param=None is the same as not passing the param

2 files changed, 7 insertions, 6 deletions

diff --git a/src/click/core.py b/src/click/core.py
index 4b96767..604d8ba 100644
--- a/src/click/core.py
+++ b/src/click/core.py
@@ -1819,7 +1819,7 @@ class Group(MultiCommand):
         """
         from .decorators import command
 
-        if self.command_class is not None and "cls" not in kwargs:
+        if self.command_class and kwargs.get("cls") is None:
             kwargs["cls"] = self.command_class
 
         func: t.Optional[t.Callable] = None
@@ -1863,7 +1863,7 @@ class Group(MultiCommand):
             func = args[0]
             args = args[1:]
 
-        if self.group_class is not None and "cls" not in kwargs:
+        if self.group_class is not None and kwargs.get("cls") is None:
             if self.group_class is type:
                 kwargs["cls"] = type(self)
             else:
diff --git a/src/click/decorators.py b/src/click/decorators.py
index a8c6d2d..a2fbadd 100644
--- a/src/click/decorators.py
+++ b/src/click/decorators.py
@@ -244,7 +244,8 @@ def group(
     .. versionchanged:: 8.1
         This decorator can be applied without parentheses.
     """
-    attrs.setdefault("cls", Group)
+    if attrs.get("cls") is None:
+        attrs["cls"] = Group
 
     if callable(name):
         grp: t.Callable[[F], Group] = t.cast(Group, command(**attrs))
@@ -275,7 +276,7 @@ def argument(*param_decls: str, **attrs: t.Any) -> t.Callable[[FC], FC]:
     """
 
     def decorator(f: FC) -> FC:
-        ArgumentClass = attrs.pop("cls", Argument)
+        ArgumentClass = attrs.pop("cls", None) or Argument
         _param_memo(f, ArgumentClass(param_decls, **attrs))
         return f
 
@@ -297,9 +298,9 @@ def option(*param_decls: str, **attrs: t.Any) -> t.Callable[[FC], FC]:
         # Issue 926, copy attrs, so pre-defined options can re-use the same cls=
         option_attrs = attrs.copy()
 
-        if "help" in option_attrs:
+        if option_attrs.get("help"):
             option_attrs["help"] = inspect.cleandoc(option_attrs["help"])
-        OptionClass = option_attrs.pop("cls", Option)
+        OptionClass = option_attrs.pop("cls", None) or Option
         _param_memo(f, OptionClass(param_decls, **option_attrs))
         return f