emacs-27 8b1ccf5: Fix tramp-sh-handle-make-process; don't merge with master

[Michael Albinus]

branch: emacs-27
commit 8b1ccf5e7bc734aa3d0de6e1906677699c7eb3b2
Author: Michael Albinus <michael.albinus@gmx.de>
Commit: Michael Albinus <michael.albinus@gmx.de>

    Fix tramp-sh-handle-make-process; don't merge with master
    
    * lisp/net/tramp-sh.el (tramp-sh-handle-make-process): Accept nil
    COMMAND.  (Bug#44151)
    
    * test/lisp/net/tramp-tests.el (tramp-test29-start-file-process):
    Extend test.
---
 lisp/net/tramp-sh.el         |  2 +-
 test/lisp/net/tramp-tests.el | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index 19d50fc..df6720b 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -2822,7 +2822,7 @@ STDERR can also be a file name."
          (signal 'wrong-type-argument (list #'stringp name)))
        (unless (or (null buffer) (bufferp buffer) (stringp buffer))
          (signal 'wrong-type-argument (list #'stringp buffer)))
-       (unless (consp command)
+       (unless (or (null command) (consp command))
          (signal 'wrong-type-argument (list #'consp command)))
        (unless (or (null coding)
                    (and (symbolp coding) (memq coding coding-system-list))
diff --git a/test/lisp/net/tramp-tests.el b/test/lisp/net/tramp-tests.el
index fb4df63..cc9ccef 100644
--- a/test/lisp/net/tramp-tests.el
+++ b/test/lisp/net/tramp-tests.el
@@ -4283,6 +4283,21 @@ This tests also `make-symbolic-link', `file-truename' 
and `add-name-to-file'."
            (should (string-match "\\`foo" (buffer-string))))
 
        ;; Cleanup.
+       (ignore-errors (delete-process proc)))
+
+      ;; PTY.
+      (unwind-protect
+         (with-temp-buffer
+           (if (not (tramp--test-sh-p))
+               (should-error
+                (start-file-process "test4" (current-buffer) nil)
+                :type 'wrong-type-argument)
+             (setq proc (start-file-process "test4" (current-buffer) nil))
+             (should (processp proc))
+             (should (equal (process-status proc) 'run))
+             (should (stringp (process-tty-name proc)))))
+
+       ;; Cleanup.
        (ignore-errors (delete-process proc))))))
 
 (ert-deftest tramp-test30-make-process ()