Add support for bracketed IPv6 addresses

Accept IPv6 addresses enclosed in brackets and add test coverage for
loopback, compressed, expanded, and IPv4-mapped forms.

Author: brauliore

src/validators/ip_address.py

@@ -118,7 +118,7 @@ def ipv6(value: str, /, *, cidr: bool = True, strict: bool = False, host_bit: bo
 
     Args:
         value:
-            IP address string to validate.
+            IP address string to validate. It may be enclosed in brackets.
         cidr:
             IP address string may contain CIDR annotation.
         strict:
@@ -134,6 +134,8 @@ def ipv6(value: str, /, *, cidr: bool = True, strict: bool = False, host_bit: bo
     """
     if not value:
         return False
+    if value.startswith("[") and value.endswith("]"):
+        value = value[1:-1]
     try:
         if cidr:
             if strict and value.count("/") != 1:

tests/test_ipv6_brackets.py

@@ -12,10 +12,13 @@
 @pytest.mark.parametrize(
     ("ip",),
     [
-        ("[2001:db8::1]", ),
+        ("[::1]",),
+        ("[2001:db8::1]",),
+        ("[2001:0db8:0000:0000:0000:0000:0000:0001]",),
+        ("[::ffff:192.0.2.128]",),
     ],
 )
 def test_ipv6_accepts_address_in_brackets(ip: str):
-    """Accept iv6 address in brackets."""
+    """Accept an IPv6 address enclosed in brackets."""
     result = validators.ipv6(ip)
     assert result is True, repr(result)