Fixes to seg-fault with moose.le ##423 (#424)

moose.le('/elmenent_that_does_not_exists') now raises ValueError like
version 3.1.x and does not fail with a seg-fault.

Author: dilawar

pybind11/helper.cpp

@@ -550,6 +550,10 @@ vector<string> mooseLe(const ObjId& obj)
 {
     vector<Id> children;
     vector<string> chPaths;
+
+    if(obj.bad())
+        throw pybind11::value_error("no such element.");
+
     Neutral::children(obj.eref(), children);
     stringstream ss;
     ss << "Elements under " << obj.path() << endl;

pybind11/pymoose.cpp

@@ -1,14 +1,11 @@
-// =====================================================================================
+// Description:  Python bindings generated by pybind11. This binding replaces
+//    binding generated in ../pymoose folder.
 //
-//    Description:  Python bindings generated by pybind11. This binding replaces
-//      binding generated in ../pymoose folder. These bindings are easier to
-//      maintain and more performant. The user API has not changed but the
-//      internal working has changed.
+//    These bindings are easier to maintain and more performant. The user API
+//    is almost the same but the internal working has changed.
 //
-//         Author:  Dilawar Singh <dilawar.s.rajput@gmail.com>
-//   Organization:  NCBS Bangalore
-//
-// =====================================================================================
+//       Author:  Dilawar Singh <dilawar.s.rajput@gmail.com>
+// Organization:  NCBS Bangalore
 
 #include <map>
 #include <typeindex>

python/moose/__init__.py

@@ -600,6 +600,7 @@ def le(el=None):
     el = _moose.getCwe() if el is None else el
     if isinstance(el, str):
         el = _moose.element(el)
+        print(el)
     elif isinstance(el, _moose.vec):
         el = el[0]
     return _moose.le(el)

tests/core/test_api.py

@@ -203,6 +203,17 @@ def test_paths():
     x = moose.Neutral('///x')
     assert x.path == '/x', x.path
 
+def test_le():
+    # see issue BhallaLab/moose-core#423
+    x = moose.le('/')
+    assert len(x) > 5, x
+    try:
+        moose.le('/abrakadabra')
+    except ValueError:
+        pass
+    else:
+        raise RuntimeError("This should have raised ValueError")
+
 def main():
     test_paths()
     test_children()
@@ -216,6 +227,7 @@ def main():
     test_vec()
     test_typing()
     test_elements()
+    test_le()
 
 if __name__ == '__main__':
     main()