def _get_ref_content(self, file_path: str) -> str:
        """
        Retrieves the content of a file from a valid Git reference.

        Args:
            file_path (str): The file path in the repository.

        Returns:
            str: The content of the file from the reference, or an empty string if unavailable.
        """
        ref = self._get_valid_ref()
        if not ref:
            return ''

        cmd = f'git --no-pager show {ref}:{file_path}'
        output = self.execute(cmd, self.cwd)
        return output.content if output.exit_code == 0 else ''

        Retrieves the content of a file from a valid Git reference.

        Args:
            file_path (str): The file path in the repository.

        Returns:
            str: The content of the file from the reference, or an empty string if unavailable.
        
openhands/runtime/utils/git_handler.py