How to jump to backward found word when switched into reverse incremental search?

Question

When I do I-search: or I-search-backward , it starts right away from the first word it find.

Original behavior:

word1                                           |[cursor]word1 ; cursor moves here 
wor[cursor]d2 ;<= I press `ctrl+r` word [enter] |word2
word3                                           |word3

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For example, when I am in I-search, I want to start doing backward search and press ctrl+r but in the first press it remains in the current found word (cursor move into its beginning) and on the second press to ctrl+r, `emacs jumps to the found word on backward.

Example:

word1                                           |word1
wor[cursor]d2 ;<= I press `ctrl+s` word [enter] |word2
word3                                           |word3[cursor]; cursor moves here

then

word1                                           |word1
word2                                           |word2
word3[cursor] ;<= I press `ctrl+r` word [enter] |[cursor]word3 ; cursor moves here                                          

at this stage I want cursor to move beginning of word2 like it should do on its original behavior.

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=> I was wondering when the switch from I-search: to I-search-backward or visa versa, can the action take place on the first click instead of two?

Answer 1

It's all based on where the cursor is when you start the search.

C-hig (emacs)Basic Isearch says:

A backward search finds matches that end before the starting point, just as a forward search finds matches that begin after it.

Hence for:

word1
wor[cursor]d2
word3

Searching backwards for word cannot find word2 because that instance of "word" doesn't end before [cursor].

word1
word2
word3[cursor]

Searching backwards here, we will initially find word3, as that instance of "word" ends before [cursor].

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Edit: The following is extremely minimally tested, but give this a whirl:

(define-advice isearch-repeat (:before (direction &optional count) goto-other-end)
  "If reversing, start the search from the other end of the current match."
  (unless (eq isearch-forward (eq direction 'forward))
    (when isearch-other-end
      (goto-char isearch-other-end))))