Allow cpptrace::detail::demangle to demangle strings that have non-identifier characters at the end

src/demangle/demangle_with_cxxabi.cpp

@@ -7,26 +7,42 @@
 #include <cxxabi.h>
 
 #include <cstdlib>
+#include <functional>
 #include <string>
 
 namespace cpptrace {
 namespace detail {
     std::string demangle(const std::string& name) {
-        int status;
         // https://itanium-cxx-abi.github.io/cxx-abi/abi.html#demangler
         // check both _Z and __Z, apple prefixes all symbols with an underscore
         if(!(starts_with(name, "_Z") || starts_with(name, "__Z"))) {
             return name;
         }
+        // Mangled names don't have spaces, we might add a space and some extra info somewhere but we still want it to
+        // be demanglable. Look for a space, if there is one swap it with a null terminator briefly.
+        auto end = name.find(' ');
+        std::string name_copy;
+        std::reference_wrapper<const std::string> to_demangle = name;
+        std::string rest;
+        if(end != std::string::npos) {
+            name_copy = name.substr(0, end);
+            rest = name.substr(end);
+            to_demangle = name_copy;
+        }
         // presumably thread-safe
         // it appears safe to pass nullptr for status however the docs don't explicitly say it's safe so I don't
         // want to rely on it
-        char* const demangled = abi::__cxa_demangle(name.c_str(), nullptr, nullptr, &status);
+        int status;
+        char* const demangled = abi::__cxa_demangle(to_demangle.get().c_str(), nullptr, nullptr, &status);
         // demangled will always be nullptr on non-zero status, and if __cxa_demangle ever fails for any reason
         // we'll just quietly return the mangled name
         if(demangled) {
+            // TODO: raii_wrap the char*?
             std::string str = demangled;
             std::free(demangled);
+            if(!rest.empty()) {
+                str += rest;
+            }
             return str;
         } else {
             return name;