Merge pull request #456 from sbmlteam/issue-455

#455: ensure we dont crash on no children

Author: skeating

src/sbml/math/ASTNode.cpp

@@ -3899,6 +3899,42 @@ ASTNode::simplify()
     delete child;
   }
 
+  // special case, ensure we dont crash
+  if (numChildren == 0)
+  {
+    if (mType == AST_PLUS)
+    {
+      (*this) = *zero;
+
+      delete zero;
+      delete one;
+      delete two;
+
+      return;
+    }
+
+    if (mType == AST_TIMES)
+    {
+      (*this) = *one;
+
+      delete zero;
+      delete one;
+      delete two;
+
+      return;
+    }
+
+    if (mType == AST_POWER || mType == AST_DIVIDE || mType == AST_FUNCTION_POWER)
+    {
+      // dont crash
+      delete zero;
+      delete one;
+      delete two;
+
+      return;
+    }
+  }
+
   // if we have 1 * x * ... dont need 1
   if (mType == AST_TIMES && util_isEqual(getChild(0)->getValue(), 1.0))
   {

src/sbml/math/test/TestInferRnFunctions.cpp

@@ -990,6 +990,41 @@ START_TEST(test_convertRootToPower)
 END_TEST
 
 
+START_TEST(test_no_children)
+{
+  {
+    ASTNode n(ASTNodeType_t::AST_PLUS);
+    n.simplify();
+    // should be 0
+    fail_unless(n.getType() == ASTNodeType_t::AST_REAL);
+    fail_unless(n.getValue() == 0.0);
+  }
+
+  {
+    ASTNode n(ASTNodeType_t::AST_TIMES);
+    n.simplify();
+    // should be 1
+    fail_unless(n.getType() == ASTNodeType_t::AST_REAL);
+    fail_unless(n.getValue() == 1.0);
+  }
+
+  {
+    ASTNode n(ASTNodeType_t::AST_DIVIDE);
+    n.simplify();
+    // should not crash, remains DIVIDE with no children
+    fail_unless(n.getType() == ASTNodeType_t::AST_DIVIDE);
+  }
+
+
+  {
+    ASTNode n(ASTNodeType_t::AST_POWER);
+    n.simplify();
+    // should not crash, remains DIVIDE with no children
+    fail_unless(n.getType() == ASTNodeType_t::AST_POWER);
+  }
+}
+END_TEST
+
 Suite *
 create_suite_TestInferRnFunctions()
 {
@@ -1024,6 +1059,7 @@ create_suite_TestInferRnFunctions()
   tcase_add_test(tcase, test_simplify4);
   tcase_add_test(tcase, test_simplify5);
   tcase_add_test(tcase, test_simplify6);
+  tcase_add_test(tcase, test_no_children);
   tcase_add_test(tcase, test_convertRootToPower);
 
   suite_add_tcase(suite, tcase);