master 484fc70a7ac: Fix "C-0 C-x C-s" with write-protected files

[Eli Zaretskii]

branch: master
commit 484fc70a7acc5a958bfeefa4b83255680c7da175
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Fix "C-0 C-x C-s" with write-protected files
    
    * lisp/files.el (basic-save-buffer-2): Call 'set-file-modes' to
    try to make the file writable, even if
    'set-file-extended-attributes' succeeded.  (Bug#66546)
---
 lisp/files.el | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/lisp/files.el b/lisp/files.el
index e1421b403bf..adfe8bd44b9 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -5933,9 +5933,10 @@ Before and after saving the buffer, this function runs
                            buffer-file-name)
                          t))
        ;; If file not writable, see if we can make it writable
-       ;; temporarily while we write it.
-       ;; But no need to do so if we have just backed it up
-       ;; (setmodes is set) because that says we're superseding.
+       ;; temporarily while we write it (its original modes will be
+       ;; restored in 'basic-save-buffer').  But no need to do so if
+       ;; we have just backed it up (setmodes is set) because that
+       ;; says we're superseding.
        (cond ((and tempsetmodes (not setmodes))
               ;; Change the mode back, after writing.
               (setq setmodes
@@ -5944,12 +5945,12 @@ Before and after saving the buffer, this function runs
                                "Error getting extended attributes: %s"
                             (file-extended-attributes buffer-file-name))
                           buffer-file-name))
-              ;; If set-file-extended-attributes fails, fall back on
-              ;; set-file-modes.
-              (unless
-                  (with-demoted-errors "Error setting attributes: %s"
-                    (set-file-extended-attributes buffer-file-name
-                                                  (nth 1 setmodes)))
+              ;; If set-file-extended-attributes fails to make the
+              ;; file writable, fall back on set-file-modes.
+              (with-demoted-errors "Error setting attributes: %s"
+                (set-file-extended-attributes buffer-file-name
+                                              (nth 1 setmodes)))
+              (unless (file-writable-p buffer-file-name)
                 (set-file-modes buffer-file-name
                                 (logior (car setmodes) 128)))))
        (let (success)