Do not modify PyConfig. Add sys_path_0 to _PyRuntimeState instead.

python · ericsnowcurrently · Nov 27, 2023 · Oct 2, 2023 · Oct 11, 2023 · Oct 11, 2023
commit d47338039acd800d71b8e524d3ecef17bf5ca081
diff --git a/Include/cpython/initconfig.h b/Include/cpython/initconfig.h
@@ -205,9 +205,6 @@ typedef struct PyConfig {
     wchar_t *run_module;
     wchar_t *run_filename;
 
-    /* --- Set by Py_Main() -------------------------- */
-    wchar_t *sys_path_0;
-
     /* --- Private fields ---------------------------- */
 
     // Install importlib? If equals to 0, importlib is not initialized at all.

diff --git a/Include/internal/pycore_runtime.h b/Include/internal/pycore_runtime.h
@@ -105,6 +105,11 @@ typedef struct pyruntimestate {
 
     unsi
8000
gned long main_thread;
 
+    /* The value to use for sys.path[0] in new subinterpreters.
+       Normally this would be part of the PyConfig struct.  However,
+       we cannot add it there in 3.12 since that's an ABI change. */
+    wchar_t *sys_path_0;
+
     /* ---------- IMPORTANT ---------------------------
      The fields above this line are declared as early as
      possible to facilitate out-of-process observability

diff --git a/Lib/test/test_embed.py b/Lib/test/test_embed.py
@@ -500,7 +500,6 @@ class InitConfigTests(EmbeddingTestsMixin, unittest.TestCase):
         'run_command': None,
         'run_module': None,
         'run_filename': None,
-        'sys_path_0': None,
 
         '_install_importlib': 1,
         'check_hash_pycs_mode': 'default',
@@ -1120,7 +1119,6 @@ def test_init_run_main(self):
             'program_name': './python3',
             'run_command': code + '\n',
             'parse_argv': 2,
-            'sys_path_0': '',
         }
         self.check_all_configs("test_init_run_main", config, api=API_PYTHON)
 
@@ -1136,7 +1134,6 @@ def test_init_main(self):
             'run_command': code + '\n',
             'parse_argv': 2,
             '_init_main': 0,
-            'sys_path_0': '',
         }
         self.check_all_configs("test_init_main", config,
                                api=API_PYTHON,

diff --git a/Modules/main.c b/Modules/main.c
@@ -559,10 +559,10 @@ pymain_run_python(int *exitcode)
         goto error;
     }
 
-    // XXX Calculate config->sys_path_0 in getpath.py.
+    // XXX Calculate runtime->sys_path_0 in getpath.py.
     // The tricky part is that we can't check the path importers yet
     // at that point.
-    assert(config->sys_path_0 == NULL);
+    assert(interp->runtime->sys_path_0 == NULL);
 
     if (config->run_filename != NULL) {
         /* If filename is a package (ex: directory or ZIP file) which contains
@@ -592,17 +592,20 @@ pymain_run_python(int *exitcode)
             Py_CLEAR(path0);
         }
     }
-    // XXX Apply config->sys_path_0 in init_interp_main().  We have
+    // XXX Apply runtime->sys_path_0 in init_interp_main().  We have
     // to be sure to get readline/rlcompleter imported at the correct time.
     if (path0 != NULL) {
         wchar_t *wstr = PyUnicode_AsWideCharString(path0, NULL);
         if (wstr == NULL) {
             Py_DECREF(path0);
             goto error;
         }
-        config->sys_path_0 = _PyMem_RawWcsdup(wstr);
+        PyMemAllocatorEx old_alloc;
+        _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+        interp->runtime->sys_path_0 = _PyMem_RawWcsdup(wstr);
+        PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
         PyMem_Free(wstr);
-        if (config->sys_path_0 == NULL) {
+        if (interp->runtime->sys_path_0 == NULL) {
             Py_DECREF(path0);
             goto error;
         }

diff --git a/Python/initconfig.c b/Python/initconfig.c
@@ -739,7 +739,6 @@ PyConfig_Clear(PyConfig *config)
     CLEAR(config->exec_prefix);
     CLEAR(config->base_exec_prefix);
     CLEAR(config->platlibdir);
-    CLEAR(config->sys_path_0);
 
     CLEAR(config->filesystem_encoding);
     CLEAR(config->filesystem_errors);
@@ -994,7 +993,6 @@ _PyConfig_Copy(PyConfig *config, const PyConfig *config2)
     COPY_WSTR_ATTR(exec_prefix);
     COPY_WSTR_ATTR(base_exec_prefix);
     COPY_WSTR_ATTR(platlibdir);
-    COPY_WSTR_ATTR(sys_path_0);
 
     COPY_ATTR(site_import);
     COPY_ATTR(bytes_warning);
@@ -1104,7 +1102,6 @@ _PyConfig_AsDict(const PyConfig *config)
     SET_ITEM_WSTR(exec_prefix);
     SET_ITEM_WSTR(base_exec_prefix);
     SET_ITEM_WSTR(platlibdir);
-    SET_ITEM_WSTR(sys_path_0);
     SET_ITEM_INT(site_import);
     SET_ITEM_INT(bytes_warning);
     SET_ITEM_INT(warn_default_encoding);
@@ -1406,7 +1403,6 @@ _PyConfig_FromDict(PyConfig *config, PyObject *dict)
     GET_WSTR_OPT(pythonpath_env);
     GET_WSTR_OPT(home);
     GET_WSTR(platlibdir);
-    GET_WSTR(sys_path_0);
 
     // Path configuration output
     GET_UINT(module_search_paths_set);
@@ -3169,7 +3165,6 @@ _Py_DumpPathConfig(PyThreadState *tstate)
     PySys_WriteStderr("  import site = %i\n", config->site_import);
     PySys_WriteStderr("  is in build tree = %i\n", config->_is_python_build);
     DUMP_CONFIG("stdlib dir", stdlib_dir);
-    DUMP_CONFIG("sys.path[0]", sys_path_0);
 #undef DUMP_CONFIG
 
 #define DUMP_SYS(NAME) \

diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
@@ -1202,8 +1202,9 @@ init_interp_main(PyThreadState *tstate)
 
     if (!is_main_interp) {
         // The main interpreter is handled in Py_Main(), for now.
-        if (config->sys_path_0 != NULL) {
-            PyObject *path0 = PyUnicode_FromWideChar(config->sys_path_0, -1);
+        wchar_t *sys_path_0 = interp->runtime->sys_path_0;
+        if (sys_path_0 != NULL) {
+            PyObject *path0 = PyUnicode_FromWideChar(sys_path_0, -1);
             if (path0 == NULL) {
                 return _PyStatus_ERR("can't initialize sys.path[0]");
             }

diff --git a/Python/pystate.c b/Python/pystate.c
@@ -524,6 +524,10 @@ _PyRuntimeState_Fini(_PyRuntimeState *runtime)
     }
 
 #undef FREE_LOCK
+    if (runtime->sys_path_0 != NULL) {
+        PyMem_RawFree(runtime->sys_path_0);
+        runtime->sys_path_0 = NULL;
+    }
     PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
 }