Suspend timers when reading Tramp process output

* lisp/net/tramp-compat.el (xdg): Require.
(tramp-compat-temporary-file-directory): Set it to
$XDG_CACHE_HOME/emacs if possible.

* lisp/net/tramp.el (tramp-debug-to-file): Fix docstring.
(tramp-wrong-passwd-regexp): Add "Authentication failed" string
(from doas).
(tramp-debug-message): Simplify backtrace check.
(with-tramp-locked-connection): Suppress timers.  (Bug#49954, Bug60534)

* test/lisp/net/tramp-tests.el (tramp-test09-insert-file-contents):
Adapt test.
(tramp-test45-asynchronous-requests): Remove :unstable tag.
Adapt test.

lisp/net/tramp-cache.el

@@ -496,12 +496,12 @@ PROPERTIES is a list of file properties (strings)."
 		(cons property (gethash property hash tramp-cache-undefined)))
 	      ,properties)))
        (unwind-protect (progn ,@body)
-       ;; Reset PROPERTIES.  Recompute hash, it could have been flushed.
-       (setq hash (tramp-get-hash-table ,key))
-       (dolist (value values)
-	 (if (not (eq (cdr value) tramp-cache-undefined))
-	     (puthash (car value) (cdr value) hash)
-	   (remhash (car value) hash)))))))
+	 ;; Reset PROPERTIES.  Recompute hash, it could have been flushed.
+	 (setq hash (tramp-get-hash-table ,key))
+	 (dolist (value values)
+	   (if (not (eq (cdr value) tramp-cache-undefined))
+	       (puthash (car value) (cdr value) hash)
+	     (remhash (car value) hash)))))))
 
 ;;;###tramp-autoload
 (defun tramp-cache-print (table)

lisp/net/tramp-compat.el

@@ -35,6 +35,7 @@
 (require 'parse-time)
 (require 'shell)
 (require 'subr-x)
+(require 'xdg)
 
 (declare-function tramp-error "tramp")
 (declare-function tramp-tramp-file-p "tramp")
@@ -64,9 +65,16 @@
      (with-no-warnings (funcall ,function ,@arguments))))
 
 ;; We must use a local directory.  If it is remote, we could run into
-;; an infloop.
+;; an infloop.  We try to follow the XDG specification, for security reasons.
 (defconst tramp-compat-temporary-file-directory
-  (eval (car (get 'temporary-file-directory 'standard-value)) t)
+  (file-name-as-directory
+   (if-let ((xdg (xdg-cache-home))
+	    ((file-directory-p xdg))
+	    ((file-writable-p xdg)))
+       ;; We can use `file-name-concat' starting with Emacs 28.1.
+       (prog1 (setq xdg (concat (file-name-as-directory xdg) "emacs"))
+	 (make-directory xdg t))
+     (eval (car (get 'temporary-file-directory 'standard-value)) t)))
   "The default value of `temporary-file-directory'.")
 
 (defsubst tramp-compat-make-temp-name ()

lisp/net/tramp.el

@@ -120,7 +120,7 @@ Any level x includes messages for all levels 1 .. x-1.  The levels are
 (defcustom tramp-debug-to-file nil
   "Whether Tramp debug messages shall be saved to file.
 The debug file has the same name as the debug buffer, written to
-`temporary-file-directory'."
+`tramp-compat-temporary-file-directory'."
   :version "28.1"
   :type 'boolean)
 
@@ -665,6 +665,7 @@ The `sudo' program appears to insert a `^@' character into the prompt."
 	 "Sorry, try again."
 	 "Name or service not known"
 	 "Host key verification failed."
+	 "Authentication failed"
 	 "No supported authentication methods left to try!"
 	 (: "Login " (| "Incorrect" "incorrect"))
 	 (: "Connection " (| "refused" "closed"))
@@ -1970,7 +1971,7 @@ of `current-buffer'."
       (+ digit) ":" (+ digit) ":" (+ digit) "." (+ digit) blank
       ;; Thread.
       (? (group "#<thread " (+ nonl) ">") blank)
-       ;; Function name, verbosity.
+      ;; Function name, verbosity.
       (+ (any "-" alnum)) " (" (group (+ digit)) ") #")
   "Used for highlighting Tramp debug buffers in `outline-mode'.")
 
@@ -2109,18 +2110,23 @@ ARGUMENTS to actually emit the message (if applicable)."
 	  (insert "\n"))
 	;; Timestamp.
 	(insert (format-time-string "%T.%6N "))
+	;; Threads.  `current-thread' might not exist when Emacs is
+	;; configured --without-threads.
+	;; (unless (eq (tramp-compat-funcall 'current-thread) main-thread)
+	;;   (insert (format "%s " (tramp-compat-funcall 'current-thread))))
 	;; Calling Tramp function.  We suppress compat and trace
 	;; functions from being displayed.
-	(let ((btn 1) btf fn)
+	(let ((frames (backtrace-frames))
+	      btf fn)
 	  (while (not fn)
-	    (setq btf (nth 1 (backtrace-frame btn)))
+	    (setq btf (cadadr frames))
 	    (if (not btf)
 		(setq fn "")
 	      (and (symbolp btf) (setq fn (symbol-name btf))
 		   (or (not (string-prefix-p "tramp" fn))
 		       (get btf 'tramp-suppress-trace))
 		   (setq fn nil))
-	      (setq btn (1+ btn))))
+	      (setq frames (cdr frames))))
 	  ;; The following code inserts filename and line number.
 	  ;; Should be inactive by default, because it is time consuming.
 	  ;; (let ((ffn (find-function-noselect (intern fn))))
@@ -3790,14 +3796,14 @@ BODY is the backend specific code."
   ;; VISIT, for example `jka-compr-handler'.  We must respect this.
   ;; See Bug#55166.
   `(let* ((filename (expand-file-name ,filename))
-	 (lockname (file-truename (or ,lockname filename)))
-	 (handler (and (stringp ,visit)
-		       (let ((inhibit-file-name-handlers
-			      `(tramp-file-name-handler
-				tramp-crypt-file-name-handler
-				. inhibit-file-name-handlers))
-			     (inhibit-file-name-operation 'write-region))
-			 (find-file-name-handler ,visit 'write-region)))))
+	  (lockname (file-truename (or ,lockname filename)))
+	  (handler (and (stringp ,visit)
+			(let ((inhibit-file-name-handlers
+			       `(tramp-file-name-handler
+				 tramp-crypt-file-name-handler
+				 . inhibit-file-name-handlers))
+			      (inhibit-file-name-operation 'write-region))
+			  (find-file-name-handler ,visit 'write-region)))))
      (with-parsed-tramp-file-name filename nil
        (if handler
 	   (progn
@@ -5821,11 +5827,14 @@ Mostly useful to protect BODY from being interrupted by timers."
 	   (throw 'non-essential 'non-essential)
 	 (tramp-error
 	  ,proc 'remote-file-error "Forbidden reentrant call of Tramp"))
-     (unwind-protect
-	 (progn
-	   (tramp-set-connection-property ,proc "locked" t)
-	   ,@body)
-       (tramp-flush-connection-property ,proc "locked"))))
+     (let ((stimers (with-timeout-suspend))
+	   timer-list timer-idle-list)
+       (unwind-protect
+	   (progn
+	     (tramp-set-connection-property ,proc "locked" t)
+	     ,@body)
+	 (tramp-flush-connection-property ,proc "locked")
+	 (with-timeout-unsuspend stimers)))))
 
 (defun tramp-accept-process-output (proc &optional _timeout)
   "Like `accept-process-output' for Tramp processes.

test/lisp/net/tramp-tests.el

@@ -2440,15 +2440,19 @@ This checks also `file-name-as-directory', `file-name-directory',
 		`(,(expand-file-name tmp-name) 0)))
 	      (should (string-equal (buffer-string) "foo"))
 	      (should (= point (point))))
-	    (let ((point (point)))
-	      (replace-string-in-region "foo" "bar" (point-min) (point-max))
-	      (goto-char point)
-	      (should
-	       (equal
-		(insert-file-contents tmp-name nil nil nil 'replace)
-		`(,(expand-file-name tmp-name) 3)))
-	      (should (string-equal (buffer-string) "foo"))
-	      (should (= point (point))))
+	    ;; Insert another string.
+	    ;; `replace-string-in-region' was introduced in Emacs 28.1.
+	    (when (tramp--test-emacs28-p)
+	      (let ((point (point)))
+		(with-no-warnings
+		  (replace-string-in-region "foo" "bar" (point-min) (point-max)))
+		(goto-char point)
+		(should
+		 (equal
+		  (insert-file-contents tmp-name nil nil nil 'replace)
+		  `(,(expand-file-name tmp-name) 3)))
+		(should (string-equal (buffer-string) "foo"))
+		(should (= point (point)))))
 	    ;; Error case.
 	    (delete-file tmp-name)
 	    (should-error
@@ -7444,12 +7448,7 @@ This is needed in timer functions as well as process filters and sentinels."
   "Check parallel asynchronous requests.
 Such requests could arrive from timers, process filters and
 process sentinels.  They shall not disturb each other."
-  ;; :tags (append '(:expensive-test :tramp-asynchronous-processes)
-  ;;       	(and (or (getenv "EMACS_HYDRA_CI")
-  ;;                        (getenv "EMACS_EMBA_CI"))
-  ;;                    '(:unstable)))
-  ;; It doesn't work sufficiently.
-  :tags '(:expensive-test :tramp-asynchronous-processes :unstable)
+  :tags '(:expensive-test :tramp-asynchronous-processes)
   (skip-unless (tramp--test-enabled))
   (skip-unless (tramp--test-supports-processes-p))
   (skip-unless (not (tramp--test-container-p)))
@@ -7517,14 +7516,12 @@ process sentinels.  They shall not disturb each other."
                   (when buffers
                     (let ((time (float-time))
                           (default-directory tmp-name)
-                          (file (buffer-name (seq-random-elt buffers)))
-			  ;; A remote operation in a timer could
-			  ;; confuse Tramp heavily.  So we ignore this
-			  ;; error here.
-			  (debug-ignored-errors
-			   (cons 'remote-file-error debug-ignored-errors)))
+                          (file (buffer-name (seq-random-elt buffers))))
                       (tramp--test-message
                        "Start timer %s %s" file (current-time-string))
+		      (dired-uncache file)
+		      (tramp--test-message
+		       "Continue timer %s %s" file (file-attributes file))
 		      (vc-registered file)
                       (tramp--test-message
                        "Stop timer %s %s" file (current-time-string))