From: Eli Zaretskii <eliz@gnu.org>
Date: Sun, 5 Feb 2023 09:14:25 +0000 (+0200)
Subject: Fix installation of tree-sitter grammar on MS-Windows
X-Git-Tag: emacs-29.0.90~510
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=f13479d9556;p=emacs.git

Fix installation of tree-sitter grammar on MS-Windows

* lisp/treesit.el (treesit--install-language-grammar-1): Fix a
failure on MS-Windows when the old DLL is still being used.
(Bug#61289)
---

diff --git a/lisp/treesit.el b/lisp/treesit.el
index 948016dc723..7e31da95ef4 100644
--- a/lisp/treesit.el
+++ b/lisp/treesit.el
@@ -2884,7 +2884,17 @@ function signals an error."
           ;; Copy out.
           (unless (file-exists-p out-dir)
             (make-directory out-dir t))
-          (copy-file lib-name (file-name-as-directory out-dir) t t)
+          (let* ((library-fname (expand-file-name lib-name out-dir))
+                 (old-fname (concat library-fname ".old")))
+            ;; Rename the existing shared library, if any, then
+            ;; install the new one, and try deleting the old one.
+            ;; This is for Windows systems, where we cannot simply
+            ;; overwrite a DLL that is being used.
+            (if (file-exists-p library-fname)
+                (rename-file library-fname old-fname t))
+            (copy-file lib-name (file-name-as-directory out-dir) t t)
+            ;; Ignore errors, in case the old version is still used.
+            (ignore-errors (delete-file old-fname)))
           (message "Library installed to %s/%s" out-dir lib-name))
       (when (file-exists-p workdir)
         (delete-directory workdir t)))))