I agree that it is not strictly necessary. It could be implemented without an option. I personally have no objections to that solution.
My arguments for the option are the following: - It enhances compatibility Without the option, source behaves exactly as before. Existing scripts will work exactly as before even if the user has defined BASH_SOURCE_PATH. I paid special attention to the posixly correct behavior. - It's opt in Users will have to explicitly choose to use the new behavior of source, preventing errors. - It simplifies and reduces cognitive load Passing -i means only the directories in BASH_SOURCE_PATH will be searched, and no other direcrories. Easy to understand. - It's clear and explicit Passing -i makes it explicit to anyone reading the scripts that they were written with this new behavior in mind. -- Matheus
