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Scripts don't work: Encoding issue? #1131
Description
Describe the bug
The script action node always crashes:
[my_bt_node] terminate called after throwing an instance of 'BT::RuntimeError'
[my_bt_node] what(): Invalid token '�' at position 1
Stacktrace:
__pthread_kill_implementation@0x00007f32e80c4b2c (./nptl/pthread_kill.c:44)
__pthread_kill_internal@0x00007f32e80c4b2c (./nptl/pthread_kill.c:78)
__GI___pthread_kill@0x00007f32e80c4b2c (./nptl/pthread_kill.c:89)
__GI_raise@0x00007f32e806b27e (../sysdeps/posix/raise.c:26)
__GI_abort@0x00007f32e804e8ff (./stdlib/abort.c:79)
??@0x00007f32e82ddff5 (Unknown Source:0)
??@0x00007f32e82f30da (Unknown Source:0)
std::terminate()@0x00007f32e82dda55 (Unknown Source:0)
__cxa_throw@0x00007f32e82f3391 (Unknown Source:0)
??@0x00007f32e87208c9 (Unknown Source:0)
std::_Function_handler<std::unique_ptr<BT::TreeNode, std::default_delete<BT::TreeNode> > (std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, BT::NodeConfig const&), BT::CreateBuilder<BT::ScriptNode>()::{lambda(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, BT::NodeConfig const&)#1}>::_M_invoke(std::_Any_data const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, BT::NodeConfig const&)@0x00007f32e8772705 (Unknown Source:0)
BT::BehaviorTreeFactory::instantiateTreeNode(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, BT::NodeConfig const&) const@0x00007f32e8761bef (Unknown Source:0)
BT::XMLParser::PImpl::createNodeFromXML(tinyxml2::XMLElement const*, std::shared_ptr<BT::Blackboard> const&, std::shared_ptr<BT::TreeNode> const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, BT::Tree&)@0x00007f32e879e00f (Unknown Source:0)
??@0x00007f32e879f22e (Unknown Source:0)
??@0x00007f32e87a0396 (Unknown Source:0)
BT::XMLParser::PImpl::recursivelyCreateSubtree(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, BT::Tree&, std::shared_ptr<BT::Blackboard>, std::shared_ptr<BT::TreeNode> const&, std::unordered_set<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::hash<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::equal_to<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > >&)@0x00007f32e87988e3 (Unknown Source:0)
BT::XMLParser::instantiateTree(std::shared_ptr<BT::Blackboard> const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)@0x00007f32e879cd17 (Unknown Source:0)
BT::BehaviorTreeFactory::createTree(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::shared_ptr<BT::Blackboard>)@0x00007f32e875c69b (Unknown Source:0)
my_bt_node::MyBtNode::run_tree@0x0000561bb07d0982 ([...]/my_bt_node.cpp:57)
main@0x0000561bb07d00f0 ([...]/my_main.cpp:27)
How to Reproduce
std::string tree_text = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
"<root BTCPP_format=\"4\">\n"
" <BehaviorTree ID=\"Pi\">\n"
" <Script code=\"pi:=3.14\"/>\n"
" </BehaviorTree>\n"
" <!-- Description of Node Models (used by Groot) -->\n"
" <TreeNodesModel/>\n"
"</root>";
factory.registerBehaviorTreeFromText(tree_text);
auto tree = factory.createTree("Pi");
tree.tickWhileRunning();
Activity
webzuweb commentedon Sep 23, 2026
I can't reproduce this on current
masterwith the exact snippet —pi:=3.14tokenizes cleanly asIdentifier(pi) ColonEqual Real(3.14). The hand-written tokenizer (PR #1099, merged 2026-02-04) supports:=as the assignment operator, andtests/script_parser_test.cpphas dozens of passing:=cases (e.g.x:= 3; y:=5; x+y).The token
�(U+FFFD) at position 1 strongly suggests the actual bytes fed to the Script node aren't valid UTF-8 — the most common cause is a UTF-8 BOM (EF BB BF) at the start of the file/string, or an XML file saved in a non-UTF-8 encoding (e.g. UTF-16 or Windows-1252). The in-memorystd::stringin the repro is pure ASCII, so it can't produce that by itself.Could you share the exact XML file (or its first bytes / encoding) that triggered the crash? If there's a BOM or non-UTF-8 byte sequence in the
codeattribute, that would pinpoint whether this is a parser robustness gap worth fixing (e.g. stripping a leading BOM) versus an input-encoding issue.facontidavide commentedon Oct 24, 2026
We can't reproduce this from the snippet:
pi:=3.14tokenizes correctly. The�in the error is a single byte of a multi-byte character, which points to a non-ASCII character in the real script (a BOM, a non-breaking space, or a Unicode lookalike such as：), while script identifiers are ASCII-only. Could you attach the exact XML file, or the output ofxxdon the attribute value? Without that we'll close this in about two weeks.