Fall back to banning host instead of exact mask

This only happens on the newly introduced account extban (in case the user
does not have an account, or the server does not provide accounts)
so this does not change existing behavior.

Falling back to the host instead of the exact mask makes it less easy
to evade these bans

plugins/Channel/test.py

@@ -245,9 +245,9 @@ def join():
                             '*[email protected]')
         join()
         with conf.supybot.protocols.irc.banmask.context(['account']):
-            # falls back from --account to config, then to exact hostmask
+            # falls back from --account to config, then to only the host
             self.assertKban('kban --account foobar',
-                            'foobar!user@host.domain.tld')
+                            '*!*@host.domain.tld')
         join()
         self.assertKban('kban --account --host foobar',
                         '*!*@host.domain.tld')
@@ -277,9 +277,9 @@ def join():
                             '*[email protected]')
         join()
         with conf.supybot.protocols.irc.banmask.context(['account']):
-            # falls back from --account to config, then to exact hostmask
+            # falls back from --account to config, then to only the host
             self.assertKban('kban --account foobar',
-                            'foobar!user@host.domain.tld')
+                            '*!*@host.domain.tld')
         join()
         self.assertKban('kban --account --host foobar',
                         '*!*@host.domain.tld')

src/conf.py

@@ -1316,7 +1316,12 @@ def makeExtBanmasks(self, hostmask, options=None, channel=None, *, network):
         if (bnick, buser, bhost) == ('*', '*', '*') and \
                 ircutils.isUserHostmask(hostmask) and \
                 not masks:
-            masks.append(hostmask)
+            # still no ban mask found, fallback to the host, if any
+            if host != '*':
+                masks.append(ircutils.joinHostmask('*', '*', host))
+            else:
+                # if no host, fall back to the exact mask provided
+                masks.append(hostmask)
 
         return masks