Validate a file argument

Internal helper used by generate_dockerfile() to check that optional file arguments (e.g. data_file, code_file, misc_file) are valid. Returns a path relative to the current working directory, which serves as the Docker/Podman build context.

Usage

.validate_file_arg(arg_name, value)

Arguments

arg_name

Character string, the name of the argument being checked (used only in error messages).

value

A character path to a file, or NULL.

Value

A file path relative to the current working directory if validation succeeds, or NULL if the input was NULL.