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[3.12] gh-124785: Revert "gh-116510: Fix crash due to shared immortal interned strings (gh-124646)" (gh-124807)#124818

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[3.12] gh-124785: Revert "gh-116510: Fix crash due to shared immortal interned strings (gh-124646)" (gh-124807) #124818

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5 changes: 0 additions & 5 deletions Misc/NEWS.d/next/Core_and_Builtins/2024-09-25-12-37-58.gh-issue-116510.WeBAx1.rst
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48 changes: 6 additions & 42 deletions Objects/unicodeobject.c
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Original file line numberDiff line numberDiff line change
Expand Up@@ -286,37 +286,13 @@ hashtable_unicode_compare(const void *key1, const void *key2)
}
}

/* Return true if this interpreter should share the main interpreter's
intern_dict. That's important for interpreters which load basic
single-phase init extension modules (m_size == -1). There could be interned
immortal strings that are shared between interpreters, due to the
PyDict_Update(mdict, m_copy) call in import_find_extension().

It's not safe to deallocate those strings until all interpreters that
potentially use them are freed. By storing them in the main interpreter, we
ensure they get freed after all other interpreters are freed.
*/
static bool
has_shared_intern_dict(PyInterpreterState *interp)
{
PyInterpreterState *main_interp = _PyInterpreterState_Main();
return interp != main_interp && interp->feature_flags & Py_RTFLAGS_USE_MAIN_OBMALLOC;
}

static int
init_interned_dict(PyInterpreterState *interp)
{
assert(get_interned_dict(interp) == NULL);
PyObject *interned;
if (has_shared_intern_dict(interp)){
interned = get_interned_dict(_PyInterpreterState_Main());
Py_INCREF(interned);
}
else{
interned = PyDict_New();
if (interned == NULL){
return -1;
}
PyObject *interned = interned = PyDict_New();
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@rruuaanngrruuaanngOct 1, 2024

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Why do you want to do this? Rather than

PyObject*interned=PyDict_New();

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@naschemenaschemeOct 1, 2024

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It's just a straight reversion of my change so that matches the previous code. I agree with you though, looks odd to write it that way.

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@Yhg1sYhg1sOct 1, 2024

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It's a revert. Even worse, it's a backport of a revert. That's what the original code was. I imagine it was a mistake in the original PR (#102339) but that, too, may have been moved from somewhere else.

If you want to send a PR to fix it (in main) I'm sure Eric wouldn't mind reviewing :)

if (interned == NULL){
return -1;
}
_Py_INTERP_CACHED_OBJECT(interp, interned_strings) = interned;
return 0;
Expand All@@ -327,10 +303,7 @@ clear_interned_dict(PyInterpreterState *interp)
{
PyObject *interned = get_interned_dict(interp);
if (interned != NULL){
if (!has_shared_intern_dict(interp)){
// only clear if the dict belongs to this interpreter
PyDict_Clear(interned);
}
PyDict_Clear(interned);
Py_DECREF(interned);
_Py_INTERP_CACHED_OBJECT(interp, interned_strings) = NULL;
}
Expand DownExpand Up@@ -15163,13 +15136,6 @@ _PyUnicode_ClearInterned(PyInterpreterState *interp)
}
assert(PyDict_CheckExact(interned));

if (has_shared_intern_dict(interp)){
// the dict doesn't belong to this interpreter, skip the debug
// checks on it and just clear the pointer to it
clear_interned_dict(interp);
return;
}

#ifdef INTERNED_STATS
fprintf(stderr, "releasing %zd interned strings\n",
PyDict_GET_SIZE(interned));
Expand DownExpand Up@@ -15688,10 +15654,8 @@ _PyUnicode_Fini(PyInterpreterState *interp)
{
struct _Py_unicode_state *state = &interp->unicode;

if (!has_shared_intern_dict(interp)){
// _PyUnicode_ClearInterned() must be called before _PyUnicode_Fini()
assert(get_interned_dict(interp) == NULL);
}
// _PyUnicode_ClearInterned() must be called before _PyUnicode_Fini()
assert(get_interned_dict(interp) == NULL);

_PyUnicode_FiniEncodings(&state->fs_codec);

Expand Down