X update (sync with master + ustr.translate fixes)

.gitmodules

+[submodule "3rdparty/ratas"]
+	path = 3rdparty/ratas
+	url = https://github.com/jsnell/ratas.git
 [submodule "3rdparty/funchook"]
 	path = 3rdparty/funchook
 	url = https://github.com/kubo/funchook.git

.lsan-ignore.txt

+# .lsan-ignore.txt lists memory leak events that LeakSanitizer should not
+# report when running pygolang tests.
+#
+# Many python allocations, whose lifetime coincides with python interpreter
+# lifetime, and which are not explicitly freed on python shutdown, are
+# reported as leaks by default. Disable leak reporting for those to avoid
+# non-pygolang related printouts.
+
+
+# >>> Everything created when initializing python, e.g. sys.stderr
+#   #0 0x7f21e74f3bd7 in malloc .../asan_malloc_linux.cpp:69
+#   #1 0x555f361ff9a4 in PyThread_allocate_lock Python/thread_pthread.h:385
+#   #2 0x555f3623f72a in _buffered_init Modules/_io/bufferedio.c:725
+#   #3 0x555f3623ff7e in _io_BufferedWriter___init___impl Modules/_io/bufferedio.c:1803
+#   #4 0x555f3623ff7e in _io_BufferedWriter___init__ Modules/_io/clinic/bufferedio.c.h:489
+#   #5 0x555f3610c086 in type_call Objects/typeobject.c:1103
+#   #6 0x555f3609cdcc in _PyObject_MakeTpCall Objects/call.c:214
+#   #7 0x555f3609d6a8 in _PyObject_VectorcallTstate Include/internal/pycore_call.h:90
+#   #8 0x555f3609d6a8 in _PyObject_VectorcallTstate Include/internal/pycore_call.h:77
+#   #9 0x555f3609d6a8 in _PyObject_CallFunctionVa Objects/call.c:536
+#   #10 0x555f3609e89c in _PyObject_CallFunction_SizeT Objects/call.c:590
+#   #11 0x555f3623a0df in _io_open_impl Modules/_io/_iomodule.c:407
+#   #12 0x555f3623a0df in _io_open Modules/_io/clinic/_iomodule.c.h:264
+#   #13 0x555f360f17da in cfunction_vectorcall_FASTCALL_KEYWORDS Objects/methodobject.c:443
+#   #14 0x555f3609d54c in _PyObject_VectorcallTstate Include/internal/pycore_call.h:92
+#   #15 0x555f3609d54c in _PyObject_CallFunctionVa Objects/call.c:536
+#   #16 0x555f3609ec34 in callmethod Objects/call.c:608
+#   #17 0x555f3609ec34 in _PyObject_CallMethod Objects/call.c:677
+#   #18 0x555f361e60cf in create_stdio Python/pylifecycle.c:2244
+#   #19 0x555f361e6523 in init_sys_streams Python/pylifecycle.c:2431
+#   #20 0x555f361e6523 in init_interp_main Python/pylifecycle.c:1154
+#   #21 0x555f361e7204 in pyinit_main Python/pylifecycle.c:1230
+#   #22 0x555f361e85ba in Py_InitializeFromConfig Python/pylifecycle.c:1261
+#   #23 0x555f3621010a in pymain_init Modules/main.c:67
+#   #24 0x555f362113de in pymain_main Modules/main.c:701
+#   #25 0x555f362113de in Py_BytesMain Modules/main.c:734
+leak:^pymain_init$
+
+# >>> Everything created when importing py modules, e.g.
+#   #0 0x7f18c86f3bd7 in malloc .../asan_malloc_linux.cpp:69
+#   #1 0x55b971430acf in PyMem_RawMalloc Objects/obmalloc.c:586
+#   #2 0x55b971430acf in _PyObject_Malloc Objects/obmalloc.c:2003
+#   #3 0x55b971430acf in _PyObject_Malloc Objects/obmalloc.c:1996
+#   #4 0x55b971415696 in new_keys_object Objects/dictobject.c:632
+#   #5 0x55b971415716 in dictresize Objects/dictobject.c:1429
+#   #6 0x55b97141961a in insertion_resize Objects/dictobject.c:1183
+#   #7 0x55b97141961a in insertdict Objects/dictobject.c:1248
+#   #8 0x55b97143eb7b in add_subclass Objects/typeobject.c:6547
+#   #9 0x55b97144ca52 in type_ready_add_subclasses Objects/typeobject.c:6345
+#   #10 0x55b97144ca52 in type_ready Objects/typeobject.c:6476
+#   #11 0x55b971451a1f in PyType_Ready Objects/typeobject.c:6508
+#   #12 0x55b971451a1f in type_new_impl Objects/typeobject.c:3189
+#   #13 0x55b971451a1f in type_new Objects/typeobject.c:3323
+#   #14 0x55b971443014 in type_call Objects/typeobject.c:1091
+#   #15 0x55b9713d3dcc in _PyObject_MakeTpCall Objects/call.c:214
+#   #16 0x55b9713d47bd in _PyObject_FastCallDictTstate Objects/call.c:141
+#   #17 0x55b9713d47bd in PyObject_VectorcallDict Objects/call.c:165
+#   #18 0x55b9714d14c2 in builtin___build_class__ Python/bltinmodule.c:209
+#   #19 0x55b9714287da in cfunction_vectorcall_FASTCALL_KEYWORDS Objects/methodobject.c:443
+#   #20 0x55b9713d4a7b in _PyObject_VectorcallTstate Include/internal/pycore_call.h:92
+#   #21 0x55b9713d4a7b in PyObject_Vectorcall Objects/call.c:299
+#   #22 0x55b97137666e in _PyEval_EvalFrameDefault Python/ceval.c:4769
+#   #23 0x55b9714d7e6b in _PyEval_EvalFrame Include/internal/pycore_ceval.h:73
+#   #24 0x55b9714d7e6b in _PyEval_Vector Python/ceval.c:6434
+#   #25 0x55b9714d7e6b in PyEval_EvalCode Python/ceval.c:1148
+#   #26 0x55b9714d2e1f in builtin_exec_impl Python/bltinmodule.c:1077
+#   #27 0x55b9714d2e1f in builtin_exec Python/clinic/bltinmodule.c.h:465
+#   #28 0x55b9714287da in cfunction_vectorcall_FASTCALL_KEYWORDS Objects/methodobject.c:443
+#   #29 0x55b971376dcb in do_call_core Python/ceval.c:7349
+#   #30 0x55b971376dcb in _PyEval_EvalFrameDefault Python/ceval.c:5376
+#   #31 0x55b9714d7faf in _PyEval_EvalFrame Include/internal/pycore_ceval.h:73
+#   #32 0x55b9714d7faf in _PyEval_Vector Python/ceval.c:6434
+#   #33 0x55b9713d436e in _PyObject_VectorcallTstate Include/internal/pycore_call.h:92
+#   #34 0x55b9713d436e in object_vacall Objects/call.c:819
+#   #35 0x55b9713d63cf in PyObject_CallMethodObjArgs Objects/call.c:879
+#   #36 0x55b9715080e1 in import_find_and_load Python/import.c:1748
+#   #37 0x55b9715080e1 in PyImport_ImportModuleLevelObject Python/import.c:1847
+#   #38 0x55b97137de9c in import_name Python/ceval.c:7422
+#   #39 0x55b97137de9c in _PyEval_EvalFrameDefault Python/ceval.c:3946
+#   #40 0x55b9714d7e6b in _PyEval_EvalFrame Include/internal/pycore_ceval.h:73
+#   #41 0x55b9714d7e6b in _PyEval_Vector Python/ceval.c:6434
+#   #42 0x55b9714d7e6b in PyEval_EvalCode Python/ceval.c:1148
+#   #43 0x55b9714d2e1f in builtin_exec_impl Python/bltinmodule.c:1077
+#   #44 0x55b9714d2e1f in builtin_exec Python/clinic/bltinmodule.c.h:465
+#   #45 0x55b9714287da in cfunction_vectorcall_FASTCALL_KEYWORDS Objects/methodobject.c:443
+#   #46 0x55b971376dcb in do_call_core Python/ceval.c:7349
+#   #47 0x55b971376dcb in _PyEval_EvalFrameDefault Python/ceval.c:5376
+leak:^PyImport_Import
+#  importlib.import_module leads to
+#   #0 0x7f1951ef3bd7 in malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:69
+#   #1 0x55f399e8cacf in PyMem_RawMalloc Objects/obmalloc.c:586
+#   #2 0x55f399e8cacf in _PyObject_Malloc Objects/obmalloc.c:2003
+#   #3 0x55f399e8cacf in _PyObject_Malloc Objects/obmalloc.c:1996
+#   #4 0x55f399e86344 in PyModule_ExecDef Objects/moduleobject.c:400
+#   #5 0x55f399f6178a in exec_builtin_or_dynamic Python/import.c:2345
+#   #6 0x55f399f6178a in _imp_exec_dynamic_impl Python/import.c:2419
+#   #7 0x55f399f6178a in _imp_exec_dynamic Python/clinic/import.c.h:474
+#   #8 0x55f399e8438a in cfunction_vectorcall_O Objects/methodobject.c:514
+leak:^_imp_exec_dynamic
+
+
+# >>> Everything allocated at DSO initialization, e.g.
+#   #0 0x7f35d2af46c8 in operator new(unsigned long) .../asan_new_delete.cpp:95
+#   #1 0x7f35ce897e9f in __static_initialization_and_destruction_0 golang/context.cpp:61
+#   #2 0x7f35ce8982ef in _GLOBAL__sub_I_context.cpp golang/context.cpp:380
+#   #3 0x7f35d32838bd in call_init elf/dl-init.c:90
+#   #4 0x7f35d32838bd in call_init elf/dl-init.c:27
+#   #5 0x7f35d32839a3 in _dl_init elf/dl-init.c:137
+#   #6 0x7f35d256e023 in __GI__dl_catch_exception elf/dl-error-skeleton.c:182
+#   #7 0x7f35d328a09d in dl_open_worker elf/dl-open.c:808
+#   #8 0x7f35d256dfc9 in __GI__dl_catch_exception elf/dl-error-skeleton.c:208
+#   #9 0x7f35d328a437 in _dl_open elf/dl-open.c:884
+#   #10 0x7f35d24a4437 in dlopen_doit dlfcn/dlopen.c:56
+#   #11 0x7f35d256dfc9 in __GI__dl_catch_exception elf/dl-error-skeleton.c:208
+#   #12 0x7f35d256e07e in __GI__dl_catch_error elf/dl-error-skeleton.c:227
+#   #13 0x7f35d24a3f26 in _dlerror_run dlfcn/dlerror.c:138
+#   #14 0x7f35d24a44e8 in dlopen_implementation dlfcn/dlopen.c:71
+#   #15 0x7f35d24a44e8 in ___dlopen dlfcn/dlopen.c:81
+#   #16 0x7f35d2a77ff9 in dlopen .../sanitizer_common_interceptors.inc:6341
+leak:^_GLOBAL_
+
+
+# global<> does not deallocate its reference on purpose
+leak:^_test_global()$

ratas @ becd5fc5

+Subproject commit becd5fc5c1e9ea600cd8b3b1c24d564794fedac4

MANIFEST.in

-include COPYING README.rst CHANGELOG.rst tox.ini pyproject.toml trun .nxdtest
+include COPYING README.rst CHANGELOG.rst tox.ini pyproject.toml trun .lsan-ignore.txt .nxdtest conftest.py
 include golang/libgolang.h
 include golang/runtime/libgolang.cpp
 include golang/runtime/libpyxruntime.cpp

conftest.py

+# pygolang | pytest config
+# Copyright (C) 2021-2024  Nexedi SA and Contributors.
+#                          Kirill Smelkov <kirr@nexedi.com>
+#
+# This program is free software: you can Use, Study, Modify and Redistribute
+# it under the terms of the GNU General Public License version 3, or (at your
+# option) any later version, as published by the Free Software Foundation.
+#
+# You can also Link and Combine this program with other software covered by
+# the terms of any of the Free Software licenses or any of the Open Source
+# Initiative approved licenses and Convey the resulting work. Corresponding
+# source of such a combination shall include the source code for all other
+# software used.
+#
+# This program is distributed WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#
+# See COPYING file for full licensing terms.
+# See https://www.nexedi.com/licensing for rationale and options.
+
+from __future__ import print_function, absolute_import
+
+import gc
+
+
+# Do full GC before pytest exits, to avoid false positives in the leak detector.
+def pytest_unconfigure():
+    gc.collect()
+
+
 # ignore tests in distorm - else it breaks as e.g.
 #
 # 3rdparty/funchook/distorm/python/test_distorm3.py:15: in <module>

golang/_golang.pyx

@@ -173,11 +173,18 @@ cdef void __goviac(void *arg) nogil:
 
 # ---- channels ----
 
+# _frompyx indicates that a constructor is called from pyx code
+cdef object _frompyx = object()
+
 @final
 cdef class pychan:
     def __cinit__(pychan pych, size=0, dtype=object):
-        pych.dtype = parse_dtype(dtype)
-        pych._ch = _makechan_pyexc(dtypeRegistry[<int>pych.dtype].size, size)
+        if dtype is _frompyx:
+            pych.dtype = DTYPE_STRUCTZ  # anything
+            pych._ch   = NULL
+        else:
+            pych.dtype = parse_dtype(dtype)
+            pych._ch = _makechan_pyexc(dtypeRegistry[<int>pych.dtype].size, size)
 
     # pychan.nil(X) creates new nil pychan with specified dtype.
     # TODO try to avoid exposing .nil on pychan instances, and expose only pychan.nil
@@ -370,7 +377,7 @@ cdef void pychan_asserttype(pychan pych, DType dtype) nogil:
         panic("pychan: channel type mismatch")
 
 cdef pychan pychan_from_raw(_chan *_ch, DType dtype):
-    cdef pychan pych = pychan.__new__(pychan)
+    cdef pychan pych = pychan.__new__(pychan, dtype=_frompyx)
     pych.dtype = dtype
     pych._ch   = _ch; _chanxincref(_ch)
     return pych
@@ -626,9 +633,7 @@ cdef object c_to_py(DType dtype, const chanElemBuf *cfrom):
 
 # mkpynil creates pychan instance that represents nil[dtype].
 cdef PyObject *mkpynil(DType dtype):
-    cdef pychan pynil = pychan.__new__(pychan)
-    pynil.dtype = dtype
-    pynil._ch   = NULL   # should be already NULL
+    cdef pychan pynil = pychan_from_raw(NULL, dtype)
     Py_INCREF(pynil)
     return <PyObject *>pynil
 
@@ -818,9 +823,6 @@ from libcpp.typeinfo cimport type_info
 from cython.operator cimport typeid
 from libc.string cimport strcmp
 
-# _frompyx indicates that a constructor is called from pyx code
-cdef object _frompyx = object()
-
 cdef class pyerror(Exception):
     # pyerror <- error
     @staticmethod

golang/_golang_str.pyx

@@ -580,6 +580,7 @@ cdef class _pybstr(bytes):   # https://github.com/cython/cython/issues/711
     def title(self):                        return pyb(pyu(self).title())
     def translate(self, table, delete=None):
         # bytes mode  (compatibility with str/py2)
+        # XXX isinstance(zbytes) -> isinstance(bytes) ?
         if table is None  or isinstance(table, zbytes)  or  delete is not None:
             if delete is None:  delete = b''
             return pyb(zbytes.translate(self, table, delete))
@@ -905,12 +906,7 @@ cdef class _pyustr(unicode):
 
     def translate(self, table):
         # unicode.translate does not accept bstr values
-        t = {}
-        for k,v in table.items():
-            if not isinstance(v, int):  # either unicode ordinal,
-                v = _xpyu_coerce(v)     # character or None
-            t[k] = v
-        return pyu(zunicode.translate(self, t))
+        return pyu(zunicode.translate(self, _pyustrTranslateTab(table)))
 
     def upper(self):                        return pyu(zunicode.upper(self))
     def zfill(self, width):                 return pyu(zunicode.zfill(self, width))
@@ -983,6 +979,18 @@ cdef class _pyustrIter:
         x = next(self.uiter)
         return pyu(x)
 
+# _pyustrTranslateTab wraps table for .translate to return bstr as unicode
+# because unicode.translate does not accept bstr values.
+cdef class _pyustrTranslateTab:
+    cdef object tab
+    def __init__(self, tab):
+        self.tab = tab
+    def __getitem__(self, k):
+        v = self.tab[k]
+        if not isinstance(v, int):  # either unicode ordinal,
+            v = _xpyu_coerce(v)     # character or None
+        return v
+
 
 # _bdata/_udata retrieve raw data from bytes/unicode.
 def _bdata(obj): # -> bytes

golang/_golang_test.pyx

@@ -2,7 +2,7 @@
 # cython: language_level=2
 # distutils: language=c++
 #
-# Copyright (C) 2018-2020  Nexedi SA and Contributors.
+# Copyright (C) 2018-2024  Nexedi SA and Contributors.
 #                          Kirill Smelkov <kirr@nexedi.com>
 #
 # This program is free software: you can Use, Study, Modify and Redistribute
@@ -344,6 +344,25 @@ cdef nogil:
         pych.chan_double().close()
 
 
+# verify that pychan_from_raw is not leaking C channel.
+def test_pychan_from_raw_noleak():
+    # pychan_from_raw used to create another channel and leak it
+    #
+    # this test _implicitly_ verifies that it is no longer the case - if it is,
+    # LSAN will report a memory leak after running the test.
+    #
+    # TODO consider adding explicit verification effective even under regular
+    #      builds. Possible options:
+    #
+    #      * verify malloc totals before and after tested code
+    #        see e.g. https://stackoverflow.com/q/1761125/9456786
+    #      * hook _makechan and verify that it is not invoked from under
+    #        pychan_from_raw. Depends on funchook integration.
+    cdef chan[int] ch   = makechan[int]()
+    cdef pychan    pych = pychan.from_chan_int(ch)  # uses pychan_from_raw internally
+    # pych and ch are freed automatically
+
+
 # ---- benchmarks ----
 
 # bench_go_nogil mirrors golang_test.py:bench_go

golang/golang_str_test.py

@@ -1567,7 +1567,10 @@ def test_strings_methods():
     # checkop verifies that `s.meth(*argv, **kw)` gives the same result for s,
     # argv and kw being various combinations of unicode,bstr,ustr, bytes/bytearray.
     def checkop(s, meth, *argv, **kw):
-        assert type(s) is str
+        if six.PY3:
+            assert type(s) is str
+        else:
+            assert type(s) in (str, unicode)    # some tests use unicode because \u does not work in str literals
         ok = kw.pop('ok')
         if six.PY2:
             ok = deepReplaceStr(ok, xunicode)
@@ -1738,7 +1741,7 @@ def test_strings_methods():
     _("123").isnumeric(                             ok=True)
     _("0x123").isnumeric(                           ok=False)
     _("мир").isprintable(                           ok=True,    optional=True)  # py3.0
-    _("\u2009").isspace(                            ok=x32(True,False))         # thin space
+    _(u"\u2009").isspace(                           ok=True)                    # thin space
     _("  ").isspace(                                ok=True)
     _("мир").isspace(                               ok=False)
     _("мир").istitle(                               ok=False)
@@ -1748,8 +1751,8 @@ def test_strings_methods():
     _("мир").ljust(10,                              ok="мир       ")
     _("мир").ljust(10, 'ж',                         ok="миржжжжжжж")
     _("МиР").lower(                                 ok="мир")
-    _("\u2009 мир").lstrip(                         ok=x32("мир", "\u2009 мир"))
-    _("\u2009 мир\u2009 ").lstrip(                  ok=x32("мир\u2009 ", "\u2009 мир\u2009 "))
+    _(u"\u2009 мир").lstrip(                        ok="мир")
+    _(u"\u2009 мир\u2009 ").lstrip(                 ok=u"мир\u2009 ")
     _("мммир").lstrip('ми',                         ok="р")
     _("миру мир").partition('ру',                   ok=("ми", "ру", " мир"))
     _("миру мир").partition('ж',                    ok=("миру мир", "", ""))
@@ -1764,15 +1767,15 @@ def test_strings_methods():
     _("миру мир").rpartition('ж',                   ok=("", "", "миру мир"))
     _("мир").rsplit(                                ok=["мир"])
     _("привет мир").rsplit(                         ok=["привет", "мир"])
-    _("привет\u2009мир").rsplit(                    ok=x32(["привет", "мир"], ["привет\u2009мир"]))
+    _(u"привет\u2009мир").rsplit(                   ok=["привет", "мир"])
     _("привет мир").rsplit("и",                     ok=["пр", "вет м", "р"])
     _("привет мир").rsplit("и", 1,                  ok=["привет м", "р"])
-    _("мир \u2009").rstrip(                         ok=x32("мир", "мир \u2009"))
-    _(" мир \u2009").rstrip(                        ok=x32(" мир", " мир \u2009"))
+    _(u"мир \u2009").rstrip(                        ok="мир")
+    _(u" мир \u2009").rstrip(                       ok=" мир")
     _("мируу").rstrip('ру',                         ok="ми")
     _("мир").split(                                 ok=["мир"])
     _("привет мир").split(                          ok=["привет", "мир"])
-    _("привет\u2009мир").split(                     ok=x32(['привет', 'мир'], ["привет\u2009мир"]))
+    _(u"привет\u2009мир").split(                    ok=['привет', 'мир'])
     _("привет мир").split("и",                      ok=["пр", "вет м", "р"])
     _("привет мир").split("и", 1,                   ok=["пр", "вет мир"])
     _("мир").splitlines(                            ok=["мир"])
@@ -1782,11 +1785,12 @@ def test_strings_methods():
     _("мир\nтруд\nмай\n").splitlines(               ok=["мир", "труд", "май"])
     _("мир\nтруд\nмай\n").splitlines(True,          ok=["мир\n", "труд\n", "май\n"])
     # startswith            - tested in test_strings_index
-    _("\u2009 мир \u2009").strip(                   ok=x32("мир", "\u2009 мир \u2009"))
+    _(u"\u2009 мир \u2009").strip(                  ok="мир")
     _("миру мир").strip('мир',                      ok="у ")
     _("МиР").swapcase(                              ok="мИр")
     _("МиР").title(                                 ok="Мир")
     _("мир").translate({ord(u'м'):ord(u'и'), ord(u'и'):'я', ord(u'р'):None},        ok="ия")
+    _(u"\u0000\u0001\u0002.").translate([u'м', ord(u'и'), None],                    ok="ми.")
     _("МиР").upper(                                 ok="МИР")
     _("мир").zfill(10,                              ok="0000000мир")
     _("123").zfill(10,                              ok="0000000123")

golang/golang_test.py

 # -*- coding: utf-8 -*-
-# Copyright (C) 2018-2023  Nexedi SA and Contributors.
+# Copyright (C) 2018-2024  Nexedi SA and Contributors.
 #                          Kirill Smelkov <kirr@nexedi.com>
 #
 # This program is free software: you can Use, Study, Modify and Redistribute
@@ -74,7 +74,8 @@ import_pyx_tests("golang._golang_test")
 # leaked goroutine behaviour check: done in separate process because we need
 # to test process termination exit there.
 def test_go_leaked():
-    pyrun([dir_testprog + "/golang_test_goleaked.py"])
+    pyrun([dir_testprog + "/golang_test_goleaked.py"],
+          lsan=False)   # there are on-purpose leaks in this test
 
 # benchmark go+join a thread/coroutine.
 # pyx/nogil mirror is in _golang_test.pyx
@@ -1756,6 +1757,11 @@ def _pyrun(argv, stdin=None, stdout=None, stderr=None, **kw):   # -> retcode, st
         assert len(enc) == 1
         env['PYTHONIOENCODING'] = enc.pop()
 
+    # disable LeakSanitizer if requested, e.g. when test is known to leak something on purpose
+    lsan = kw.pop('lsan', True)
+    if not lsan:
+        env['ASAN_OPTIONS'] = env.get('ASAN_OPTIONS', '') + ',detect_leaks=0'
+
     p = Popen(argv, stdin=(PIPE if stdin else None), stdout=stdout, stderr=stderr, env=env, **kw)
     stdout, stderr = p.communicate(stdin)
 

golang/libgolang.h

@@ -345,8 +345,13 @@ typedef struct _libgolang_runtime_ops {
     // previously successfully allocated via sema_alloc.
     void             (*sema_free)   (_libgolang_sema*);
 
-    // sema_acquire/sema_release should acquire/release live semaphore allocated via sema_alloc.
-    void             (*sema_acquire)(_libgolang_sema*);
+    // sema_acquire should try to acquire live semaphore allocated via sema_alloc during given time.
+    // it returns whether acquisition succeeded or timed out.
+    // the timeout is specified in nanoseconds.
+    // UINT64_MAX means no timeout.
+    bool             (*sema_acquire)(_libgolang_sema*, uint64_t timeout_ns);
+
+    // sema_release should release live semaphore allocated via sema_alloc.
     void             (*sema_release)(_libgolang_sema*);
 
     // nanosleep should pause current goroutine for at least dt nanoseconds.

golang/pyx/build_test.py

 # -*- coding: utf-8 -*-
-# Copyright (C) 2019  Nexedi SA and Contributors.
-#                     Kirill Smelkov <kirr@nexedi.com>
+# Copyright (C) 2019-2024  Nexedi SA and Contributors.
+#                          Kirill Smelkov <kirr@nexedi.com>
 #
 # This program is free software: you can Use, Study, Modify and Redistribute
 # it under the terms of the GNU General Public License version 3, or (at your
@@ -28,7 +28,8 @@ testprog = dirname(__file__) + "/testprog"
 # verify that we can build/run external package that uses pygolang in pyx mode.
 def test_pyx_build():
     pyxuser = testprog + "/golang_pyx_user"
-    pyrun(["setup.py", "build_ext", "-i"], cwd=pyxuser)
+    pyrun(["setup.py", "build_ext", "-i"], cwd=pyxuser,
+          lsan=False)   # gcc leaks
 
     # run built test.
     _ = pyout(["-c",
@@ -44,8 +45,8 @@ def test_pyx_build():
 # verify that we can build/run external dso that uses libgolang.
 def test_dso_build():
     dsouser = testprog + "/golang_dso_user"
-    pyrun(["setup.py", "build_dso", "-i"], cwd=dsouser)
-    pyrun(["setup.py", "build_ext", "-i"], cwd=dsouser)
+    pyrun(["setup.py", "build_dso", "-i"], cwd=dsouser,  lsan=False) # gcc leaks
+    pyrun(["setup.py", "build_ext", "-i"], cwd=dsouser,  lsan=False) # gcc leaks
 
     # run built test.
     _ = pyout(["-c",

golang/runtime/_libgolang.pxd

 # cython: language_level=2
-# Copyright (C) 2019-2022  Nexedi SA and Contributors.
+# Copyright (C) 2019-2024  Nexedi SA and Contributors.
 #                          Kirill Smelkov <kirr@nexedi.com>
 #
 # This program is free software: you can Use, Study, Modify and Redistribute
@@ -36,7 +36,7 @@ cdef extern from "golang/libgolang.h" namespace "golang" nogil:
 
         _libgolang_sema* (*sema_alloc)  ()
         void             (*sema_free)   (_libgolang_sema*)
-        void             (*sema_acquire)(_libgolang_sema*)
+        bint             (*sema_acquire)(_libgolang_sema*, uint64_t timeout_ns)
         void             (*sema_release)(_libgolang_sema*)
 
         void        (*nanosleep)(uint64_t)

golang/runtime/_runtime_gevent.pyx

 # cython: language_level=2
-# Copyright (C) 2019-2023  Nexedi SA and Contributors.
+# Copyright (C) 2019-2024  Nexedi SA and Contributors.
 #                          Kirill Smelkov <kirr@nexedi.com>
 #
 # This program is free software: you can Use, Study, Modify and Redistribute
@@ -40,7 +40,10 @@ ELSE:
 
 from gevent import sleep as pygsleep
 
-from libc.stdint cimport uint64_t
+from libc.stdint cimport uint8_t, uint64_t, UINT64_MAX
+cdef extern from *:
+    ctypedef bint cbool "bool"
+
 from cpython cimport PyObject, Py_INCREF, Py_DECREF
 from cython cimport final
 
@@ -95,9 +98,12 @@ cdef:
         Py_DECREF(pygsema)
         return True
 
-    bint _sema_acquire(_libgolang_sema *gsema):
+    bint _sema_acquire(_libgolang_sema *gsema, uint64_t timeout_ns, cbool* pacq):
         pygsema = <PYGSema>gsema
-        pygsema.acquire()
+        timeout = None
+        if timeout_ns != UINT64_MAX:
+            timeout = float(timeout_ns) * 1e-9
+        pacq[0] = pygsema.acquire(timeout=timeout)
         return True
 
     bint _sema_release(_libgolang_sema *gsema):
@@ -142,14 +148,16 @@ cdef nogil:
         if not ok:
             panic("pyxgo: gevent: sema: free: failed")
 
-    void sema_acquire(_libgolang_sema *gsema):
+    cbool sema_acquire(_libgolang_sema *gsema, uint64_t timeout_ns):
         cdef PyExc exc
+        cdef cbool acq
         with gil:
             pyexc_fetch(&exc)
-            ok = _sema_acquire(gsema)
+            ok = _sema_acquire(gsema, timeout_ns, &acq)
             pyexc_restore(exc)
         if not ok:
             panic("pyxgo: gevent: sema: acquire: failed")
+        return acq
 
     void sema_release(_libgolang_sema *gsema):
         cdef PyExc exc

golang/runtime/_runtime_thread.pyx

 # cython: language_level=2
-# Copyright (C) 2019-2022  Nexedi SA and Contributors.
+# Copyright (C) 2019-2024  Nexedi SA and Contributors.
 #                          Kirill Smelkov <kirr@nexedi.com>
 #
 # This program is free software: you can Use, Study, Modify and Redistribute
@@ -35,7 +35,12 @@ from __future__ import print_function, absolute_import
 #
 # NOTE Cython declares PyThread_acquire_lock/PyThread_release_lock as nogil
 from cpython.pythread cimport PyThread_acquire_lock, PyThread_release_lock, \
-        PyThread_type_lock, WAIT_LOCK
+        PyThread_type_lock, WAIT_LOCK, NOWAIT_LOCK, PyLockStatus, PY_LOCK_ACQUIRED, PY_LOCK_FAILURE
+
+cdef extern from * nogil:
+    ctypedef int PY_TIMEOUT_T   # long long there
+    PyLockStatus PyThread_acquire_lock_timed(PyThread_type_lock, PY_TIMEOUT_T timeout_us, int intr_flag)
+
 
 # NOTE On Darwin, even though this is considered as POSIX, Python uses
 # mutex+condition variable to implement its lock, and, as of 20190828, Py2.7
@@ -98,6 +103,9 @@ from libc.errno  cimport errno, EINTR, EBADF
 from posix.fcntl cimport mode_t
 from posix.stat cimport struct_stat
 from posix.strings cimport bzero
+cdef extern from *:
+    ctypedef bint cbool "bool"
+
 IF POSIX:
     from posix.time cimport clock_gettime, nanosleep as posix_nanosleep, timespec, CLOCK_REALTIME
 ELSE:
@@ -138,11 +146,46 @@ cdef nogil:
         pysema = <PyThread_type_lock>gsema
         PyThread_free_lock(pysema)
 
-    void sema_acquire(_libgolang_sema *gsema):
+    cbool sema_acquire(_libgolang_sema *gsema, uint64_t timeout_ns):
         pysema = <PyThread_type_lock>gsema
-        ok = PyThread_acquire_lock(pysema, WAIT_LOCK)
-        if ok == 0:
-            panic("pyxgo: thread: sema_acquire: PyThread_acquire_lock failed")
+        IF PY3:
+            cdef PY_TIMEOUT_T timeout_us
+        ELSE:
+            cdef uint64_t tprev, t, tsleep
+        if timeout_ns == UINT64_MAX:
+            ok = PyThread_acquire_lock(pysema, WAIT_LOCK)
+            if ok == 0:
+                panic("pyxgo: thread: sema_acquire: PyThread_acquire_lock failed")
+            return 1
+        else:
+            IF PY3:
+                timeout_us = timeout_ns // 1000
+                lkok = PyThread_acquire_lock_timed(pysema, timeout_us, 0)
+                if lkok == PY_LOCK_FAILURE:
+                    return 0
+                elif lkok == PY_LOCK_ACQUIRED:
+                    return 1
+                else:
+                    panic("pyxgo: thread: sema_acquire: PyThread_acquire_lock_timed failed")
+            ELSE:
+                # py2 misses PyThread_acquire_lock_timed - provide fallback ourselves
+                tprev = nanotime()
+                while 1:
+                     ok = PyThread_acquire_lock(pysema, NOWAIT_LOCK)
+                     if ok:
+                         return 1
+                     tsleep = min(timeout_ns, 50*1000)    # poll every 50 μs = 20 Hz
+                     if tsleep == 0:
+                         break
+                     nanosleep(tsleep)
+                     t = nanotime()
+                     if t < tprev:
+                         break  # clock skew
+                     if t - tprev >= timeout_ns:
+                         break
+                     timeout_ns -= t - tprev
+                     tprev = t
+                return 0
 
     void sema_release(_libgolang_sema *gsema):
         pysema = <PyThread_type_lock>gsema

golang/runtime/libgolang.cpp

@@ -131,6 +131,7 @@ using internal::_runtime;
 
 namespace internal { namespace atomic { extern void _init(); } }
 namespace os { namespace signal { extern void _init(); } }
+namespace time { extern void _init(); }
 void _libgolang_init(const _libgolang_runtime_ops *runtime_ops) {
     if (_runtime != nil) // XXX better check atomically
         panic("libgolang: double init");
@@ -138,6 +139,7 @@ void _libgolang_init(const _libgolang_runtime_ops *runtime_ops) {
 
     internal::atomic::_init();
     os::signal::_init();
+    time::_init();
 }
 
 void _taskgo(void (*f)(void *), void *arg) {
@@ -166,7 +168,15 @@ void _semafree(_sema *sema) {
 }
 
 void _semaacquire(_sema *sema) {
-    _runtime->sema_acquire((_libgolang_sema *)sema);
+    bool ok;
+    ok = _runtime->sema_acquire((_libgolang_sema *)sema, UINT64_MAX);
+    if (!ok)
+        panic("semaacquire: failed");
+}
+
+// NOTE not currently exposed in public API
+bool _semaacquire_timed(_sema *sema, uint64_t timeout_ns) {
+    return _runtime->sema_acquire((_libgolang_sema *)sema, timeout_ns);
 }
 
 void _semarelease(_sema *sema) {

golang/time.h

 #ifndef _NXD_LIBGOLANG_TIME_H
 #define	_NXD_LIBGOLANG_TIME_H
 
-// Copyright (C) 2019-2023  Nexedi SA and Contributors.
+// Copyright (C) 2019-2024  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 //
 // This program is free software: you can Use, Study, Modify and Redistribute
@@ -118,6 +118,7 @@ private:
     double      _dt;
     sync::Mutex _mu;
     bool        _stop;
+    Timer       _timer;
 
     // don't new - create only via new_ticker()
 private:
@@ -147,18 +148,12 @@ LIBGOLANG_API Timer new_timer(double dt);
 struct _Timer : object {
     chan<double> c;
 
-private:
-    func<void()> _f;
-
-    sync::Mutex  _mu;
-    double       _dt;  // +inf - stopped, otherwise - armed
-    int          _ver; // current timer was armed by n'th reset
-
     // don't new - create only via new_timer() & co
 private:
     _Timer();
     ~_Timer();
     friend Timer _new_timer(double dt, func<void()> f);
+    friend class _TimerImpl;
 public:
     LIBGOLANG_API void decref();
 
@@ -182,9 +177,6 @@ public:
     //
     // the timer must be either already stopped or expired.
     LIBGOLANG_API void reset(double dt);
-
-private:
-    void _fire(double dt, int ver);
 };
 
 

golang/time_test.py

 # -*- coding: utf-8 -*-
-# Copyright (C) 2019  Nexedi SA and Contributors.
-#                     Kirill Smelkov <kirr@nexedi.com>
+# Copyright (C) 2019-2024  Nexedi SA and Contributors.
+#                          Kirill Smelkov <kirr@nexedi.com>
 #
 # This program is free software: you can Use, Study, Modify and Redistribute
 # it under the terms of the GNU General Public License version 3, or (at your
@@ -20,9 +20,10 @@
 
 from __future__ import print_function, absolute_import
 
-from golang import select
-from golang import time
+from golang import select, func, defer
+from golang import time, sync
 from golang.golang_test import panics
+from six.moves import range as xrange
 
 # all timer tests operate in dt units
 dt = 10*time.millisecond
@@ -65,6 +66,7 @@ def test_ticker_time():
 
 
 # test_timer verifies that Timer/Ticker fire as expected.
+@func
 def test_timer():
     # start timers at x5, x7 and x11 intervals an verify that the timers fire
     # in expected sequence. The times when the timers fire do not overlap in
@@ -73,15 +75,15 @@ def test_timer():
     tv = [] # timer events
     Tstart = time.now()
 
-    t23 = time.Timer(23*dt)
-    t5  = time.Timer( 5*dt)
+    t23 = time.Timer(23*dt);        defer(t23.stop)
+    t5  = time.Timer( 5*dt);        defer(t5 .stop)
 
     def _():
         tv.append(7)
         t7f.reset(7*dt)
-    t7f = time.Timer( 7*dt, f=_)
+    t7f = time.Timer( 7*dt, f=_);   defer(t7f.stop)
 
-    tx11 = time.Ticker(11*dt)
+    tx11 = time.Ticker(11*dt);      defer(tx11.stop)
 
     while 1:
         _, _rx = select(
@@ -108,19 +110,20 @@ def test_timer():
 
 
 # test_timer_misc, similarly to test_timer, verifies misc timer convenience functions.
+@func
 def test_timer_misc():
     tv = []
     Tstart = time.now()
 
-    c23 = time.after(23*dt)
-    c5  = time.after( 5*dt)
+    c23 = time.after(23*dt)         # cannot stop
+    c5  = time.after( 5*dt)         # cannot stop
 
     def _():
         tv.append(7)
         t7f.reset(7*dt)
-    t7f = time.after_func(7*dt, _)
+    t7f = time.after_func(7*dt, _); defer(t7f.stop)
 
-    cx11 = time.tick(11*dt)
+    cx11 = time.tick(11*dt)         # cannot stop
 
     while 1:
         _, _rx = select(
@@ -148,13 +151,14 @@ def test_timer_misc():
 
 
 # test_timer_stop verifies that .stop() cancels Timer or Ticker.
+@func
 def test_timer_stop():
     tv = []
 
-    t10 = time.Timer (10*dt)
-    t2  = time.Timer ( 2*dt)    # will fire and cancel t3, tx5
-    t3  = time.Timer ( 3*dt)    # will be canceled
-    tx5 = time.Ticker( 5*dt)    # will be canceled
+    t10 = time.Timer (10*dt);   defer(t10.stop)
+    t2  = time.Timer ( 2*dt);   defer(t2 .stop) # will fire and cancel t3, tx5
+    t3  = time.Timer ( 3*dt);   defer(t3 .stop) # will be canceled
+    tx5 = time.Ticker( 5*dt);   defer(tx5.stop) # will be canceled
 
     while 1:
         _, _rx = select(
@@ -180,9 +184,10 @@ def test_timer_stop():
 
 
 # test_timer_stop_drain verifies that Timer/Ticker .stop() drains timer channel.
+@func
 def test_timer_stop_drain():
-    t  = time.Timer (1*dt)
-    tx = time.Ticker(1*dt)
+    t  = time.Timer (1*dt);     defer(t.stop)
+    tx = time.Ticker(1*dt);     defer(tx.stop)
 
     time.sleep(2*dt)
     assert len(t.c)  == 1
@@ -195,9 +200,45 @@ def test_timer_stop_drain():
     assert len(tx.c) == 0
 
 
+# test_timer_stop_vs_func verifies that Timer .stop() works correctly with func-timer.
+@func
+def test_timer_stop_vs_func():
+    tv = []
+    def _1(): tv.append(1)
+    def _2(): tv.append(2)
+
+    t1 = time.after_func(1e6*dt, _1);   defer(t1.stop)
+    t2 = time.after_func(  1*dt, _2);   defer(t2.stop)
+
+    time.sleep(2*dt)
+    assert t1.stop() == True
+    assert t2.stop() == False
+    assert tv == [2]
+
+
 # test_timer_reset_armed verifies that .reset() panics if called on armed timer.
+@func
 def test_timer_reset_armed():
     # reset while armed
-    t = time.Timer(10*dt)
+    t = time.Timer(10*dt);  defer(t.stop)
     with panics("Timer.reset: the timer is armed; must be stopped or expired"):
         t.reset(5*dt)
+
+
+# bench_timer_arm_cancel benchmarks arming timers that do not fire.
+# it shows how cheap or expensive it is to use timers to implement timeouts.
+def bench_timer_arm_cancel(b):
+    for i in xrange(b.N):
+        t = time.Timer(10*time.second)
+        _ = t.stop()
+        assert _ is True
+
+
+# bench_timer_arm_fire benchmarks arming timers that do fire.
+# it shows what it costs to go through all steps related to timer loop and firing timers.
+def bench_timer_arm_fire(b):
+    wg = sync.WaitGroup()
+    wg.add(b.N)
+    for i in xrange(b.N):
+        t = time.after_func(1*time.millisecond, wg.done)
+    wg.wait()

setup.py

@@ -188,7 +188,7 @@ class develop(XInstallGPython, _develop):
 
 # requirements of packages under "golang." namespace
 R = {
-    'cmd.pybench':      {'pytest', 'py'},
+    'cmd.pybench':      {'pytest', 'py ; python_version >= "3"'},
     'pyx.build':        {'setuptools', 'wheel', 'cython < 3', 'setuptools_dso >= 2.8'},
     'x.perf.benchlib':  {'numpy'},
 }
@@ -467,8 +467,11 @@ setup(
                             'golang/os/signal.h',
                             'golang/strings.h',
                             'golang/sync.h',
-                            'golang/time.h'],
-                        include_dirs    = ['3rdparty/include'],
+                            'golang/time.h',
+                            '3rdparty/ratas/src/timer-wheel.h'],
+                        include_dirs    = [
+                            '3rdparty/include',
+                            '3rdparty/ratas/src'],
                         define_macros   = [('BUILDING_LIBGOLANG', None)],
                         soversion       = '0.1'),
 
@@ -604,9 +607,6 @@ setup(
         Programming Language :: Python :: 2
         Programming Language :: Python :: 2.7
         Programming Language :: Python :: 3
-        Programming Language :: Python :: 3.5
-        Programming Language :: Python :: 3.6
-        Programming Language :: Python :: 3.7
         Programming Language :: Python :: 3.8
         Programming Language :: Python :: 3.9
         Programming Language :: Python :: 3.10

tox.ini

 [tox]
 envlist =
-    {py27d,py27,py37,py38,py39d,py39,py310d,py310,py311d,py311,py312,pypy,pypy3}-{thread,gevent}
+    {py27d,py27,py38,py39d,py39,py310d,py310,py311d,py311,py312,pypy,pypy3}-{thread,gevent}
 
 
 # ThreadSanitizer
@@ -10,24 +10,23 @@ envlist =
 # (*) PyPy locks its GIL (see RPyGilAcquire) by manually doing atomic cmpxchg
 # and other games, which TSAN cannot see if PyPy itself was not compiled with
 # -fsanitize=thread.
-    {py27d,py27,py37,py38,py39d,py39,py310d,py310,py311d,py311,py312           }-{thread       }-tsan
+    {py27d,py27,py38,py39d,py39,py310d,py310,py311d,py311,py312           }-{thread       }-tsan
 # XXX py*-gevent-tsan would be nice to have, but at present TSAN is not
 # effective with gevent, because it does not understand greenlet "thread"
 # switching and so perceives the program as having only one thread where races
 # are impossible. Disabled to save time.
-#   {py27d,py27,py37,py38,py39d,py39,py310d,py310,py311d,py311,py312           }-{       gevent}-tsan
+#   {py27d,py27,py38,py39d,py39,py310d,py310,py311d,py311,py312           }-{       gevent}-tsan
 
 
 # AddressSanitizer
 
 # XXX asan does not work with gevent: https://github.com/python-greenlet/greenlet/issues/113
-    {py27d,py27,py37,py38,py39d,py39,py310d,py310,py311d,py311,py312,pypy,pypy3}-{thread       }-asan
+    {py27d,py27,py38,py39d,py39,py310d,py310,py311d,py311,py312,pypy,pypy3}-{thread       }-asan
 
 [testenv]
 basepython =
     py27d:  python2.7-dbg
     py27:   python2.7
-    py37:   python3.7
     py38:   python3.8
     py39d:  python3.9-dbg
     py39:   python3.9
@@ -43,16 +42,16 @@ basepython =
 setenv =
 # distutils take CFLAGS for both C and C++.
 # distutils use  CFLAGS also at link stage -> we don't need to set LDFLAGS separately.
-    tsan: CFLAGS=-g -fsanitize=thread
-    asan: CFLAGS=-g -fsanitize=address
+    tsan: CFLAGS=-g -fsanitize=thread   -fno-omit-frame-pointer
+    asan: CFLAGS=-g -fsanitize=address  -fno-omit-frame-pointer
 # XXX however distutils' try_link, which is used by numpy.distutils use only CC
 # as linker without CFLAGS and _without_ LDFLAGS, which fails if *.o were
 # compiled with -fsanitize=X and linked without that option. Work it around
 # with also adjusting CC.
 # XXX better arrange to pass CFLAGS to pygolang only, e.g. by adding --race or
 # --sanitize=thread to `setup.py build_ext`.
-    tsan: CC=cc -fsanitize=thread
-    asan: CC=cc -fsanitize=address
+    tsan: CC=cc -fsanitize=thread   -fno-omit-frame-pointer
+    asan: CC=cc -fsanitize=address  -fno-omit-frame-pointer
 
 # always compile pygolang from source and don't reuse binary pygolang wheels as
 # we compile each case with different CFLAGS.
@@ -76,3 +75,5 @@ commands=
 # likewise for python debug builds.
         asan,tsan,py{27,39,310,311,312}d: -s    \
         gpython/ golang/
+
+allowlist_externals={toxinidir}/trun

trun

 #!/usr/bin/env python
+# -*- coding: utf-8 -*-
 # Copyright (C) 2019-2024  Nexedi SA and Contributors.
 #                          Kirill Smelkov <kirr@nexedi.com>
 #
@@ -34,7 +35,7 @@ trun cares to run python with LD_PRELOAD set appropriately to /path/to/libtsan.s
 
 from __future__ import print_function, absolute_import
 
-import os, sys, re, subprocess, types
+import os, os.path, sys, re, subprocess, platform, types
 PY3 = (bytes is not str)
 if PY3:
     from importlib import machinery as imp_machinery
@@ -87,6 +88,7 @@ def main():
 
     # determine if _golang.so is linked to a sanitizer, and if yes, to which
     # particular sanitizer DSO. Set LD_PRELOAD appropriately.
+    libxsan    = None
     ld_preload = None
     if 'linux' in sys.platform:
         p = subprocess.Popen(["ldd", _golang_so.path], stdout=subprocess.PIPE)
@@ -127,7 +129,8 @@ def main():
 
             _ = grep1("DYLD_INSERT_LIBRARIES=(.*)$", err)
             if _ is not None:
-                ld_preload = ("DYLD_INSERT_LIBRARIES", _.group(1))
+                libxsan = _.group(1)
+                ld_preload = ("DYLD_INSERT_LIBRARIES", libxsan)
             else:
                 print("trun %r: `import golang` failed with unexpected error:" % sys.argv[1:], file=sys.stderr)
                 print(err, file=sys.stderr)
@@ -144,7 +147,7 @@ def main():
     env_prepend("TSAN_OPTIONS", "halt_on_error=1")
     env_prepend("ASAN_OPTIONS", "halt_on_error=1")
 
-    # tweak TSAN/ASAN defaults:
+    # tweak TSAN/ASAN/LSAN defaults:
 
     # enable TSAN deadlock detector
     # (unfortunately it caughts only few _potential_ deadlocks and actually
@@ -152,15 +155,49 @@ def main():
     env_prepend("TSAN_OPTIONS", "detect_deadlocks=1")
     env_prepend("TSAN_OPTIONS", "second_deadlock_stack=1")
 
-    # many python allocations, whose lifetime coincides with python interpreter
-    # lifetime and which are not explicitly freed on python shutdown, are
-    # reported as leaks. Disable leak reporting to avoid huge non-pygolang
-    # related printouts.
-    env_prepend("ASAN_OPTIONS", "detect_leaks=0")
-
     # tune ASAN to check more aggressively by default
     env_prepend("ASAN_OPTIONS", "detect_stack_use_after_return=1")
 
+    # enable ASAN/LSAN leak detector.
+    #
+    # Do it only on CPython ≥ 3.11 because on py2 and on earlier py3 versions
+    # there are many many python allocations, whose lifetime coincide with
+    # python interpreter lifetime, and which are not explicitly freed on python
+    # shutdown. For py3 they significantly improved this step by step and
+    # starting from 3.11 it becomes practical to silence some still-leaks with
+    # suppressions, while for earlier py3 versions and especially for py2 it
+    # is, unfortunately, not manageable. Do not spend engineering time with
+    # activating LSAN on PyPy as that is tier 2 platform and bug tail history
+    # of memory leaks is very long even only on cpython.
+    if sys.version_info < (3,11):
+        env_prepend("ASAN_OPTIONS", "detect_leaks=0")
+        if libxsan is not None:
+            if 'asan' in libxsan.lower():
+                print("W: trun %r: asan: leak detection deactivated on %s %s" % (
+                    sys.argv[1:], platform.python_implementation(), platform.python_version()),
+                    file=sys.stderr)
+    else:
+        env_prepend("ASAN_OPTIONS", "detect_leaks=1")
+        env_prepend("LSAN_OPTIONS", "suppressions=%s" % os.path.abspath(os.path.join(
+                                        os.path.dirname(__file__), ".lsan-ignore.txt")))
+        # do not print statistics for suppressed leaks - else it breaks tests that verify program output
+        env_prepend("LSAN_OPTIONS", "print_suppressions=0")
+
+        # enable DWARF-based unwinding.
+        # else, if python is not compiled with -fno-omit-frame-pointer, it can show
+        # the whole traceback as e.g. just
+        #   Direct leak of 32 byte(s) in 1 object(s) allocated from:
+        #     #0 0x7f88522f3bd7 in malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:69
+        #     #1 0x55f910a3d9a4 in PyThread_allocate_lock Python/thread_pthread.h:385
+        # and our leak suppressions won't work.
+        # this is slower compared to default frame-pointer based unwinding, but
+        # still works reasonably timely when run with just tests.
+        env_prepend("ASAN_OPTIONS", "fast_unwind_on_malloc=0")
+        # leak suppression also needs full tracebacks to work correctly, since with
+        # python there are many levels of call nesting at C level, and to filter-out e.g.
+        # top-level PyImport_Import we need to go really deep.
+        env_prepend("ASAN_OPTIONS", "malloc_context_size=255")
+
     # exec `...`
     os.execvp(sys.argv[1], sys.argv[1:])