Handle context changes in Tramp kubernetes method

* doc/misc/tramp.texi (Inline methods): Remove note about cache reset.
(File name completion): Add tramp-completion-use-cache.

* etc/NEWS: Add 'tramp-completion-use-cache'.

* lisp/net/tramp-cache.el (tramp-completion-use-cache): New defcustom.
(tramp-parse-connection-properties): Use it.

* lisp/net/tramp-container.el (tramp-docker--completion-function)
(tramp-kubernetes--completion-function): Ensure the processes run
locally.
(tramp-kubernetes--current-context-data): New defun.
(tramp-methods) <kubernetes>: Add `tramp-config-check'.

* lisp/net/tramp-sh.el (tramp-open-connection-setup-interactive-shell):
Handle `tramp-login-args'.

* lisp/net/tramp.el (tramp-methods): Adapt docstring.

6 files changed, 89 insertions, 20 deletions

diff --git a/doc/misc/tramp.texi b/doc/misc/tramp.texi
index e74d382fa18..99a268367b8 100644
--- a/doc/misc/tramp.texi
+++ b/doc/misc/tramp.texi
@@ -925,12 +925,6 @@ Integration for containers in Kubernetes pods.  The host name is a pod
 name returned by @samp{kubectl get pods}.  The first container in a
 pod is used.
 
-@samp{kubectl get pods} returns pods in the current context and
-namespace.  Current namespace can be changed with @samp{kubectl config
-set-context --current --namespace=<name>}.  After invoking this or
-other command which modifies Kubernetes environment outside of Emacs,
-call @code{tramp-cleanup-all-connections} to reset Tramp cache data.
-
 This method does not support user names.
 
 @end table
@@ -3538,9 +3532,14 @@ the @file{~/.authinfo.gpg} authentication file.  The user option
 @code{tramp-completion-use-auth-sources} controls, whether such a
 search is performed during completion.
 
+@vindex tramp-completion-use-cache
 Remote hosts previously visited or hosts whose connections are kept
 persistently (@pxref{Connection caching}) will be included in the
-completion lists.
+completion lists.  If you want to suppress this completion because
+there are invalid entries in the persistency file, for example if the
+host configuration changes often, or if you plug your laptop to
+different networks frequently, you can set the user option
+@code{tramp-completion-use-cache} to nil.
 
 After remote host name completion comes completion of file names on
 the remote host.  It works the same as with local host file completion
diff --git a/etc/NEWS b/etc/NEWS
index aacad8bc4df..6622f2d4ad6 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2517,6 +2517,12 @@ the user requesting such a connection, and not of the user who is the
 target.  This has always been needed, just the password prompt and the
 related 'auth-sources' entry were wrong.
 
++++
+*** New user option 'tramp-completion-use-cache'.
+During user and host name completion in the minibuffer, results from
+Tramp's connection cache are taken into account.  This can be disabled
+by setting the user option 'tramp-completion-use-cache' to nil.
+
 ** Browse URL
 
 ---
diff --git a/lisp/net/tramp-cache.el b/lisp/net/tramp-cache.el
index 4d7d35a4de6..912ea5f8bbd 100644
--- a/lisp/net/tramp-cache.el
+++ b/lisp/net/tramp-cache.el
@@ -602,18 +602,29 @@ PROPERTIES is a list of file properties (strings)."
                          #'tramp-dump-connection-properties)))
 
 ;;;###tramp-autoload
+(defcustom tramp-completion-use-cache t
+  "Whether to use the Tramp cache for completion of user and host names.
+Set it to nil if there are invalid entries in the cache, for
+example if the host configuration changes often, or if you plug
+your laptop to different networks frequently."
+  :group 'tramp
+  :version "29.1"
+  :type 'boolean)
+
+;;;###tramp-autoload
 (defun tramp-parse-connection-properties (method)
   "Return a list of (user host) tuples allowed to access for METHOD.
 This function is added always in `tramp-get-completion-function'
 for all methods.  Resulting data are derived from connection history."
-  (mapcar
-   (lambda (key)
-     (and (tramp-file-name-p key)
-          (string-equal method (tramp-file-name-method key))
-          (not (tramp-file-name-localname key))
-          (list (tramp-file-name-user key)
-                (tramp-file-name-host key))))
-   (hash-table-keys tramp-cache-data)))
+  (and tramp-completion-use-cache
+       (mapcar
+        (lambda (key)
+          (and (tramp-file-name-p key)
+               (string-equal method (tramp-file-name-method key))
+               (not (tramp-file-name-localname key))
+               (list (tramp-file-name-user key)
+                     (tramp-file-name-host key))))
+        (hash-table-keys tramp-cache-data))))
 
 ;; When "emacs -Q" has been called, both variables are nil.  We do not
 ;; load the persistency file then, in order to have a clean test environment.
diff --git a/lisp/net/tramp-container.el b/lisp/net/tramp-container.el
index e104babed27..0879d6f1856 100644
--- a/lisp/net/tramp-container.el
+++ b/lisp/net/tramp-container.el
@@ -101,7 +101,8 @@
 
 This function is used by `tramp-set-completion-function', please
 see its function help for a description of the format."
-  (when-let ((raw-list (shell-command-to-string
+  (when-let ((default-directory tramp-compat-temporary-file-directory)
+             (raw-list (shell-command-to-string
                         (concat tramp-docker-program
                                 " ps --format '{{.ID}}\t{{.Names}}'")))
              (lines (split-string raw-list "\n" 'omit))
@@ -121,7 +122,8 @@ see its function help for a description of the format."
 
 This function is used by `tramp-set-completion-function', please
 see its function help for a description of the format."
-  (when-let ((raw-list (shell-command-to-string
+  (when-let ((default-directory tramp-compat-temporary-file-directory)
+             (raw-list (shell-command-to-string
                         (concat tramp-kubernetes-program
                                 " get pods --no-headers "
                                 "-o custom-columns=NAME:.metadata.name")))
@@ -130,6 +132,24 @@ see its function help for a description of the format."
               (list nil name))
             names)))
 
+(defun tramp-kubernetes--current-context-data (vec)
+  "Return Kubernetes current context data as JSONPATH string."
+  (with-temp-buffer
+    (when (zerop
+           (tramp-call-process
+            vec tramp-kubernetes-program nil t nil
+            "config" "current-context"))
+      (goto-char (point-min))
+      (let ((current-context (buffer-substring (point) (line-end-position))))
+        (erase-buffer)
+        (when (zerop
+               (tramp-call-process
+                vec tramp-kubernetes-program nil t nil
+                "config" "view" "-o"
+                (format
+                 "jsonpath='{.contexts[?(@.name == \"%s\")]}'" current-context)))
+          (buffer-string))))))
+
 ;;;###tramp-autoload
 (defvar tramp-default-remote-shell) ;; Silence byte compiler.
 
@@ -165,6 +185,7 @@ see its function help for a description of the format."
                                    ("-it")
                                    ("--")
                                    ("%l")))
+                (tramp-config-check tramp-kubernetes--current-context-data)
                 (tramp-remote-shell ,tramp-default-remote-shell)
                 (tramp-remote-shell-login ("-l"))
                 (tramp-remote-shell-args ("-i" "-c"))))
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index d74afc84126..3904348232b 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -4472,7 +4472,8 @@ process to set up.  VEC specifies the connection."
   ;; Check whether the output of "uname -sr" has been changed.  If
   ;; yes, this is a strong indication that we must expire all
   ;; connection properties.  We start again with
-  ;; `tramp-maybe-open-connection', it will be caught there.
+  ;; `tramp-maybe-open-connection', it will be caught there.  The same
+  ;; check will be applied with the function kept in`tramp-config-check'.
   (tramp-message vec 5 "Checking system information")
   (let* ((old-uname (tramp-get-connection-property vec "uname"))
          (uname
@@ -4481,8 +4482,23 @@ process to set up.  VEC specifies the connection."
               old-uname
             (tramp-set-connection-property
              vec "uname"
-             (tramp-send-command-and-read vec "echo \\\"`uname -sr`\\\"")))))
-    (when (and (stringp old-uname) (not (string-equal old-uname uname)))
+             (tramp-send-command-and-read vec "echo \\\"`uname -sr`\\\""))))
+         (config-check-function
+          (tramp-get-method-parameter vec 'tramp-config-check))
+         (old-config-check
+          (and config-check-function
+               (tramp-get-connection-property vec "config-check-data")))
+         (config-check
+          (and config-check-function
+               ;; If we are in `make-process', we don't need to recompute.
+               (if (and old-config-check
+                        (tramp-get-connection-property vec "process-name"))
+                   old-config-check
+                 (tramp-set-connection-property
+                  vec "config-check-data"
+                  (tramp-compat-funcall config-check-function vec))))))
+    (when (and (stringp old-uname) (stringp uname)
+               (not (string-equal old-uname uname)))
       (tramp-message
        vec 3
        "Connection reset, because remote host changed from `%s' to `%s'"
@@ -4490,6 +4506,15 @@ process to set up.  VEC specifies the connection."
       ;; We want to keep the password.
       (tramp-cleanup-connection vec t t)
       (throw 'uname-changed (tramp-maybe-open-connection vec)))
+    (when (and (stringp old-config-check) (stringp config-check)
+               (not (string-equal old-config-check config-check)))
+      (tramp-message
+       vec 3
+       "Connection reset, because remote configuration changed from `%s' to `%s'"
+       old-config-check config-check)
+      ;; We want to keep the password.
+      (tramp-cleanup-connection vec t t)
+      (throw 'uname-changed (tramp-maybe-open-connection vec)))
 
     ;; Try to set up the coding system correctly.
     ;; CCC this can't be the right way to do it.  Hm.
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index c06adb01e8c..63f313dc509 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -281,6 +281,13 @@ pair of the form (KEY VALUE).  The following KEYs are defined:
     Until now, just \"ssh\"-based, \"sshfs\"-based and
     \"adb\"-based methods do.
 
+  * `tramp-config-check'
+    A function to be called with one argument, VEC.  It should
+    return a string which is used to check, whether the
+    configuration of the remote host has been changed (which
+    would require to flush the cache data).  This string is kept
+    as connection property \"config-check-data\".
+
   * `tramp-copy-program'
     This specifies the name of the program to use for remotely copying
     the file; this might be the absolute filename of scp or the name of