email validation: "example@example" returns an error

[stationname]

Like in the title: basically a@a shall be valid.
A "." is not necessary.

https://www.rfc-editor.org/rfc/rfc5322.html page 18 top.

[yozachar]

Hi @stationname, example@example is validated when simple_host = True

$ python -c "from validators import email; print(email('example@example', simple_host=True))"
True

The host-part validation call:

validators/src/validators/email.py

Lines 80 to 88 in 9e94fee

	hostname(
	domain_part,
	skip_ipv6_addr=not ipv6_address,
	skip_ipv4_addr=not ipv4_address,
	may_have_port=False,
	maybe_simple=simple_host,
	rfc_1034=rfc_1034,
	rfc_2782=rfc_2782,
	)

Simple host validation:

validators/src/validators/hostname.py

Lines 24 to 26 in 9e94fee

	def _simple_hostname_regex():
	"""Simple hostname validation regex."""
	return re.compile(r"^[a-zA-Z0-9][a-zA-Z0-9-]{0,61}[a-zA-Z0-9]$")

But a@a isn't validated because of the regex:

^[a-zA-Z0-9][a-zA-Z0-9-]{0,61}[a-zA-Z0-9]$

---

Here's a patch:

diff --git a/src/validators/hostname.py b/src/validators/hostname.py
index 4c7d609..b9dfbd5 100644
--- a/src/validators/hostname.py
+++ b/src/validators/hostname.py
@@ -23,7 +23,9 @@ def _port_regex():
 @lru_cache
 def _simple_hostname_regex():
     """Simple hostname validation regex."""
-    return re.compile(r"^[a-zA-Z0-9][a-zA-Z0-9-]{0,61}[a-zA-Z0-9]$")
+    # {0,59} because two characters are already matched at
+    # the beginning and at the end making the range {1, 61}
+    return re.compile(r"^(?!-)[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,59}[a-zA-Z0-9])?(?<!-)$")
 
 
 def _port_validator(value: str):

PR is welcome.

[stationname]

❤️