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.

1 files changed, 12 insertions, 12 deletions

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