thanks @hetaozdh for the PR, and @pablogsal for merging it 🌮🎉.. I'm working now to backport this PR to: 3.15.
🐍🍒⛏🤖

bedevere-app · 2026-10-05T13:52:06Z

GH-158844 is a backport of this pull request to the 3.15 branch.

…-158548) (#158844) gh-158540: Add the profiled script's directory to sys.path (GH-158548) * gh-158540: Add the profiled script's directory to sys.path When a script is profiled with ``python -m profiling.sampling run script.py`` from another directory, the script cannot import modules placed next to it, because ``_sync_coordinator._execute_script()`` executes it with the working directory (added by ``_setup_environment()`` for the module case) as ``sys.path[0]`` instead of the script's own directory. Make the script's directory importable in ``_execute_script()``, matching the behavior of ``python script.py``. Add a regression test that runs the coordinator on a script importing a sibling module. * Update _sync_coordinator.py Comment simplified * gh-158540: Resolve symlinks when adding the script directory to sys.path ``python script.py`` resolves symlinks when computing ``sys.path[0]``, so a script reached through a symlink (``link.py -> sub/where.py``) imports modules from the real script's directory. Apply ``os.path.realpath()`` before taking the directory name, and make sure the result is placed at the front of ``sys.path`` even if it was already listed. Add a regression test for a symlinked script. --------- (cherry picked from commit 3f02aab) Co-authored-by: he_tao <53343436+hetaozdh@users.noreply.github.com> Co-authored-by: Eduardo Villalpando Mello <eduardo.villalpando.mello@gmail.com>

…o sys.path (pythonGH-158548) (python#158844)" This reverts commit f52d831.

…58882) * [3.15] gh-153364: Make frame, coroutine, and task-waiter chain walks iterative and bounded (GH-153365) (#158813) gh-153364: Make frame, coroutine, and task-waiter chain walks iterative and bounded (GH-153365) * let me declare single limit * use our new limit in process_frame_chain() * add it in parse_async_frame_chain() * parse_coro_chain() * NEWS * async in the message? * test * no race * process_task_awaited_by * process_task_awaited_by limit test * NEWS * MAX_TASK_WAITER_CHAIN_DEPTH * TASK_WAITER_CHAIN_DEPTH in test * TASK_WAITER_CHAIN_DEPTH 256 * prevent the drift with the comment * better naming, better style * MAX_TASK_WAITER_CHAIN_DEPTH comment * task-waiter iterative bfs walk * iterative coro-walk * nicer news * 1 << 14 * comment * unused read_Py_ssize_t * fix tombstones * simplify * correct msg * better test * news for tombstones * left-over from when testing buggy version * redundant new line (cherry picked from commit e0861c6) Co-authored-by: Maurycy Pawłowski-Wieroński <maurycy@maurycy.com> (cherry picked from commit 9e401cf) * [3.15] gh-155811: Add a seqcount to `gc_stats` to prevent torn reads (GH-155828) (#158829) * update_seq * no need for XCHGL, MOVL is enough? * gh-155811: Retry an inconsistent GC snapshot once --------- (cherry picked from commit 5fecd44) Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com> Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com> (cherry picked from commit 0281240) * [3.15] gh-151292: `_remote_debugging`: Do not corrupt the binary file when hitting `OverflowError` (GH-152892) (#158830) gh-151292: `_remote_debugging`: Do not corrupt the binary file when hitting `OverflowError` (GH-152892) * the kolektor * test * better test * news * =Q, move const to the base, not self.running * gh-151292: Track binary writer finalization state --------- (cherry picked from commit f839c06) Co-authored-by: Maurycy Pawłowski-Wieroński <maurycy@maurycy.com> Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com> (cherry picked from commit 8a7c23f) * [3.15] gh-158583: Fix uninitialized memory read in bytes.fromhex() (GH-158584) (#158691) gh-158583: Fix uninitialized memory read in bytes.fromhex() (GH-158584) (cherry picked from commit 9d22a53) Co-authored-by: Victor Stinner <vstinner@python.org> (cherry picked from commit 4f7af46) * [3.15] gh-154194: Degrade frames in Tachyon instead of failing the sample (GH-154195) (#158831) * gh-154194: Degrade frames in Tachyon instead of failing the sample (#154195) * degrade gracefully * news * better NEWS wording * do not raise on MAX_REMOTE_STR_READ * bye MAX_REMOTE_STR_READ * fix -m asyncio ps|pstree * test truncation and linetable sentinel * simpler * simpler * redundant now * respect #157790 in the news --------- Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com> (cherry picked from commit 7d25916) * Preserve the stable ABI when creating fallback frame names --------- Co-authored-by: Maurycy Pawłowski-Wieroński <maurycy@maurycy.com> (cherry picked from commit c27f494) * [3.15] Add MSan to CI (GH-158625) (#158832) Run a job that the test suite with MSan to the CI (#158625) * Run the test suite with MSan in CI * Additional fixes * Add `_Py_MSAN_UNPOISON_STRING` * Apply Victor's suggestions * Apply Victor's suggestions --------- (cherry picked from commit b93fb19) Co-authored-by: Stan Ulbrych <stan@python.org> Co-authored-by: Victor Stinner <victor.stinner@gmail.com> (cherry picked from commit 1bc78de) * [3.15] gh-156810: Write the profiler's collapsed-stack export as UTF-8 (GH-156811) (#156814) gh-156810: Write the profiler's collapsed-stack export as UTF-8 (GH-156811) (cherry picked from commit c3706f4) Co-authored-by: tonghuaroot (童话) <tonghuaroot@gmail.com> (cherry picked from commit fce28da) * [3.15] gh-158552: Wait for Windows threads to suspend before blocking sampling (GH-158802) (#158845) gh-158552: Wait for Windows threads to suspend before blocking sampling (GH-158802) * gh-158552: Wait for Windows threads to suspend before blocking sampling * Use a named Windows thread enumeration status constant (cherry picked from commit 1643525) Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com> (cherry picked from commit 31288da) * [3.15] gh-152721: Fix quadratic RLE replay time in the profiling binary reader (GH-152722) (#158850) Backport of GH-152722. Co-authored-by: tonghuaroot <tonghuaroot@gmail.com> (cherry picked from commit ebaca2a) * [3.15] gh-156545: Fix flamegraph export RecursionError on deeply recursive programs (GH-156546) (#158851) Backport of GH-156546. Co-authored-by: tonghuaroot (童话) <tonghuaroot@gmail.com> (cherry picked from commit 0ac7217) * [3.15] gh-158540: Add the profiled script's directory to sys.path (GH-158548) (#158844) gh-158540: Add the profiled script's directory to sys.path (GH-158548) * gh-158540: Add the profiled script's directory to sys.path When a script is profiled with ``python -m profiling.sampling run script.py`` from another directory, the script cannot import modules placed next to it, because ``_sync_coordinator._execute_script()`` executes it with the working directory (added by ``_setup_environment()`` for the module case) as ``sys.path[0]`` instead of the script's own directory. Make the script's directory importable in ``_execute_script()``, matching the behavior of ``python script.py``. Add a regression test that runs the coordinator on a script importing a sibling module. * Update _sync_coordinator.py Comment simplified * gh-158540: Resolve symlinks when adding the script directory to sys.path ``python script.py`` resolves symlinks when computing ``sys.path[0]``, so a script reached through a symlink (``link.py -> sub/where.py``) imports modules from the real script's directory. Apply ``os.path.realpath()`` before taking the directory name, and make sure the result is placed at the front of ``sys.path`` even if it was already listed. Add a regression test for a symlinked script. --------- (cherry picked from commit 3f02aab) Co-authored-by: he_tao <53343436+hetaozdh@users.noreply.github.com> Co-authored-by: Eduardo Villalpando Mello <eduardo.villalpando.mello@gmail.com> (cherry picked from commit f52d831) * [3.15] gh-153838: Skip non-regular source files in the heatmap exporter (GH-153839) (#158853) Backport of GH-153839. Co-authored-by: tonghuaroot <tonghuaroot@gmail.com> (cherry picked from commit 48998df) * [3.15] gh-158539: Fix exception mode missing handlers in generators/coroutines (GH-158581) (#158852) * [3.15] gh-158539: Fix exception mode missing handlers in generators/coroutines (GH-158581) Backport of GH-158581. Co-authored-by: LucasZhou <donghao.zhou@outlook.com> * [3.15] gh-158539: Use portable static assertion messages * [3.15] gh-158539: Keep layout assertions with debug-offset validation * [3.15] gh-158539: Use the platform guard for in-process inspection tests --------- Co-authored-by: LucasZhou <donghao.zhou@outlook.com> (cherry picked from commit d625ecb) * [3.15] gh-158522: Fix truncated stack for a task whose coroutine recurses (GH-158526) (#158870) Co-authored-by: Timofei Ivankov <128279579+deadlovelll@users.noreply.github.com> (cherry picked from commit a904b39) * gh-156545, gh-158539: Fix deep flamegraph export on small C stacks and macOS runtime lookup (#158874) (cherry picked from commit 114de19) Include the C-stack test helper from main, introduced by ce5ae29, which the regression test requires but 3.15 does not yet provide. --------- Co-authored-by: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Co-authored-by: Maurycy Pawłowski-Wieroński <maurycy@maurycy.com> Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com> Co-authored-by: Victor Stinner <vstinner@python.org> Co-authored-by: Stan Ulbrych <stan@python.org> Co-authored-by: Victor Stinner <victor.stinner@gmail.com> Co-authored-by: tonghuaroot (童话) <tonghuaroot@gmail.com> Co-authored-by: he_tao <53343436+hetaozdh@users.noreply.github.com> Co-authored-by: Eduardo Villalpando Mello <eduardo.villalpando.mello@gmail.com> Co-authored-by: LucasZhou <donghao.zhou@outlook.com> Co-authored-by: Timofei Ivankov <128279579+deadlovelll@users.noreply.github.com>

hetaozdh requested a review from pablogsal as a code owner October 1, 2026 05:01

bedevere-app Bot mentioned this pull request Oct 1, 2026

profiling.sampling: run script.py does not put the script's directory on sys.path, so sibling imports fail #158540

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hetaozdh force-pushed the fix-sampling-script-path-main branch from 6c4dd14 to 16ff1ec Compare October 1, 2026 05:40

edvilme reviewed Oct 1, 2026

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Comment thread Lib/profiling/sampling/_sync_coordinator.py Outdated

Update _sync_coordinator.py Comment simplified

91c5ab3

Co-authored-by: Eduardo Villalpando Mello <eduardo.villalpando.mello@gmail.com>

maurycy reviewed Oct 1, 2026

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hetaozdh added 2 commits October 1, 2026 12:05

Merge branch 'main' into fix-sampling-script-path-main

c8242dd

hetaozdh force-pushed the fix-sampling-script-path-main branch from d9d8e40 to c8242dd Compare October 1, 2026 17:06

Merge branch 'main' into fix-sampling-script-path-main

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pablogsal merged commit 3f02aab into python:main Oct 5, 2026
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pablogsal added the needs backport to 3.15 bugs and security fixes label Oct 5, 2026

bedevere-app Bot removed the needs backport to 3.15 bugs and security fixes label Oct 5, 2026

pablogsal added a commit to pablogsal/cpython that referenced this pull request Oct 5, 2026

Revert "[3.15] pythongh-158540: Add the profiled script's directory t…

078fa23

…o sys.path (pythonGH-158548) (python#158844)" This reverts commit f52d831.

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gh-158540: Add the profiled script's directory to sys.path - #158548

gh-158540: Add the profiled script's directory to sys.path#158548
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	self._target = self._safe_realpath(target)

	# If PYTHONSAFEPATH (-P) is not set, sys.path[0] is the directory
	# of pdb, and we should replace it with the directory of the script
	if not sys.flags.safe_path:
	sys.path[0] = os.path.dirname(self._target)

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