From f7d199ff329f0cb68f367c7aa169e058b2ab50f4 Mon Sep 17 00:00:00 2001 From: Victor Stinner Date: Thu, 24 Nov 2016 22:33:01 +0100 Subject: Fix _PyGen_yf() Issue #28782: Fix a bug in the implementation ``yield from`` when checking if the next instruction is YIELD_FROM. Regression introduced by WORDCODE (issue #26647). Reviewed by Serhiy Storchaka and Yury Selivanov. --- Objects/genobject.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'Objects/genobject.c') diff --git a/Objects/genobject.c b/Objects/genobject.c index 558f809b02..2680ab0e12 100644 --- a/Objects/genobject.c +++ b/Objects/genobject.c @@ -355,6 +355,14 @@ _PyGen_yf(PyGenObject *gen) PyObject *bytecode = f->f_code->co_code; unsigned char *code = (unsigned char *)PyBytes_AS_STRING(bytecode); + if (f->f_lasti < 0) { + /* Return immediately if the frame didn't start yet. YIELD_FROM + always come after LOAD_CONST: a code object should not start + with YIELD_FROM */ + assert(code[0] != YIELD_FROM); + return NULL; + } + if (code[f->f_lasti + sizeof(_Py_CODEUNIT)] != YIELD_FROM) return NULL; yf = f->f_stacktop[-1]; @@ -463,6 +471,7 @@ _gen_throw(PyGenObject *gen, int close_on_genexit, assert(ret == yf); Py_DECREF(ret); /* Termination repetition of YIELD_FROM */ + assert(gen->gi_frame->f_lasti >= 0); gen->gi_frame->f_lasti += sizeof(_Py_CODEUNIT); if (_PyGen_FetchStopIterationValue(&val) == 0) { ret = gen_send_ex(gen, val, 0, 0); -- cgit v1.2.1