Make eglot-ensure's post-command-hook run a bit later (bug#62065)

'eglot-ensure', typically used in the major-mode-hook, use
'post-command-hook' to schedule an automated, non-interactive
connection attempt to a server.  The goal is to connect when the
buffer is ready, i.e. after the user command that found the file.

However, if there are dir-local or buffer-local variables to confirm,
finding the file will cause a minibuffer prompt to appear.

In that case, 'eglot-ensure's addition to the global post-command-hook
runs before it was intended too and a connection is started
prematurely.

In turn, this means that a call to 'hack-dir-local-variables' -- which
is part of the connection process -- which also needs a minibuffer
prompt, collides with the previous one.  This generates an error and
confuses the user, who doesn't know if the directory-local variables
have been applied or not.

This commit fixes the clash by having 'eglot-ensure' set
'post-command-hook' buffer-locally.  This causes the automated
connection to take place, as intended, after the user's original
file-finding command has ended.

However, the problem reported in bug#62065 is not completely fixed.
If the user answers "no" to the first "confirm local variables"
"prompt, she will be prompted again in the second one.  A subsequent
commit will address this separate problem.

* lisp/progmodes/eglot.el (eglot-ensure): Use buffer-local post-command-hook.

diff --git a/lisp/progmodes/eglot.el b/lisp/progmodes/eglot.el
index 2679773c11784cf15c6f27c0ffc068ade15eab7e..758be48868065c8160606926dcf1833b7125c80a 100644 (file)
--- a/lisp/progmodes/eglot.el
+++ b/lisp/progmodes/eglot.el
@@ -1155,12 +1155,13 @@ INTERACTIVE is t if called interactively."
     (cl-labels
         ((maybe-connect
            ()
-           (remove-hook 'post-command-hook #'maybe-connect nil)
            (eglot--when-live-buffer buffer
+             (remove-hook 'post-command-hook #'maybe-connect t)
              (unless eglot--managed-mode
                (apply #'eglot--connect (eglot--guess-contact))))))
-      (when buffer-file-name
-        (add-hook 'post-command-hook #'maybe-connect 'append nil)))))
+      (when (and this-command
+                 buffer-file-name)
+        (add-hook 'post-command-hook #'maybe-connect 'append t)))))
 
 (defun eglot-events-buffer (server)
   "Display events buffer for SERVER.