[Python-checkins] bpo-1635741: Convert _imp to multi-phase init (GH-23378)
vstinner
webhook-mailer at python.org
Wed Nov 18 17:18:39 EST 2020
https://github.com/python/cpython/commit/622307142130d36a30644233441333247838af38
commit: 622307142130d36a30644233441333247838af38
branch: master
author: Victor Stinner <vstinner at python.org>
committer: vstinner <vstinner at python.org>
date: 2020-11-18T23:18:29+01:00
summary:
bpo-1635741: Convert _imp to multi-phase init (GH-23378)
Convert the _imp extension module to the multi-phase initialization
API (PEP 489).
* Add _PyImport_BootstrapImp() which fix a bootstrap issue: import
the _imp module before importlib is initialized.
* Add create_builtin() sub-function, used by _imp_create_builtin().
* Initialize PyInterpreterState.import_func earlier, in
pycore_init_builtins().
* Remove references to _PyImport_Cleanup(). This function has been
renamed to finalize_modules() and moved to pylifecycle.c.
files:
M Include/internal/pycore_import.h
M Modules/posixmodule.c
M Python/import.c
M Python/pylifecycle.c
diff --git a/Include/internal/pycore_import.h b/Include/internal/pycore_import.h
index 35a67abebac6f..fd9fa5ab23faa 100644
--- a/Include/internal/pycore_import.h
+++ b/Include/internal/pycore_import.h
@@ -13,7 +13,7 @@ PyAPI_FUNC(PyObject *) _PyImport_FindBuiltin(
#ifdef HAVE_FORK
extern PyStatus _PyImport_ReInitLock(void);
#endif
-extern void _PyImport_Cleanup(PyThreadState *tstate);
+extern PyObject* _PyImport_BootstrapImp(PyThreadState *tstate);
#ifdef __cplusplus
}
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 703309f58687d..efa96531d49c1 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -14501,7 +14501,7 @@ os__remove_dll_directory_impl(PyObject *module, PyObject *cookie)
os.waitstatus_to_exitcode() is implemented in C and not in Python, so
subprocess can safely call it during late Python finalization without
- risking that used os attributes were set to None by _PyImport_Cleanup(). */
+ risking that used os attributes were set to None by finalize_modules(). */
#if defined(WIFEXITED) || defined(MS_WINDOWS)
/*[clinic input]
os.waitstatus_to_exitcode
diff --git a/Python/import.c b/Python/import.c
index 51630c3486af6..1522abc705ffb 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -4,6 +4,7 @@
#include "Python-ast.h"
#undef Yield /* undefine macro conflicting with <winbase.h> */
+#include "pycore_import.h" // _PyImport_BootstrapImp()
#include "pycore_initconfig.h"
#include "pycore_pyerrors.h"
#include "pycore_pyhash.h"
@@ -978,84 +979,80 @@ PyImport_GetImporter(PyObject *path)
return importer;
}
-/*[clinic input]
-_imp.create_builtin
-
- spec: object
- /
-
-Create an extension module.
-[clinic start generated code]*/
-
-static PyObject *
-_imp_create_builtin(PyObject *module, PyObject *spec)
-/*[clinic end generated code: output=ace7ff22271e6f39 input=37f966f890384e47]*/
+static PyObject*
+create_builtin(PyThreadState *tstate, PyObject *name, PyObject *spec)
{
- PyThreadState *tstate = _PyThreadState_GET();
- struct _inittab *p;
- PyObject *name;
- const char *namestr;
- PyObject *mod;
-
- name = PyObject_GetAttrString(spec, "name");
- if (name == NULL) {
- return NULL;
- }
-
- mod = _PyImport_FindExtensionObject(name, name);
+ PyObject *mod = _PyImport_FindExtensionObject(name, name);
if (mod || _PyErr_Occurred(tstate)) {
- Py_DECREF(name);
Py_XINCREF(mod);
return mod;
}
- namestr = PyUnicode_AsUTF8(name);
- if (namestr == NULL) {
- Py_DECREF(name);
- return NULL;
- }
-
PyObject *modules = tstate->interp->modules;
- for (p = PyImport_Inittab; p->name != NULL; p++) {
- PyModuleDef *def;
+ for (struct _inittab *p = PyImport_Inittab; p->name != NULL; p++) {
if (_PyUnicode_EqualToASCIIString(name, p->name)) {
if (p->initfunc == NULL) {
/* Cannot re-init internal module ("sys" or "builtins") */
- mod = PyImport_AddModule(namestr);
- Py_DECREF(name);
- return mod;
+ return PyImport_AddModuleObject(name);
}
+
mod = (*p->initfunc)();
if (mod == NULL) {
- Py_DECREF(name);
return NULL;
}
+
if (PyObject_TypeCheck(mod, &PyModuleDef_Type)) {
- Py_DECREF(name);
return PyModule_FromDefAndSpec((PyModuleDef*)mod, spec);
- } else {
+ }
+ else {
/* Remember pointer to module init function. */
- def = PyModule_GetDef(mod);
+ PyModuleDef *def = PyModule_GetDef(mod);
if (def == NULL) {
- Py_DECREF(name);
return NULL;
}
+
def->m_base.m_init = p->initfunc;
if (_PyImport_FixupExtensionObject(mod, name, name,
modules) < 0) {
- Py_DECREF(name);
return NULL;
}
- Py_DECREF(name);
return mod;
}
}
}
- Py_DECREF(name);
+
+ // not found
Py_RETURN_NONE;
}
+
+/*[clinic input]
+_imp.create_builtin
+
+ spec: object
+ /
+
+Create an extension module.
+[clinic start generated code]*/
+
+static PyObject *
+_imp_create_builtin(PyObject *module, PyObject *spec)
+/*[clinic end generated code: output=ace7ff22271e6f39 input=37f966f890384e47]*/
+{
+ PyThreadState *tstate = _PyThreadState_GET();
+
+ PyObject *name = PyObject_GetAttrString(spec, "name");
+ if (name == NULL) {
+ return NULL;
+ }
+
+ PyObject *mod = create_builtin(tstate, name, spec);
+ Py_DECREF(name);
+ return mod;
+}
+
+
/* Frozen modules */
static const struct _frozen *
@@ -2127,46 +2124,88 @@ static PyMethodDef imp_methods[] = {
};
-static struct PyModuleDef impmodule = {
+static int
+imp_module_exec(PyObject *module)
+{
+ const wchar_t *mode = _Py_GetConfig()->check_hash_pycs_mode;
+ PyObject *pyc_mode = PyUnicode_FromWideChar(mode, -1);
+ if (pyc_mode == NULL) {
+ return -1;
+ }
+ if (PyModule_AddObjectRef(module, "check_hash_based_pycs", pyc_mode) < 0) {
+ Py_DECREF(pyc_mode);
+ return -1;
+ }
+ Py_DECREF(pyc_mode);
+
+ return 0;
+}
+
+
+static PyModuleDef_Slot imp_slots[] = {
+ {Py_mod_exec, imp_module_exec},
+ {0, NULL}
+};
+
+static struct PyModuleDef imp_module = {
PyModuleDef_HEAD_INIT,
- "_imp",
- doc_imp,
- 0,
- imp_methods,
- NULL,
- NULL,
- NULL,
- NULL
+ .m_name = "_imp",
+ .m_doc = doc_imp,
+ .m_size = 0,
+ .m_methods = imp_methods,
+ .m_slots = imp_slots,
};
PyMODINIT_FUNC
PyInit__imp(void)
{
- PyObject *m, *d;
+ return PyModuleDef_Init(&imp_module);
+}
- m = PyModule_Create(&impmodule);
- if (m == NULL) {
- goto failure;
+
+// Import the _imp extension by calling manually _imp.create_builtin() and
+// _imp.exec_builtin() since importlib is not initialized yet. Initializing
+// importlib requires the _imp module: this function fix the bootstrap issue.
+PyObject*
+_PyImport_BootstrapImp(PyThreadState *tstate)
+{
+ PyObject *name = PyUnicode_FromString("_imp");
+ if (name == NULL) {
+ return NULL;
}
- d = PyModule_GetDict(m);
- if (d == NULL) {
- goto failure;
+
+ // Mock a ModuleSpec object just good enough for PyModule_FromDefAndSpec():
+ // an object with just a name attribute.
+ //
+ // _imp.__spec__ is overriden by importlib._bootstrap._instal() anyway.
+ PyObject *attrs = Py_BuildValue("{sO}", "name", name);
+ if (attrs == NULL) {
+ goto error;
+ }
+ PyObject *spec = _PyNamespace_New(attrs);
+ Py_DECREF(attrs);
+ if (spec == NULL) {
+ goto error;
}
- const wchar_t *mode = _Py_GetConfig()->check_hash_pycs_mode;
- PyObject *pyc_mode = PyUnicode_FromWideChar(mode, -1);
- if (pyc_mode == NULL) {
- goto failure;
+ // Create the _imp module from its definition.
+ PyObject *mod = create_builtin(tstate, name, spec);
+ Py_CLEAR(name);
+ Py_DECREF(spec);
+ if (mod == NULL) {
+ goto error;
}
- if (PyDict_SetItemString(d, "check_hash_based_pycs", pyc_mode) < 0) {
- Py_DECREF(pyc_mode);
- goto failure;
+ assert(mod != Py_None); // not found
+
+ // Execute the _imp module: call imp_module_exec().
+ if (exec_builtin_or_dynamic(mod) < 0) {
+ Py_DECREF(mod);
+ goto error;
}
- Py_DECREF(pyc_mode);
+ return mod;
- return m;
- failure:
- Py_XDECREF(m);
+error:
+ Py_XDECREF(name);
return NULL;
}
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 9771951d2d84c..428c887ef41c5 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -8,6 +8,7 @@
#include "pycore_ceval.h" // _PyEval_FiniGIL()
#include "pycore_context.h" // _PyContext_Init()
#include "pycore_fileutils.h" // _Py_ResetForceASCII()
+#include "pycore_import.h" // _PyImport_BootstrapImp()
#include "pycore_initconfig.h" // _PyStatus_OK()
#include "pycore_object.h" // _PyDebug_PrintTotalRefs()
#include "pycore_pathconfig.h" // _PyConfig_WritePathConfig()
@@ -155,18 +156,11 @@ init_importlib(PyThreadState *tstate, PyObject *sysmod)
}
interp->importlib = Py_NewRef(importlib);
- PyObject *import_func = _PyDict_GetItemStringWithError(interp->builtins,
- "__import__");
- if (import_func == NULL) {
- return -1;
- }
- interp->import_func = Py_NewRef(import_func);
-
// Import the _imp module
if (verbose) {
PySys_FormatStderr("import _imp # builtin\n");
}
- PyObject *imp_mod = PyInit__imp();
+ PyObject *imp_mod = _PyImport_BootstrapImp(tstate);
if (imp_mod == NULL) {
return -1;
}
@@ -741,6 +735,14 @@ pycore_init_builtins(PyThreadState *tstate)
}
Py_DECREF(bimod);
+ // Get the __import__ function
+ PyObject *import_func = _PyDict_GetItemStringWithError(interp->builtins,
+ "__import__");
+ if (import_func == NULL) {
+ goto error;
+ }
+ interp->import_func = Py_NewRef(import_func);
+
assert(!_PyErr_Occurred(tstate));
return _PyStatus_OK();
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