Introduce process-file-return-signal-string

* doc/lispref/processes.texi (Synchronous Processes):
Describe `process-file-return-signal-string'.

* doc/misc/tramp.texi: Adapt Tramp and Emacs version numbers.
(Remote processes): Describe `process-file-return-signal-string'
and $INSIDE_EMACS.

* etc/NEWS: Describe `process-file-return-signal-string'.  Fix typos.

* lisp/simple.el (process-file-return-signal-string): New user option.

* lisp/net/tramp-adb.el (tramp-adb-handle-process-file):
* lisp/net/tramp-sh.el (tramp-sh-handle-process-file): Use it.

* lisp/net/tramp.el (tramp-get-signal-strings): New defun.

* test/lisp/net/tramp-tests.el (tramp-test28-process-file): Adapt test.

1 files changed, 14 insertions, 0 deletions

diff --git a/lisp/simple.el b/lisp/simple.el
index b5ba05426f5..d151d6c9aeb 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -4141,6 +4141,20 @@ its behavior with respect to remote file attribute caching.
 You should only ever change this variable with a let-binding;
 never with `setq'.")
 
+(defcustom process-file-return-signal-string nil
+  "Whether to return a string describing the signal interrupting a process.
+When a process returns an exit code greater than 128, it is
+interpreted as a signal.  `process-file' requires to return a
+string describing this signal.
+Since there are processes violating this rule, returning exit
+codes greater than 128 which are not bound to a signal,
+`process-file' returns the exit code as natural number also in
+this case.  Setting this user option to non-nil forces
+`process-file' to interpret such exit codes as signals, and to
+return a corresponding string."
+  :version "28.1"
+  :type 'boolean)
+
 (defun start-file-process (name buffer program &rest program-args)
   "Start a program in a subprocess.  Return the process object for it.