gh-98401: Invalid escape sequences emits SyntaxWarning (#99011)

A backslash-character pair that is not a valid escape sequence now
generates a SyntaxWarning, instead of DeprecationWarning.  For
example, re.compile("\d+\.\d+") now emits a SyntaxWarning ("\d" is an
invalid escape sequence), use raw strings for regular expression:
re.compile(r"\d+\.\d+"). In a future Python version, SyntaxError will
eventually be raised, instead of SyntaxWarning.

Octal escapes with value larger than 0o377 (ex: "\477"), deprecated
in Python 3.11, now produce a SyntaxWarning, instead of
DeprecationWarning. In a future Python version they will be
eventually a SyntaxError.

codecs.escape_decode() and codecs.unicode_escape_decode() are left
unchanged: they still emit DeprecationWarning.

* The parser only emits SyntaxWarning for Python 3.12 (feature
  version), and still emits DeprecationWarning on older Python
  versions.
* Fix SyntaxWarning by using raw strings in Tools/c-analyzer/ and
  wasm_build.py.

3 files changed, 18 insertions, 18 deletions

diff --git a/Lib/test/test_codeop.py b/Lib/test/test_codeop.py
index 133096d..d7b51be 100644
--- a/Lib/test/test_codeop.py
+++ b/Lib/test/test_codeop.py
@@ -310,8 +310,8 @@ class CodeopTests(unittest.TestCase):
     def test_warning(self):
         # Test that the warning is only returned once.
         with warnings_helper.check_warnings(
-                (".*literal", SyntaxWarning),
-                (".*invalid", DeprecationWarning),
+                ('"is" with a literal', SyntaxWarning),
+                ("invalid escape sequence", SyntaxWarning),
                 ) as w:
             compile_command(r"'\e' is 0")
             self.assertEqual(len(w.warnings), 2)
@@ -321,9 +321,9 @@ class CodeopTests(unittest.TestCase):
             warnings.simplefilter('error', SyntaxWarning)
             compile_command('1 is 1', symbol='exec')
 
-        # Check DeprecationWarning treated as an SyntaxError
+        # Check SyntaxWarning treated as an SyntaxError
         with warnings.catch_warnings(), self.assertRaises(SyntaxError):
-            warnings.simplefilter('error', DeprecationWarning)
+            warnings.simplefilter('error', SyntaxWarning)
             compile_command(r"'\e'", symbol='exec')
 
     def test_incomplete_warning(self):
@@ -337,7 +337,7 @@ class CodeopTests(unittest.TestCase):
             warnings.simplefilter('always')
             self.assertInvalid("'\\e' 1")
         self.assertEqual(len(w), 1)
-        self.assertEqual(w[0].category, DeprecationWarning)
+        self.assertEqual(w[0].category, SyntaxWarning)
         self.assertRegex(str(w[0].message), 'invalid escape sequence')
         self.assertEqual(w[0].filename, '<input>')
 
diff --git a/Lib/test/test_fstring.py b/Lib/test/test_fstring.py
index bf3a5b0..318f38a 100644
--- a/Lib/test/test_fstring.py
+++ b/Lib/test/test_fstring.py
@@ -776,7 +776,7 @@ x = (
         self.assertEqual(f'2\x203', '2 3')
         self.assertEqual(f'\x203', ' 3')
 
-        with self.assertWarns(DeprecationWarning):  # invalid escape sequence
+        with self.assertWarns(SyntaxWarning):  # 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 7247b7e..9b663c0 100644
--- a/Lib/test/test_string_literals.py
+++ b/Lib/test/test_string_literals.py
@@ -109,11 +109,11 @@ class TestLiterals(unittest.TestCase):
         for b in range(1, 128):
             if b in b"""\n\r"'01234567NU\\abfnrtuvx""":
                 continue
-            with self.assertWarns(DeprecationWarning):
+            with self.assertWarns(SyntaxWarning):
                 self.assertEqual(eval(r"'\%c'" % b), '\\' + chr(b))
 
         with warnings.catch_warnings(record=True) as w:
-            warnings.simplefilter('always', category=DeprecationWarning)
+            warnings.simplefilter('always', category=SyntaxWarning)
             eval("'''\n\\z'''")
         self.assertEqual(len(w), 1)
         self.assertEqual(str(w[0].message), r"invalid escape sequence '\z'")
@@ -121,7 +121,7 @@ class TestLiterals(unittest.TestCase):
         self.assertEqual(w[0].lineno, 1)
 
         with warnings.catch_warnings(record=True) as w:
-            warnings.simplefilter('error', category=DeprecationWarning)
+            warnings.simplefilter('error', category=SyntaxWarning)
             with self.assertRaises(SyntaxError) as cm:
                 eval("'''\n\\z'''")
             exc = cm.exception
@@ -133,11 +133,11 @@ class TestLiterals(unittest.TestCase):
 
     def test_eval_str_invalid_octal_escape(self):
         for i in range(0o400, 0o1000):
-            with self.assertWarns(DeprecationWarning):
+            with self.assertWarns(SyntaxWarning):
                 self.assertEqual(eval(r"'\%o'" % i), chr(i))
 
         with warnings.catch_warnings(record=True) as w:
-            warnings.simplefilter('always', category=DeprecationWarning)
+            warnings.simplefilter('always', category=SyntaxWarning)
             eval("'''\n\\407'''")
         self.assertEqual(len(w), 1)
         self.assertEqual(str(w[0].message),
@@ -146,7 +146,7 @@ class TestLiterals(unittest.TestCase):
         self.assertEqual(w[0].lineno, 1)
 
         with warnings.catch_warnings(record=True) as w:
-            warnings.simplefilter('error', category=DeprecationWarning)
+            warnings.simplefilter('error', category=SyntaxWarning)
             with self.assertRaises(SyntaxError) as cm:
                 eval("'''\n\\407'''")
             exc = cm.exception
@@ -186,11 +186,11 @@ class TestLiterals(unittest.TestCase):
         for b in range(1, 128):
             if b in b"""\n\r"'01234567\\abfnrtvx""":
                 continue
-            with self.assertWarns(DeprecationWarning):
+            with self.assertWarns(SyntaxWarning):
                 self.assertEqual(eval(r"b'\%c'" % b), b'\\' + bytes([b]))
 
         with warnings.catch_warnings(record=True) as w:
-            warnings.simplefilter('always', category=DeprecationWarning)
+            warnings.simplefilter('always', category=SyntaxWarning)
             eval("b'''\n\\z'''")
         self.assertEqual(len(w), 1)
         self.assertEqual(str(w[0].message), r"invalid escape sequence '\z'")
@@ -198,7 +198,7 @@ class TestLiterals(unittest.TestCase):
         self.assertEqual(w[0].lineno, 1)
 
         with warnings.catch_warnings(record=True) as w:
-            warnings.simplefilter('error', category=DeprecationWarning)
+            warnings.simplefilter('error', category=SyntaxWarning)
             with self.assertRaises(SyntaxError) as cm:
                 eval("b'''\n\\z'''")
             exc = cm.exception
@@ -209,11 +209,11 @@ class TestLiterals(unittest.TestCase):
 
     def test_eval_bytes_invalid_octal_escape(self):
         for i in range(0o400, 0o1000):
-            with self.assertWarns(DeprecationWarning):
+            with self.assertWarns(SyntaxWarning):
                 self.assertEqual(eval(r"b'\%o'" % i), bytes([i & 0o377]))
 
         with warnings.catch_warnings(record=True) as w:
-            warnings.simplefilter('always', category=DeprecationWarning)
+            warnings.simplefilter('always', category=SyntaxWarning)
             eval("b'''\n\\407'''")
         self.assertEqual(len(w), 1)
         self.assertEqual(str(w[0].message),
@@ -222,7 +222,7 @@ class TestLiterals(unittest.TestCase):
         self.assertEqual(w[0].lineno, 1)
 
         with warnings.catch_warnings(record=True) as w:
-            warnings.simplefilter('error', category=DeprecationWarning)
+            warnings.simplefilter('error', category=SyntaxWarning)
             with self.assertRaises(SyntaxError) as cm:
                 eval("b'''\n\\407'''")
             exc = cm.exception