From c6d324d75d488b6646dd04b72f13a858e4fefb19 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 27 Nov 2024 17:03:13 +0100
Subject: [PATCH 01/30] gh-59705: Add _thread.set_name() function

On Linux, threading.Thread now sets the thread name to the operating
system.

configure now checks if pthread_setname_np() function is available.
---
 Lib/threading.py                              |  7 ++
 ...4-11-27-17-04-38.gh-issue-59705.sAGyvs.rst |  2 +
 Modules/_threadmodule.c                       | 31 +++++++
 Modules/clinic/_threadmodule.c.h              | 86 +++++++++++++++++++
 configure                                     |  6 ++
 configure.ac                                  |  6 +-
 pyconfig.h.in                                 |  3 +
 7 files changed, 139 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2024-11-27-17-04-38.gh-issue-59705.sAGyvs.rst
 create mode 100644 Modules/clinic/_threadmodule.c.h

diff --git a/Lib/threading.py b/Lib/threading.py
index 94ea2f08178369..e7365790cc09f1 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -48,6 +48,11 @@
     __all__.append('get_native_id')
 except AttributeError:
     _HAVE_THREAD_NATIVE_ID = False
+try:
+    _set_name = _thread.set_name
+    _HAVE_SET_NAME = True
+except AttributeError:
+    _HAVE_SET_NAME = False
 ThreadError = _thread.error
 try:
     _CRLock = _thread.RLock
@@ -1027,6 +1032,8 @@ def _bootstrap_inner(self):
             self._set_ident()
             if _HAVE_THREAD_NATIVE_ID:
                 self._set_native_id()
+            if _HAVE_SET_NAME and self._name:
+                _set_name(self._name)
             self._started.set()
             with _active_limbo_lock:
                 _active[self._ident] = self
diff --git a/Misc/NEWS.d/next/Library/2024-11-27-17-04-38.gh-issue-59705.sAGyvs.rst b/Misc/NEWS.d/next/Library/2024-11-27-17-04-38.gh-issue-59705.sAGyvs.rst
new file mode 100644
index 00000000000000..a8c7b3d00755e6
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-11-27-17-04-38.gh-issue-59705.sAGyvs.rst
@@ -0,0 +1,2 @@
+On Linux, :class:`threading.Thread` now sets the thread name to the
+operating system. Patch by Victor Stinner.
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index f2a420ac1c589d..4fe5c7cdbb3fb5 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -17,6 +17,8 @@
 #  include <signal.h>             // SIGINT
 #endif
 
+#include "clinic/_threadmodule.c.h"
+
 // ThreadError is just an alias to PyExc_RuntimeError
 #define ThreadError PyExc_RuntimeError
 
@@ -44,6 +46,13 @@ get_thread_state(PyObject *module)
     return (thread_module_state *)state;
 }
 
+
+/*[clinic input]
+module _thread
+[clinic start generated code]*/
+/*[clinic end generated code: output=da39a3ee5e6b4b0d input=be8dbe5cc4b16df7]*/
+
+
 // _ThreadHandle type
 
 // Handles state transitions according to the following diagram:
@@ -2354,6 +2363,27 @@ PyDoc_STRVAR(thread__get_main_thread_ident_doc,
 Internal only. Return a non-zero integer that uniquely identifies the main thread\n\
 of the main interpreter.");
 
+
+#ifdef HAVE_PTHREAD_SETNAME_NP
+/*[clinic input]
+_thread.set_name
+
+    name: str
+
+Set the name of the current thread.
+[clinic start generated code]*/
+
+static PyObject *
+_thread_set_name_impl(PyObject *module, const char *name)
+/*[clinic end generated code: output=f051ce549bcd6b8e input=7e29bbdbfb046a04]*/
+{
+    pthread_t thread = pthread_self();
+    pthread_setname_np(thread, name);
+    Py_RETURN_NONE;
+}
+#endif  // HAVE_PTHREAD_SETNAME_NP
+
+
 static PyMethodDef thread_methods[] = {
     {"start_new_thread",        (PyCFunction)thread_PyThread_start_new_thread,
      METH_VARARGS, start_new_thread_doc},
@@ -2393,6 +2423,7 @@ static PyMethodDef thread_methods[] = {
      METH_O, thread__make_thread_handle_doc},
     {"_get_main_thread_ident", thread__get_main_thread_ident,
      METH_NOARGS, thread__get_main_thread_ident_doc},
+    _THREAD_SET_NAME_METHODDEF
     {NULL,                      NULL}           /* sentinel */
 };
 
diff --git a/Modules/clinic/_threadmodule.c.h b/Modules/clinic/_threadmodule.c.h
new file mode 100644
index 00000000000000..877ecfbedaf4b7
--- /dev/null
+++ b/Modules/clinic/_threadmodule.c.h
@@ -0,0 +1,86 @@
+/*[clinic input]
+preserve
+[clinic start generated code]*/
+
+#if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+#  include "pycore_gc.h"          // PyGC_Head
+#  include "pycore_runtime.h"     // _Py_ID()
+#endif
+#include "pycore_modsupport.h"    // _PyArg_UnpackKeywords()
+
+#if defined(HAVE_PTHREAD_SETNAME_NP)
+
+PyDoc_STRVAR(_thread_set_name__doc__,
+"set_name($module, /, name)\n"
+"--\n"
+"\n"
+"Set the name of the current thread.");
+
+#define _THREAD_SET_NAME_METHODDEF    \
+    {"set_name", _PyCFunction_CAST(_thread_set_name), METH_FASTCALL|METH_KEYWORDS, _thread_set_name__doc__},
+
+static PyObject *
+_thread_set_name_impl(PyObject *module, const char *name);
+
+static PyObject *
+_thread_set_name(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 1
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(name), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"name", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "set_name",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[1];
+    const char *name;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser,
+            /*minpos*/ 1, /*maxpos*/ 1, /*minkw*/ 0, /*varpos*/ 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(args[0])) {
+        _PyArg_BadArgument("set_name", "argument 'name'", "str", args[0]);
+        goto exit;
+    }
+    Py_ssize_t name_length;
+    name = PyUnicode_AsUTF8AndSize(args[0], &name_length);
+    if (name == NULL) {
+        goto exit;
+    }
+    if (strlen(name) != (size_t)name_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
+        goto exit;
+    }
+    return_value = _thread_set_name_impl(module, name);
+
+exit:
+    return return_value;
+}
+
+#endif /* defined(HAVE_PTHREAD_SETNAME_NP) */
+
+#ifndef _THREAD_SET_NAME_METHODDEF
+    #define _THREAD_SET_NAME_METHODDEF
+#endif /* !defined(_THREAD_SET_NAME_METHODDEF) */
+/*[clinic end generated code: output=bfb5c47ecc9e2cb8 input=a9049054013a1b77]*/
diff --git a/configure b/configure
index 84b74ac3584bcd..c57b493070872f 100755
--- a/configure
+++ b/configure
@@ -18832,6 +18832,12 @@ if test "x$ac_cv_func_pthread_kill" = xyes
 then :
   printf "%s\n" "#define HAVE_PTHREAD_KILL 1" >>confdefs.h
 
+fi
+ac_fn_c_check_func "$LINENO" "pthread_setname_np" "ac_cv_func_pthread_setname_np"
+if test "x$ac_cv_func_pthread_setname_np" = xyes
+then :
+  printf "%s\n" "#define HAVE_PTHREAD_SETNAME_NP 1" >>confdefs.h
+
 fi
 ac_fn_c_check_func "$LINENO" "ptsname" "ac_cv_func_ptsname"
 if test "x$ac_cv_func_ptsname" = xyes
diff --git a/configure.ac b/configure.ac
index 8fa6cb60900ad1..d7b32e8299a01f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5105,8 +5105,10 @@ AC_CHECK_FUNCS([ \
   mknod mknodat mktime mmap mremap nice openat opendir pathconf pause pipe \
   pipe2 plock poll posix_fadvise posix_fallocate posix_openpt posix_spawn posix_spawnp \
   posix_spawn_file_actions_addclosefrom_np \
-  pread preadv preadv2 process_vm_readv pthread_cond_timedwait_relative_np pthread_condattr_setclock pthread_init \
-  pthread_kill ptsname ptsname_r pwrite pwritev pwritev2 readlink readlinkat readv realpath renameat \
+  pread preadv preadv2 process_vm_readv \
+  pthread_cond_timedwait_relative_np pthread_condattr_setclock pthread_init \
+  pthread_kill pthread_setname_np \
+  ptsname ptsname_r pwrite pwritev pwritev2 readlink readlinkat readv realpath renameat \
   rtpSpawn sched_get_priority_max sched_rr_get_interval sched_setaffinity \
   sched_setparam sched_setscheduler sem_clockwait sem_getvalue sem_open \
   sem_timedwait sem_unlink sendfile setegid seteuid setgid sethostname \
diff --git a/pyconfig.h.in b/pyconfig.h.in
index 924d86627b0e9b..74ec9eb5fc5ed9 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -990,6 +990,9 @@
 /* Define to 1 if you have the `pthread_kill' function. */
 #undef HAVE_PTHREAD_KILL
 
+/* Define to 1 if you have the `pthread_setname_np' function. */
+#undef HAVE_PTHREAD_SETNAME_NP
+
 /* Define to 1 if you have the `pthread_sigmask' function. */
 #undef HAVE_PTHREAD_SIGMASK
 

From 63b5d52518685123cc3d7274f2f9abb26376558c Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 27 Nov 2024 17:21:38 +0100
Subject: [PATCH 02/30] Port to macOS

---
 Modules/_threadmodule.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index 4fe5c7cdbb3fb5..ff814236d0fe87 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2377,8 +2377,12 @@ static PyObject *
 _thread_set_name_impl(PyObject *module, const char *name)
 /*[clinic end generated code: output=f051ce549bcd6b8e input=7e29bbdbfb046a04]*/
 {
+#ifdef __APPLE__
+    pthread_setname_np(name);
+#else
     pthread_t thread = pthread_self();
     pthread_setname_np(thread, name);
+#endif
     Py_RETURN_NONE;
 }
 #endif  // HAVE_PTHREAD_SETNAME_NP

From 9f6a8ab3edb577a1dda44ec47734980eb39c193e Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 27 Nov 2024 17:34:36 +0100
Subject: [PATCH 03/30] Add tests

---
 Lib/test/test_threading.py       | 20 ++++++++++++++
 Modules/_threadmodule.c          | 33 ++++++++++++++++++++---
 Modules/clinic/_threadmodule.c.h | 46 +++++++++++++++++++++-----------
 configure                        |  6 +++++
 configure.ac                     |  2 +-
 pyconfig.h.in                    |  3 +++
 6 files changed, 91 insertions(+), 19 deletions(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index b666533466e578..a2525044db018b 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2103,6 +2103,26 @@ def test__all__(self):
         support.check__all__(self, threading, ('threading', '_thread'),
                              extra=extra, not_exported=not_exported)
 
+    def test_set_name(self):
+        try:
+            get_name = _thread._get_name
+            set_name = _thread.set_name
+        except AttributeError:
+            self.skipTest("need thread._get_name() and thread.set_name()")
+
+        work_name = None
+        def work():
+            nonlocal work_name
+            work_name = get_name()
+
+        # name not too long to fit into Linux 15 bytes limit
+        name = "CustomName"
+
+        thread = threading.Thread(target=work, name=name)
+        thread.start()
+        thread.join()
+        self.assertEqual(work_name, name)
+
 
 class InterruptMainTests(unittest.TestCase):
     def check_interrupt_main_with_signal_handler(self, signum):
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index ff814236d0fe87..4e36e0713a42c9 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2364,19 +2364,45 @@ Internal only. Return a non-zero integer that uniquely identifies the main threa
 of the main interpreter.");
 
 
+#ifdef HAVE_PTHREAD_SETNAME_NP
+/*[clinic input]
+_thread._get_name
+
+Get the name of the current thread.
+[clinic start generated code]*/
+
+static PyObject *
+_thread__get_name_impl(PyObject *module)
+/*[clinic end generated code: output=20026e7ee3da3dd7 input=35cec676833d04c8]*/
+{
+    char name[17];
+    size_t size = Py_ARRAY_LENGTH(name) - 1;
+#ifdef __APPLE__
+    pthread_getname_np(name, size);
+#else
+    pthread_t thread = pthread_self();
+    pthread_getname_np(thread, name, size);
+#endif
+    name[size] = 0;
+    return PyUnicode_DecodeFSDefault(name);
+}
+#endif  // HAVE_PTHREAD_SETNAME_NP
+
+
 #ifdef HAVE_PTHREAD_SETNAME_NP
 /*[clinic input]
 _thread.set_name
 
-    name: str
+    name as name_obj: object(converter="PyUnicode_FSConverter")
 
 Set the name of the current thread.
 [clinic start generated code]*/
 
 static PyObject *
-_thread_set_name_impl(PyObject *module, const char *name)
-/*[clinic end generated code: output=f051ce549bcd6b8e input=7e29bbdbfb046a04]*/
+_thread_set_name_impl(PyObject *module, PyObject *name_obj)
+/*[clinic end generated code: output=402b0c68e0c0daed input=a0459bd64f771808]*/
 {
+    const char *name = PyBytes_AS_STRING(name_obj);
 #ifdef __APPLE__
     pthread_setname_np(name);
 #else
@@ -2428,6 +2454,7 @@ static PyMethodDef thread_methods[] = {
     {"_get_main_thread_ident", thread__get_main_thread_ident,
      METH_NOARGS, thread__get_main_thread_ident_doc},
     _THREAD_SET_NAME_METHODDEF
+    _THREAD__GET_NAME_METHODDEF
     {NULL,                      NULL}           /* sentinel */
 };
 
diff --git a/Modules/clinic/_threadmodule.c.h b/Modules/clinic/_threadmodule.c.h
index 877ecfbedaf4b7..f638c29fdd28e2 100644
--- a/Modules/clinic/_threadmodule.c.h
+++ b/Modules/clinic/_threadmodule.c.h
@@ -10,6 +10,28 @@ preserve
 
 #if defined(HAVE_PTHREAD_SETNAME_NP)
 
+PyDoc_STRVAR(_thread__get_name__doc__,
+"_get_name($module, /)\n"
+"--\n"
+"\n"
+"Get the name of the current thread.");
+
+#define _THREAD__GET_NAME_METHODDEF    \
+    {"_get_name", (PyCFunction)_thread__get_name, METH_NOARGS, _thread__get_name__doc__},
+
+static PyObject *
+_thread__get_name_impl(PyObject *module);
+
+static PyObject *
+_thread__get_name(PyObject *module, PyObject *Py_UNUSED(ignored))
+{
+    return _thread__get_name_impl(module);
+}
+
+#endif /* defined(HAVE_PTHREAD_SETNAME_NP) */
+
+#if defined(HAVE_PTHREAD_SETNAME_NP)
+
 PyDoc_STRVAR(_thread_set_name__doc__,
 "set_name($module, /, name)\n"
 "--\n"
@@ -20,7 +42,7 @@ PyDoc_STRVAR(_thread_set_name__doc__,
     {"set_name", _PyCFunction_CAST(_thread_set_name), METH_FASTCALL|METH_KEYWORDS, _thread_set_name__doc__},
 
 static PyObject *
-_thread_set_name_impl(PyObject *module, const char *name);
+_thread_set_name_impl(PyObject *module, PyObject *name_obj);
 
 static PyObject *
 _thread_set_name(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
@@ -52,27 +74,17 @@ _thread_set_name(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyOb
     };
     #undef KWTUPLE
     PyObject *argsbuf[1];
-    const char *name;
+    PyObject *name_obj;
 
     args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser,
             /*minpos*/ 1, /*maxpos*/ 1, /*minkw*/ 0, /*varpos*/ 0, argsbuf);
     if (!args) {
         goto exit;
     }
-    if (!PyUnicode_Check(args[0])) {
-        _PyArg_BadArgument("set_name", "argument 'name'", "str", args[0]);
+    if (!PyUnicode_FSConverter(args[0], &name_obj)) {
         goto exit;
     }
-    Py_ssize_t name_length;
-    name = PyUnicode_AsUTF8AndSize(args[0], &name_length);
-    if (name == NULL) {
-        goto exit;
-    }
-    if (strlen(name) != (size_t)name_length) {
-        PyErr_SetString(PyExc_ValueError, "embedded null character");
-        goto exit;
-    }
-    return_value = _thread_set_name_impl(module, name);
+    return_value = _thread_set_name_impl(module, name_obj);
 
 exit:
     return return_value;
@@ -80,7 +92,11 @@ _thread_set_name(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyOb
 
 #endif /* defined(HAVE_PTHREAD_SETNAME_NP) */
 
+#ifndef _THREAD__GET_NAME_METHODDEF
+    #define _THREAD__GET_NAME_METHODDEF
+#endif /* !defined(_THREAD__GET_NAME_METHODDEF) */
+
 #ifndef _THREAD_SET_NAME_METHODDEF
     #define _THREAD_SET_NAME_METHODDEF
 #endif /* !defined(_THREAD_SET_NAME_METHODDEF) */
-/*[clinic end generated code: output=bfb5c47ecc9e2cb8 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=6611486fd37f22bf input=a9049054013a1b77]*/
diff --git a/configure b/configure
index c57b493070872f..f14eb5f04b780c 100755
--- a/configure
+++ b/configure
@@ -18832,6 +18832,12 @@ if test "x$ac_cv_func_pthread_kill" = xyes
 then :
   printf "%s\n" "#define HAVE_PTHREAD_KILL 1" >>confdefs.h
 
+fi
+ac_fn_c_check_func "$LINENO" "pthread_getname_np" "ac_cv_func_pthread_getname_np"
+if test "x$ac_cv_func_pthread_getname_np" = xyes
+then :
+  printf "%s\n" "#define HAVE_PTHREAD_GETNAME_NP 1" >>confdefs.h
+
 fi
 ac_fn_c_check_func "$LINENO" "pthread_setname_np" "ac_cv_func_pthread_setname_np"
 if test "x$ac_cv_func_pthread_setname_np" = xyes
diff --git a/configure.ac b/configure.ac
index d7b32e8299a01f..caeeef905f3663 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5107,7 +5107,7 @@ AC_CHECK_FUNCS([ \
   posix_spawn_file_actions_addclosefrom_np \
   pread preadv preadv2 process_vm_readv \
   pthread_cond_timedwait_relative_np pthread_condattr_setclock pthread_init \
-  pthread_kill pthread_setname_np \
+  pthread_kill pthread_getname_np pthread_setname_np \
   ptsname ptsname_r pwrite pwritev pwritev2 readlink readlinkat readv realpath renameat \
   rtpSpawn sched_get_priority_max sched_rr_get_interval sched_setaffinity \
   sched_setparam sched_setscheduler sem_clockwait sem_getvalue sem_open \
diff --git a/pyconfig.h.in b/pyconfig.h.in
index 74ec9eb5fc5ed9..f9c1235c837c67 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -981,6 +981,9 @@
 /* Define to 1 if you have the `pthread_getcpuclockid' function. */
 #undef HAVE_PTHREAD_GETCPUCLOCKID
 
+/* Define to 1 if you have the `pthread_getname_np' function. */
+#undef HAVE_PTHREAD_GETNAME_NP
+
 /* Define to 1 if you have the <pthread.h> header file. */
 #undef HAVE_PTHREAD_H
 

From d79e7af7cfcf59f088f10f3300a621bf218ca13b Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 27 Nov 2024 17:51:17 +0100
Subject: [PATCH 04/30] Try to fix macOS _get_name()

---
 Modules/_threadmodule.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index 4e36e0713a42c9..ecdfd6a25dcfc8 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2377,12 +2377,8 @@ _thread__get_name_impl(PyObject *module)
 {
     char name[17];
     size_t size = Py_ARRAY_LENGTH(name) - 1;
-#ifdef __APPLE__
-    pthread_getname_np(name, size);
-#else
     pthread_t thread = pthread_self();
     pthread_getname_np(thread, name, size);
-#endif
     name[size] = 0;
     return PyUnicode_DecodeFSDefault(name);
 }

From ebd97522d2b7428d66409a390443ff63811512f6 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Thu, 28 Nov 2024 11:12:17 +0100
Subject: [PATCH 05/30] Truncate to 15 bytes; add error handling

---
 Modules/_threadmodule.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index ecdfd6a25dcfc8..1768e5527f1aa4 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2378,7 +2378,12 @@ _thread__get_name_impl(PyObject *module)
     char name[17];
     size_t size = Py_ARRAY_LENGTH(name) - 1;
     pthread_t thread = pthread_self();
-    pthread_getname_np(thread, name, size);
+    int rc = pthread_getname_np(thread, name, size);
+    if (rc) {
+        errno = rc;
+        return PyErr_SetFromErrno(PyExc_OSError);
+    }
+
     name[size] = 0;
     return PyUnicode_DecodeFSDefault(name);
 }
@@ -2400,11 +2405,27 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
 {
     const char *name = PyBytes_AS_STRING(name_obj);
 #ifdef __APPLE__
-    pthread_setname_np(name);
+    int rc = pthread_setname_np(name);
 #else
+
+#if defined(__linux__)
+    // Truncate to 16 bytes including the NUL byte
+    char buffer[16];
+    size_t len = strlen(name);
+    if (len > 15) {
+        memcpy(buffer, name, 15);
+        buffer[15] = 0;
+        name = buffer;
+    }
+#endif
+
     pthread_t thread = pthread_self();
-    pthread_setname_np(thread, name);
+    int rc = pthread_setname_np(thread, name);
 #endif
+    if (rc) {
+        errno = rc;
+        return PyErr_SetFromErrno(PyExc_OSError);
+    }
     Py_RETURN_NONE;
 }
 #endif  // HAVE_PTHREAD_SETNAME_NP

From a7f565186ab018cd679dd55850dfa5e2a3cfa6dc Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Thu, 28 Nov 2024 15:36:19 +0100
Subject: [PATCH 06/30] Address review

---
 Lib/threading.py                 | 5 ++---
 Modules/_threadmodule.c          | 4 ++--
 Modules/clinic/_threadmodule.c.h | 6 +++---
 3 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/Lib/threading.py b/Lib/threading.py
index e7365790cc09f1..e8ae5b156a5db9 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -50,9 +50,8 @@
     _HAVE_THREAD_NATIVE_ID = False
 try:
     _set_name = _thread.set_name
-    _HAVE_SET_NAME = True
 except AttributeError:
-    _HAVE_SET_NAME = False
+    _set_name = None
 ThreadError = _thread.error
 try:
     _CRLock = _thread.RLock
@@ -1032,7 +1031,7 @@ def _bootstrap_inner(self):
             self._set_ident()
             if _HAVE_THREAD_NATIVE_ID:
                 self._set_native_id()
-            if _HAVE_SET_NAME and self._name:
+            if _set_name is not None and self._name:
                 _set_name(self._name)
             self._started.set()
             with _active_limbo_lock:
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index 1768e5527f1aa4..77e905980d642a 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2364,7 +2364,7 @@ Internal only. Return a non-zero integer that uniquely identifies the main threa
 of the main interpreter.");
 
 
-#ifdef HAVE_PTHREAD_SETNAME_NP
+#ifdef HAVE_PTHREAD_GETNAME_NP
 /*[clinic input]
 _thread._get_name
 
@@ -2387,7 +2387,7 @@ _thread__get_name_impl(PyObject *module)
     name[size] = 0;
     return PyUnicode_DecodeFSDefault(name);
 }
-#endif  // HAVE_PTHREAD_SETNAME_NP
+#endif  // HAVE_PTHREAD_GETNAME_NP
 
 
 #ifdef HAVE_PTHREAD_SETNAME_NP
diff --git a/Modules/clinic/_threadmodule.c.h b/Modules/clinic/_threadmodule.c.h
index f638c29fdd28e2..52f4ef9c1008a9 100644
--- a/Modules/clinic/_threadmodule.c.h
+++ b/Modules/clinic/_threadmodule.c.h
@@ -8,7 +8,7 @@ preserve
 #endif
 #include "pycore_modsupport.h"    // _PyArg_UnpackKeywords()
 
-#if defined(HAVE_PTHREAD_SETNAME_NP)
+#if defined(HAVE_PTHREAD_GETNAME_NP)
 
 PyDoc_STRVAR(_thread__get_name__doc__,
 "_get_name($module, /)\n"
@@ -28,7 +28,7 @@ _thread__get_name(PyObject *module, PyObject *Py_UNUSED(ignored))
     return _thread__get_name_impl(module);
 }
 
-#endif /* defined(HAVE_PTHREAD_SETNAME_NP) */
+#endif /* defined(HAVE_PTHREAD_GETNAME_NP) */
 
 #if defined(HAVE_PTHREAD_SETNAME_NP)
 
@@ -99,4 +99,4 @@ _thread_set_name(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyOb
 #ifndef _THREAD_SET_NAME_METHODDEF
     #define _THREAD_SET_NAME_METHODDEF
 #endif /* !defined(_THREAD_SET_NAME_METHODDEF) */
-/*[clinic end generated code: output=6611486fd37f22bf input=a9049054013a1b77]*/
+/*[clinic end generated code: output=82f504f284712f68 input=a9049054013a1b77]*/

From 97ea6452f06e9728197dcaff0105d4c20ebe6a65 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Thu, 28 Nov 2024 15:52:26 +0100
Subject: [PATCH 07/30] Add test on non-ASCII name truncation

---
 Lib/test/test_threading.py | 33 +++++++++++++++++++++++++++------
 1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index a2525044db018b..6e6e465a4ac985 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2106,22 +2106,43 @@ def test__all__(self):
     def test_set_name(self):
         try:
             get_name = _thread._get_name
-            set_name = _thread.set_name
+            _thread.set_name
         except AttributeError:
             self.skipTest("need thread._get_name() and thread.set_name()")
 
-        work_name = None
         def work():
             nonlocal work_name
             work_name = get_name()
 
         # name not too long to fit into Linux 15 bytes limit
         name = "CustomName"
+        tests = [(name, name)]
 
-        thread = threading.Thread(target=work, name=name)
-        thread.start()
-        thread.join()
-        self.assertEqual(work_name, name)
+        if sys.platform == "linux":
+            # On Linux, set_name() truncates the name to 15 bytes.
+
+            # Test ASCII name
+            name = "x" * 100
+            tests.append((name, name[:15]))
+
+            # Test non-ASCII name
+            name = "x" * 14 + "é€"
+            try:
+                encoded = os.fsencode(name)
+            except UnicodeEncodeError:
+                # name cannot be encoded to the filesystem encoding
+                pass
+            else:
+                expected = os.fsdecode(encoded[:15])
+                tests.append((name, expected))
+
+        for name, expected in tests:
+            with self.subTest(name=name, expected=expected):
+                work_name = None
+                thread = threading.Thread(target=work, name=name)
+                thread.start()
+                thread.join()
+                self.assertEqual(work_name, expected)
 
 
 class InterruptMainTests(unittest.TestCase):

From 78a9ab90d5e27b2f5f716026c508dae4f3995cee Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Thu, 28 Nov 2024 15:55:42 +0100
Subject: [PATCH 08/30] Add test on non-ASCII name

---
 Lib/test/test_threading.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 6e6e465a4ac985..04fd217a07ba50 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2118,6 +2118,16 @@ def work():
         name = "CustomName"
         tests = [(name, name)]
 
+        # Test non-ASCII short name
+        name = "namé€"
+        try:
+            os.fsencode(name)
+        except UnicodeEncodeError:
+            # name cannot be encoded to the filesystem encoding
+            pass
+        else:
+            tests.append((name, name))
+
         if sys.platform == "linux":
             # On Linux, set_name() truncates the name to 15 bytes.
 

From dcf13f480fa71d8561240bd0a85754216b451a00 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Thu, 28 Nov 2024 15:58:21 +0100
Subject: [PATCH 09/30] Test long name on non-Linux platforms

---
 Lib/test/test_threading.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 04fd217a07ba50..b1722cb78866d6 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2145,6 +2145,10 @@ def work():
             else:
                 expected = os.fsdecode(encoded[:15])
                 tests.append((name, expected))
+        else:
+            # Test long name
+            name = "x" * 100
+            tests.append((name, name))
 
         for name, expected in tests:
             with self.subTest(name=name, expected=expected):

From 6ea7e5adedb27766148de3c8686774c192936e5c Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Thu, 28 Nov 2024 16:55:46 +0100
Subject: [PATCH 10/30] macOS is limited to 63 bytes

---
 Lib/test/test_threading.py | 16 ++++++++++++----
 Modules/_threadmodule.c    | 26 +++++++++++++++++---------
 2 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index b1722cb78866d6..bd7035b6fca121 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2129,21 +2129,29 @@ def work():
             tests.append((name, name))
 
         if sys.platform == "linux":
-            # On Linux, set_name() truncates the name to 15 bytes.
+            limit = 15
+        elif sys.platform == "darwin":
+            limit = 63
+        else:
+            limit = None
+
+        if limit is not None:
+            # On Linux and macOS, set_name() truncates the name to,
+            # respectively, 15 and 63 bytes.
 
             # Test ASCII name
             name = "x" * 100
-            tests.append((name, name[:15]))
+            tests.append((name, name[:limit]))
 
             # Test non-ASCII name
-            name = "x" * 14 + "é€"
+            name = "x" * (limit - 1) + "é€"
             try:
                 encoded = os.fsencode(name)
             except UnicodeEncodeError:
                 # name cannot be encoded to the filesystem encoding
                 pass
             else:
-                expected = os.fsdecode(encoded[:15])
+                expected = os.fsdecode(encoded[:limit])
                 tests.append((name, expected))
         else:
             # Test long name
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index 77e905980d642a..8cc532913a9e41 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2375,7 +2375,8 @@ static PyObject *
 _thread__get_name_impl(PyObject *module)
 /*[clinic end generated code: output=20026e7ee3da3dd7 input=35cec676833d04c8]*/
 {
-    char name[17];
+    // Linux and macOS are limited to respectively 16 and 64 bytes
+    char name[100];
     size_t size = Py_ARRAY_LENGTH(name) - 1;
     pthread_t thread = pthread_self();
     int rc = pthread_getname_np(thread, name, size);
@@ -2405,20 +2406,25 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
 {
     const char *name = PyBytes_AS_STRING(name_obj);
 #ifdef __APPLE__
-    int rc = pthread_setname_np(name);
-#else
+#  define NAME_LIMIT 63
+#elif defined(__linux__)
+#  define NAME_LIMIT 15
+#endif
 
-#if defined(__linux__)
-    // Truncate to 16 bytes including the NUL byte
-    char buffer[16];
+#ifdef NAME_LIMIT
+    // Truncate to NAME_LIMIT bytes + the NUL byte
+    char buffer[NAME_LIMIT + 1];
     size_t len = strlen(name);
-    if (len > 15) {
-        memcpy(buffer, name, 15);
-        buffer[15] = 0;
+    if (len > NAME_LIMIT) {
+        memcpy(buffer, name, NAME_LIMIT);
+        buffer[NAME_LIMIT] = 0;
         name = buffer;
     }
 #endif
 
+#ifdef __APPLE__
+    int rc = pthread_setname_np(name);
+#else
     pthread_t thread = pthread_self();
     int rc = pthread_setname_np(thread, name);
 #endif
@@ -2427,6 +2433,8 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
         return PyErr_SetFromErrno(PyExc_OSError);
     }
     Py_RETURN_NONE;
+
+#undef NAME_LIMIT
 }
 #endif  // HAVE_PTHREAD_SETNAME_NP
 

From 46721bb36aed95dded64c6d697916770a5623423 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Thu, 28 Nov 2024 17:08:48 +0100
Subject: [PATCH 11/30] Catch UnicodeEncodeError when seting the name

Refactor also tests.
---
 Lib/test/test_threading.py | 67 ++++++++++++++++++--------------------
 Lib/threading.py           |  7 +++-
 2 files changed, 37 insertions(+), 37 deletions(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index bd7035b6fca121..babda6b75e289e 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2114,57 +2114,52 @@ def work():
             nonlocal work_name
             work_name = get_name()
 
-        # name not too long to fit into Linux 15 bytes limit
-        name = "CustomName"
-        tests = [(name, name)]
-
-        # Test non-ASCII short name
-        name = "namé€"
-        try:
-            os.fsencode(name)
-        except UnicodeEncodeError:
-            # name cannot be encoded to the filesystem encoding
-            pass
-        else:
-            tests.append((name, name))
-
+        # On Linux and macOS, set_name() truncates the name to,
+        # respectively, 15 and 63 bytes.
         if sys.platform == "linux":
-            limit = 15
+            truncate = 15
         elif sys.platform == "darwin":
-            limit = 63
+            truncate = 63
         else:
-            limit = None
-
-        if limit is not None:
-            # On Linux and macOS, set_name() truncates the name to,
-            # respectively, 15 and 63 bytes.
+            truncate = None
+        limit = truncate or 100
 
-            # Test ASCII name
-            name = "x" * 100
-            tests.append((name, name[:limit]))
-
-            # Test non-ASCII name
-            name = "x" * (limit - 1) + "é€"
+        def create_test(name):
             try:
                 encoded = os.fsencode(name)
             except UnicodeEncodeError:
-                # name cannot be encoded to the filesystem encoding
-                pass
+                expected = None
             else:
-                expected = os.fsdecode(encoded[:limit])
-                tests.append((name, expected))
-        else:
-            # Test long name
-            name = "x" * 100
-            tests.append((name, name))
+                if truncate is not None:
+                    expected = os.fsdecode(encoded[:truncate])
+                else:
+                    expected = name
+            return (name, expected)
+
+        tests = [
+            # test short ASCII name
+            create_test("CustomName"),
+
+            # test short non-ASCII name
+            create_test("namé€"),
 
+            # Test long ASCII names (not truncated)
+            create_test("x" * limit),
+
+            # Test long ASCII names (truncated)
+            create_test("x" * (limit + 10)),
+
+            # Test long non-ASCII name (truncated)
+            create_test("x" * (limit - 1) + "é€"),
+        ]
         for name, expected in tests:
             with self.subTest(name=name, expected=expected):
                 work_name = None
                 thread = threading.Thread(target=work, name=name)
                 thread.start()
                 thread.join()
-                self.assertEqual(work_name, expected)
+                if expected is not None:
+                    self.assertEqual(work_name, expected)
 
 
 class InterruptMainTests(unittest.TestCase):
diff --git a/Lib/threading.py b/Lib/threading.py
index e8ae5b156a5db9..bb892bb5a8b39a 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -1032,7 +1032,12 @@ def _bootstrap_inner(self):
             if _HAVE_THREAD_NATIVE_ID:
                 self._set_native_id()
             if _set_name is not None and self._name:
-                _set_name(self._name)
+                try:
+                    _set_name(self._name)
+                except UnicodeEncodeError:
+                    # cannot set the name if the name cannot be encoded
+                    # to the filesystem encoding
+                    pass
             self._started.set()
             with _active_limbo_lock:
                 _active[self._ident] = self

From 69621160bf45aee2dbeaee90f3c9535fdc791fe9 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Thu, 28 Nov 2024 18:17:26 +0100
Subject: [PATCH 12/30] Add tests

---
 Lib/test/test_threading.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index babda6b75e289e..00b44359b8ff4a 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2152,6 +2152,11 @@ def create_test(name):
             # Test long non-ASCII name (truncated)
             create_test("x" * (limit - 1) + "é€"),
         ]
+        if os_helper.FS_NONASCII:
+            tests.append(create_test(f"nonascii:{os_helper.FS_NONASCII}"))
+        if os_helper.TESTFN_UNENCODABLE:
+            tests.append(create_test(os_helper.TESTFN_UNENCODABLE))
+
         for name, expected in tests:
             with self.subTest(name=name, expected=expected):
                 work_name = None

From 5d27da0650b9cd7d8547bf75a1c7be3d7f017b38 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Thu, 28 Nov 2024 18:18:35 +0100
Subject: [PATCH 13/30] Use "replace" error handler

---
 Lib/test/test_threading.py       | 16 ++++++----------
 Modules/_threadmodule.c          | 23 ++++++++++++++++++++---
 Modules/clinic/_threadmodule.c.h |  6 ++----
 3 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 00b44359b8ff4a..f69dc5499e6e0f 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2125,15 +2125,12 @@ def work():
         limit = truncate or 100
 
         def create_test(name):
-            try:
-                encoded = os.fsencode(name)
-            except UnicodeEncodeError:
-                expected = None
+            if truncate is not None:
+                encoding = sys.getfilesystemencoding()
+                encoded = name.encode(encoding, "replace")
+                expected = os.fsdecode(encoded[:truncate])
             else:
-                if truncate is not None:
-                    expected = os.fsdecode(encoded[:truncate])
-                else:
-                    expected = name
+                expected = name
             return (name, expected)
 
         tests = [
@@ -2163,8 +2160,7 @@ def create_test(name):
                 thread = threading.Thread(target=work, name=name)
                 thread.start()
                 thread.join()
-                if expected is not None:
-                    self.assertEqual(work_name, expected)
+                self.assertEqual(work_name, expected)
 
 
 class InterruptMainTests(unittest.TestCase):
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index 8cc532913a9e41..2e71a14f6a4e73 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2395,16 +2395,33 @@ _thread__get_name_impl(PyObject *module)
 /*[clinic input]
 _thread.set_name
 
-    name as name_obj: object(converter="PyUnicode_FSConverter")
+    name as name_obj: object
 
 Set the name of the current thread.
 [clinic start generated code]*/
 
 static PyObject *
 _thread_set_name_impl(PyObject *module, PyObject *name_obj)
-/*[clinic end generated code: output=402b0c68e0c0daed input=a0459bd64f771808]*/
+/*[clinic end generated code: output=402b0c68e0c0daed input=b55d3d4279e2e831]*/
 {
-    const char *name = PyBytes_AS_STRING(name_obj);
+    if (!PyUnicode_Check(name_obj)) {
+        PyErr_Format(PyExc_TypeError, "expected str, got %T", name_obj);
+        return NULL;
+    }
+
+    const PyConfig *config = _Py_GetConfig();
+    char *encoding = Py_EncodeLocale(config->filesystem_encoding, NULL);
+    if (encoding == NULL) {
+        return NULL;
+    }
+
+    PyObject *name_encoded = PyUnicode_AsEncodedString(name_obj, encoding, "replace");
+    PyMem_Free(encoding);
+    if (name_encoded == NULL) {
+        return NULL;
+    }
+
+    const char *name = PyBytes_AS_STRING(name_encoded);
 #ifdef __APPLE__
 #  define NAME_LIMIT 63
 #elif defined(__linux__)
diff --git a/Modules/clinic/_threadmodule.c.h b/Modules/clinic/_threadmodule.c.h
index 52f4ef9c1008a9..8b87a9b6f2a428 100644
--- a/Modules/clinic/_threadmodule.c.h
+++ b/Modules/clinic/_threadmodule.c.h
@@ -81,9 +81,7 @@ _thread_set_name(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyOb
     if (!args) {
         goto exit;
     }
-    if (!PyUnicode_FSConverter(args[0], &name_obj)) {
-        goto exit;
-    }
+    name_obj = args[0];
     return_value = _thread_set_name_impl(module, name_obj);
 
 exit:
@@ -99,4 +97,4 @@ _thread_set_name(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyOb
 #ifndef _THREAD_SET_NAME_METHODDEF
     #define _THREAD_SET_NAME_METHODDEF
 #endif /* !defined(_THREAD_SET_NAME_METHODDEF) */
-/*[clinic end generated code: output=82f504f284712f68 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=37809e7cbdb7f7ef input=a9049054013a1b77]*/

From b713910bccf6b95efda8a89ed13eb57a6fbb8305 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Fri, 29 Nov 2024 15:54:04 +0100
Subject: [PATCH 14/30] Address review

---
 Lib/threading.py        |  4 +---
 Modules/_threadmodule.c | 13 +++++++++++--
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/Lib/threading.py b/Lib/threading.py
index bb892bb5a8b39a..3abd22a2aa1b72 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -1034,9 +1034,7 @@ def _bootstrap_inner(self):
             if _set_name is not None and self._name:
                 try:
                     _set_name(self._name)
-                except UnicodeEncodeError:
-                    # cannot set the name if the name cannot be encoded
-                    # to the filesystem encoding
+                except OSError:
                     pass
             self._started.set()
             with _active_limbo_lock:
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index 2e71a14f6a4e73..72c3e198eb12b6 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2410,8 +2410,16 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
     }
 
     const PyConfig *config = _Py_GetConfig();
-    char *encoding = Py_EncodeLocale(config->filesystem_encoding, NULL);
-    if (encoding == NULL) {
+    char *encoding;
+    int res = _Py_EncodeUTF8Ex(config->filesystem_encoding, &encoding,
+                               NULL, NULL, 0, _Py_ERROR_STRICT);
+    if (res == -2) {
+        PyErr_Format(PyExc_RuntimeWarning,
+                     "cannot encode filesystem_encoding");
+        return NULL;
+    }
+    if (res < 0) {
+        PyErr_NoMemory();
         return NULL;
     }
 
@@ -2445,6 +2453,7 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
     pthread_t thread = pthread_self();
     int rc = pthread_setname_np(thread, name);
 #endif
+    Py_DECREF(name_encoded);
     if (rc) {
         errno = rc;
         return PyErr_SetFromErrno(PyExc_OSError);

From 5c20ea1a7f5526ee09a64de353b1e022b143cf8a Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Fri, 29 Nov 2024 16:55:48 +0100
Subject: [PATCH 15/30] Use  PyInterpreterState filesystem encoding

---
 Modules/_threadmodule.c | 22 ++++++----------------
 1 file changed, 6 insertions(+), 16 deletions(-)

diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index 72c3e198eb12b6..a01321a43cfb33 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2409,22 +2409,12 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
         return NULL;
     }
 
-    const PyConfig *config = _Py_GetConfig();
-    char *encoding;
-    int res = _Py_EncodeUTF8Ex(config->filesystem_encoding, &encoding,
-                               NULL, NULL, 0, _Py_ERROR_STRICT);
-    if (res == -2) {
-        PyErr_Format(PyExc_RuntimeWarning,
-                     "cannot encode filesystem_encoding");
-        return NULL;
-    }
-    if (res < 0) {
-        PyErr_NoMemory();
-        return NULL;
-    }
-
-    PyObject *name_encoded = PyUnicode_AsEncodedString(name_obj, encoding, "replace");
-    PyMem_Free(encoding);
+    // Encode the thread name to the filesystem encoding using the "replace"
+    // error handler
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    char *encoding = interp->unicode.fs_codec.encoding;
+    PyObject *name_encoded;
+    name_encoded = PyUnicode_AsEncodedString(name_obj, encoding, "replace");
     if (name_encoded == NULL) {
         return NULL;
     }

From 6088b37759f0ce6cc1414a092ee7c4814d182256 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Mon, 2 Dec 2024 15:53:40 +0100
Subject: [PATCH 16/30] FreeBSD truncates to 98 bytes silently

---
 Lib/test/test_threading.py | 2 ++
 Modules/_threadmodule.c    | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index f69dc5499e6e0f..e0bc9463e8b5ac 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2120,6 +2120,8 @@ def work():
             truncate = 15
         elif sys.platform == "darwin":
             truncate = 63
+        elif sys.platform.startswith("freebsd"):
+            truncate = 98
         else:
             truncate = None
         limit = truncate or 100
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index a01321a43cfb33..733510c0160be4 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2424,6 +2424,8 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
 #  define NAME_LIMIT 63
 #elif defined(__linux__)
 #  define NAME_LIMIT 15
+#elif defined(__FreeBSD__)
+#  define NAME_LIMIT 98
 #endif
 
 #ifdef NAME_LIMIT

From bde935f684a8040b1a587df7ad79de31b8aeafca Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Tue, 3 Dec 2024 09:19:17 +0100
Subject: [PATCH 17/30] Fix test_threading on iOS

iOS also truncates to 63 bytes, same as macOS.
---
 Lib/test/test_threading.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index e0bc9463e8b5ac..2b9cd3c04cabe5 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2118,7 +2118,7 @@ def work():
         # respectively, 15 and 63 bytes.
         if sys.platform == "linux":
             truncate = 15
-        elif sys.platform == "darwin":
+        elif sys.platform in ("darwin", "ios"):
             truncate = 63
         elif sys.platform.startswith("freebsd"):
             truncate = 98

From 0584ca3398c406b35ea4f295070397e220ddbbda Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Tue, 3 Dec 2024 14:11:02 +0100
Subject: [PATCH 18/30] Fix create_test(): always encode using "replace"

---
 Lib/test/test_threading.py | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 2b9cd3c04cabe5..0f4dbb63c58738 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2114,8 +2114,7 @@ def work():
             nonlocal work_name
             work_name = get_name()
 
-        # On Linux and macOS, set_name() truncates the name to,
-        # respectively, 15 and 63 bytes.
+        # set_name() limit in bytes
         if sys.platform == "linux":
             truncate = 15
         elif sys.platform in ("darwin", "ios"):
@@ -2127,12 +2126,12 @@ def work():
         limit = truncate or 100
 
         def create_test(name):
+            encoding = sys.getfilesystemencoding()
+            encoded = name.encode(encoding, "replace")
             if truncate is not None:
-                encoding = sys.getfilesystemencoding()
-                encoded = name.encode(encoding, "replace")
                 expected = os.fsdecode(encoded[:truncate])
             else:
-                expected = name
+                expected = os.fsdecode(encoded)
             return (name, expected)
 
         tests = [
@@ -2162,7 +2161,8 @@ def create_test(name):
                 thread = threading.Thread(target=work, name=name)
                 thread.start()
                 thread.join()
-                self.assertEqual(work_name, expected)
+                self.assertEqual(work_name, expected,
+                                 f"{len(work_name)=} and {len(expected)=}")
 
 
 class InterruptMainTests(unittest.TestCase):

From 7508b6cb2c83a47b38ac27b218a3fccba69bcc53 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Tue, 3 Dec 2024 14:22:13 +0100
Subject: [PATCH 19/30] Solaris truncates to 31 bytes

---
 Lib/test/test_threading.py | 2 ++
 Modules/_threadmodule.c    | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 0f4dbb63c58738..22325495f9c67e 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2121,6 +2121,8 @@ def work():
             truncate = 63
         elif sys.platform.startswith("freebsd"):
             truncate = 98
+        elif sys.platform.startswith("solaris"):
+            truncate = 31
         else:
             truncate = None
         limit = truncate or 100
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index e3962013d1c7e1..be8efe641bf6a9 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2426,6 +2426,8 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
 #  define NAME_LIMIT 15
 #elif defined(__FreeBSD__)
 #  define NAME_LIMIT 98
+#elif defined(__sun)
+#  define NAME_LIMIT 31
 #endif
 
 #ifdef NAME_LIMIT

From f4a9f401f7576f387aedcee856c254000b4a397d Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 4 Dec 2024 14:05:40 +0100
Subject: [PATCH 20/30] Solaris always uses UTF-8

---
 Lib/test/test_threading.py | 5 ++++-
 Modules/_threadmodule.c    | 5 +++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 22325495f9c67e..0aa95c79d0c657 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2128,7 +2128,10 @@ def work():
         limit = truncate or 100
 
         def create_test(name):
-            encoding = sys.getfilesystemencoding()
+            if sys.platform.startswith("solaris"):
+                encoding = "utf-8"
+            else:
+                encoding = sys.getfilesystemencoding()
             encoded = name.encode(encoding, "replace")
             if truncate is not None:
                 expected = os.fsdecode(encoded[:truncate])
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index be8efe641bf6a9..02f4254960bda2 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2409,10 +2409,15 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
         return NULL;
     }
 
+#ifdef __sun
+    // Solaris always uses UTF-8
+    char *encoding = "utf-8";
+#else
     // Encode the thread name to the filesystem encoding using the "replace"
     // error handler
     PyInterpreterState *interp = _PyInterpreterState_GET();
     char *encoding = interp->unicode.fs_codec.encoding;
+#endif
     PyObject *name_encoded;
     name_encoded = PyUnicode_AsEncodedString(name_obj, encoding, "replace");
     if (name_encoded == NULL) {

From ac6d7263489b665b9d5b1c8e7433bcf58213fcd0 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 4 Dec 2024 14:32:29 +0100
Subject: [PATCH 21/30] Add PYTHREAD_NAME_MAXLEN macro

Add also _thread._NAME_MAXLEN constant for test_threading.
---
 Lib/test/test_threading.py | 11 +----------
 Modules/_threadmodule.c    | 31 +++++++++++++------------------
 configure                  | 18 ++++++++++++++++++
 configure.ac               | 16 ++++++++++++++++
 pyconfig.h.in              |  3 +++
 5 files changed, 51 insertions(+), 28 deletions(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 0aa95c79d0c657..16fffc8341ac05 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2115,16 +2115,7 @@ def work():
             work_name = get_name()
 
         # set_name() limit in bytes
-        if sys.platform == "linux":
-            truncate = 15
-        elif sys.platform in ("darwin", "ios"):
-            truncate = 63
-        elif sys.platform.startswith("freebsd"):
-            truncate = 98
-        elif sys.platform.startswith("solaris"):
-            truncate = 31
-        else:
-            truncate = None
+        truncate = getattr(_thread, "_NAME_MAXLEN", None)
         limit = truncate or 100
 
         def create_test(name):
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index 02f4254960bda2..d184f81fb69e74 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2425,23 +2425,13 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
     }
 
     const char *name = PyBytes_AS_STRING(name_encoded);
-#ifdef __APPLE__
-#  define NAME_LIMIT 63
-#elif defined(__linux__)
-#  define NAME_LIMIT 15
-#elif defined(__FreeBSD__)
-#  define NAME_LIMIT 98
-#elif defined(__sun)
-#  define NAME_LIMIT 31
-#endif
-
-#ifdef NAME_LIMIT
-    // Truncate to NAME_LIMIT bytes + the NUL byte
-    char buffer[NAME_LIMIT + 1];
+#ifdef PYTHREAD_NAME_MAXLEN
+    // Truncate to PYTHREAD_NAME_MAXLEN bytes + the NUL byte
+    char buffer[PYTHREAD_NAME_MAXLEN + 1];
     size_t len = strlen(name);
-    if (len > NAME_LIMIT) {
-        memcpy(buffer, name, NAME_LIMIT);
-        buffer[NAME_LIMIT] = 0;
+    if (len > PYTHREAD_NAME_MAXLEN) {
+        memcpy(buffer, name, PYTHREAD_NAME_MAXLEN);
+        buffer[PYTHREAD_NAME_MAXLEN] = 0;
         name = buffer;
     }
 #endif
@@ -2458,8 +2448,6 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
         return PyErr_SetFromErrno(PyExc_OSError);
     }
     Py_RETURN_NONE;
-
-#undef NAME_LIMIT
 }
 #endif  // HAVE_PTHREAD_SETNAME_NP
 
@@ -2596,6 +2584,13 @@ thread_module_exec(PyObject *module)
 
     llist_init(&state->shutdown_handles);
 
+#ifdef PYTHREAD_NAME_MAXLEN
+    if (PyModule_AddIntConstant(module, "_NAME_MAXLEN",
+                                PYTHREAD_NAME_MAXLEN) < 0) {
+        return -1;
+    }
+#endif
+
     return 0;
 }
 
diff --git a/configure b/configure
index e24418f4478f9a..4cea70d9d988f6 100755
--- a/configure
+++ b/configure
@@ -821,6 +821,7 @@ MODULE_TIME_TRUE
 MODULE__IO_FALSE
 MODULE__IO_TRUE
 MODULE_BUILDTYPE
+PYTHREAD_NAME_MAXLEN
 TEST_MODULES
 OPENSSL_LDFLAGS
 OPENSSL_LIBS
@@ -29086,6 +29087,23 @@ fi
 CPPFLAGS=$save_CPPFLAGS
 
 
+# gh-59705: Maximum length in bytes of a thread name
+case "$ac_sys_system" in
+  Linux*) PYTHREAD_NAME_MAXLEN=15;;
+  SunOS*) PYTHREAD_NAME_MAXLEN=31;;
+  Darwin) PYTHREAD_NAME_MAXLEN=63;;
+  iOS) PYTHREAD_NAME_MAXLEN=63;;
+  FreeBSD*) PYTHREAD_NAME_MAXLEN=98;;
+  *) PYTHREAD_NAME_MAXLEN=;;
+esac
+if test -n $PYTHREAD_NAME_MAXLEN; then
+
+printf "%s\n" "#define PYTHREAD_NAME_MAXLEN $PYTHREAD_NAME_MAXLEN" >>confdefs.h
+
+fi
+
+
+
 # stdlib
 
 
diff --git a/configure.ac b/configure.ac
index 5550acde958fab..1dda6c9590f519 100644
--- a/configure.ac
+++ b/configure.ac
@@ -7499,6 +7499,22 @@ AS_VAR_IF([ac_cv_libatomic_needed], [yes],
 _RESTORE_VAR([CPPFLAGS])
 
 
+# gh-59705: Maximum length in bytes of a thread name
+case "$ac_sys_system" in
+  Linux*) PYTHREAD_NAME_MAXLEN=15;;
+  SunOS*) PYTHREAD_NAME_MAXLEN=31;;
+  Darwin) PYTHREAD_NAME_MAXLEN=63;;
+  iOS) PYTHREAD_NAME_MAXLEN=63;;
+  FreeBSD*) PYTHREAD_NAME_MAXLEN=98;;
+  *) PYTHREAD_NAME_MAXLEN=;;
+esac
+if test -n $PYTHREAD_NAME_MAXLEN; then
+    AC_DEFINE_UNQUOTED([PYTHREAD_NAME_MAXLEN], [$PYTHREAD_NAME_MAXLEN],
+                       [Maximum length in bytes of a thread name])
+fi
+AC_SUBST([PYTHREAD_NAME_MAXLEN])
+
+
 # stdlib
 AC_DEFUN([PY_STDLIB_MOD_SET_NA], [
   m4_foreach([mod], [$@], [
diff --git a/pyconfig.h.in b/pyconfig.h.in
index f9c1235c837c67..91d14669a90d62 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -1653,6 +1653,9 @@
 /* Define as the preferred size in bits of long digits */
 #undef PYLONG_BITS_IN_DIGIT
 
+/* Maximum length in bytes of a thread name */
+#undef PYTHREAD_NAME_MAXLEN
+
 /* enabled builtin hash modules */
 #undef PY_BUILTIN_HASHLIB_HASHES
 

From 08e5922f19355e3494f64ea0a5e656de88871a8e Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 4 Dec 2024 14:43:36 +0100
Subject: [PATCH 22/30] Fix configure.ac if PYTHREAD_NAME_MAXLEN is not set

---
 configure    | 2 +-
 configure.ac | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/configure b/configure
index 4cea70d9d988f6..4d8db7941d0eb0 100755
--- a/configure
+++ b/configure
@@ -29096,7 +29096,7 @@ case "$ac_sys_system" in
   FreeBSD*) PYTHREAD_NAME_MAXLEN=98;;
   *) PYTHREAD_NAME_MAXLEN=;;
 esac
-if test -n $PYTHREAD_NAME_MAXLEN; then
+if test -n "$PYTHREAD_NAME_MAXLEN"; then
 
 printf "%s\n" "#define PYTHREAD_NAME_MAXLEN $PYTHREAD_NAME_MAXLEN" >>confdefs.h
 
diff --git a/configure.ac b/configure.ac
index 1dda6c9590f519..b1462cd42db3b0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -7508,7 +7508,7 @@ case "$ac_sys_system" in
   FreeBSD*) PYTHREAD_NAME_MAXLEN=98;;
   *) PYTHREAD_NAME_MAXLEN=;;
 esac
-if test -n $PYTHREAD_NAME_MAXLEN; then
+if test -n "$PYTHREAD_NAME_MAXLEN"; then
     AC_DEFINE_UNQUOTED([PYTHREAD_NAME_MAXLEN], [$PYTHREAD_NAME_MAXLEN],
                        [Maximum length in bytes of a thread name])
 fi

From 681624e07b5f3f6e5d33a719c3a0b639253e5ce0 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Thu, 5 Dec 2024 16:30:29 +0100
Subject: [PATCH 23/30] Address Serhiy's review

---
 Modules/_threadmodule.c          | 30 +++++++++++++-----------------
 Modules/clinic/_threadmodule.c.h |  6 +++++-
 configure                        |  2 +-
 configure.ac                     |  2 +-
 4 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index d184f81fb69e74..8dc38bc59517d2 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2377,15 +2377,13 @@ _thread__get_name_impl(PyObject *module)
 {
     // Linux and macOS are limited to respectively 16 and 64 bytes
     char name[100];
-    size_t size = Py_ARRAY_LENGTH(name) - 1;
     pthread_t thread = pthread_self();
-    int rc = pthread_getname_np(thread, name, size);
+    int rc = pthread_getname_np(thread, name, Py_ARRAY_LENGTH(name));
     if (rc) {
         errno = rc;
         return PyErr_SetFromErrno(PyExc_OSError);
     }
 
-    name[size] = 0;
     return PyUnicode_DecodeFSDefault(name);
 }
 #endif  // HAVE_PTHREAD_GETNAME_NP
@@ -2395,28 +2393,23 @@ _thread__get_name_impl(PyObject *module)
 /*[clinic input]
 _thread.set_name
 
-    name as name_obj: object
+    name as name_obj: unicode
 
 Set the name of the current thread.
 [clinic start generated code]*/
 
 static PyObject *
 _thread_set_name_impl(PyObject *module, PyObject *name_obj)
-/*[clinic end generated code: output=402b0c68e0c0daed input=b55d3d4279e2e831]*/
+/*[clinic end generated code: output=402b0c68e0c0daed input=7e7acd98261be82f]*/
 {
-    if (!PyUnicode_Check(name_obj)) {
-        PyErr_Format(PyExc_TypeError, "expected str, got %T", name_obj);
-        return NULL;
-    }
-
 #ifdef __sun
     // Solaris always uses UTF-8
-    char *encoding = "utf-8";
+    const char *encoding = "utf-8";
 #else
     // Encode the thread name to the filesystem encoding using the "replace"
     // error handler
     PyInterpreterState *interp = _PyInterpreterState_GET();
-    char *encoding = interp->unicode.fs_codec.encoding;
+    const char *encoding = interp->unicode.fs_codec.encoding;
 #endif
     PyObject *name_encoded;
     name_encoded = PyUnicode_AsEncodedString(name_obj, encoding, "replace");
@@ -2426,13 +2419,16 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
 
     const char *name = PyBytes_AS_STRING(name_encoded);
 #ifdef PYTHREAD_NAME_MAXLEN
-    // Truncate to PYTHREAD_NAME_MAXLEN bytes + the NUL byte
-    char buffer[PYTHREAD_NAME_MAXLEN + 1];
+    // Truncate to PYTHREAD_NAME_MAXLEN bytes + the NUL byte if needed
     size_t len = strlen(name);
     if (len > PYTHREAD_NAME_MAXLEN) {
-        memcpy(buffer, name, PYTHREAD_NAME_MAXLEN);
-        buffer[PYTHREAD_NAME_MAXLEN] = 0;
-        name = buffer;
+        PyObject *truncated = PyBytes_FromStringAndSize(name, PYTHREAD_NAME_MAXLEN);
+        if (truncated == NULL) {
+            Py_DECREF(name_encoded);
+            return NULL;
+        }
+        Py_SETREF(name_encoded, truncated);
+        name = PyBytes_AS_STRING(name_encoded);
     }
 #endif
 
diff --git a/Modules/clinic/_threadmodule.c.h b/Modules/clinic/_threadmodule.c.h
index 8b87a9b6f2a428..8f0507d40285b3 100644
--- a/Modules/clinic/_threadmodule.c.h
+++ b/Modules/clinic/_threadmodule.c.h
@@ -81,6 +81,10 @@ _thread_set_name(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyOb
     if (!args) {
         goto exit;
     }
+    if (!PyUnicode_Check(args[0])) {
+        _PyArg_BadArgument("set_name", "argument 'name'", "str", args[0]);
+        goto exit;
+    }
     name_obj = args[0];
     return_value = _thread_set_name_impl(module, name_obj);
 
@@ -97,4 +101,4 @@ _thread_set_name(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyOb
 #ifndef _THREAD_SET_NAME_METHODDEF
     #define _THREAD_SET_NAME_METHODDEF
 #endif /* !defined(_THREAD_SET_NAME_METHODDEF) */
-/*[clinic end generated code: output=37809e7cbdb7f7ef input=a9049054013a1b77]*/
+/*[clinic end generated code: output=b5cb85aaccc45bf6 input=a9049054013a1b77]*/
diff --git a/configure b/configure
index 4d8db7941d0eb0..1f3787fa9a1a1f 100755
--- a/configure
+++ b/configure
@@ -29089,7 +29089,7 @@ CPPFLAGS=$save_CPPFLAGS
 
 # gh-59705: Maximum length in bytes of a thread name
 case "$ac_sys_system" in
-  Linux*) PYTHREAD_NAME_MAXLEN=15;;
+  Linux*) PYTHREAD_NAME_MAXLEN=15;;  # Linux and Android
   SunOS*) PYTHREAD_NAME_MAXLEN=31;;
   Darwin) PYTHREAD_NAME_MAXLEN=63;;
   iOS) PYTHREAD_NAME_MAXLEN=63;;
diff --git a/configure.ac b/configure.ac
index b1462cd42db3b0..a0f3fed8d11ef7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -7501,7 +7501,7 @@ _RESTORE_VAR([CPPFLAGS])
 
 # gh-59705: Maximum length in bytes of a thread name
 case "$ac_sys_system" in
-  Linux*) PYTHREAD_NAME_MAXLEN=15;;
+  Linux*) PYTHREAD_NAME_MAXLEN=15;;  # Linux and Android
   SunOS*) PYTHREAD_NAME_MAXLEN=31;;
   Darwin) PYTHREAD_NAME_MAXLEN=63;;
   iOS) PYTHREAD_NAME_MAXLEN=63;;

From f57339f3d6096e1b026f26a41c9fa76d02ba88b1 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Fri, 6 Dec 2024 10:25:44 +0100
Subject: [PATCH 24/30] Solaris always use UTF-8

---
 Modules/_threadmodule.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index 8dc38bc59517d2..c8f1a3112b3a9a 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2384,7 +2384,11 @@ _thread__get_name_impl(PyObject *module)
         return PyErr_SetFromErrno(PyExc_OSError);
     }
 
+#ifdef __sun
+    return PyUnicode_DecodeUTF8(name, strlen(name), "surrogateescape");
+#else
     return PyUnicode_DecodeFSDefault(name);
+#endif
 }
 #endif  // HAVE_PTHREAD_GETNAME_NP
 

From 3941123b2ede5872d0e18b54c91dd6df900891a4 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Fri, 6 Dec 2024 10:25:56 +0100
Subject: [PATCH 25/30] Simplify tests

---
 Lib/test/test_threading.py | 39 +++++++++++++++++++-------------------
 1 file changed, 19 insertions(+), 20 deletions(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 16fffc8341ac05..bfdb2544f38eba 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2118,40 +2118,39 @@ def work():
         truncate = getattr(_thread, "_NAME_MAXLEN", None)
         limit = truncate or 100
 
-        def create_test(name):
-            if sys.platform.startswith("solaris"):
-                encoding = "utf-8"
-            else:
-                encoding = sys.getfilesystemencoding()
-            encoded = name.encode(encoding, "replace")
-            if truncate is not None:
-                expected = os.fsdecode(encoded[:truncate])
-            else:
-                expected = os.fsdecode(encoded)
-            return (name, expected)
-
         tests = [
             # test short ASCII name
-            create_test("CustomName"),
+            "CustomName",
 
             # test short non-ASCII name
-            create_test("namé€"),
+            "namé€",
 
             # Test long ASCII names (not truncated)
-            create_test("x" * limit),
+            "x" * limit,
 
             # Test long ASCII names (truncated)
-            create_test("x" * (limit + 10)),
+            "x" * (limit + 10),
 
             # Test long non-ASCII name (truncated)
-            create_test("x" * (limit - 1) + "é€"),
+            "x" * (limit - 1) + "é€",
         ]
         if os_helper.FS_NONASCII:
-            tests.append(create_test(f"nonascii:{os_helper.FS_NONASCII}"))
+            tests.append(f"nonascii:{os_helper.FS_NONASCII}")
         if os_helper.TESTFN_UNENCODABLE:
-            tests.append(create_test(os_helper.TESTFN_UNENCODABLE))
+            tests.append(os_helper.TESTFN_UNENCODABLE)
+
+        if sys.platform.startswith("solaris"):
+            encoding = "utf-8"
+        else:
+            encoding = sys.getfilesystemencoding()
+
+        for name in tests:
+            encoded = name.encode(encoding, "replace")
+            if truncate is not None:
+                expected = os.fsdecode(encoded[:truncate])
+            else:
+                expected = os.fsdecode(encoded)
 
-        for name, expected in tests:
             with self.subTest(name=name, expected=expected):
                 work_name = None
                 thread = threading.Thread(target=work, name=name)

From 2e270435262491e458cbdcdaa3c23bce53f15b16 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Fri, 6 Dec 2024 10:29:09 +0100
Subject: [PATCH 26/30] Use @unittest.skipUnless

---
 Lib/test/test_threading.py | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index bfdb2544f38eba..cae1d5b8b7cf38 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2103,17 +2103,9 @@ def test__all__(self):
         support.check__all__(self, threading, ('threading', '_thread'),
                              extra=extra, not_exported=not_exported)
 
+    @unittest.skipUnless(hasattr(_thread, 'set_name'), "missing _thread.set_name")
+    @unittest.skipUnless(hasattr(_thread, '_get_name'), "missing _thread._get_name")
     def test_set_name(self):
-        try:
-            get_name = _thread._get_name
-            _thread.set_name
-        except AttributeError:
-            self.skipTest("need thread._get_name() and thread.set_name()")
-
-        def work():
-            nonlocal work_name
-            work_name = get_name()
-
         # set_name() limit in bytes
         truncate = getattr(_thread, "_NAME_MAXLEN", None)
         limit = truncate or 100
@@ -2144,6 +2136,10 @@ def work():
         else:
             encoding = sys.getfilesystemencoding()
 
+        def work():
+            nonlocal work_name
+            work_name = _thread._get_name()
+
         for name in tests:
             encoded = name.encode(encoding, "replace")
             if truncate is not None:

From 6ab29446495a6d558cf7c1bbbe4ac92208030a4d Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Fri, 6 Dec 2024 12:38:20 +0100
Subject: [PATCH 27/30] Solaris uses UTF-8

---
 Lib/test/test_threading.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index cae1d5b8b7cf38..8994d1afd81a8a 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2143,7 +2143,9 @@ def work():
         for name in tests:
             encoded = name.encode(encoding, "replace")
             if truncate is not None:
-                expected = os.fsdecode(encoded[:truncate])
+                encoded = encoded[:truncate]
+            if sys.platform.startswith("solaris"):
+                expected = encoded.decode("utf-8")
             else:
                 expected = os.fsdecode(encoded)
 

From b370c49cb9a424150f1136f80a5d8bdd2642e4d6 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Fri, 6 Dec 2024 14:22:44 +0100
Subject: [PATCH 28/30] Update Lib/test/test_threading.py

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
---
 Lib/test/test_threading.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 8994d1afd81a8a..e951fcd23b91b7 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2145,7 +2145,7 @@ def work():
             if truncate is not None:
                 encoded = encoded[:truncate]
             if sys.platform.startswith("solaris"):
-                expected = encoded.decode("utf-8")
+                expected = encoded.decode("utf-8", "surrogateescape")
             else:
                 expected = os.fsdecode(encoded)
 

From beeae59ac36995d2d85e74244261527982279862 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Fri, 6 Dec 2024 16:52:57 +0100
Subject: [PATCH 29/30] add test on embedded null character

---
 Lib/test/test_threading.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index e951fcd23b91b7..7d16b0a1a87f1a 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -2117,6 +2117,10 @@ def test_set_name(self):
             # test short non-ASCII name
             "namé€",
 
+            # embedded null character: name is truncated
+            # at the first null character
+            "embed\0null",
+
             # Test long ASCII names (not truncated)
             "x" * limit,
 
@@ -2142,6 +2146,8 @@ def work():
 
         for name in tests:
             encoded = name.encode(encoding, "replace")
+            if b'\0' in encoded:
+                encoded = encoded.split(b'\0', 1)[0]
             if truncate is not None:
                 encoded = encoded[:truncate]
             if sys.platform.startswith("solaris"):

From ae956a0149b3867e04e55a90508af816aa635014 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Fri, 6 Dec 2024 16:53:07 +0100
Subject: [PATCH 30/30] Optimize code truncating the name

---
 Modules/_threadmodule.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index c8f1a3112b3a9a..35c032fbeaa94f 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2421,21 +2421,22 @@ _thread_set_name_impl(PyObject *module, PyObject *name_obj)
         return NULL;
     }
 
-    const char *name = PyBytes_AS_STRING(name_encoded);
 #ifdef PYTHREAD_NAME_MAXLEN
     // Truncate to PYTHREAD_NAME_MAXLEN bytes + the NUL byte if needed
-    size_t len = strlen(name);
+    size_t len = PyBytes_GET_SIZE(name_encoded);
     if (len > PYTHREAD_NAME_MAXLEN) {
-        PyObject *truncated = PyBytes_FromStringAndSize(name, PYTHREAD_NAME_MAXLEN);
+        PyObject *truncated;
+        truncated = PyBytes_FromStringAndSize(PyBytes_AS_STRING(name_encoded),
+                                              PYTHREAD_NAME_MAXLEN);
         if (truncated == NULL) {
             Py_DECREF(name_encoded);
             return NULL;
         }
         Py_SETREF(name_encoded, truncated);
-        name = PyBytes_AS_STRING(name_encoded);
     }
 #endif
 
+    const char *name = PyBytes_AS_STRING(name_encoded);
 #ifdef __APPLE__
     int rc = pthread_setname_np(name);
 #else