Another update to config file parsing

The last update to the config file parser still didn't handle the
conversion of equals to space in some cases. Specifically, this was
a problem for SetEnv commands. This commit should fix that case,
and also adds an explicit unit test for it.

asyncssh/config.py

@@ -321,11 +321,15 @@ def parse(self, path: Path) -> None:
 
                 args = []
                 loption = ''
+                allow_equal = True
 
                 for i, arg in enumerate(split_args, 1):
                     if arg.startswith('='):
                         if len(arg) > 1:
                             args.append(arg[1:])
+                    elif not allow_equal:
+                        args.extend(split_args[i-1:])
+                        break
                     elif arg.endswith('='):
                         args.append(arg[:-1])
                     elif '=' in arg:
@@ -337,9 +341,7 @@ def parse(self, path: Path) -> None:
 
                     if i == 1:
                         loption = args.pop(0).lower()
-                    elif i > 1 and loption not in self._conditionals:
-                        args.extend(split_args[i:])
-                        break
+                        allow_equal = loption in self._conditionals
 
                 if loption in self._no_split:
                     args = [line.lstrip()[len(loption):].strip()]

asyncssh/connection.py

@@ -4232,7 +4232,7 @@ async def create_session(self, session_factory: SSHClientSessionFactory,
         if env:
             try:
                 if isinstance(env, list):
-                    new_env.update((item.split('=', 2) for item in env))
+                    new_env.update((item.split('=', 1) for item in env))
                 else:
                     new_env.update(cast(Mapping[str, str], env))
             except ValueError:

tests/test_config.py

@@ -286,9 +286,15 @@ def test_set_string_list(self):
     def test_append_string_list(self):
         """Test appending multiple string config options to a list"""
 
-        config = self._parse_config('SendEnv foo\nSendEnv  bar baz')
+        config = self._parse_config('SendEnv foo\nSendEnv bar baz')
         self.assertEqual(config.get('SendEnv'), ['foo', 'bar', 'baz'])
 
+    def test_set_environment(self):
+        """Test setting environment with equals-separated key/value pairs"""
+
+        config = self._parse_config('SetEnv A=1 B= C=D=2\nSetEnv E=3')
+        self.assertEqual(config.get('SetEnv'), ['A=1', 'B=', 'C=D=2'])
+
     def test_set_remote_command(self):
         """Test setting a remote command"""