New error symbol 'permission-denied'

* src/fileio.c (syms_of_fileio) <permission-denied>: Define the
symbol and its 'err-conditions' and 'error-message' properties.
(get_file_errno_data): Return permission-denied on EACCES.

* test/src/filelock-tests.el (filelock-tests-file-locked-p-spoiled)
(filelock-tests-unlock-spoiled)
(filelock-tests-kill-buffer-spoiled): Adapt the tests to the new
error symbol.

* doc/lispref/errors.texi (Standard Errors):
* etc/NEWS: Document 'permission-denied' error.

doc/lispref/errors.texi

@@ -98,6 +98,10 @@ Lisp reader, not to file I/O@.  @xref{Input Functions}.
 @item file-already-exists
 This is a subcategory of @code{file-error}.  @xref{Writing to Files}.
 
+@item permission-denied
+This is a subcategory of @code{file-error}, which occurs when the OS
+doesn't allow Emacs to access a file or a directory for some reason.
+
 @item file-date-error
 This is a subcategory of @code{file-error}.  It occurs when
 @code{copy-file} tries and fails to set the last-modification time of

etc/NEWS

@@ -1186,6 +1186,12 @@ The events 'touchscreen-begin, 'touchscreen-update', and
 'touchscreen-end' have been added to take better advantage of
 touch-capable display panels.
 
++++
+** New error symbol 'permission-denied'.
+This is a subcategory of 'file-error', and is signaled when some file
+operation fails because the OS doesn't allow Emacs to access a file or
+a directory.
+
 
 * Changes in Emacs 29.1 on Non-Free Operating Systems
 

src/fileio.c

@@ -195,7 +195,11 @@ get_file_errno_data (char const *string, Lisp_Object name, int errorno)
   if (errorno == EEXIST)
     return Fcons (Qfile_already_exists, errdata);
   else
-    return Fcons (errorno == ENOENT ? Qfile_missing : Qfile_error,
+    return Fcons (errorno == ENOENT
+		  ? Qfile_missing
+		  : (errorno == EACCES
+		     ? Qpermission_denied
+		     : Qfile_error),
 		  Fcons (build_string (string), errdata));
 }
 
@@ -6380,6 +6384,7 @@ syms_of_fileio (void)
   DEFSYM (Qfile_already_exists, "file-already-exists");
   DEFSYM (Qfile_date_error, "file-date-error");
   DEFSYM (Qfile_missing, "file-missing");
+  DEFSYM (Qpermission_denied, "permission-denied");
   DEFSYM (Qfile_notify_error, "file-notify-error");
   DEFSYM (Qremote_file_error, "remote-file-error");
   DEFSYM (Qexcl, "excl");
@@ -6438,6 +6443,11 @@ behaves as if file names were encoded in `utf-8'.  */);
   Fput (Qfile_missing, Qerror_message,
 	build_pure_c_string ("File is missing"));
 
+  Fput (Qpermission_denied, Qerror_conditions,
+	Fpurecopy (list3 (Qpermission_denied, Qfile_error, Qerror)));
+  Fput (Qpermission_denied, Qerror_message,
+	build_pure_c_string ("Cannot access file or directory"));
+
   Fput (Qfile_notify_error, Qerror_conditions,
 	Fpurecopy (list3 (Qfile_notify_error, Qfile_error, Qerror)));
   Fput (Qfile_notify_error, Qerror_message,

test/src/filelock-tests.el

@@ -123,7 +123,7 @@ the case)."
      (filelock-tests--spoil-lock-file buffer-file-truename)
      (let ((err (should-error (file-locked-p (buffer-file-name)))))
        (should (equal (seq-subseq err 0 2)
-                      '(file-error "Testing file lock")))))))
+                      '(permission-denied "Testing file lock")))))))
 
 (ert-deftest filelock-tests-unlock-spoiled ()
   "Check that `unlock-buffer' fails if the lockfile is \"spoiled\"."
@@ -144,7 +144,7 @@ the case)."
                   (lambda (err) (push err errors))))
          (unlock-buffer))
        (should (consp errors))
-       (should (equal '(file-error "Unlocking file")
+       (should (equal '(permission-denied "Unlocking file")
                       (seq-subseq (car errors) 0 2)))
        (should (equal (length errors) 1))))))
 
@@ -174,7 +174,7 @@ the case)."
                   (lambda (err) (push err errors))))
          (kill-buffer))
        (should (consp errors))
-       (should (equal '(file-error "Unlocking file")
+       (should (equal '(permission-denied "Unlocking file")
                       (seq-subseq (car errors) 0 2)))
        (should (equal (length errors) 1))))))