Tramp code cleanup

* lisp/net/tramp-adb.el
(tramp-adb-handle-directory-files-and-attributes): Use it.

* lisp/net/tramp-compat.el (tramp-compat-replace-regexp-in-region):
New defalias.

* lisp/net/tramp-crypt.el (tramp-crypt-do-encrypt-or-decrypt-file-name):
Fix root filename for cache.

* lisp/net/tramp-gvfs.el (tramp-gvfs-do-copy-or-rename-file):
Adapt check for proper remote command.

* lisp/net/tramp-sh.el (tramp-open-shell): Add sanity check for
shell prompt.
(tramp-get-ls-command): Check, that argument "--color=never" has
the intended effect.

lisp/net/tramp-adb.el

@@ -324,7 +324,7 @@ arguments to pass to the OPERATION."
 		      (tramp-compat-file-name-concat localname "."))
 		     (tramp-shell-quote-argument
 		      (tramp-compat-file-name-concat localname ".."))))
-	  (replace-regexp-in-region
+	  (tramp-compat-replace-regexp-in-region
 	   (regexp-quote
 	    (tramp-compat-file-name-unquote
 	     (file-name-as-directory localname)))

lisp/net/tramp-compat.el

@@ -330,6 +330,29 @@ CONDITION can also be a list of error conditions."
       (autoload 'netrc-parse "netrc")
       (netrc-parse file))))
 
+;; Function `replace-regexp-in-region' is new in Emacs 28.1.
+(defalias 'tramp-compat-replace-regexp-in-region
+  (if (fboundp 'replace-regexp-in-region)
+      #'replace-regexp-in-region
+    (lambda (regexp replacement &optional start end)
+      (if start
+	  (when (< start (point-min))
+            (error "Start before start of buffer"))
+	(setq start (point)))
+      (if end
+	  (when (> end (point-max))
+            (error "End after end of buffer"))
+	(setq end (point-max)))
+      (save-excursion
+	(let ((matches 0)
+              (case-fold-search nil))
+	  (goto-char start)
+	  (while (re-search-forward regexp end t)
+            (replace-match replacement t)
+            (setq matches (1+ matches)))
+	  (and (not (zerop matches))
+               matches))))))
+
 (dolist (elt (all-completions "tramp-compat-" obarray 'functionp))
   (put (intern elt) 'tramp-suppress-trace t))
 

lisp/net/tramp-crypt.el

@@ -426,7 +426,7 @@ Otherwise, return NAME."
        (if (directory-name-p name) #'file-name-as-directory #'identity)
        (concat
 	dir
-	(unless (string-equal localname "/")
+	(unless (string-match-p (rx (seq bos (opt "/") eos)) localname)
 	  (with-tramp-file-property
 	      crypt-vec localname (concat (symbol-name op) "-file-name")
 	    (unless (tramp-crypt-send-command

lisp/net/tramp-gvfs.el

@@ -1055,9 +1055,10 @@ file names."
 			 ;; code in case of direct copy/move.  Apply
 			 ;; sanity checks.
 			 (or (not equal-remote)
-			     (tramp-gvfs-info newname)
-			     (eq op 'copy)
-			     (not (tramp-gvfs-info filename))))
+			     (and
+			      (tramp-gvfs-info newname)
+			      (or (eq op 'copy)
+				  (not (tramp-gvfs-info filename))))))
 
 		  (if (or (not equal-remote)
 			  (and equal-remote

lisp/net/tramp-sh.el

@@ -4205,14 +4205,17 @@ file exists and nonzero exit status otherwise."
     ;; by some sh implementations (eg, bash when called as sh) on
     ;; startup; this way, we avoid the startup file clobbering $PS1.
     ;; $PROMPT_COMMAND is another way to set the prompt in /bin/bash,
-    ;; it must be discarded as well.  $HISTFILE is set according to
-    ;; `tramp-histfile-override'.  $TERM and $INSIDE_EMACS set here to
-    ;; ensure they have the correct values when the shell starts, not
-    ;; just processes run within the shell.  (Which processes include
-    ;; our initial probes to ensure the remote shell is usable.)
-    ;; For the time being, we assume that all shells interpret -i as
-    ;; interactive shell.  Must be the last argument, because (for
-    ;; example) bash expects long options first.
+    ;; it must be discarded as well.  Some ssh daemons (for example,
+    ;; on Android devices) do not acknowledge the $PS1 setting in
+    ;; that call, so we make a further sanity check.  (Bug#57044)
+    ;; $HISTFILE is set according to `tramp-histfile-override'.  $TERM
+    ;; and $INSIDE_EMACS set here to ensure they have the correct
+    ;; values when the shell starts, not just processes run within the
+    ;; shell.  (Which processes include our initial probes to ensure
+    ;; the remote shell is usable.)  For the time being, we assume
+    ;; that all shells interpret -i as interactive shell.  Must be the
+    ;; last argument, because (for example) bash expects long options
+    ;; first.
     (tramp-send-command
      vec (format
 	  (concat
@@ -4228,7 +4231,21 @@ file exists and nonzero exit status otherwise."
 	      ""))
 	  (tramp-shell-quote-argument tramp-end-of-output)
 	  shell (or (tramp-get-sh-extra-args shell) ""))
-     t)
+     t t)
+
+    ;; Sanity check.
+    (tramp-barf-if-no-shell-prompt
+     (tramp-get-connection-process vec) 10
+     "Couldn't find remote shell prompt for %s" shell)
+    (unless
+	(tramp-check-for-regexp
+	 (tramp-get-connection-process vec) (regexp-quote tramp-end-of-output))
+      (tramp-message vec 5 "Setting shell prompt")
+      (tramp-send-command
+       vec (format "PS1=%s PS2='' PS3='' PROMPT_COMMAND=''"
+		   (tramp-shell-quote-argument tramp-end-of-output))
+       t))
+
     ;; Check proper HISTFILE setting.  We give up when not working.
     (when (and (stringp tramp-histfile-override)
 	       (file-name-directory tramp-histfile-override))
@@ -5524,10 +5541,14 @@ Nonexistent directories are removed from spec."
 	     ;; "--color=never" argument (for example on FreeBSD).
 	     (when (tramp-send-command-and-check
 		    vec (format "%s -lnd /" result))
-	       (when (tramp-send-command-and-check
-		      vec (format
-			   "%s --color=never -al %s"
-                           result (tramp-get-remote-null-device vec)))
+	       (when (and (tramp-send-command-and-check
+			   vec (format
+				"%s --color=never -al %s"
+				result (tramp-get-remote-null-device vec)))
+			  (not (string-match-p
+				(regexp-quote "\e")
+				(tramp-get-buffer-string
+				 (tramp-get-buffer vec)))))
 		 (setq result (concat result " --color=never")))
 	       (throw 'ls-found result))
 	     (setq dl (cdr dl))))))