scratch/icomplete-vertical-mode-improvements 00c0648 2/2: Don't break icomplete-vertical-mode scrolling when moving non-destructively

[João Távora]

branch: scratch/icomplete-vertical-mode-improvements
commit 00c0648dc00475ed9666dbe2e03f6a1d177a2140
Author: João Távora <joaotavora@gmail.com>
Commit: João Távora <joaotavora@gmail.com>

    Don't break icomplete-vertical-mode scrolling when moving non-destructively
    
    * lisp/icomplete.el (icomplete--render-vertical): Rework.
---
 lisp/icomplete.el | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/lisp/icomplete.el b/lisp/icomplete.el
index abb13e5..2575b3c 100644
--- a/lisp/icomplete.el
+++ b/lisp/icomplete.el
@@ -721,13 +721,15 @@ Return a list of (COMP PREFIX SUFFIX)."
 (cl-defun icomplete--render-vertical (comps md)
   ;; This is loopapalooza
   ;;
-  ;; First, attempt to keep selection stable.
+  ;; First, attempt to keep selection stable.  Do this only if the
+  ;; selection didn't change but the candidates did.
   (when (and icomplete--last-selected
+             (not (eq (cdr icomplete--last-selected) (buffer-modified-tick)))
              (null icomplete-rotate))
     (cl-loop
      with preds
      for (comp . rest) on comps
-     when (equal comp icomplete--last-selected)
+     when (equal comp (car icomplete--last-selected))
      do
      (setq icomplete--comp-predecessors preds
            comps (cons comp rest))
@@ -760,15 +762,16 @@ Return a list of (COMP PREFIX SUFFIX)."
    (setq neighbour (pop succs)) into after
    while neighbour
    finally
+   (setq icomplete--last-selected
+         (cons (propertize (car comps) 'face
+                           'icomplete-selected-match)
+               (buffer-modified-tick)))
    ;; Now figure out spacing and layout
    ;;
    (cl-loop
     with torender
     = (nconc before
-             (list
-              (setq icomplete--last-selected
-                    (propertize (car comps) 'face
-                                'icomplete-selected-match)))
+             (list (car icomplete--last-selected))
              after)
     with triplets = (icomplete--affixate md torender)
     initially (when (eq triplets torender)