Index: Lib/re.py
===================================================================
--- Lib/re.py	(revision 87986)
+++ Lib/re.py	(working copy)
@@ -214,38 +214,12 @@
     "Compile a template pattern, returning a pattern object"
     return _compile(pattern, flags|T)
 
-_alphanum_str = frozenset(
-    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890")
-_alphanum_bytes = frozenset(
-    b"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890")
-
 def escape(pattern):
-    "Escape all non-alphanumeric characters in pattern."
-    if isinstance(pattern, str):
-        alphanum = _alphanum_str
-        s = list(pattern)
-        for i in range(len(pattern)):
-            c = pattern[i]
-            if c not in alphanum:
-                if c == "\000":
-                    s[i] = "\\000"
-                else:
-                    s[i] = "\\" + c
-        return "".join(s)
-    else:
-        alphanum = _alphanum_bytes
-        s = []
-        esc = ord(b"\\")
-        for c in pattern:
-            if c in alphanum:
-                s.append(c)
-            else:
-                if c == 0:
-                    s.extend(b"\\000")
-                else:
-                    s.append(esc)
-                    s.append(c)
-        return bytes(s)
+    "Escape special regex characters in pattern."
+    specials, repl = r'([][.^$*+?{}\\|()])', r'\\\1'
+    if isinstance(pattern, bytes):
+        specials, repl = specials.encode(), repl.encode()
+    return sub(specials, repl, pattern)
 
 # --------------------------------------------------------------------
 # internals
Index: Lib/test/test_re.py
===================================================================
--- Lib/test/test_re.py	(revision 87986)
+++ Lib/test/test_re.py	(working copy)
@@ -412,30 +412,32 @@
         self.assertEqual(re.search("a\s", "a ").group(0), "a ")
 
     def test_re_escape(self):
-        p=""
-        self.assertEqual(re.escape(p), p)
-        for i in range(0, 256):
-            p = p + chr(i)
-            self.assertEqual(re.match(re.escape(chr(i)), chr(i)) is not None,
-                             True)
-            self.assertEqual(re.match(re.escape(chr(i)), chr(i)).span(), (0,1))
+        p = ""
+        for c in {'\0', '_', '!', '\t', p}:
+            self.assertEqual(re.escape(c), c)
+        for i in range(256):
+            c = chr(i)
+            p += chr(i)
+            self.assertIsNotNone(re.match(re.escape(c), c))
+            self.assertEqual(re.match(re.escape(c), c).span(), (0, 1))
 
-        pat=re.compile(re.escape(p))
-        self.assertEqual(pat.match(p) is not None, True)
-        self.assertEqual(pat.match(p).span(), (0,256))
+        pat = re.compile(re.escape(p))
+        self.assertIsNotNone(pat.match(p))
+        self.assertEqual(pat.match(p).span(), (0, 256))
 
     def test_re_escape_byte(self):
-        p=b""
-        self.assertEqual(re.escape(p), p)
-        for i in range(0, 256):
+        p = b""
+        for b in {b'\0', b'_', b'!', b'\t', p}:
+            self.assertEqual(re.escape(b), b)
+        for i in range(256):
             b = bytes([i])
             p += b
-            self.assertEqual(re.match(re.escape(b), b) is not None, True)
-            self.assertEqual(re.match(re.escape(b), b).span(), (0,1))
+            self.assertIsNotNone(re.match(re.escape(b), b))
+            self.assertEqual(re.match(re.escape(b), b).span(), (0, 1))
 
-        pat=re.compile(re.escape(p))
-        self.assertEqual(pat.match(p) is not None, True)
-        self.assertEqual(pat.match(p).span(), (0,256))
+        pat = re.compile(re.escape(p))
+        self.assertIsNotNone(pat.match(p))
+        self.assertEqual(pat.match(p).span(), (0, 256))
 
     def pickle_test(self, pickle):
         oldpat = re.compile('a(?:b|(c|e){1,2}?|d)+?(.)')