Add _PyImport_SwapPackageContext() and _PyImport_ResolveNameWithPacka…

…geContext().
python · ericsnowcurrently · Feb 15, 2023 · Feb 14, 2023 · Feb 14, 2023 · Feb 14, 2023
commit bc031c17f78245a482fc344daf1be79698ea7c5e
@@ -37,6 +37,8 @@ struct _import_runtime_state {
 };
 
 extern Py_ssize_t _PyImport_GetNextModuleIndex(void);
+extern const char * _PyImport_ResolveNameWithPackageContext(const char *name);
+extern const char * _PyImport_SwapPackageContext(const char *newcontext);
 
 
 #ifdef HAVE_FORK

@@ -208,24 +208,7 @@ _PyModule_CreateInitialized(PyModuleDef* module, int module_api_version)
             "module %s: PyModule_Create is incompatible with m_slots", name);
         return NULL;
     }
-    /* Make sure name is fully qualified.
-
-       This is a bit of a hack: when the shared library is loaded,
-       the module name is "package.module", but the module calls
-       PyModule_Create*() with just "module" for the name.  The shared
-       library loader squirrels away the true name of the module in
-       _Py_PackageContext, and PyModule_Create*() will substitute this
-       (if the name actually matches).
-    */
-#define _Py_PackageContext (_PyRuntime.imports.pkgcontext)
-    if (_Py_PackageContext != NULL) {
-        const char *p = strrchr(_Py_PackageContext, '.');
-        if (p != NULL && strcmp(module->m_name, p+1) == 0) {
-            name = _Py_PackageContext;
-            _Py_PackageContext = NULL;
-        }
-    }
-#undef _Py_PackageContext
+    name = _PyImport_ResolveNameWithPackageContext(name);
     if ((m = (PyModuleObject*)PyModule_New(name)) == NULL)
         return NULL;
 

@@ -56,6 +56,8 @@ static struct _inittab *inittab_copy = NULL;
 #define import_lock_thread _PyRuntime.imports.lock.thread
 #define import_lock_level _PyRuntime.imports.lock.level
 
+#define _Py_PackageContext (_PyRuntime.imports.pkgcontext)
+
 
 /*********************/
 /* runtime lifecycle */
@@ -719,6 +721,37 @@ Generally, when multiple interpreters are involved, some of the above
 gets even messier.
 */
 
+/* Make sure name is fully qualified.
+
+   This is a bit of a hack: when the shared library is loaded,
+   the module name is "package.module", but the module calls
+   PyModule_Create*() with just "module" for the name.  The shared
+   library loader squirrels away the true name of the module in
+   _Py_PackageContext, and PyModule_Create*() will substitute this
+   (if the name actually matches).
+*/
+const char *
+_PyImport_ResolveNameWithPackageContext(const char *name)
+{
+    if (_Py_PackageContext != NULL) {
+        const char *p = strrchr(_Py_PackageContext, '.');
+        if (p != NULL && strcmp(name, p+1) == 0) {
+            name = _Py_PackageContext;
+            _Py_PackageContext = NULL;
+        }
+    }
+    return name;
+}
+
+const char *
+_PyImport_SwapPackageContext(const char *newcontext)
+{
+    const char *oldcontext = _Py_PackageContext;
+    _Py_PackageContext = newcontext;
+    return oldcontext;
+}
+
+
 /* Magic for extension modules (built-in as well as dynamically
    loaded).  To prevent initializing an extension module more than
    once, we keep a static dictionary 'extensions' keyed by the tuple

@@ -99,7 +99,7 @@ _PyImport_LoadDynamicModuleWithSpec(PyObject *spec, FILE *fp)
 #endif
     PyObject *name_unicode = NULL, *name = NULL, *path = NULL, *m = NULL;
     const char *name_buf, *hook_prefix;
-    const char *oldcontext;
+    const char *oldcontext, *newcontext;
     dl_funcptr exportfunc;
     PyModuleDef *def;
     PyModInitFunction p0;
@@ -113,6 +113,10 @@ _PyImport_LoadDynamicModuleWithSpec(PyObject *spec, FILE *fp)
                         "spec.name must be a string");
         goto error;
     }
+    newcontext = PyUnicode_AsUTF8(name_unicode);
+    if (newcontext == NULL) {
+        goto error;
+    }
 
     name = get_encoded_name(name_unicode, &hook_prefix);
     if (name == NULL) {
@@ -160,16 +164,9 @@ _PyImport_LoadDynamicModuleWithSpec(PyObject *spec, FILE *fp)
     p0 = (PyModInitFunction)exportfunc;
 
     /* Package context is needed for single-phase init */
-#define _Py_PackageContext (_PyRuntime.imports.pkgcontext)
-    oldcontext = _Py_PackageContext;
-    _Py_PackageContext = PyUnicode_AsUTF8(name_unicode);
-    if (_Py_PackageContext == NULL) {
-        _Py_PackageContext = oldcontext;
-        goto error;
-    }
+    oldcontext = _PyImport_SwapPackageContext(newcontext);
     m = _PyImport_InitFunc_TrampolineCall(p0);
-    _Py_PackageContext = oldcontext;
-#undef _Py_PackageContext
+    _PyImport_SwapPackageContext(oldcontext);
 
     if (m == NULL) {
         if (!PyErr_Occurred()) {