Looks like an off-by-one introduced in the utf8 conversion.
The following fixes the bug for me. I will file a PR upstream.
- todd
Index: usr.bin/awk/run.c
===================================================================
RCS file: /cvs/src/usr.bin/awk/run.c,v
retrieving revision 1.79
diff -u -p -u -r1.79 run.c
--- usr.bin/awk/run.c 6 Oct 2023 22:29:24 -0000 1.79
+++ usr.bin/awk/run.c 28 Oct 2023 16:32:18 -0000
@@ -1018,10 +1018,10 @@ Cell *substr(Node **a, int nnn) /* subs
mb = u8_char2byte(s, m-1); /* byte offset of start char in s */
nb = u8_char2byte(s, m-1+n); /* byte offset of end+1 char in s */
- temp = s[nb]; /* with thanks to John Linderman */
- s[nb] = '\0';
+ temp = s[nb-1]; /* with thanks to John Linderman */
+ s[nb-1] = '\0';
setsval(y, s + mb);
- s[nb] = temp;
+ s[nb-1] = temp;
tempfree(x);
return(y);
}
