Fix Bug#33781

* lisp/net/tramp-sh.el (tramp-set-remote-path): Use a temporary
file for setting $PATH, if it exceeds PATH_MAX on the remote system.
(tramp-send-command-and-read): Ignore errors if NOERROR.  (Bug#33781)

* test/lisp/net/tramp-tests.el (tramp-test34-remote-path): New test.

1 files changed, 12 insertions, 13 deletions

diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index 14ae2cb51b4..2959422a5da 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -3885,22 +3885,21 @@ This function expects to be in the right *tramp* buffer."
 I.e., for each directory in `tramp-remote-path', it is tested
 whether it exists and if so, it is added to the environment
 variable PATH."
-  (let ((path (mapconcat 'identity (tramp-get-remote-path vec) ":"))
+  (let ((command
+         (format "PATH=%s; export PATH"
+                 (mapconcat 'identity (tramp-get-remote-path vec) ":")))
         (path-max
          (with-tramp-connection-property vec "path-max"
            (tramp-send-command-and-read vec "getconf PATH_MAX /")))
-        index)
+        tmpfile)
     (tramp-message vec 5 "Setting $PATH environment variable")
-    (unless (< (length path) path-max)
-      (setq index path-max)
-      (while (not (string-equal (substring path (1- index) index) ":"))
-        (setq index (1- index)))
-      ;; FIXME: Is this sufficient? Or shall we raise an error?
-      (tramp-message
-       vec 2 "$PATH environment variable is too long. Ignoring \"%s\""
-       (substring path index))
-      (setq path (substring path 0 (1- index))))
-    (tramp-send-command vec (format "PATH=%s; export PATH" path))))
+    (if (< (length command) path-max)
+        (tramp-send-command vec command)
+      ;; Use a temporary file.
+      (setq tmpfile (tramp-make-tramp-temp-file vec))
+      (write-region command nil tmpfile)
+      (tramp-send-command vec (format ". %s" tmpfile))
+      (delete-file tmpfile))))
 
 ;; ------------------------------------------------------------
 ;; -- Communication with external shell --
@@ -5066,7 +5065,7 @@ If MARKER is a regexp, read the output after that string.
 In case there is no valid Lisp expression and NOERROR is nil, it
 raises an error."
   (when (if noerror
-            (tramp-send-command-and-check vec command)
+            (ignore-errors (tramp-send-command-and-check vec command))
           (tramp-barf-unless-okay
            vec command "`%s' returns with error" command))
     (with-current-buffer (tramp-get-connection-buffer vec)