From 85ed1712e428f93408f56fc684816f9a85b0ebc0 Mon Sep 17 00:00:00 2001 From: "Miss Islington (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Fri, 17 May 2019 03:59:48 -0700 Subject: [PATCH] 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. (cherry picked from commit af8646c8054d0f4180a2013383039b6a472f9698) Co-authored-by: Pablo Galindo --- Lib/test/test_syntax.py | 14 ++++++++++++++ .../2019-05-15-01-29-29.bpo-1875.9oxXFX.rst | 3 +++ Python/compile.c | 9 ++++----- Python/peephole.c | 16 ++++++++++++---- 4 files changed, 33 insertions(+), 9 deletions(-) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2019-05-15-01-29-29.bpo-1875.9oxXFX.rst diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py index 2b96a94401a8..4918e5c4c428 100644 --- a/Lib/test/test_syntax.py +++ b/Lib/test/test_syntax.py @@ -650,6 +650,20 @@ 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) diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-05-15-01-29-29.bpo-1875.9oxXFX.rst b/Misc/NEWS.d/next/Core and Builtins/2019-05-15-01-29-29.bpo-1875.9oxXFX.rst new file mode 100644 index 000000000000..8f095ed9f16b --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2019-05-15-01-29-29.bpo-1875.9oxXFX.rst @@ -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. diff --git a/Python/compile.c b/Python/compile.c index 5688ef8479c0..d2729d4c6ca3 100644 --- a/Python/compile.c +++ b/Python/compile.c @@ -2301,13 +2301,12 @@ 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)) { diff --git a/Python/peephole.c b/Python/peephole.c index 95b3dbb6bf51..1ae62fa39a27 100644 --- a/Python/peephole.c +++ b/Python/peephole.c @@ -304,11 +304,19 @@ 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. -- 2.47.3