bug#48375: coding-system-for-read in net-utils-run-simple is not properly set

[Eli Zaretskii]

> From: iquiw <iku.iwasa@gmail.com>
> Date: Wed, 12 May 2021 18:39:25 +0900
> 
> In the following code, `let' binding of `coding-system-for-read'
> covers only `erase-buffer' call.
> 
> https://emba.gnu.org/emacs/emacs/-/blob/47070ed39eda524d334e5f82dc7f4a50b8d3252c/lisp/net/net-utils.el#L366-375
> 
> So it does not affect to executed process and output characters are garbled.
> e.g. "M-x ifconfig" on Windows.

Thanks.  Does the patch below fix the problem?

diff --git a/lisp/net/net-utils.el b/lisp/net/net-utils.el
index 24f2aba..90cca7d 100644
--- a/lisp/net/net-utils.el
+++ b/lisp/net/net-utils.el
@@ -363,24 +363,24 @@ net-utils-run-simple
       (when proc
         (set-process-filter proc nil)
         (delete-process proc)))
-    (let ((inhibit-read-only t)
-       (coding-system-for-read
-        ;; MS-Windows versions of network utilities output text
-        ;; encoded in the console (a.k.a. "OEM") codepage, which is
-        ;; different from the default system (a.k.a. "ANSI")
-        ;; codepage.
-        (if (eq system-type 'windows-nt)
-            (intern (format "cp%d" (w32-get-console-output-codepage)))
-          coding-system-for-read)))
+    (let ((inhibit-read-only t))
       (erase-buffer))
     (net-utils-mode)
     (setq-local net-utils--revert-cmd
                 `(net-utils-run-simple ,(current-buffer)
                                        ,program-name ,args nodisplay))
-    (set-process-filter
-     (apply #'start-process program-name
-            (current-buffer) program-name args)
-     #'net-utils-remove-ctrl-m-filter)
+    (let ((coding-system-for-read
+          ;; MS-Windows versions of network utilities output text
+          ;; encoded in the console (a.k.a. "OEM") codepage, which is
+          ;; different from the default system (a.k.a. "ANSI")
+          ;; codepage.
+          (if (eq system-type 'windows-nt)
+              (intern (format "cp%d" (w32-get-console-output-codepage)))
+            coding-system-for-read)))
+      (set-process-filter
+       (apply #'start-process program-name
+              (current-buffer) program-name args)
+       #'net-utils-remove-ctrl-m-filter))
     (unless nodisplay (display-buffer (current-buffer)))))
 
 (defun net-utils--revert-function (&optional _ignore-auto _noconfirm)