Merge 3.6

vstinner · vstinner · commit ed6de7345e7b · 2016-11-24T22:33:49.000+01:00
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -10,6 +10,10 @@ What's New in Python 3.7.0 alpha 1
 Core and Builtins
 -----------------
 
+- 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).
+
 - Issue #28774: Fix error position of the unicode error in ASCII and Latin1
   encoders when a string returned by the error handler contains multiple
   non-encodable characters (non-ASCII for the ASCII codec, characters out
diff --git 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);
diff --git a/Python/ceval.c b/Python/ceval.c
@@ -2049,6 +2049,7 @@ _PyEval_EvalFrameDefault(PyFrameObject *f, int throwflag)
             f->f_stacktop = stack_pointer;
             why = WHY_YIELD;
             /* and repeat... */
+            assert(f->f_lasti >= (int)sizeof(_Py_CODEUNIT));
             f->f_lasti -= sizeof(_Py_CODEUNIT);
             goto fast_yield;
         }

Original file line number	Diff line number	Diff line change
`@@ -2049,6 +2049,7 @@ _PyEval_EvalFrameDefault(PyFrameObject *f, int throwflag)`
`2049`	`2049`	`f->f_stacktop = stack_pointer;`
`2050`	`2050`	`why = WHY_YIELD;`
`2051`	`2051`	`/* and repeat... */`
	`2052`	`+ assert(f->f_lasti >= (int)sizeof(_Py_CODEUNIT));`
`2052`	`2053`	`f->f_lasti -= sizeof(_Py_CODEUNIT);`
`2053`	`2054`	`goto fast_yield;`
`2054`	`2055`	`}`