Combine archive-int-to-mode and tar-grind-file-modebug27952_combine-tar-grind-file-mode_archive-int-to-mode

Add a new function, file-modes-number-to-symbolic.
Make archive-int-to-mode and obsolete alias of it; use it
to define tar-grind-file-mode (Bug#27952).

* lisp/files.el (file-modes-number-to-symbolic): New defun.
* lisp/arc-mode.el (archive-int-to-mode): Make it an obsolete alias.
* lisp/tar-mode.el (tar-grind-file-mode):
Use file-modes-number-to-symbolic.

* test/lisp/arc-mode-tests.el (arc-mode-test-archive-int-to-mode)
* test/lisp/tar-mode-tests.el (tar-mode-test-tar-grind-file-mode):
Update test.

* test/lisp/files-tests.el (files-tests-file-modes-symbolic-to-number)
(files-tests-file-modes-number-to-symbolic): New tests.

* doc/lispref/files.texi (Changing Files): Document the new funtion.
* etc/NEWS (Lisp Changes in Emacs 28.1): Announce it.

1 files changed, 5 insertions, 0 deletions

diff --git a/doc/lispref/files.texi b/doc/lispref/files.texi
index b3ad9b99649..686dbdb1caf 100644
--- a/doc/lispref/files.texi
+++ b/doc/lispref/files.texi
@@ -1909,6 +1909,11 @@ omitted or @code{nil}, it defaults to 0, i.e., no access rights at
 all.
 @end defun
 
+@defun file-modes-number-to-symbolic modes
+This function converts a numeric file mode specification in
+@var{modes} into the equivalent symbolic form.
+@end defun
+
 @defun set-file-times filename &optional time flag
 This function sets the access and modification times of @var{filename}
 to @var{time}.  The return value is @code{t} if the times are successfully