fixup fromstring return types (#10162)

in https://github.com/certbot/certbot/pull/9124 we had the problem of
certbot-nginx's `Addr.fromstring` method possibly returning None which
is not possible in the `Addr` method in the certbot base class or in
certbot-apache. we fixed this by telling mypy the common
`Addr.fromstring` method returns an `Optional[Addr]` (despite it
actually always returning an `Addr`) and then unnecessarily complicating
certbot-apache's code a bit. the need for extra complexity with this
approach is going even further in
https://github.com/certbot/certbot/pull/10151 where we have to use
`cast` to assure mypy that the type isn't actually `Optional`. i
personally don't like all this

certbot-apache/certbot_apache/_internal/configurator.py

@@ -994,9 +994,7 @@ class ApacheConfigurator(common.Configurator):
         for arg in args:
             arg_value = self.parser.get_arg(arg)
             if arg_value is not None:
-                addr = obj.Addr.fromstring(arg_value)
-                if addr is not None:
-                    addrs.add(addr)
+                addrs.add(obj.Addr.fromstring(arg_value))
         is_ssl = False
 
         if self.parser.find_dir("SSLEngine", "on", start=path, exclude=False):
@@ -1126,9 +1124,7 @@ class ApacheConfigurator(common.Configurator):
         """
         addrs = set()
         for param in node.parameters:
-            addr = obj.Addr.fromstring(param)
-            if addr:
-                addrs.add(addr)
+            addrs.add(obj.Addr.fromstring(param))
 
         is_ssl = False
         # Exclusion to match the behavior in get_virtual_hosts_v2
@@ -1646,10 +1642,9 @@ class ApacheConfigurator(common.Configurator):
         for addr in ssl_addr_p:
             old_addr = obj.Addr.fromstring(
                 str(self.parser.get_arg(addr)))
-            if old_addr:
-                ssl_addr = old_addr.get_addr_obj("443")
-                self.parser.aug.set(addr, str(ssl_addr))
-                ssl_addrs.add(ssl_addr)
+            ssl_addr = old_addr.get_addr_obj("443")
+            self.parser.aug.set(addr, str(ssl_addr))
+            ssl_addrs.add(ssl_addr)
 
         return ssl_addrs
 

certbot-nginx/certbot_nginx/_internal/http_01.py

@@ -146,7 +146,7 @@ class NginxHttp01(common.ChallengePerformer):
         :returns: list of :class:`certbot_nginx._internal.obj.Addr` to apply
         :rtype: list
         """
-        addresses: List[Optional[Addr]] = []
+        addresses: List[Addr] = []
         default_addr = "%s" % self.configurator.config.http01_port
         ipv6_addr = "[::]:{0}".format(
             self.configurator.config.http01_port)
@@ -169,7 +169,7 @@ class NginxHttp01(common.ChallengePerformer):
             logger.debug("Using default address %s for authentication.",
                         default_addr)
 
-        return [address for address in addresses if address]
+        return addresses
 
     def _get_validation_path(self, achall: KeyAuthorizationAnnotatedChallenge) -> str:
         return os.sep + os.path.join(challenges.HTTP01.URI_ROOT_PATH, achall.chall.encode("token"))

certbot-nginx/certbot_nginx/_internal/obj.py

@@ -12,6 +12,10 @@ from certbot.plugins import common
 ADD_HEADER_DIRECTIVE = 'add_header'
 
 
+class SocketAddrError(Exception):
+    """Raised when a UNIX-domain socket address is encountered."""
+
+
 class Addr(common.Addr):
     r"""Represents an Nginx address, i.e. what comes after the 'listen'
     directive.
@@ -51,8 +55,15 @@ class Addr(common.Addr):
         self.unspecified_address = host in self.UNSPECIFIED_IPV4_ADDRESSES
 
     @classmethod
-    def fromstring(cls, str_addr: str) -> Optional["Addr"]:
-        """Initialize Addr from string."""
+    def fromstring(cls, str_addr: str) -> "Addr":
+        """Initialize Addr from string.
+
+        :param str str_addr: nginx address string
+        :returns: parsed nginx address
+        :rtype: Addr
+        :raises SocketAddrError: if a UNIX-domain socket address is given
+
+        """
         parts = str_addr.split(' ')
         ssl = False
         default = False
@@ -64,9 +75,9 @@ class Addr(common.Addr):
         # The first part must be the address
         addr = parts.pop(0)
 
-        # Ignore UNIX-domain sockets
+        # Raise for UNIX-domain sockets
         if addr.startswith('unix:'):
-            return None
+            raise SocketAddrError(f'encountered UNIX-domain socket address {str_addr}')
 
         # IPv6 check
         ipv6_match = re.match(r'\[.*\]', addr)

certbot-nginx/certbot_nginx/_internal/parser.py

@@ -794,11 +794,14 @@ def _parse_server_raw(server: UnspacedList) -> Dict[str, Any]:
         if not directive:
             continue
         if directive[0] == 'listen':
-            addr = obj.Addr.fromstring(" ".join(directive[1:]))
-            if addr:
-                addrs.add(addr)
-                if addr.ssl:
-                    ssl = True
+            try:
+                addr = obj.Addr.fromstring(" ".join(directive[1:]))
+            except obj.SocketAddrError:
+                # Ignore UNIX-domain socket addresses
+                continue
+            addrs.add(addr)
+            if addr.ssl:
+                ssl = True
         elif directive[0] == 'server_name':
             names.update(x.strip('"\'') for x in directive[1:])
         elif _is_ssl_on_directive(directive):

certbot-nginx/certbot_nginx/_internal/tests/obj_test.py

@@ -16,8 +16,7 @@ class AddrTest(unittest.TestCase):
         self.addr4 = Addr.fromstring("*:80 default_server ssl")
         self.addr5 = Addr.fromstring("myhost")
         self.addr6 = Addr.fromstring("80 default_server spdy")
-        self.addr7 = Addr.fromstring("unix:/var/run/nginx.sock")
-        self.addr8 = Addr.fromstring("*:80 default ssl")
+        self.addr7 = Addr.fromstring("*:80 default ssl")
 
     def test_fromstring(self):
         assert self.addr1.get_addr() == "192.168.1.1"
@@ -50,9 +49,13 @@ class AddrTest(unittest.TestCase):
         assert self.addr6.ssl is False
         assert self.addr6.default is True
 
-        assert self.addr8.default is True
+        assert self.addr7.default is True
 
-        assert self.addr7 is None
+    def test_fromstring_socket(self):
+        from certbot_nginx._internal.obj import Addr, SocketAddrError
+        socket_string = r"unix:/var/run/nginx.sock"
+        with pytest.raises(SocketAddrError, match=socket_string):
+            Addr.fromstring(socket_string)
 
     def test_str(self):
         assert str(self.addr1) == "192.168.1.1"
@@ -61,7 +64,7 @@ class AddrTest(unittest.TestCase):
         assert str(self.addr4) == "*:80 default_server ssl"
         assert str(self.addr5) == "myhost"
         assert str(self.addr6) == "80 default_server"
-        assert str(self.addr8) == "*:80 default_server ssl"
+        assert str(self.addr7) == "*:80 default_server ssl"
 
     def test_to_string(self):
         assert self.addr1.to_string() == "192.168.1.1"

certbot/certbot/plugins/common.py

@@ -261,7 +261,7 @@ class Addr:
         self.ipv6 = ipv6
 
     @classmethod
-    def fromstring(cls: Type[GenericAddr], str_addr: str) -> Optional[GenericAddr]:
+    def fromstring(cls: Type[GenericAddr], str_addr: str) -> GenericAddr:
         """Initialize Addr from string."""
         if str_addr.startswith('['):
             # ipv6 addresses starts with [