Fix various problems in treesit-explore-mode (bug#60800)

* lisp/treesit.el:
(treesit--explorer-kill-explorer-buffer): New function.
(treesit-explore-mode):
1. Move prompt for language earlier, and terminate early if language
not available.
2. Make sure desktop-save doesn't save the explorer buffer.
3. Kill the explorer buffer when the source buffer is killed.

diff --git a/lisp/treesit.el b/lisp/treesit.el
index 5a65d565236b8fd9ac7f9227275ba463eb3b7b15..660039cc7cc56cbde714522c43108dea6586f017 100644 (file)
--- a/lisp/treesit.el
+++ b/lisp/treesit.el
@@ -2621,6 +2621,11 @@ leaves point at the end of the last line of NODE."
       (when (not named)
         (overlay-put ov 'face 'treesit-explorer-anonymous-node)))))
 
+(defun treesit--explorer-kill-explorer-buffer ()
+  "Kill the explorer buffer of this buffer."
+  (when (buffer-live-p treesit--explorer-buffer)
+    (kill-buffer treesit--explorer-buffer)))
+
 (define-derived-mode treesit--explorer-tree-mode special-mode
   "TS Explorer"
   "Mode for displaying syntax trees for `treesit-explore-mode'."
@@ -2632,30 +2637,46 @@ Pops up a window showing the syntax tree of the source in the
 current buffer in real time.  The corresponding node enclosing
 the text in the active region is highlighted in the explorer
 window."
-  :lighter " TSplay"
+  :lighter " TSexplore"
   (if treesit-explore-mode
-      (progn
-        (unless (buffer-live-p treesit--explorer-buffer)
-          (setq-local treesit--explorer-buffer
-                      (get-buffer-create
-                       (format "*tree-sitter explorer for %s*"
-                               (buffer-name))))
-          (setq-local treesit--explorer-language
-                      (intern (completing-read
+      (let ((language (intern (completing-read
                                "Language: "
                                (mapcar #'treesit-parser-language
-                                       (treesit-parser-list)))))
-          (with-current-buffer treesit--explorer-buffer
-            (treesit--explorer-tree-mode)))
-        (display-buffer treesit--explorer-buffer
-                        (cons nil '((inhibit-same-window . t))))
-        (treesit--explorer-refresh)
-        (add-hook 'post-command-hook
-                  #'treesit--explorer-post-command 0 t)
-        (setq-local treesit--explorer-last-node nil))
+                                       (treesit-parser-list))))))
+        (if (not (treesit-language-available-p language))
+            (user-error "Cannot find tree-sitter grammar for %s: %s"
+                        language (cdr (treesit-language-available-p
+                                       language t)))
+          ;; Create explorer buffer.
+          (unless (buffer-live-p treesit--explorer-buffer)
+            (setq-local treesit--explorer-buffer
+                        (get-buffer-create
+                         (format "*tree-sitter explorer for %s*"
+                                 (buffer-name))))
+            (setq-local treesit--explorer-language language)
+            (with-current-buffer treesit--explorer-buffer
+              (treesit--explorer-tree-mode)))
+          (display-buffer treesit--explorer-buffer
+                          (cons nil '((inhibit-same-window . t))))
+          (treesit--explorer-refresh)
+          ;; Setup variables and hooks.
+          (add-hook 'post-command-hook
+                    #'treesit--explorer-post-command 0 t)
+          (add-hook 'kill-buffer-hook
+                    #'treesit--explorer-kill-explorer-buffer 0 t)
+          (setq-local treesit--explorer-last-node nil)
+          ;; Tell `desktop-save' to not save explorer buffers.
+          (when (boundp 'desktop-modes-not-to-save)
+            (unless (memq 'treesit--explorer-tree-mode
+                          desktop-modes-not-to-save)
+              (push 'treesit--explorer-tree-mode
+                    desktop-modes-not-to-save)))))
+    ;; Turn off explore mode.
     (remove-hook 'post-command-hook
                  #'treesit--explorer-post-command t)
-    (kill-buffer treesit--explorer-buffer)))
+    (remove-hook 'post-command-hook
+                 #'treesit--explorer-kill-explorer-buffer t)
+    (treesit--explorer-kill-explorer-buffer)))
 
 ;;; Install & build language grammar