[bugfix] log_series: avoid infinite recursion

[ginac.git] / ginac / inifcns_trans.cpp

diff --git a/ginac/inifcns_trans.cpp b/ginac/inifcns_trans.cpp
index c5551f7..682a981 100644 (file)
--- a/ginac/inifcns_trans.cpp
+++ b/ginac/inifcns_trans.cpp
@@ -204,6 +204,10 @@ static ex log_series(const ex &arg,
        if (arg_pt.is_zero())
                must_expand_arg = true;
        
+       if (arg.diff(ex_to<symbol>(rel.lhs())).is_zero()) {
+               throw do_taylor();
+       }
+
        if (must_expand_arg) {
                // method:
                // This is the branch point: Series expand the argument first, then