Skip to content

gh-151238: Check for _get_resized_exprs failure in _PyPegen_{joined,template}_str#151259

Open
StanFromIreland wants to merge 1 commit into
python:mainfrom
StanFromIreland:_get_resized_exprs
Open

gh-151238: Check for _get_resized_exprs failure in _PyPegen_{joined,template}_str#151259
StanFromIreland wants to merge 1 commit into
python:mainfrom
StanFromIreland:_get_resized_exprs

Conversation

@StanFromIreland

@StanFromIreland StanFromIreland commented Jun 10, 2026 •
edited by bedevere-app Bot
Loading

Copy link
Copy Markdown
Member

There are several cases where _get_resized_exprs can fail and return NULL (all of which are quite rare, however):

cpython/Parser/action_helpers.c

Lines 1341 to 1344 in e2bd50d

const char* quote_str = PyBytes_AsString(a->bytes);
if (quote_str == NULL) {
return NULL;
}

cpython/Parser/action_helpers.c

Lines 1362 to 1368 in e2bd50d

if (asdl_seq_LEN(values) != 2) {
PyErr_Format(PyExc_SystemError,
string_kind == TSTRING
? "unexpected TemplateStr node without debug data in t-string at line %d"
: "unexpected JoinedStr node without debug data in f-string at line %d",
item->lineno);
return NULL;

cpython/Parser/action_helpers.c

Lines 1347 to 1351 in e2bd50d

asdl_expr_seq *seq = _Py_asdl_expr_seq_new(total_items, p->arena);
if (seq == NULL) {
return NULL;
}

cpython/Parser/action_helpers.c

Lines 1401 to 1404 in e2bd50d

resized_exprs = _Py_asdl_expr_seq_new(index, p->arena);
if (resized_exprs == NULL) {
return NULL;
}

And the one triggered by the reproducer in the issue (which I test):

cpython/Parser/action_helpers.c

Lines 1383 to 1386 in e2bd50d

item = _PyPegen_decode_fstring_part(p, is_raw, item, b);
if (item == NULL) {
return NULL;
}

_PyPegen_decode_fstring_part returns NULL because it calls _PyPegen_decode_string which in turn calls warn_invalid_escape_sequence which triggers the failure as it tries to import modules to issue a warning, but gets a TypeError.

@StanFromIreland StanFromIreland changed the title Check for _get_resized_exprs failure in _PyPegen_{joined,template}_str gh-151238: Check for _get_resized_exprs failure in _PyPegen_{joined,template}_str Jun 10, 2026
@bedevere-app bedevere-app Bot mentioned this pull request Jun 10, 2026
Open
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

@pablogsal pablogsal Awaiting requested review from pablogsal pablogsal is a code owner

@lysnikolaou lysnikolaou Awaiting requested review from lysnikolaou lysnikolaou is a code owner

Assignees

No one assigned

Labels

awaiting core review

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

1 participant

@StanFromIreland