https://github.com/python/cpython/commit/265fcc5fc25d65afb33fda480c603f1e974... commit: 265fcc5fc25d65afb33fda480c603f1e974e374e branch: master author: Serhiy Storchaka <storchaka@gmail.com> committer: GitHub <noreply@github.com> date: 2017-08-29T15:47:44+03:00 summary: bpo-31286, bpo-30024: Fixed stack usage in absolute imports with (#3217) binding a submodule to a name. files: M Lib/test/test_import/__init__.py M Python/compile.c diff --git a/Lib/test/test_import/__init__.py b/Lib/test/test_import/__init__.py index 1b04de24dd1..ddef27d9cd4 100644 --- a/Lib/test/test_import/__init__.py +++ b/Lib/test/test_import/__init__.py @@ -237,6 +237,23 @@ def test_import_name_binding(self): import test.support as y self.assertIs(y, test.support, y.__name__) + def test_issue31286(self): + # import in a 'finally' block resulted in SystemError + try: + x = ... + finally: + import test.support.script_helper as x + + # import in a 'while' loop resulted in stack overflow + i = 0 + while i < 10: + import test.support.script_helper as x + i += 1 + + # import in a 'for' loop resulted in segmentation fault + for i in range(2): + import test.support.script_helper as x + def test_failing_reload(self): # A failing reload should leave the module object in sys.modules. source = TESTFN + os.extsep + "py" diff --git a/Python/compile.c b/Python/compile.c index 78e797a2c33..e547c2fd591 100644 --- a/Python/compile.c +++ b/Python/compile.c @@ -2673,28 +2673,34 @@ compiler_import_as(struct compiler *c, identifier name, identifier asname) If there is a dot in name, we need to split it and emit a IMPORT_FROM for each name. */ - Py_ssize_t dot = PyUnicode_FindChar(name, '.', 0, - PyUnicode_GET_LENGTH(name), 1); + Py_ssize_t len = PyUnicode_GET_LENGTH(name); + Py_ssize_t dot = PyUnicode_FindChar(name, '.', 0, len, 1); if (dot == -2) return 0; if (dot != -1) { /* Consume the base module name to get the first attribute */ - Py_ssize_t pos = dot + 1; - while (dot != -1) { + while (1) { + Py_ssize_t pos = dot + 1; PyObject *attr; - dot = PyUnicode_FindChar(name, '.', pos, - PyUnicode_GET_LENGTH(name), 1); + dot = PyUnicode_FindChar(name, '.', pos, len, 1); if (dot == -2) return 0; - attr = PyUnicode_Substring(name, pos, - (dot != -1) ? dot : - PyUnicode_GET_LENGTH(name)); + attr = PyUnicode_Substring(name, pos, (dot != -1) ? dot : len); if (!attr) return 0; ADDOP_O(c, IMPORT_FROM, attr, names); Py_DECREF(attr); - pos = dot + 1; + if (dot == -1) { + break; + } + ADDOP(c, ROT_TWO); + ADDOP(c, POP_TOP); } + if (!compiler_nameop(c, asname, Store)) { + return 0; + } + ADDOP(c, POP_TOP); + return 1; } return compiler_nameop(c, asname, Store); }