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IPv6Network.next_network() raises the wrong error when addresses run out #156680
Description
Bug description:
_BaseNetwork.next_network() guards address-space exhaustion with except OverflowError, which only the IPv4 path raises, so on IPv6 the internal ValueError from _string_from_ip_int() escapes instead.
from ipaddress import IPv4Network, IPv6Network
for net in (IPv4Network('255.255.255.0/24'),
IPv6Network('ffff:ffff:ffff:ffff:ffff:ffff:ffff:0/112')):
try:
net.next_network()
except ValueError as e:
print(f"{net}: {e}")Output:
255.255.255.0/24: out of address space, cannot make another /24 network ffff:ffff:ffff:ffff:ffff:ffff:ffff:0/112: IPv6 address is too large
Expected: out of address space, cannot make another /112 network, the message Doc/library/ipaddress.rst gives for next_network().
CPython versions tested on:
CPython main branch
Operating systems tested on:
Linux
Activity
777GE90 commented on Aug 30, 2026
Hopefully should be resolved under c6b1d1a
gh-156680: Raise the documented error from IPv6Network.next_network() (…
orsenthil commented on Sep 10, 2026
Reopening this to update a doc string of the module.
pythongh-156680 - Update IPv4Network and IPv6Network docstring.
pythongh-156680: Raise the documented error from IPv6Network.next_net…
pythongh-156680: Raise the documented error from IPv6Network.next_net…
gh-156680 - Update IPv4Network and IPv6Network docstring. (#157280)