Fix config file search and inclusion in header

Author: chrysle

piptools/scripts/options.py

@@ -245,6 +245,7 @@ def _get_default_option(option_name: str) -> Any:
 src_files = click.argument(
     "src_files",
     nargs=-1,
+    is_eager=True,
     type=click.Path(exists=True, allow_dash=True),
 )
 

piptools/utils.py

@@ -630,7 +630,7 @@ def select_config_file(src_files: tuple[str, ...]) -> Path | None:
     # NOTE: input.
     working_directory = Path.cwd()
     src_files_as_paths = (
-        (working_directory / src_file).resolve() for src_file in src_files or (".",)
+        (working_directory / src_file).resolve() for src_file in src_files + (".",)
     )
     candidate_dirs = (src if src.is_dir() else src.parent for src in src_files_as_paths)
     config_file_path = next(