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gh-102660: Fix Refleaks in import.c #102744

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Merged
merged 6 commits into from
Mar 16, 2023
Merged

gh-102660: Fix Refleaks in import.c #102744

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0512932
match_mod_name() -> get_core_module_dict().
ericsnowcurrently Mar 15, 2023
16348eb
Stop using None as the m_copy sentinel.
ericsnowcurrently Mar 15, 2023
d91bd09
Fix a comment.
ericsnowcurrently Mar 15, 2023
d6046c3
Drop an outdated comment.
ericsnowcurrently Mar 15, 2023
a2e5ab8
Fix a typo.
ericsnowcurrently Mar 15, 2023
8da964f
Flip a conditional check.
ericsnowcurrently Mar 16, 2023
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3 changes: 0 additions & 3 deletions Python/bltinmodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3098,9 +3098,6 @@ _PyBuiltin_Init(PyInterpreterState *interp)
}
Py_DECREF(debug);

/* m_copy of Py_None means it is copied some other way. */
builtinsmodule.m_base.m_copy = Py_NewRef(Py_None);

return mod;
#undef ADD_TO_ALL
#undef SETBUILTIN
Expand Down
50 changes: 28 additions & 22 deletions Python/import.c
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Expand Up @@ -978,14 +978,29 @@ _PyImport_CheckSubinterpIncompatibleExtensionAllowed(const char *name)
return 0;
}

static inline int
match_mod_name(PyObject *actual, const char *expected)
static PyObject *
get_core_module_dict(PyInterpreterState *interp,
PyObject *name, PyObject *filename)
{
if (PyUnicode_CompareWithASCIIString(actual, expected) == 0) {
return 1;
/* Only builtin modules are core. */
if (filename == name) {
assert(!PyErr_Occurred());
if (PyUnicode_CompareWithASCIIString(name, "sys") == 0) {
return interp->sysdict_copy;
}
assert(!PyErr_Occurred());
if (PyUnicode_CompareWithASCIIString(name, "builtins") == 0) {
return interp->builtins_copy;
}
assert(!PyErr_Occurred());
}
assert(!PyErr_Occurred());
return 0;
return NULL;
}

static inline int
is_core_module(PyInterpreterState *interp, PyObject *name, PyObject *filename)
{
return get_core_module_dict(interp, name, filename) != NULL;
}

static int
Expand All @@ -1009,10 +1024,8 @@ fix_up_extension(PyObject *mod, PyObject *name, PyObject *filename)

// bpo-44050: Extensions and def->m_base.m_copy can be updated
// when the extension module doesn't support sub-interpreters.
// XXX Why special-case the main interpreter?
if (_Py_IsMainInterpreter(tstate->interp) || def->m_size == -1) {
/* m_copy of Py_None means it is copied some other way. */
if (def->m_size == -1 && def->m_base.m_copy != Py_None) {
if (def->m_size == -1) {
if (!is_core_module(tstate->interp, name, filename)) {
if (def->m_base.m_copy) {
/* Somebody already imported the module,
likely under a different name.
Expand All @@ -1028,7 +1041,10 @@ fix_up_extension(PyObject *mod, PyObject *name, PyObject *filename)
return -1;
}
}
}

// XXX Why special-case the main interpreter?
if (_Py_IsMainInterpreter(tstate->interp) || def->m_size == -1) {
if (_extensions_cache_set(filename, name, def) < 0) {
return -1;
}
Expand Down Expand Up @@ -1069,21 +1085,11 @@ import_find_extension(PyThreadState *tstate, PyObject *name,
PyObject *m_copy = def->m_base.m_copy;
/* Module does not support repeated initialization */
if (m_copy == NULL) {
return NULL;
}
else if (m_copy == Py_None) {
if (match_mod_name(name, "sys")) {
m_copy = tstate->interp->sysdict_copy;
}
else if (match_mod_name(name, "builtins")) {
m_copy = tstate->interp->builtins_copy;
}
else {
_PyErr_SetString(tstate, PyExc_ImportError, "missing m_copy");
m_copy = get_core_module_dict(tstate->interp, name, filename);
if (m_copy == NULL) {
return NULL;
}
}
/* m_copy of Py_None means it is copied some other way. */
mod = import_add_module(tstate, name);
if (mod == NULL) {
return NULL;
Expand Down
3 changes: 0 additions & 3 deletions Python/sysmodule.c
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Expand Up @@ -3425,9 +3425,6 @@ _PySys_Create(PyThreadState *tstate, PyObject **sysmod_p)
return _PyStatus_ERR("failed to create a module object");
}

/* m_copy of Py_None means it is copied some other way. */
sysmodule.m_base.m_copy = Py_NewRef(Py_None);

PyObject *sysdict = PyModule_GetDict(sysmod);
if (sysdict == NULL) {
goto error;
Expand Down