Fix remote-host directory tracking for shells in `term' buffers

* lisp/term.el (term-handle-ansi-terminal-messages): Use an explicit
tramp method when constructing the tramp path for a non-local host,
as this is now mandatory.  "-" is a pseudo-method for the user's
`tramp-default-method'.  (Bug#31355)

Specify the remote username explicitly in all cases, as
`tramp-default-user' and `tramp-default-user-alist' could cause the
previous logic to fail.

Minor related improvements to the commentary.

1 files changed, 16 insertions, 15 deletions

diff --git a/lisp/term.el b/lisp/term.el
index 75c27797838..419ddb2db5c 100644
--- a/lisp/term.el
+++ b/lisp/term.el
@@ -233,31 +233,33 @@
 ;;
 ;;  Notice: for directory/host/user tracking you need to have something
 ;; like this in your shell startup script (this is for a POSIXish shell
-;; like Bash but should be quite easy to port to other shells)
+;; like Bash but should be quite easy to port to other shells).
+;;
+;; For troubleshooting in Bash, you can check the definition of the
+;; custom functions with the "type" command.  e.g. "type cd".  If you
+;; do not see the expected definition from the config below, then the
+;; directory tracking will not work.
 ;;
 ;;             ----------------------------------------
 ;;
-;;  # Set HOSTNAME if not already set.
+;;      # Set HOSTNAME if not already set.
 ;;      : ${HOSTNAME=$(uname -n)}
 ;;
-;;  # su does not change this but I'd like it to
-;;
+;;      # su does not change this but I'd like it to
 ;;      USER=$(whoami)
 ;;
-;;  # ...
+;;      # ...
 ;;
 ;;      case $TERM in
 ;;          eterm*)
 ;;
 ;;              printf '%s\n' \
 ;;               -------------------------------------------------------------- \
-;;               "Hello $user" \
+;;               "Hello $USER" \
 ;;               "Today is $(date)" \
 ;;               "We are on $HOSTNAME running $(uname) under Emacs term mode" \
 ;;               --------------------------------------------------------------
 ;;
-;;              export EDITOR=emacsclient
-;;
 ;;              # The \033 stands for ESC.
 ;;              # There is a space between "AnSiT?" and $whatever.
 ;;
@@ -269,10 +271,11 @@
 ;;              printf '\033AnSiTh %s\n' "$HOSTNAME"
 ;;              printf '\033AnSiTu %s\n' "$USER"
 ;;
-;;              eval $(dircolors $HOME/.emacs_dircolors)
+;;              # Use custom dircolors in term buffers.
+;;              # eval $(dircolors $HOME/.emacs_dircolors)
 ;;      esac
 ;;
-;;  # ...
+;;      # ...
 ;;
 ;;
 
@@ -2750,12 +2753,10 @@ See `term-prompt-regexp'."
         (setq default-directory
               (file-name-as-directory
                (if (and (string= term-ansi-at-host (system-name))
-                                        (string= term-ansi-at-user (user-real-login-name)))
+                        (string= term-ansi-at-user (user-real-login-name)))
                    (expand-file-name term-ansi-at-dir)
-                 (if (string= term-ansi-at-user (user-real-login-name))
-                     (concat "/" term-ansi-at-host ":" term-ansi-at-dir)
-                   (concat "/" term-ansi-at-user "@" term-ansi-at-host ":"
-                           term-ansi-at-dir)))))
+                 (concat "/-:" term-ansi-at-user "@" term-ansi-at-host ":"
+                         term-ansi-at-dir))))
 
         ;; I'm not sure this is necessary,
         ;; but it's best to be on the safe side.