Implement EXCL of write-region for Tramp

* lisp/net/ange-ftp.el (ange-ftp-write-region):
* lisp/net/tramp-adb.el (tramp-adb-handle-write-region)
* lisp/net/tramp-gvfs.el (tramp-gvfs-handle-write-region):
* lisp/net/tramp-sh.el (tramp-sh-handle-write-region)
* lisp/net/tramp-smb.el (tramp-smb-handle-write-region):
Implement MUSTBENEW.

* lisp/net/tramp-gvfs.el (tramp-gvfs-do-copy-or-rename-file)
* lisp/net/tramp-sh.el (tramp-sh-handle-make-symbolic-link)
(tramp-sh-handle-add-name-to-file)
(tramp-do-copy-or-rename-file)
* lisp/net/tramp-smb.el (tramp-smb-handle-make-symbolic-link):
Adapt error message for `file-already-exists'.

* src/lisp.h:
* src/eval.c (call8): New function.

* src/fileio.c (write_region): Pass also lockname and
mustbenew to the file name handler.

* test/lisp/net/tramp-tests.el (tramp-test10-write-region):
Add tests for MUSTBENEW.

1 files changed, 17 insertions, 1 deletions

diff --git a/test/lisp/net/tramp-tests.el b/test/lisp/net/tramp-tests.el
index 50dfd6fac2e..45cf95fcfe0 100644
--- a/test/lisp/net/tramp-tests.el
+++ b/test/lisp/net/tramp-tests.el
@@ -1846,7 +1846,23 @@ This checks also `file-name-as-directory', `file-name-directory',
               (write-region 3 5 tmp-name))
             (with-temp-buffer
               (insert-file-contents tmp-name)
-              (should (string-equal (buffer-string) "34"))))
+              (should (string-equal (buffer-string) "34")))
+
+            ;; Do not overwrite if excluded.
+            (cl-letf (((symbol-function 'y-or-n-p) (lambda (_prompt) t)))
+              (write-region "foo" nil tmp-name nil nil nil 'mustbenew))
+            ;; `mustbenew' is passed to Tramp since Emacs 26.1.  We
+            ;; have no test for this, so we check function
+            ;; `temporary-file-directory', which has been added to
+            ;; Emacs 26.1 as well.
+            (when (fboundp 'temporary-file-directory)
+              (should-error
+               (cl-letf (((symbol-function 'y-or-n-p) 'ignore))
+                 (write-region "foo" nil tmp-name nil nil nil 'mustbenew))
+               :type 'file-already-exists)
+              (should-error
+               (write-region "foo" nil tmp-name nil nil nil 'excl)
+               :type 'file-already-exists)))
 
         ;; Cleanup.
         (ignore-errors (delete-file tmp-name))))))