Fix multiple references to the same user defined symbolic expression

The expression needs to be cloned so transformations don't corrupt the original
expression. This could be slightly optimized by only taking a reference and
COW'ing when necessary (which is actually quite rare).

Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/src/evaluate.c b/src/evaluate.c
index 706ec2e58a38152f9bedd5311e87415c58dbdfda..cf3ff7f7145da2c197e0c4c8de55eec0a02353c0 100644 (file)
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -113,8 +113,7 @@ static int expr_evaluate_symbol(struct eval_ctx *ctx, struct expr **expr)
                        return expr_error(ctx, *expr,
                                          "undefined identifier '%s'",
                                          (*expr)->identifier);
-               // FIXME: need to copy (on write)
-               new = expr_get(sym->expr);
+               new = expr_clone(sym->expr);
        } else {
                erec = symbol_parse(*expr, &new);
                if (erec != NULL) {