diff --git a/Doc/reference/lexical_analysis.rst b/Doc/reference/lexical_analysis.rst index cc1b2f57a70e3b..7e1e17edb2d8da 100644 --- a/Doc/reference/lexical_analysis.rst +++ b/Doc/reference/lexical_analysis.rst @@ -594,11 +594,9 @@ escape sequences only recognized in string literals fall into the category of unrecognized escapes for bytes literals. .. versionchanged:: 3.6 - Unrecognized escape sequences produce a :exc:`DeprecationWarning`. - - .. versionchanged:: 3.8 - Unrecognized escape sequences produce a :exc:`SyntaxWarning`. In - some future version of Python they will be a :exc:`SyntaxError`. + Unrecognized escape sequences produce a :exc:`DeprecationWarning`. In + a future Python version they will be a :exc:`SyntaxWarning` and + eventually a :exc:`SyntaxError`. Even in a raw literal, quotes can be escaped with a backslash, but the backslash remains in the result; for example, ``r"\""`` is a valid string diff --git a/Doc/whatsnew/3.8.rst b/Doc/whatsnew/3.8.rst index 9f70582745147b..83caa2cc5abc43 100644 --- a/Doc/whatsnew/3.8.rst +++ b/Doc/whatsnew/3.8.rst @@ -414,11 +414,6 @@ Other Language Changes and :keyword:`return` statements. (Contributed by David Cuthbert and Jordan Chapman in :issue:`32117`.) -* A backslash-character pair that is not a valid escape sequence generates - a :exc:`DeprecationWarning` since Python 3.6. In Python 3.8 it generates - a :exc:`SyntaxWarning` instead. - (Contributed by Serhiy Storchaka in :issue:`32912`.) - * The compiler now produces a :exc:`SyntaxWarning` in some cases when a comma is missed before tuple or list. For example:: diff --git a/Lib/test/test_fstring.py b/Lib/test/test_fstring.py index fb761441fcee5c..49663923e7f5aa 100644 --- a/Lib/test/test_fstring.py +++ b/Lib/test/test_fstring.py @@ -649,7 +649,7 @@ def test_backslashes_in_string_part(self): self.assertEqual(f'2\x203', '2 3') self.assertEqual(f'\x203', ' 3') - with self.assertWarns(SyntaxWarning): # invalid escape sequence + with self.assertWarns(DeprecationWarning): # invalid escape sequence value = eval(r"f'\{6*7}'") self.assertEqual(value, '\\42') self.assertEqual(f'\\{6*7}', '\\42') diff --git a/Lib/test/test_string_literals.py b/Lib/test/test_string_literals.py index 5961d591c44803..0cea2edc32afa2 100644 --- a/Lib/test/test_string_literals.py +++ b/Lib/test/test_string_literals.py @@ -32,6 +32,7 @@ import shutil import tempfile import unittest +import warnings TEMPLATE = r"""# coding: %s @@ -110,10 +111,24 @@ def test_eval_str_invalid_escape(self): for b in range(1, 128): if b in b"""\n\r"'01234567NU\\abfnrtuvx""": continue - with self.assertWarns(SyntaxWarning): + with self.assertWarns(DeprecationWarning): self.assertEqual(eval(r"'\%c'" % b), '\\' + chr(b)) - self.check_syntax_warning("'''\n\\z'''") + with warnings.catch_warnings(record=True) as w: + warnings.simplefilter('always', category=DeprecationWarning) + eval("'''\n\\z'''") + self.assertEqual(len(w), 1) + self.assertEqual(w[0].filename, '') + self.assertEqual(w[0].lineno, 1) + + with warnings.catch_warnings(record=True) as w: + warnings.simplefilter('error', category=DeprecationWarning) + with self.assertRaises(SyntaxError) as cm: + eval("'''\n\\z'''") + exc = cm.exception + self.assertEqual(w, []) + self.assertEqual(exc.filename, '') + self.assertEqual(exc.lineno, 1) def test_eval_str_raw(self): self.assertEqual(eval(""" r'x' """), 'x') @@ -145,10 +160,24 @@ def test_eval_bytes_invalid_escape(self): for b in range(1, 128): if b in b"""\n\r"'01234567\\abfnrtvx""": continue - with self.assertWarns(SyntaxWarning): + with self.assertWarns(DeprecationWarning): self.assertEqual(eval(r"b'\%c'" % b), b'\\' + bytes([b])) - self.check_syntax_warning("b'''\n\\z'''") + with warnings.catch_warnings(record=True) as w: + warnings.simplefilter('always', category=DeprecationWarning) + eval("b'''\n\\z'''") + self.assertEqual(len(w), 1) + self.assertEqual(w[0].filename, '') + self.assertEqual(w[0].lineno, 1) + + with warnings.catch_warnings(record=True) as w: + warnings.simplefilter('error', category=DeprecationWarning) + with self.assertRaises(SyntaxError) as cm: + eval("b'''\n\\z'''") + exc = cm.exception + self.assertEqual(w, []) + self.assertEqual(exc.filename, '') + self.assertEqual(exc.lineno, 1) def test_eval_bytes_raw(self): self.assertEqual(eval(""" br'x' """), b'x') diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-08-06-14-03-59.bpo-32912.UDwSMJ.rst b/Misc/NEWS.d/next/Core and Builtins/2019-08-06-14-03-59.bpo-32912.UDwSMJ.rst new file mode 100644 index 00000000000000..e18d8adfbee9e6 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2019-08-06-14-03-59.bpo-32912.UDwSMJ.rst @@ -0,0 +1,3 @@ +Reverted :issue:`32912`: emitting :exc:`SyntaxWarning` instead of +:exc:`DeprecationWarning` for invalid escape sequences in string and bytes +literals. diff --git a/Python/ast.c b/Python/ast.c index f6c2049ae2cfdf..9947824de7446c 100644 --- a/Python/ast.c +++ b/Python/ast.c @@ -4674,12 +4674,12 @@ warn_invalid_escape_sequence(struct compiling *c, const node *n, if (msg == NULL) { return -1; } - if (PyErr_WarnExplicitObject(PyExc_SyntaxWarning, msg, + if (PyErr_WarnExplicitObject(PyExc_DeprecationWarning, msg, c->c_filename, LINENO(n), NULL, NULL) < 0) { - if (PyErr_ExceptionMatches(PyExc_SyntaxWarning)) { - /* Replace the SyntaxWarning exception with a SyntaxError + if (PyErr_ExceptionMatches(PyExc_DeprecationWarning)) { + /* Replace the DeprecationWarning exception with a SyntaxError to get a more accurate error report */ PyErr_Clear(); ast_error(c, n, "%U", msg);