process-file in Tramp must return exit code (Bug#41099)

* lisp/net/tramp-adb.el (tramp-adb-send-command-and-check): Add optional
argument EXIT-STATUS.
(tramp-adb-handle-process-file): Use it.

* lisp/net/tramp-sh.el (tramp-send-command-and-check): Add optional
argument EXIT-STATUS.
(tramp-sh-handle-process-file): Use it.  (Bug#41099)

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

3 files changed, 29 insertions, 21 deletions

diff --git a/lisp/net/tramp-adb.el b/lisp/net/tramp-adb.el
index aae25d1dbf3..7f829f15205 100644
--- a/lisp/net/tramp-adb.el
+++ b/lisp/net/tramp-adb.el
@@ -896,14 +896,13 @@ PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are completely ignored."
       ;; it.  Call it in a subshell, in order to preserve working
       ;; directory.
       (condition-case nil
-          (progn
-            (setq ret
-                  (if (tramp-adb-send-command-and-check
-                       v
-                       (format "(cd %s; %s)"
-                               (tramp-shell-quote-argument localname) command))
-                      ;; Set return status accordingly.
-                      0 1))
+          (unwind-protect
+              (setq ret (tramp-adb-send-command-and-check
+                         v (format
+                            "(cd %s; %s)"
+                            (tramp-shell-quote-argument localname) command)
+                         t))
+            (unless (natnump ret) (setq ret 1))
             ;; We should add the output anyway.
             (when outbuf
               (with-current-buffer outbuf
@@ -1186,11 +1185,14 @@ This happens for Android >= 4.0."
         (while (re-search-forward "\r+$" nil t)
           (replace-match "" nil nil))))))
 
-(defun tramp-adb-send-command-and-check (vec command)
+(defun tramp-adb-send-command-and-check (vec command &optional exit-status)
   "Run COMMAND and check its exit status.
 Sends `echo $?' along with the COMMAND for checking the exit
 status.  If COMMAND is nil, just sends `echo $?'.  Returns nil if
-the exit status is not equal 0, and t otherwise."
+the exit status is not equal 0, and t otherwise.
+
+Optional argument EXIT-STATUS, if non-nil, triggers the return of
+the exit status."
   (tramp-adb-send-command
    vec (if command
            (format "%s; echo tramp_exit_status $?" command)
@@ -1201,7 +1203,9 @@ the exit status is not equal 0, and t otherwise."
        vec 'file-error "Couldn't find exit status of `%s'" command))
     (skip-chars-forward "^ ")
     (prog1
-        (zerop (read (current-buffer)))
+        (if exit-status
+            (read (current-buffer))
+          (zerop (read (current-buffer))))
       (let ((inhibit-read-only t))
         (delete-region (match-beginning 0) (point-max))))))
 
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index 592dcf67159..c6eb7a8ff49 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -3136,13 +3136,12 @@ STDERR can also be a file name."
       ;; directory.
       (condition-case nil
           (unwind-protect
-              (setq ret
-                    (if (tramp-send-command-and-check
-                         v (format "cd %s && %s"
-                                   (tramp-shell-quote-argument localname)
-                                   command)
-                         t t)
-                        0 1))
+              (setq ret (tramp-send-command-and-check
+                         v (format
+                            "cd %s && %s"
+                            (tramp-shell-quote-argument localname) command)
+                         t t t))
+            (unless (natnump ret) (setq ret 1))
             ;; We should add the output anyway.
             (when outbuf
               (with-current-buffer outbuf
@@ -5239,7 +5238,7 @@ function waits for output unless NOOUTPUT is set."
       found)))
 
 (defun tramp-send-command-and-check
-  (vec command &optional subshell dont-suppress-err)
+  (vec command &optional subshell dont-suppress-err exit-status)
   "Run COMMAND and check its exit status.
 Send `echo $?' along with the COMMAND for checking the exit status.
 If COMMAND is nil, just send `echo $?'.  Return t if the exit
@@ -5247,7 +5246,9 @@ status is 0, and nil otherwise.
 
 If the optional argument SUBSHELL is non-nil, the command is
 executed in a subshell, ie surrounded by parentheses.  If
-DONT-SUPPRESS-ERR is non-nil, stderr won't be sent to /dev/null."
+DONT-SUPPRESS-ERR is non-nil, stderr won't be sent to /dev/null.
+Optional argument EXIT-STATUS, if non-nil, triggers the return of
+the exit status."
   (tramp-send-command
    vec
    (concat (if subshell "( " "")
@@ -5261,7 +5262,9 @@ DONT-SUPPRESS-ERR is non-nil, stderr won't be sent to /dev/null."
        vec 'file-error "Couldn't find exit status of `%s'" command))
     (skip-chars-forward "^ ")
     (prog1
-        (zerop (read (current-buffer)))
+        (if exit-status
+            (read (current-buffer))
+          (zerop (read (current-buffer))))
       (let ((inhibit-read-only t))
         (delete-region (match-beginning 0) (point-max))))))
 
diff --git a/test/lisp/net/tramp-tests.el b/test/lisp/net/tramp-tests.el
index 28d20e39f8c..462539a7c17 100644
--- a/test/lisp/net/tramp-tests.el
+++ b/test/lisp/net/tramp-tests.el
@@ -4208,6 +4208,7 @@ This tests also `make-symbolic-link', `file-truename' and `add-name-to-file'."
             (should (zerop (process-file "true")))
             (should-not (zerop (process-file "false")))
             (should-not (zerop (process-file "binary-does-not-exist")))
+            (should (= 42 (process-file "sh" nil nil nil "-c" "exit 42")))
             (with-temp-buffer
               (write-region "foo" nil tmp-name)
               (should (file-exists-p tmp-name))