Re: should search ring contain duplicates?

[Richard Stallman]

    > BTW, add-to-history should probably be fixed to _not_ add an element
    > which is already at the head of the history.

    Then it becomes a complete duplicate of C code.  Isn't then better
    to call the Lisp function add-to-history from the C implementation of
    read_minibuf?

Looking at the code of add-to-history, it appears to me that it
already behaves as requested here.  If the new element matches the
head of the history list, add-to-history does not add another copy.

More precisely, it does not preserve the old head.
Instead it deletes that and then adds a new element.
But the result is, all the same, to have just one, not two.
This is all that matters, as far as I can see.

Is there a real issue here?