Mirror
/
cpython
mirror of https://github.com/python/cpython
4
1
Fork 0
Code Issues Releases Wiki Activity

bpo-1875: Raise SyntaxError in invalid blocks that will be optimised away (GH-13332) 

Move the check for dead conditionals (if 0) to the peephole optimizer
and make sure that the code block is still compiled to report any
existing syntax errors within.
This commit is contained in:
Pablo Galindo 2019-05-17 11:37:08 +01:00 committed by GitHub
parent a8b46944d7
commit af8646c805
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 33 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
Lib/test/test_syntax.py
View File

@ -696,6 +696,20 @@ class SyntaxTestCase(unittest.TestCase):
def test_break_outside_loop(self):
self._check_error("break", "outside loop")
def test_yield_outside_function(self):
self._check_error("if 0: yield", "outside function")
self._check_error("class C:\n if 0: yield", "outside function")
def test_return_outside_function(self):
self._check_error("if 0: return", "outside function")
self._check_error("class C:\n if 0: return", "outside function")
def test_break_outside_loop(self):
self._check_error("if 0: break", "outside loop")
def test_continue_outside_loop(self):
self._check_error("if 0: continue", "not properly in loop")
def test_unexpected_indent(self):
self._check_error("foo()\n bar()\n", "unexpected indent",
subclass=IndentationError)

3
Misc/NEWS.d/next/Core and Builtins/2019-05-15-01-29-29.bpo-1875.9oxXFX.rst Normal file
View File

@ -0,0 +1,3 @@
A :exc:`SyntaxError` is now raised if a code blocks that will be optimized
away (e.g. if conditions that are always false) contains syntax errors.
Patch by Pablo Galindo.

9
Python/compile.c
View File

@ -2546,13 +2546,12 @@ compiler_if(struct compiler *c, stmt_ty s)
return 0;
constant = expr_constant(s->v.If.test);
/* constant = 0: "if 0"
/* constant = 0: "if 0" Leave the optimizations to
* the pephole optimizer to check for syntax errors
* in the block.
* constant = 1: "if 1", "if 2", ...
* constant = -1: rest */
if (constant == 0) {
if (s->v.If.orelse)
VISIT_SEQ(c, stmt, s->v.If.orelse);
} else if (constant == 1) {
if (constant == 1) {
VISIT_SEQ(c, stmt, s->v.If.body);
} else {
if (asdl_seq_LEN(s->v.If.orelse)) {

16
Python/peephole.c
View File

@ -302,11 +302,19 @@ PyCode_Optimize(PyObject *code, PyObject* consts, PyObject *names,
case LOAD_CONST:
cumlc = lastlc + 1;
if (nextop != POP_JUMP_IF_FALSE ||
!ISBASICBLOCK(blocks, op_start, i + 1) ||
!PyObject_IsTrue(PyList_GET_ITEM(consts, get_arg(codestr, i))))
!ISBASICBLOCK(blocks, op_start, i + 1)) {
break;
fill_nops(codestr, op_start, nexti + 1);
cumlc = 0;
}
PyObject* cnt = PyList_GET_ITEM(consts, get_arg(codestr, i));
int is_true = PyObject_IsTrue(cnt);
if (is_true == 1) {
fill_nops(codestr, op_start, nexti + 1);
cumlc = 0;
} else if (is_true == 0) {
h = get_arg(codestr, nexti) / sizeof(_Py_CODEUNIT);
tgt = find_op(codestr, codelen, h);
fill_nops(codestr, op_start, tgt);
}
break;
/* Try to fold tuples of constants.