fix: magnifier buffer-switch + cursor visibility (architect-critic-coder pipeline)

config.el

@@ -824,16 +824,15 @@ Keeps the status bar and tab bar fully visible at any zoom level.")
 ;;   RIGHT pane (60%): zvětšený pohled — indirect buffer, sleduje cursor
 ;;
 ;; Funkce:
-;;   - Sleduje cursor v aktivním okně (post-command-hook)
+;;   - Sleduje cursor v aktivním okně (post-command-hook + buffer-list-update-hook)
-;;   - Přepíná automaticky při změně bufferu/okna (buffer switch)
+;;   - Přepíná automaticky při změně bufferu/okna
 ;;   - SPC z + / SPC z =   zoom in  (jen magnifier, ne globálně)
 ;;   - SPC z -             zoom out (jen magnifier)
 ;;   - SPC z 0             reset zoom magnifieru na výchozí
 ;;   - SPC z m             toggle on/off
-;;   - Všechny zoom příkazy jsou no-op pokud magnifier vypnut
+;;   - Kurzor v magnifier pane viditelný (hollow cursor v non-selected windows)
-;;   - Kurzor v magnifier pane skrytý (cursor-type nil)
+;;   - Magnifier pane je dedicated — Emacs do něj neotevírá jiné buffery
-;;   - Magnifier pane je read-only zobrazení (žádné edit v indirect buf)
+;;   - Správné cleanup při window close, buffer kill, workspace switch
-;;   - Správné cleanup při window-configuration-change
 
 (defvar my/mag--active nil "Non-nil when split magnifier is enabled.")
 (defvar my/mag--window nil "The magnified (right) window.")
@@ -848,51 +847,64 @@ Keeps the status bar and tab bar fully visible at any zoom level.")
     (kill-buffer my/mag--buffer))
   (setq my/mag--buffer nil))
 
+(defun my/mag--setup-mag-window ()
+  "Configure magnifier window display settings.
+Call after `set-window-buffer' on `my/mag--window'."
+  (when (and my/mag--window (window-live-p my/mag--window))
+    (set-window-dedicated-p my/mag--window t)
+    (set-window-parameter my/mag--window 'no-other-window t)
+    (with-selected-window my/mag--window
+      (text-scale-set my/mag--zoom-level)
+      (setq-local cursor-type 'box)
+      (setq-local cursor-in-non-selected-windows 'hollow)
+      (setq-local scroll-margin 0)
+      (when (bound-and-true-p display-line-numbers-mode)
+        (display-line-numbers-mode -1))
+      (when (bound-and-true-p hl-line-mode)
+        (hl-line-mode -1)))))
+
+(defun my/mag--valid-source-p (buf)
+  "Return non-nil if BUF is a valid magnifier source buffer."
+  (and (buffer-live-p buf)
+       (not (minibufferp buf))
+       (not (string-prefix-p " " (buffer-name buf)))
+       (not (string-prefix-p "*mag:" (buffer-name buf)))))
+
 (defun my/mag--switch-source ()
   "Switch magnifier to track the current buffer."
-  (cl-block my/mag--switch-source
+  (let ((new-source (window-buffer (selected-window))))
-    (let* ((new-source (current-buffer))
+    (when (my/mag--valid-source-p new-source)
-           (mag-name (format "*mag:%s*" (buffer-name new-source))))
-      ;; Don't switch to transient/minibuffer buffers
-      (when (or (minibufferp new-source)
-                (string-prefix-p " " (buffer-name new-source)))
-        (cl-return-from my/mag--switch-source))
       (my/mag--kill-indirect)
       (setq my/mag--source new-source)
-      (setq my/mag--buffer (make-indirect-buffer new-source mag-name t))
+      (let ((mag-name (format "*mag:%s*" (buffer-name new-source))))
+        ;; Clean up stale buffer with same name
+        (when-let ((old (get-buffer mag-name)))
+          (kill-buffer old))
+        (setq my/mag--buffer (make-indirect-buffer new-source mag-name t)))
       (when (and my/mag--window (window-live-p my/mag--window))
+        (set-window-dedicated-p my/mag--window nil)  ; temporarily un-dedicate
         (set-window-buffer my/mag--window my/mag--buffer)
-        (with-selected-window my/mag--window
+        (my/mag--setup-mag-window)))))
-          (text-scale-set my/mag--zoom-level)
-          (setq-local cursor-type 'box)
-          (setq-local scroll-margin 0)
-          (when (bound-and-true-p display-line-numbers-mode)
-            (display-line-numbers-mode -1))
-          (when (bound-and-true-p hl-line-mode)
-            (hl-line-mode -1)))))))
 
 (defun my/mag--sync ()
   "Sync magnified pane to current cursor position."
-  (when my/mag--active
+  (when (and my/mag--active
-    ;; Skip when minibuffer is active (M-x, vertico, which-key, etc.)
+             my/mag--window (window-live-p my/mag--window)
-    (when (or (active-minibuffer-window)
+             (not (active-minibuffer-window))
-              (window-minibuffer-p))
+             (not (window-minibuffer-p))
-      (cl-return-from my/mag--sync))
+             (not (eq (selected-window) my/mag--window))
-    ;; Ignore if we're in the magnifier pane itself
+             (not (window-parameter (selected-window) 'window-side)))
-    (when (eq (selected-window) my/mag--window)
+    (let ((cur-buf (window-buffer (selected-window))))
-      (cl-return-from my/mag--sync))
+      ;; Switch source if buffer changed (only for valid buffers)
-    ;; Check magnifier window is still alive
+      (when (and (not (eq cur-buf my/mag--source))
-    (unless (and my/mag--window (window-live-p my/mag--window))
+                 (my/mag--valid-source-p cur-buf))
-      (cl-return-from my/mag--sync))
+        (my/mag--switch-source))
-    ;; Switch source if buffer changed
+      ;; Sync point + recenter
-    (unless (eq (current-buffer) my/mag--source)
+      (when (and my/mag--buffer (buffer-live-p my/mag--buffer))
-      (my/mag--switch-source))
+        (let ((pt (window-point (selected-window))))
-    ;; Sync point + recenter
+          (with-selected-window my/mag--window
-    (when (and my/mag--buffer (buffer-live-p my/mag--buffer))
+            (goto-char pt)
-      (let ((pt (point)))
+            (recenter)))))))
-        (with-selected-window my/mag--window
-          (goto-char pt)
-          (recenter))))))
 
 (defun my/mag--on-window-change ()
   "Clean up if magnifier window was closed by user."
@@ -901,6 +913,23 @@ Keeps the status bar and tab bar fully visible at any zoom level.")
              (not (and my/mag--window (window-live-p my/mag--window))))
     (my/mag--disable)))
 
+(defun my/mag--on-source-killed ()
+  "Handle source buffer being killed."
+  (when (and my/mag--active
+             (eq (current-buffer) my/mag--source))
+    ;; Try to switch to another visible buffer, or disable
+    (let ((alt (cl-find-if
+                (lambda (b)
+                  (and (not (eq b (current-buffer)))
+                       (my/mag--valid-source-p b)))
+                (buffer-list))))
+      (if alt
+          (progn
+            (set-window-buffer (selected-window) alt)
+            (setq my/mag--source nil)  ; force switch
+            (my/mag--switch-source))
+        (my/mag--disable)))))
+
 (defun my/mag--enable ()
   "Enable split-screen magnifier."
   (delete-other-windows)
@@ -916,24 +945,32 @@ Keeps the status bar and tab bar fully visible at any zoom level.")
                       (floor (* 0.4 (window-total-width)))
                       'right))
   (set-window-buffer my/mag--window my/mag--buffer)
-  (with-selected-window my/mag--window
+  (my/mag--setup-mag-window)
-    (text-scale-set my/mag--zoom-level)
-    (setq-local cursor-type 'box)
-    (setq-local scroll-margin 0)
-    (when (bound-and-true-p display-line-numbers-mode)
-      (display-line-numbers-mode -1))
-    (when (bound-and-true-p hl-line-mode)
-      (hl-line-mode -1)))
   (setq my/mag--active t)
   (add-hook 'post-command-hook #'my/mag--sync)
+  (add-hook 'buffer-list-update-hook #'my/mag--sync)
   (add-hook 'window-configuration-change-hook #'my/mag--on-window-change)
+  (add-hook 'kill-buffer-hook #'my/mag--on-source-killed)
+  (when (boundp 'persp-activated-functions)
+    (add-hook 'persp-activated-functions #'my/mag--on-persp-change))
   (message "Split magnifier ON (zoom %+d)" my/mag--zoom-level))
 
+(defun my/mag--on-persp-change (&rest _)
+  "Disable magnifier if window is dead after workspace switch."
+  (when (and my/mag--active
+             (not (window-live-p my/mag--window)))
+    (my/mag--disable)))
+
 (defun my/mag--disable ()
   "Disable split-screen magnifier."
   (remove-hook 'post-command-hook #'my/mag--sync)
+  (remove-hook 'buffer-list-update-hook #'my/mag--sync)
   (remove-hook 'window-configuration-change-hook #'my/mag--on-window-change)
+  (remove-hook 'kill-buffer-hook #'my/mag--on-source-killed)
+  (when (boundp 'persp-activated-functions)
+    (remove-hook 'persp-activated-functions #'my/mag--on-persp-change))
   (when (and my/mag--window (window-live-p my/mag--window))
+    (set-window-dedicated-p my/mag--window nil)
     (delete-window my/mag--window))
   ;; Kill all *mag:* buffers
   (dolist (buf (buffer-list))