2 files changed, 28 insertions, 9 deletions

diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index 953ca54ffda..c83a7a9978d 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -4693,7 +4693,21 @@ process to set up.  VEC specifies the connection."
          t))
       (when unset
         (tramp-send-command
-         vec (format "unset %s" (string-join unset " ")) t)))))
+         vec (format "unset %s" (string-join unset " ")) t)))
+
+    ;; Set connection-local variable `command-line-max-length'.
+    ;; `command-line-max-length' exists since Emacs 31.
+    ;; `connection-local-profile-name-for-criteria' exists since Emacs 29.1.
+    ;; We simulate it with `make-symbol'.
+    (when (boundp 'command-line-max-length)
+      (let* ((criteria (tramp-get-connection-local-criteria vec))
+             (profile (if (fboundp 'connection-local-profile-name-for-criteria)
+                          (connection-local-profile-name-for-criteria criteria)
+                        (make-symbol "generated-profile-name"))))
+        (connection-local-set-profile-variables
+         profile
+         `((command-line-max-length . ,(tramp-get-remote-pipe-buf vec))))
+        (connection-local-set-profiles criteria profile)))))
 
 ;; Old text from documentation of tramp-methods:
 ;; Using a uuencode/uudecode inline method is discouraged, please use one
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 475392b68d8..5441a26d7a0 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -2097,16 +2097,24 @@ In case a second asynchronous communication has been started, it is different
 from the default one."
   (and (tramp-file-name-p vec) (get-process (tramp-get-connection-name vec))))
 
+(defsubst tramp-get-connection-local-criteria (vec)
+  "Get connection-local criteria for VEC."
+  (append
+   '(:application tramp)
+   (when (tramp-file-name-method vec)
+     `(:protocol ,(substring-no-properties (tramp-file-name-method vec))))
+   (when (tramp-file-name-user-domain vec)
+     `(:user ,(substring-no-properties (tramp-file-name-user-domain vec))))
+   (when (tramp-file-name-host-port vec)
+     `(:machine ,(substring-no-properties (tramp-file-name-host-port vec))))))
+
 (defun tramp-set-connection-local-variables (vec)
   "Set connection-local variables in the connection buffer used for VEC.
 If connection-local variables are not supported by this Emacs
 version, the function does nothing."
   (with-current-buffer (tramp-get-connection-buffer vec)
     (hack-connection-local-variables-apply
-     `(:application tramp
-       :protocol    ,(tramp-file-name-method vec)
-       :user        ,(tramp-file-name-user-domain vec)
-       :machine     ,(tramp-file-name-host-port vec)))))
+     (tramp-get-connection-local-criteria vec))))
 
 (defun tramp-set-connection-local-variables-for-buffer ()
   "Set connection-local variables in the current buffer.
@@ -2114,10 +2122,7 @@ If connection-local variables are not supported by this Emacs
 version, the function does nothing."
   (when (tramp-tramp-file-p default-directory)
     (hack-connection-local-variables-apply
-     `(:application tramp
-       :protocol    ,(file-remote-p default-directory 'method)
-       :user        ,(file-remote-p default-directory 'user)
-       :machine     ,(file-remote-p default-directory 'host)))))
+     (connection-local-criteria-for-default-directory))))
 
 (defsubst tramp-get-default-directory (buffer)
   "Return `default-directory' of BUFFER."