tags-add-tables / list of tag tables

Question

I can't find a concise answer to this question, only big manuals for which I'm not sure reading them will give me the answer... Spacemacs & haskell-mode are now giving me tag navigation by default (appeared with a MELPA upgrade, it's a feature I didn't have before). I'm using it now, however each time I change folder with tag navigation, emacs is asking:

Keep current list of tags tables also? (y or n)

I've seen that other question and so I see that the tags-add-tables setting is the way to go, however I honestly have no idea whether I want to answer yes or no... Is there a builtin emacs manual I can look at with brief information on the topic of tag tables, that would explain which is the compromise here?

Honestly I would expect spacemacs, or maybe haskell-mode to make that decision for me :-(

Answer 1

From emacs describe-variable (SPC h d v):

tags-add-tables is a variable defined in ‘etags.el’.
Its value is nil
Original value was ask-user

Documentation:
Control whether to add a new tags table to the current list.
t means do; nil means don’t (always start a new list).
Any other value means ask the user whether to add a new tags table
to the current list (as opposed to starting a new list).

You can customize this variable.

So whether you want to answer yes or no depends on if you want to keep the previous directory's symbols in your symbol table or not.