Remove a conflict between the text variable substitution like

set text = "mytext"
set newtext = new.{$text}
echo $newtext
and the command circbyline, which may have to process strings
containing braces {...} without any change to the string.

Do not call cp_doglob() when command circbyline is executed.

src/frontend/control.c

@@ -152,7 +152,9 @@ docommand(wordlist *wlist)
     wlist = cp_bquote(wlist);
     pwlist(wlist, "After backquote substitution");
 
-    wlist = cp_doglob(wlist);
+    /* Do not expand braces after command circbyline, keep them intact */
+    if (!eq(wlist->wl_word, "circbyline"))
+        wlist = cp_doglob(wlist);
     pwlist(wlist, "After globbing");
 
     pwlist_echo(wlist, "Becomes >");