Tramp: Do not raise an error when not connected (Bug#78572)

* lisp/net/tramp-cmds.el (tramp-cleanup-connection):
Use read syntax #' for `tramp-timeout-session',

* lisp/net/tramp.el (tramp-barf-if-file-missing): Do not raise an error
when not connected.  (Bug#78572)
(tramp-file-name-handler): Do not force the backtrace.
(tramp-connectable-p): Check also, whether initial handshake is finished.
(tramp-skeleton-directory-files)
(tramp-skeleton-directory-files-and-attributes)
(tramp-skeleton-set-file-modes-times-uid-gid): Rearrange sending
`file-missing' error.
(tramp-handle-access-file, tramp-handle-unlock-file):
Use `tramp-connectable-p'.

* test/lisp/net/tramp-tests.el (project-mode-line-format)
(project-mode-line): Declare.
(tramp-test48-session-timeout): New test.
(tramp-test49-auto-load, tramp-test49-delay-load)
(tramp-test49-recursive-load, tramp-test49-remote-load-path)
(tramp-test50-without-remote-files, tramp-test51-unload): Rename.

lisp/net/tramp-cmds.el

@@ -177,7 +177,7 @@ interactively, a Tramp connection has to be selected."
 
     ;; Cancel timer.
     (dolist (timer timer-list)
-      (when (and (eq (timer--function timer) 'tramp-timeout-session)
+      (when (and (eq (timer--function timer) #'tramp-timeout-session)
 		 (tramp-file-name-equal-p vec (car (timer--args timer))))
 	(cancel-timer timer)))
 

lisp/net/tramp-sh.el

@@ -5162,6 +5162,7 @@ If there is just some editing, retry it after 5 seconds."
 Does not do anything if a connection is already open, but re-opens the
 connection if a previous connection has died for some reason."
   ;; During completion, don't reopen a new connection.
+  ;; Same for slide-in timer or process-{filter,sentinel}.
   (unless (tramp-connectable-p vec)
     (throw 'non-essential 'non-essential))
 

lisp/net/tramp.el

@@ -2105,10 +2105,11 @@ does not exist, otherwise propagate the error."
   (declare (indent 2) (debug (symbolp form body)))
   (let ((err (make-symbol "err")))
     `(condition-case ,err
-         (progn ,@body)
+	 (let (signal-hook-function) ,@body)
        (error
 	(if (not (or (file-exists-p ,filename) (file-symlink-p ,filename)))
-	    (tramp-error ,vec 'file-missing ,filename)
+	    (when (tramp-connectable-p ,vec)
+	      (tramp-error ,vec 'file-missing ,filename))
 	  (signal (car ,err) (cdr ,err)))))))
 
 ;; This function provides traces in case of errors not triggered by
@@ -2561,7 +2562,7 @@ Fall back to normal file name handler if no Tramp file name handler exists."
 			  (tramp-message
 			   v 5 "Non-essential received in operation %s"
 			   (cons operation args))
-			  (let ((tramp-verbose 10)) (tramp-backtrace v))
+			  (tramp-backtrace v)
 			  (tramp-run-real-handler operation args))
 		         ((eq result 'suppress)
 			  (let ((inhibit-message t))
@@ -2793,13 +2794,15 @@ They are completed by `M-x TAB' only if there's an active connection or buffer."
   "Check if it is possible to connect the remote host without side-effects.
 This is true, if either the remote host is already connected, or if we are
 not in completion mode."
-  (let ((tramp-verbose 0)
+  (or (not non-essential)
-	(vec (tramp-ensure-dissected-file-name vec-or-filename)))
+      ;; We check this for the process related to `tramp-buffer-name';
-    (or ;; We check this for the process related to
+      ;; otherwise `make-process' wouldn't run ever when
-	;; `tramp-buffer-name'; otherwise `make-process' wouldn't run
+      ;; `non-essential' is non-nil.
-	;; ever when `non-essential' is non-nil.
+      (and-let* ((tramp-verbose 0)
-        (process-live-p (tramp-get-process vec))
+		 (vec (tramp-ensure-dissected-file-name vec-or-filename))
-	(not non-essential))))
+		 (p (tramp-get-process vec))
+		 ((process-live-p p))
+		 ((tramp-get-connection-property p "connected"))))))
 
 (defun tramp-completion-handle-expand-file-name (filename &optional directory)
   "Like `expand-file-name' for partial Tramp files."
@@ -3470,79 +3473,69 @@ BODY is the backend specific code."
   "Skeleton for `tramp-*-handle-directory-files'.
 BODY is the backend specific code."
   (declare (indent 5) (debug t))
-  `(or
+  `(with-parsed-tramp-file-name (expand-file-name ,directory) nil
-    (with-parsed-tramp-file-name (expand-file-name ,directory) nil
+     (tramp-barf-if-file-missing v ,directory
-      (tramp-barf-if-file-missing v ,directory
+       (if (not (file-directory-p ,directory))
-	(when (file-directory-p ,directory)
+	   ;; Trigger the `file-missing' error.
-	  (setf ,directory
+	   (signal 'error nil)
-		(file-name-as-directory (expand-file-name ,directory)))
+	 (setf ,directory
-	  (let ((temp
+	       (file-name-as-directory (expand-file-name ,directory)))
-		 (with-tramp-file-property v localname "directory-files" ,@body))
+	 (let ((temp
-		result item)
+		(with-tramp-file-property v localname "directory-files" ,@body))
-	    (while temp
+	       result item)
-	      (setq item (directory-file-name (pop temp)))
+	   (while temp
-	      (when (or (null ,match) (string-match-p ,match item))
+	     (setq item (directory-file-name (pop temp)))
-		(push (if ,full (concat ,directory item) item)
+	     (when (or (null ,match) (string-match-p ,match item))
-		      result)))
+	       (push (if ,full (concat ,directory item) item)
-	    (unless ,nosort
+		     result)))
-              (setq result (sort result #'string<)))
+	   (unless ,nosort
-	    (when (and (natnump ,count) (> ,count 0))
+             (setq result (sort result #'string<)))
-	      (setq result (tramp-compat-ntake ,count result)))
+	   (when (and (natnump ,count) (> ,count 0))
-	    result))))
+	     (setq result (tramp-compat-ntake ,count result)))
-
+	   result)))))
-    ;; Error handling.
-    (if (not (file-exists-p ,directory))
-	(tramp-error
-	 (tramp-dissect-file-name ,directory) 'file-missing ,directory)
-      nil)))
 
 (defmacro tramp-skeleton-directory-files-and-attributes
     (directory &optional full match nosort id-format count &rest body)
   "Skeleton for `tramp-*-handle-directory-files-and-attributes'.
 BODY is the backend specific code."
   (declare (indent 6) (debug t))
-  `(or
+  `(with-parsed-tramp-file-name (expand-file-name ,directory) nil
-    (with-parsed-tramp-file-name (expand-file-name ,directory) nil
+     (tramp-barf-if-file-missing v ,directory
-      (tramp-barf-if-file-missing v ,directory
+       (if (not (file-directory-p ,directory))
-	(when (file-directory-p ,directory)
+	   ;; Trigger the `file-missing' error.
-	  (let ((temp
+	   (signal 'error nil)
-		 (copy-tree
+	 (let ((temp
-		  (mapcar
+		(copy-tree
-		   (lambda (x)
+		 (mapcar
-		     (cons
+		  (lambda (x)
-		      (car x)
+		    (cons
-		      (tramp-convert-file-attributes
+		     (car x)
-			  v (expand-file-name (car x) localname)
+		     (tramp-convert-file-attributes
-			  ,id-format (cdr x))))
+			 v (expand-file-name (car x) localname)
-		   (with-tramp-file-property
+			 ,id-format (cdr x))))
-		       v localname "directory-files-and-attributes"
+		  (with-tramp-file-property
-		     ,@body))))
+		      v localname "directory-files-and-attributes"
-		result item)
+		    ,@body))))
+	       result item)
 
-	    (while temp
+	   (while temp
-	      (setq item (pop temp))
+	     (setq item (pop temp))
-	      (when (or (null ,match) (string-match-p ,match (car item)))
+	     (when (or (null ,match) (string-match-p ,match (car item)))
-		(when ,full
+	       (when ,full
-		  (setcar item (expand-file-name (car item) ,directory)))
+		 (setcar item (expand-file-name (car item) ,directory)))
-		(push item result)))
+	       (push item result)))
 
-	    (unless ,nosort
+	   (unless ,nosort
-	      (setq result
+	     (setq result
-		    (sort result (lambda (x y) (string< (car x) (car y))))))
+		   (sort result (lambda (x y) (string< (car x) (car y))))))
 
-	    (when (and (natnump ,count) (> ,count 0))
+	   (when (and (natnump ,count) (> ,count 0))
-	      (setq result (tramp-compat-ntake ,count result)))
+	     (setq result (tramp-compat-ntake ,count result)))
 
-	    (or result
+	   (or result
-		;; The scripts could fail, for example with huge file size.
+	       ;; The scripts could fail, for example with huge file size.
-		(tramp-handle-directory-files-and-attributes
+	       (tramp-handle-directory-files-and-attributes
-		 ,directory ,full ,match ,nosort ,id-format ,count))))))
+		,directory ,full ,match ,nosort ,id-format ,count)))))))
-
-    ;; Error handling.
-    (if (not (file-exists-p ,directory))
-	(tramp-error
-	 (tramp-dissect-file-name ,directory) 'file-missing ,directory)
-      nil)))
 
 (defcustom tramp-use-file-attributes t
   "Whether to use \"file-attributes\" connection property for check.
@@ -3850,20 +3843,23 @@ BODY is the backend specific code."
 BODY is the backend specific code."
   (declare (indent 1) (debug t))
   `(with-parsed-tramp-file-name (expand-file-name ,filename) nil
-     (when (not (file-exists-p ,filename))
+     (tramp-barf-if-file-missing v ,filename
-       (tramp-error v 'file-missing ,filename))
+       (if (not (file-exists-p ,filename))
-     (with-tramp-saved-file-properties
+	   ;; Trigger the `file-missing' error.
-	 v localname
+	   (signal 'error nil)
-	 ;; We cannot add "file-attributes", "file-executable-p",
+	 (with-tramp-saved-file-properties
-	 ;; "file-ownership-preserved-p", "file-readable-p",
+	     v localname
-	 ;; "file-writable-p".
+	     ;; We cannot add "file-attributes", "file-executable-p",
-	 '("file-directory-p" "file-exists-p" "file-symlink-p" "file-truename")
+	     ;; "file-ownership-preserved-p", "file-readable-p",
-       (tramp-flush-file-properties v localname))
+	     ;; "file-writable-p".
-     (condition-case err
+	     '("file-directory-p" "file-exists-p"
-	 (progn ,@body)
+	       "file-symlink-p" "file-truename")
-       (error (if tramp-inhibit-errors-if-setting-file-attributes-fail
+	   (tramp-flush-file-properties v localname))
-		  (display-warning 'tramp (error-message-string err))
+	 (condition-case err
-		(signal (car err) (cdr err)))))))
+	     (progn ,@body)
+	   (error (if tramp-inhibit-errors-if-setting-file-attributes-fail
+		      (display-warning 'tramp (error-message-string err))
+		    (signal (car err) (cdr err)))))))))
 
 (defmacro tramp-skeleton-write-region
   (start end filename append visit lockname mustbenew &rest body)
@@ -4051,9 +4047,7 @@ Let-bind it when necessary.")
 	(tramp-dont-suspend-timers t))
     (with-tramp-timeout
 	(timeout
-	 (unless (and-let* ((p (tramp-get-connection-process v))
+	 (unless (and (not non-essential) (tramp-connectable-p v))
-			    ((process-live-p p))
-			    ((tramp-get-connection-property p "connected"))))
 	   (tramp-cleanup-connection v 'keep-debug 'keep-password))
 	 (tramp-error
 	  v 'file-error
@@ -4939,6 +4933,7 @@ Do not set it manually, it is used buffer-local in `tramp-get-lock-pid'.")
       ;; functions like `kill-buffer' would try to reestablish the
       ;; connection.  See Bug#61663.
       (if-let* ((v (tramp-dissect-file-name file))
+		((tramp-connectable-p v))
 		((process-live-p (tramp-get-process v)))
 		(lockname (make-lock-file-name file)))
           (delete-file lockname)

test/lisp/net/tramp-tests.el

@@ -67,6 +67,7 @@
 (require 'vc-git)
 (require 'vc-hg)
 
+(declare-function project-mode-line-format "project")
 (declare-function tramp-check-remote-uname "tramp-sh")
 (declare-function tramp-find-executable "tramp-sh")
 (declare-function tramp-get-remote-chmod-h "tramp-sh")
@@ -89,6 +90,7 @@
 (defvar tramp-use-connection-share)
 
 ;; Declared in Emacs 30.1.
+(defvar project-mode-line)
 (defvar remote-file-name-access-timeout)
 (defvar remote-file-name-inhibit-delete-by-moving-to-trash)
 
@@ -8374,8 +8376,52 @@ process sentinels.  They shall not disturb each other."
   ;; Cleanup.
   (tramp-cleanup-connection tramp-test-vec 'keep-debug))
 
+;; This test is inspired by Bug#78572.
+(ert-deftest tramp-test48-session-timeout ()
+  "Check that Tramp handles a session timeout properly."
+  (skip-unless (tramp--test-enabled))
+  (skip-unless
+   (tramp-get-method-parameter tramp-test-vec 'tramp-session-timeout))
+
+  ;; We want to see the timeout message.
+  (tramp--test-instrument-test-case 3
+    (let ((remote-file-name-inhibit-cache t)
+	  (tmp-name (tramp--test-make-temp-name)))
+      (unwind-protect
+	  (progn
+	    (should-not (file-exists-p tmp-name))
+	    (write-region "foo" nil tmp-name)
+	    (should (file-exists-p tmp-name))
+
+	    (tramp-timeout-session tramp-test-vec)
+	    (should (file-exists-p tmp-name))
+	    (should (directory-files (file-name-directory tmp-name)))
+
+	    ;; `project-mode-line' was introduced in Emacs 30.1.
+	    (when (boundp 'project-mode-line)
+	      (require 'project)
+	      (ert-with-message-capture captured-messages
+		(let ((project-mode-line t))
+		  (with-temp-buffer
+		    (set-visited-file-name tmp-name)
+		    (insert "foo")
+		    (should (buffer-modified-p))
+		    (tramp-timeout-session tramp-test-vec)
+		    ;; This calls `file-directory-p' and
+		    ;; `directory-files'.  Shouldn't raise an error when
+		    ;; not connected.
+		    (project-mode-line-format)
+		    ;; Steal the file lock.
+		    (cl-letf (((symbol-function #'ask-user-about-lock) #'always))
+		      (save-buffer)))
+		  (should-not
+		   (string-match-p "File is missing:" captured-messages))))))
+
+	;; Cleanup.
+	(ignore-errors (delete-file tmp-name))))))
+
 ;; This test is inspired by Bug#29163.
-(ert-deftest tramp-test48-auto-load ()
+(ert-deftest tramp-test49-auto-load ()
   "Check that Tramp autoloads properly."
   ;; If we use another syntax but `default', Tramp is already loaded
   ;; due to the `tramp-change-syntax' call.
@@ -8400,7 +8446,7 @@ process sentinels.  They shall not disturb each other."
 	(mapconcat #'shell-quote-argument load-path " -L ")
 	(shell-quote-argument code)))))))
 
-(ert-deftest tramp-test48-delay-load ()
+(ert-deftest tramp-test49-delay-load ()
   "Check that Tramp is loaded lazily, only when needed."
   ;; Tramp is neither loaded at Emacs startup, nor when completing a
   ;; non-Tramp file name like "/foo".  Completing a Tramp-alike file
@@ -8430,7 +8476,7 @@ process sentinels.  They shall not disturb each other."
 	  (mapconcat #'shell-quote-argument load-path " -L ")
 	  (shell-quote-argument (format code tm)))))))))
 
-(ert-deftest tramp-test48-recursive-load ()
+(ert-deftest tramp-test49-recursive-load ()
   "Check that Tramp does not fail due to recursive load."
   (skip-unless (tramp--test-enabled))
 
@@ -8454,7 +8500,7 @@ process sentinels.  They shall not disturb each other."
 	  (mapconcat #'shell-quote-argument load-path " -L ")
 	  (shell-quote-argument code))))))))
 
-(ert-deftest tramp-test48-remote-load-path ()
+(ert-deftest tramp-test49-remote-load-path ()
   "Check that Tramp autoloads its packages with remote `load-path'."
   ;; `tramp-cleanup-all-connections' is autoloaded from tramp-cmds.el.
   ;; It shall still work, when a remote file name is in the
@@ -8479,7 +8525,7 @@ process sentinels.  They shall not disturb each other."
 	(mapconcat #'shell-quote-argument load-path " -L ")
 	(shell-quote-argument code)))))))
 
-(ert-deftest tramp-test49-without-remote-files ()
+(ert-deftest tramp-test50-without-remote-files ()
   "Check that Tramp can be suppressed."
   (skip-unless (tramp--test-enabled))
 
@@ -8494,7 +8540,7 @@ process sentinels.  They shall not disturb each other."
   (setq tramp-mode t)
   (should (file-remote-p ert-remote-temporary-file-directory)))
 
-(ert-deftest tramp-test50-unload ()
+(ert-deftest tramp-test51-unload ()
   "Check that Tramp and its subpackages unload completely.
 Since it unloads Tramp, it shall be the last test to run."
   :tags '(:expensive-test)