texlive[73678] Build/source/texk/web2c: save and restore arith_error

[commits+karl at tug.org]

Revision: 73678
          https://tug.org/svn/texlive?view=revision&revision=73678
Author:   karl
Date:     2025-02-01 23:53:37 +0100 (Sat, 01 Feb 2025)
Log Message:
-----------
save and restore arith_error around new font scaling check

Modified Paths:
--------------
    trunk/Build/source/texk/web2c/ChangeLog
    trunk/Build/source/texk/web2c/tex.ch

Modified: trunk/Build/source/texk/web2c/ChangeLog
===================================================================
--- trunk/Build/source/texk/web2c/ChangeLog	2025-02-01 20:49:38 UTC (rev 73677)
+++ trunk/Build/source/texk/web2c/ChangeLog	2025-02-01 22:53:37 UTC (rev 73678)
@@ -1,3 +1,9 @@
+2025-02-01  Karl Berry  <karl at freefriends.org>
+
+	* tex.ch (save_arith_error): declare in Glob...
+	(30.568): save and restore arith_error around the new
+	check for font scaling to >= 2048pt.
+
 2025-01-29  Andreas Scherer  <https://ascherer.github.io>
 
 	* bibtex.ch,

Modified: trunk/Build/source/texk/web2c/tex.ch
===================================================================
--- trunk/Build/source/texk/web2c/tex.ch	2025-02-01 20:49:38 UTC (rev 73677)
+++ trunk/Build/source/texk/web2c/tex.ch	2025-02-01 22:53:37 UTC (rev 73678)
@@ -956,16 +956,22 @@
 
 % [7.104] `remainder' is a library routine on some systems, so change
 % its name to avoid conflicts.
- at x [7.104] l.2248 - avoid name conflicts with lib routine remainder()
+ at x [7.104] l.2248 - avoid conflict with libc remainder(), save_arith_error
 |remainder|, holds the remainder after a division.
 
 @<Glob...@>=
 @y
-|remainder|, holds the remainder after a division.
+|remainder|, holds the remainder after a division. For Web2C, we rename
+it to |tex_remainder| to avoid conflicts with a system library routine
+named |remainder|.
 
+Also, we define a new variable |save_arith_error| for when we want to
+save and restore |arith_error|, down below.
+
 @d remainder==tex_remainder
 
 @<Glob...@>=
+@!save_arith_error:boolean;
 @z
 
 @x [7.109] l.2373 - Define glue_ratio in C.
@@ -2432,17 +2438,19 @@
 % user's value. See tests/fonttoobig.tex for examples. Reports from
 % Igor Liferenko (https://tug.org/pipermail/tex-k/2021-June/003604.html)
 % and Tyge Tiessen (https://tug.org/pipermail/tex-k/2022-January/003752.html).
-% Patch from Tyge.
-% [30.568] Avoid scaling fonts to >= 2048pt, which can cause overflow.
+% Original patch from Tyge.
 @x [30.568] l.11072 - Avoid scaling fonts to 2048pt or more.
   else z:=xn_over_d(z,-s,1000);
 @y
-  else begin sw:=z; arith_error:=false; z:=xn_over_d(z,-s,1000);
+  else begin
+    save_arith_error:=arith_error;
+    sw:=z; z:=xn_over_d(z,-s,1000);
     if arith_error or z>=@'1000000000 then begin
        start_font_error_message; print(" scaled to 2048pt or higher");
        help1("I will ignore the scaling factor."); error; z:=sw;
        end;
-    end;
+    arith_error:=save_arith_error;
+  end;
 @z
 
 @x [30.570] l.11100 - MLTeX: fix for bug while loading font