* lisp/minibuffer.el (completion--all-sorted-completions-location): New var.

(completion--cache-all-sorted-completions)
(completion--flush-all-sorted-completions): Use it.
(completion-in-region, completion-in-region--postch)
(completion-at-point, completion-help-at-point): Use markers in
completion-in-region--data.

Fixes: debbugs:12619

2 files changed, 69 insertions, 47 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index df7420c30a3..c84d0110fc7 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,12 @@
+2012-10-24  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+        * minibuffer.el (completion--all-sorted-completions-location): New var.
+        (completion--cache-all-sorted-completions)
+        (completion--flush-all-sorted-completions): Use it.
+        (completion-in-region, completion-in-region--postch)
+        (completion-at-point, completion-help-at-point): Use markers in
+        completion-in-region--data (bug#12619).
+
 2012-10-23  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * progmodes/compile.el (compilation-start): Try to handle common
diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index f865a0269d4..3f9ec339c78 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -871,6 +871,7 @@ completion candidates than this number."
 
 (defvar completion-all-sorted-completions nil)
 (make-variable-buffer-local 'completion-all-sorted-completions)
+(defvar-local completion--all-sorted-completions-location nil)
 (defvar completion-cycling nil)
 
 (defvar completion-fail-discreetly nil
@@ -1048,14 +1049,19 @@ scroll the window of possible completions."
 
 (defun completion--cache-all-sorted-completions (comps)
   (add-hook 'after-change-functions
-               'completion--flush-all-sorted-completions nil t)
+            'completion--flush-all-sorted-completions nil t)
+  (setq completion--all-sorted-completions-location
+        (cons (copy-marker (field-beginning)) (copy-marker (field-end))))
   (setq completion-all-sorted-completions comps))
 
-(defun completion--flush-all-sorted-completions (&rest _ignore)
-  (remove-hook 'after-change-functions
-               'completion--flush-all-sorted-completions t)
-  (setq completion-cycling nil)
-  (setq completion-all-sorted-completions nil))
+(defun completion--flush-all-sorted-completions (&rest start end len)
+  (unless (and start end
+               (or (> start (cdr completion--all-sorted-completions-location))
+                   (< end (car completion--all-sorted-completions-location))))
+    (remove-hook 'after-change-functions
+                 'completion--flush-all-sorted-completions t)
+    (setq completion-cycling nil)
+    (setq completion-all-sorted-completions nil)))
 
 (defun completion--metadata (string base md-at-point table pred)
   ;; Like completion-metadata, but for the specific case of getting the
@@ -1758,7 +1764,10 @@ exit."
       (when completion-in-region-mode-predicate
         (completion-in-region-mode 1)
         (setq completion-in-region--data
-              (list (current-buffer) start end collection)))
+              (list (if (markerp start) start (copy-marker start))
+                    (copy-marker end) collection)))
+      ;; FIXME: `minibuffer-complete' should call `completion-in-region' rather
+      ;; than the other way around!
       (unwind-protect
           (call-interactively 'minibuffer-complete)
         (delete-overlay ol)))))
@@ -1782,12 +1791,12 @@ exit."
   (or unread-command-events ;Don't pop down the completions in the middle of
                             ;mouse-drag-region/mouse-set-point.
       (and completion-in-region--data
-           (and (eq (car completion-in-region--data)
+           (and (eq (marker-buffer (nth 0 completion-in-region--data))
                     (current-buffer))
-                (>= (point) (nth 1 completion-in-region--data))
+                (>= (point) (nth 0 completion-in-region--data))
                 (<= (point)
                     (save-excursion
-                      (goto-char (nth 2 completion-in-region--data))
+                      (goto-char (nth 1 completion-in-region--data))
                       (line-end-position)))
                 (funcall completion-in-region-mode--predicate)))
       (completion-in-region-mode -1)))
@@ -1892,17 +1901,19 @@ The completion method is determined by `completion-at-point-functions'."
   (let ((res (run-hook-wrapped 'completion-at-point-functions
                                #'completion--capf-wrapper 'all)))
     (pcase res
-     (`(,_ . ,(and (pred functionp) f)) (funcall f))
-     (`(,hookfun . (,start ,end ,collection . ,plist))
-      (let* ((completion-extra-properties plist)
-             (completion-in-region-mode-predicate
-              (lambda ()
-                ;; We're still in the same completion field.
-                (eq (car-safe (funcall hookfun)) start))))
-        (completion-in-region start end collection
-                              (plist-get plist :predicate))))
-     ;; Maybe completion already happened and the function returned t.
-     (_ (cdr res)))))
+      (`(,_ . ,(and (pred functionp) f)) (funcall f))
+      (`(,hookfun . (,start ,end ,collection . ,plist))
+       (unless (markerp start) (setq start (copy-marker start)))
+       (let* ((completion-extra-properties plist)
+              (completion-in-region-mode-predicate
+               (lambda ()
+                 ;; We're still in the same completion field.
+                 (let ((newstart (car-safe (funcall hookfun))))
+                   (and newstart (= newstart start))))))
+         (completion-in-region start end collection
+                               (plist-get plist :predicate))))
+      ;; Maybe completion already happened and the function returned t.
+      (_ (cdr res)))))
 
 (defun completion-help-at-point ()
   "Display the completions on the text around point.
@@ -1914,32 +1925,34 @@ The completion method is determined by `completion-at-point-functions'."
     (pcase res
       (`(,_ . ,(and (pred functionp) f))
        (message "Don't know how to show completions for %S" f))
-     (`(,hookfun . (,start ,end ,collection . ,plist))
-      (let* ((minibuffer-completion-table collection)
-             (minibuffer-completion-predicate (plist-get plist :predicate))
-             (completion-extra-properties plist)
-             (completion-in-region-mode-predicate
-              (lambda ()
-                ;; We're still in the same completion field.
-                (eq (car-safe (funcall hookfun)) start)))
-             (ol (make-overlay start end nil nil t)))
-        ;; FIXME: We should somehow (ab)use completion-in-region-function or
-        ;; introduce a corresponding hook (plus another for word-completion,
-        ;; and another for force-completion, maybe?).
-        (overlay-put ol 'field 'completion)
-        (overlay-put ol 'priority 100)
-        (completion-in-region-mode 1)
-        (setq completion-in-region--data
-              (list (current-buffer) start end collection))
-        (unwind-protect
-            (call-interactively 'minibuffer-completion-help)
-          (delete-overlay ol))))
-     (`(,hookfun . ,_)
-      ;; The hook function already performed completion :-(
-      ;; Not much we can do at this point.
-      (message "%s already performed completion!" hookfun)
-      nil)
-     (_ (message "Nothing to complete at point")))))
+      (`(,hookfun . (,start ,end ,collection . ,plist))
+       (unless (markerp start) (setq start (copy-marker start)))
+       (let* ((minibuffer-completion-table collection)
+              (minibuffer-completion-predicate (plist-get plist :predicate))
+              (completion-extra-properties plist)
+              (completion-in-region-mode-predicate
+               (lambda ()
+                 ;; We're still in the same completion field.
+                 (let ((newstart (car-safe (funcall hookfun))))
+                   (and newstart (= newstart start)))))
+              (ol (make-overlay start end nil nil t)))
+         ;; FIXME: We should somehow (ab)use completion-in-region-function or
+         ;; introduce a corresponding hook (plus another for word-completion,
+         ;; and another for force-completion, maybe?).
+         (overlay-put ol 'field 'completion)
+         (overlay-put ol 'priority 100)
+         (completion-in-region-mode 1)
+         (setq completion-in-region--data
+               (list start (copy-marker end) collection))
+         (unwind-protect
+             (call-interactively 'minibuffer-completion-help)
+           (delete-overlay ol))))
+      (`(,hookfun . ,_)
+       ;; The hook function already performed completion :-(
+       ;; Not much we can do at this point.
+       (message "%s already performed completion!" hookfun)
+       nil)
+      (_ (message "Nothing to complete at point")))))
 
 ;;; Key bindings.