diff --git a/lib/spack/spack/util/executable.py b/lib/spack/spack/util/executable.py
index 529ed458622..9502b0e63f0 100644
--- a/lib/spack/spack/util/executable.py
+++ b/lib/spack/spack/util/executable.py
@@ -82,48 +82,48 @@ def path(self) -> str:
     def __call__(
         self,
         *args: str,
-        fail_on_error: bool = True,
-        ignore_errors: Union[int, Sequence[int]] = (),
-        ignore_quotes: Optional[bool] = None,
-        timeout: Optional[int] = None,
-        env: Optional[Union[Dict[str, str], EnvironmentModifications]] = None,
-        extra_env: Optional[Union[Dict[str, str], EnvironmentModifications]] = None,
-        input: Optional[TextIO] = None,
-        output: Union[Optional[TextIO], str] = None,
-        error: Union[Optional[TextIO], str] = None,
-        _dump_env: Optional[Dict[str, str]] = None,
+        fail_on_error: bool = ...,
+        ignore_errors: Union[int, Sequence[int]] = ...,
+        ignore_quotes: Optional[bool] = ...,
+        timeout: Optional[int] = ...,
+        env: Optional[Union[Dict[str, str], EnvironmentModifications]] = ...,
+        extra_env: Optional[Union[Dict[str, str], EnvironmentModifications]] = ...,
+        input: Optional[TextIO] = ...,
+        output: Union[Optional[TextIO], str] = ...,
+        error: Union[Optional[TextIO], str] = ...,
+        _dump_env: Optional[Dict[str, str]] = ...,
     ) -> None: ...
 
     @overload
     def __call__(
         self,
         *args: str,
-        fail_on_error: bool = True,
-        ignore_errors: Union[int, Sequence[int]] = (),
-        ignore_quotes: Optional[bool] = None,
-        timeout: Optional[int] = None,
-        env: Optional[Union[Dict[str, str], EnvironmentModifications]] = None,
-        extra_env: Optional[Union[Dict[str, str], EnvironmentModifications]] = None,
-        input: Optional[TextIO] = None,
-        output: Union[Type[str], Callable] = ...,
-        error: Union[Optional[TextIO], str, Type[str], Callable] = None,
-        _dump_env: Optional[Dict[str, str]] = None,
+        fail_on_error: bool = ...,
+        ignore_errors: Union[int, Sequence[int]] = ...,
+        ignore_quotes: Optional[bool] = ...,
+        timeout: Optional[int] = ...,
+        env: Optional[Union[Dict[str, str], EnvironmentModifications]] = ...,
+        extra_env: Optional[Union[Dict[str, str], EnvironmentModifications]] = ...,
+        input: Optional[TextIO] = ...,
+        output: Union[Type[str], Callable],
+        error: Union[Optional[TextIO], str, Type[str], Callable] = ...,
+        _dump_env: Optional[Dict[str, str]] = ...,
     ) -> str: ...
 
     @overload
     def __call__(
         self,
         *args: str,
-        fail_on_error: bool = True,
-        ignore_errors: Union[int, Sequence[int]] = (),
-        ignore_quotes: Optional[bool] = None,
-        timeout: Optional[int] = None,
-        env: Optional[Union[Dict[str, str], EnvironmentModifications]] = None,
-        extra_env: Optional[Union[Dict[str, str], EnvironmentModifications]] = None,
-        input: Optional[TextIO] = None,
-        output: Union[Optional[TextIO], str, Type[str], Callable] = None,
-        error: Union[Type[str], Callable] = ...,
-        _dump_env: Optional[Dict[str, str]] = None,
+        fail_on_error: bool = ...,
+        ignore_errors: Union[int, Sequence[int]] = ...,
+        ignore_quotes: Optional[bool] = ...,
+        timeout: Optional[int] = ...,
+        env: Optional[Union[Dict[str, str], EnvironmentModifications]] = ...,
+        extra_env: Optional[Union[Dict[str, str], EnvironmentModifications]] = ...,
+        input: Optional[TextIO] = ...,
+        output: Union[Optional[TextIO], str, Type[str], Callable] = ...,
+        error: Union[Type[str], Callable],
+        _dump_env: Optional[Dict[str, str]] = ...,
     ) -> str: ...
 
     def __call__(