reject trailing characters in SwitchNode numeric comparison (#1178)

Author: aysha-afrah26

src/controls/switch_node.cpp

@@ -39,13 +39,15 @@ bool CheckStringEquality(const std::string& v1, const std::string& v2,
       }
     }
 #if __cpp_lib_to_chars >= 201611L
-    auto [ptr, ec] = std::from_chars(str.data(), str.data() + str.size(), result);
-    return (ec == std::errc());
+    const char* end = str.data() + str.size();
+    auto [ptr, ec] = std::from_chars(str.data(), end, result);
+    return ec == std::errc() && ptr == end;
 #else
     try
     {
-      result = std::stoi(str);
-      return true;
+      std::size_t pos = 0;
+      result = std::stoi(str, &pos);
+      return pos == str.size();
     }
     catch(...)
     {
@@ -60,15 +62,26 @@ bool CheckStringEquality(const std::string& v1, const std::string& v2,
     return true;
   }
   // compare as real numbers next
-  auto ToReal = [](const std::string& str, auto& result) -> bool {
+  auto ToReal = [enums](const std::string& str, auto& result) -> bool {
+    if(enums)
+    {
+      auto it = enums->find(str);
+      if(it != enums->end())
+      {
+        result = it->second;
+        return true;
+      }
+    }
 #if __cpp_lib_to_chars >= 201611L
-    auto [ptr, ec] = std::from_chars(str.data(), str.data() + str.size(), result);
-    return (ec == std::errc());
+    const char* end = str.data() + str.size();
+    auto [ptr, ec] = std::from_chars(str.data(), end, result);
+    return ec == std::errc() && ptr == end;
 #else
     try
     {
-      result = std::stod(str);
-      return true;
+      std::size_t pos = 0;
+      result = std::stod(str, &pos);
+      return pos == str.size();
     }
     catch(...)
     {

tests/gtest_switch.cpp

@@ -3,6 +3,7 @@
 
 #include "behaviortree_cpp/behavior_tree.h"
 #include "behaviortree_cpp/bt_factory.h"
+#include "behaviortree_cpp/controls/switch_node.h"
 #include "behaviortree_cpp/tree_node.h"
 
 #include <gtest/gtest.h>
@@ -245,3 +246,21 @@ TEST_F(SwitchTest, ActionFailure)
   ASSERT_EQ(NodeStatus::IDLE, action_42.status());
   ASSERT_EQ(NodeStatus::IDLE, action_def.status());
 }
+
+TEST(SwitchStringEquality, RejectsTrailingCharacters)
+{
+  using BT::details::CheckStringEquality;
+
+  // legitimate matches must keep working
+  EXPECT_TRUE(CheckStringEquality("5", "5", nullptr));
+  EXPECT_TRUE(CheckStringEquality("5", "5.0", nullptr));
+  EXPECT_TRUE(CheckStringEquality("42", "42", nullptr));
+  EXPECT_TRUE(CheckStringEquality("-7", "-7", nullptr));
+
+  // a selector with trailing bytes must not match a numeric case
+  EXPECT_FALSE(CheckStringEquality("5abc", "5", nullptr));
+  EXPECT_FALSE(CheckStringEquality("42xxxx", "42", nullptr));
+  EXPECT_FALSE(CheckStringEquality("1.0junk", "1.0", nullptr));
+  EXPECT_FALSE(CheckStringEquality("5 ", "5", nullptr));
+  EXPECT_FALSE(CheckStringEquality("none", "1", nullptr));
+}