From c3d8d999f889c49a7b025513eb1b57533554a3da Mon Sep 17 00:00:00 2001
From: Pip Cet <pipcet@protonmail.com>
Date: Mon, 17 Feb 2025 15:21:16 +0000
Subject: [PATCH] Fix compilation errors due to insufficient compiler safety
 (bug#63288)

The default safety level is 1.  Restoring the default safety level to
1 after it was temporarily 0 should reset byte-compile-delete-errors
to nil, its default level.  Failing to do that resulted in
miscompilation of code in highly-parallel builds.

* lisp/emacs-lisp/cl-macs.el (cl--do-proclaim): Change
'byte-compile-delete-errors' to become t only at 'safety' level 0, not
levels 1 or 2.

(cherry picked from commit 53a5dada413662389a17c551a00d215e51f5049f)
---
 lisp/emacs-lisp/cl-macs.el | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lisp/emacs-lisp/cl-macs.el b/lisp/emacs-lisp/cl-macs.el
index 566b03b76da..d59384efa60 100644
--- a/lisp/emacs-lisp/cl-macs.el
+++ b/lisp/emacs-lisp/cl-macs.el
@@ -2701,7 +2701,7 @@ Example:
 	 (let ((speed (assq (nth 1 (assq 'speed (cdr spec)))
 			    '((0 nil) (1 t) (2 t) (3 t))))
 	       (safety (assq (nth 1 (assq 'safety (cdr spec)))
-			     '((0 t) (1 t) (2 t) (3 nil)))))
+			     '((0 t) (1 nil) (2 nil) (3 nil)))))
 	   (if speed (setq cl--optimize-speed (car speed)
 			   byte-optimize (nth 1 speed)))
 	   (if safety (setq cl--optimize-safety (car safety)
-- 
2.39.5