Stronger check for Tramp method

* lisp/net/tramp-gvfs.el (tramp-gvfs-maybe-open-connection):
* lisp/net/tramp-rclone.el (tramp-rclone-maybe-open-connection):
* lisp/net/tramp-sudoedit.el (tramp-sudoedit-maybe-open-connection):
Use `tramp-get-connection-name'.

* lisp/net/tramp-sh.el (tramp-sh-handle-make-symbolic-link):
* lisp/net/tramp-smb.el (tramp-smb-handle-make-symbolic-link):
* lisp/net/tramp-sudoedit.el (tramp-sudoedit-handle-make-symbolic-link):
Don't check remote TARGET.

* lisp/net/tramp.el (tramp-dissect-file-name): Check for proper method.
(tramp-file-name-for-operation): Take only 2nd argument into
account for file name handler.
(tramp-file-name-handler): Suppress checks for `file-remote-p'.

* test/lisp/net/tramp-archive-tests.el
(tramp-archive-test02-file-name-dissect): Suppress check for wrong
method.

* test/lisp/net/tramp-tests.el (tramp--test-instrument-test-case):
Dump *all* Tramp buffers.
(tramp-test02-file-name-dissect)
(tramp-test02-file-name-dissect-simplified)
(tramp-test02-file-name-dissect-separate): Check also wrong method.
(tramp-test03-file-name-defaults): Check, that the respective
Tramp package is loaded.
(tramp-test04-substitute-in-file-name)
(tramp-test05-expand-file-name)
(tramp-test06-directory-file-name, tramp-test44-auto-load):
Suppress check for wrong method.
(tramp-test30-make-process): Remove instrumentation code.
(tramp-test31-interrupt-process, tramp-test36-vc-registered):
Guarantee that connection is established prior starting process.

6 files changed, 39 insertions, 25 deletions

diff --git a/lisp/net/tramp-gvfs.el b/lisp/net/tramp-gvfs.el
index 38102318240..17c2e79833b 100644
--- a/lisp/net/tramp-gvfs.el
+++ b/lisp/net/tramp-gvfs.el
@@ -1765,7 +1765,7 @@ connection if a previous connection has died for some reason."
   ;; better solution?
   (unless (get-buffer-process (tramp-get-connection-buffer vec))
     (let ((p (make-network-process
-	      :name (tramp-buffer-name vec)
+	      :name (tramp-get-connection-name vec)
 	      :buffer (tramp-get-connection-buffer vec)
 	      :server t :host 'local :service t :noquery t)))
       (process-put p 'vector vec)
diff --git a/lisp/net/tramp-rclone.el b/lisp/net/tramp-rclone.el
index 0148116d739..9e99493cbf6 100644
--- a/lisp/net/tramp-rclone.el
+++ b/lisp/net/tramp-rclone.el
@@ -543,7 +543,7 @@ connection if a previous connection has died for some reason."
       ;; we create a dummy process.  Maybe there is a better solution?
       (unless (get-buffer-process (tramp-get-connection-buffer vec))
 	(let ((p (make-network-process
-		  :name (tramp-buffer-name vec)
+		  :name (tramp-get-connection-name vec)
 		  :buffer (tramp-get-connection-buffer vec)
 		  :server t :host 'local :service t :noquery t)))
 	  (process-put p 'vector vec)
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index 2d27baf454a..34fda5af176 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -1027,11 +1027,13 @@ component is used as the target of the symlink."
 
     (with-parsed-tramp-file-name linkname nil
       ;; If TARGET is a Tramp name, use just the localname component.
-      (when (and (tramp-tramp-file-p target)
-		 (tramp-file-name-equal-p v (tramp-dissect-file-name target)))
-	(setq target
-	      (tramp-file-name-localname
-	       (tramp-dissect-file-name (expand-file-name target)))))
+      ;; Don't check for a proper method.
+      (let ((non-essential t))
+	(when (and (tramp-tramp-file-p target)
+		   (tramp-file-name-equal-p v (tramp-dissect-file-name target)))
+	  (setq target
+		(tramp-file-name-localname
+		 (tramp-dissect-file-name (expand-file-name target))))))
 
       ;; If TARGET is still remote, quote it.
       (if (tramp-tramp-file-p target)
diff --git a/lisp/net/tramp-smb.el b/lisp/net/tramp-smb.el
index 9d15c0562bf..84725db2168 100644
--- a/lisp/net/tramp-smb.el
+++ b/lisp/net/tramp-smb.el
@@ -1161,11 +1161,13 @@ component is used as the target of the symlink."
 
     (with-parsed-tramp-file-name linkname nil
       ;; If TARGET is a Tramp name, use just the localname component.
-      (when (and (tramp-tramp-file-p target)
-		 (tramp-file-name-equal-p v (tramp-dissect-file-name target)))
-	(setq target
-	      (tramp-file-name-localname
-	       (tramp-dissect-file-name (expand-file-name target)))))
+      ;; Don't check for a proper method.
+      (let ((non-essential t))
+	(when (and (tramp-tramp-file-p target)
+		   (tramp-file-name-equal-p v (tramp-dissect-file-name target)))
+	  (setq target
+		(tramp-file-name-localname
+		 (tramp-dissect-file-name (expand-file-name target))))))
 
       ;; If TARGET is still remote, quote it.
       (if (tramp-tramp-file-p target)
diff --git a/lisp/net/tramp-sudoedit.el b/lisp/net/tramp-sudoedit.el
index 0d9e04d0bd1..f056e73366e 100644
--- a/lisp/net/tramp-sudoedit.el
+++ b/lisp/net/tramp-sudoedit.el
@@ -607,11 +607,13 @@ component is used as the target of the symlink."
 
     (with-parsed-tramp-file-name linkname nil
       ;; If TARGET is a Tramp name, use just the localname component.
-      (when (and (tramp-tramp-file-p target)
-		 (tramp-file-name-equal-p v (tramp-dissect-file-name target)))
-	(setq target
-	      (tramp-file-name-localname
-	       (tramp-dissect-file-name (expand-file-name target)))))
+      ;; Don't check for a proper method.
+      (let ((non-essential t))
+	(when (and (tramp-tramp-file-p target)
+		   (tramp-file-name-equal-p v (tramp-dissect-file-name target)))
+	  (setq target
+		(tramp-file-name-localname
+		 (tramp-dissect-file-name (expand-file-name target))))))
 
       ;; If TARGET is still remote, quote it.
       (if (tramp-tramp-file-p target)
@@ -780,7 +782,7 @@ connection if a previous connection has died for some reason."
       (throw 'non-essential 'non-essential))
 
     (let ((p (make-network-process
-	      :name (tramp-buffer-name vec)
+	      :name (tramp-get-connection-name vec)
 	      :buffer (tramp-get-connection-buffer vec)
 	      :server t :host 'local :service t :noquery t)))
       (process-put p 'vector vec)
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index a2558184fb4..f6dd6b5866d 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -1435,6 +1435,12 @@ default values are used."
 	    (setq v (make-tramp-file-name
 		     :method method :user user :domain domain :host host
 		     :port port :localname localname :hop hop))
+	  ;; The method must be known.
+	  (unless (or (tramp-completion-mode-p)
+		      (string-equal method tramp-default-method-marker)
+		      (assoc method tramp-methods))
+	    (tramp-user-error
+	     v "Method `%s' is not known." method))
 	  ;; Only some methods from tramp-sh.el do support multi-hops.
 	  (when (and
 		 hop
@@ -2175,17 +2181,16 @@ Must be handled by the callers."
     (if (file-name-absolute-p (nth 0 args))
 	(nth 0 args)
       default-directory))
+   ;; STRING FILE.
+   ;; Starting with Emacs 26.1, just the 2nd argument of
+   ;; `make-symbolic-link' matters.
+   ((eq operation 'make-symbolic-link) (nth 1 args))
    ;; FILE DIRECTORY resp FILE1 FILE2.
    ((member operation
 	    '(add-name-to-file copy-directory copy-file
 	      file-equal-p file-in-directory-p
 	      file-name-all-completions file-name-completion
-	      ;; Starting with Emacs 26.1, just the 2nd argument of
-	      ;; `make-symbolic-link' matters.  For backward
-	      ;; compatibility, we still accept the first argument as
-	      ;; file name to be checked.  Handled properly in
-	      ;; `tramp-handle-*-make-symbolic-link'.
-	      file-newer-than-file-p make-symbolic-link rename-file))
+	      file-newer-than-file-p rename-file))
     (cond
      ((tramp-tramp-file-p (nth 0 args)) (nth 0 args))
      ((tramp-tramp-file-p (nth 1 args)) (nth 1 args))
@@ -2280,7 +2285,10 @@ preventing reentrant calls of Tramp.")
 (defun tramp-file-name-handler (operation &rest args)
   "Invoke Tramp file name handler.
 Falls back to normal file name handler if no Tramp file name handler exists."
-  (let ((filename (apply #'tramp-file-name-for-operation operation args)))
+  (let ((filename (apply #'tramp-file-name-for-operation operation args))
+	;; `file-remote-p' is called for everything, even for symbolic
+	;; links which look remote.  We don't want to get an error.
+	(non-essential (or non-essential (eq operation 'file-remote-p))))
     (if (tramp-tramp-file-p filename)
 	(save-match-data
           (setq filename (tramp-replace-environment-variables filename))