Subject: Re: bug#25562: 25.1; isearch-forward-word first matches a non-word

From: Juri Linkov <[email-masked]>
Date: Fri, 10 Feb 2017 01:28:55 +0200

>>> I agree it's an ill defined problem ; but then, so is isearching for foo\|bar.
>>>
>>> I disabled the beeping and screen flashing, so it doesn't bother me, but I get the point.
>>>
>>> In the end, it's mostly a matter of personal convenience. The patched behavior suits me better, and seems
>>> more consistent with the way regexp are handled.
>>
>> Did you try typing RET right after "C-s M-s w", then typing the word
>> to search, and then typing "C-s C-s" again to repeat that?  This might
>> be better suited to your needs, I think, and it doesn't require any
>> changes.
>
> Since incrementality of word search is not well-defined,
> it makes sense to type the word in non-incremental mode indeed.
>
> One problem I noticed is that it's not easy to get back to incremental
> mode: after typing a word in non-incremental mode ‘M-s w RET it’
> typing ‘C-s’ in the minibuffer doesn't go back to incremental mode.

IIRC, it was supposed to work this way, i.e.:

‘M-s w RET it RET’ to quit isearch and search the word nonincrementally,
as documented in (info "(emacs) Word Search")

‘M-s w RET it C-s’ to enter the word and continue searching incrementally,
as documented in the docstrings of ‘isearch-forward-exit-minibuffer’ and
‘isearch-reverse-exit-minibuffer’, but at some point the implementation
deviated from its documentation.  Here is the patch to restore it:

diff --git a/lisp/isearch.el b/lisp/isearch.el
index 4b35f25..23ca18c 100644
--- a/lisp/isearch.el
+++ b/lisp/isearch.el
@@ -638,6 +638,9 @@ (defvar isearch-recursive-edit nil)
 ;; Should isearch be terminated after doing one search?
 (defvar isearch-nonincremental nil)
 
+;; New value of isearch-nonincremental after isearch-edit-string.
+(defvar isearch-new-nonincremental nil)
+
 ;; New value of isearch-forward after isearch-edit-string.
 (defvar isearch-new-forward nil)
 
@@ -1228,7 +1231,7 @@ (defmacro with-isearch-suspended (&rest body)
   "Exit Isearch mode, run BODY, and reinvoke the pending search.
 You can update the global isearch variables by setting new values to
 `isearch-new-string', `isearch-new-message', `isearch-new-forward',
-`isearch-new-regexp-function', `isearch-new-case-fold'."
+`isearch-new-nonincremental', `isearch-new-regexp-function', `isearch-new-case-fold'."
   ;; This code is very hairy for several reasons, explained in the code.
   ;; Mainly, isearch-mode must be terminated while editing and then restarted.
   ;; If there were a way to catch any change of buffer from the minibuffer,
@@ -1236,7 +1239,7 @@ (defmacro with-isearch-suspended (&rest body)
   ;; Editing doesn't back up the search point.  Should it?
   `(condition-case nil
       (progn
-	(let ((isearch-nonincremental isearch-nonincremental)
+	(let ((isearch-new-nonincremental isearch-nonincremental)
 
 	      ;; Locally bind all isearch global variables to protect them
 	      ;; from recursive isearching.
@@ -1315,6 +1318,7 @@ (defmacro with-isearch-suspended (&rest body)
 	    (setq isearch-string isearch-new-string
 		  isearch-message isearch-new-message
 		  isearch-forward isearch-new-forward
+		  isearch-nonincremental isearch-new-nonincremental
 		  isearch-regexp-function isearch-new-regexp-function
 		  isearch-case-fold-search isearch-new-case-fold
 		  multi-isearch-current-buffer multi-isearch-current-buffer-new
@@ -1405,22 +1409,22 @@ (defun isearch-edit-string ()
 
 (defun isearch-nonincremental-exit-minibuffer ()
   (interactive)
-  (setq isearch-nonincremental t)
+  (setq isearch-new-nonincremental t)
   (exit-minibuffer))
-;; Changing the value of `isearch-nonincremental' has no effect here,
-;; because `isearch-edit-string' ignores this change.  Thus marked as obsolete.
+;; It makes no sense to change the value of `isearch-new-nonincremental'
+;; from nil to t during `isearch-edit-string'.   Thus marked as obsolete.
 (make-obsolete 'isearch-nonincremental-exit-minibuffer 'exit-minibuffer "24.4")
 
 (defun isearch-forward-exit-minibuffer ()
   "Resume isearching forward from the minibuffer that edits the search string."
   (interactive)
-  (setq isearch-new-forward t)
+  (setq isearch-new-forward t isearch-new-nonincremental nil)
   (exit-minibuffer))
 
 (defun isearch-reverse-exit-minibuffer ()
   "Resume isearching backward from the minibuffer that edits the search string."
   (interactive)
-  (setq isearch-new-forward nil)
+  (setq isearch-new-forward nil isearch-new-nonincremental nil)
   (exit-minibuffer))