Re: Should ending successful Isearch with C-g restore the relative window position?

[Juri Linkov <juri@jurta.org>]

> That patch did not fix the problem when searching across Info nodes.

A more general approach would be to save the window start position on
the stack and restore it in `isearch-cancel' like the patch below does.

`isearch-done' already does something like this by restoring
the original window configuration with `set-window-configuration'
from `isearch-window-configuration'.  But it does this only
on slow terminals where baud-rate is less than 1200.  So perhaps
this patch will also make `isearch-window-configuration' obsolete.

The remaining problem is how to take into account the case
when `isearch-allow-scroll' is non-nil and the user scrolled the
window-start to another position.  We should find the right place
to update the window-start of the previous state on the search stack
to be able to restore it later.

=== modified file 'lisp/isearch.el'
--- lisp/isearch.el	2013-01-02 16:13:04 +0000
+++ lisp/isearch.el	2013-01-16 21:28:52 +0000
@@ -1036,6 +1036,7 @@ (cl-defstruct (isearch--state
                  (string isearch-string)
                  (message isearch-message)
                  (point (point))
+                 (window-start (window-start))
                  (success isearch-success)
                  (forward isearch-forward)
                  (other-end isearch-other-end)
@@ -1049,6 +1050,7 @@ (cl-defstruct (isearch--state
   (string :read-only t)
   (message :read-only t)
   (point :read-only t)
+  (window-start :read-only t)
   (success :read-only t)
   (forward :read-only t)
   (other-end :read-only t)
@@ -1072,7 +1074,9 @@ (defun isearch--set-state (cmd)
 	isearch-case-fold-search (isearch--state-case-fold-search cmd))
   (if (functionp (isearch--state-pop-fun cmd))
       (funcall (isearch--state-pop-fun cmd) cmd))
-  (goto-char (isearch--state-point cmd)))
+  (goto-char (isearch--state-point cmd))
+  (unless (eq (isearch--state-window-start cmd) (window-start))
+    (set-window-start nil (isearch--state-window-start cmd))))
 
 (defun isearch-pop-state ()
   (setq isearch-cmds (cdr isearch-cmds))
@@ -1303,12 +1307,8 @@ (defun isearch-reverse-exit-minibuffer (
 (defun isearch-cancel ()
   "Terminate the search and go back to the starting point."
   (interactive)
-  (if (and isearch-push-state-function isearch-cmds)
-      ;; For defined push-state function, restore the first state.
-      ;; This calls pop-state function and restores original point.
-      (let ((isearch-cmds (last isearch-cmds)))
-	(isearch--set-state (car isearch-cmds)))
-    (goto-char isearch-opoint))
+  (let ((isearch-cmds (last isearch-cmds)))
+    (isearch--set-state (car isearch-cmds)))
   (isearch-done t)                      ; Exit isearch..
   (isearch-clean-overlays)
   (signal 'quit nil))                   ; ..and pass on quit signal.
@@ -2646,7 +2646,9 @@ (defun isearch-search ()
     (if (functionp (isearch--state-pop-fun (car isearch-cmds)))
         (funcall (isearch--state-pop-fun (car isearch-cmds))
                  (car isearch-cmds)))
-    (goto-char (isearch--state-point (car isearch-cmds)))))
+    (goto-char (isearch--state-point (car isearch-cmds)))
+    (unless (eq (isearch--state-window-start (car isearch-cmds)) (window-start))
+      (set-window-start nil (isearch--state-window-start (car isearch-cmds))))))