[Bug]: Use after free via SetDParamStr for STR_CONFIG_ERROR_INVALID_GRF

[JGRennison]

Version of OpenTTD

master

Expected result

No use after frees.

Actual result

SetDParamStr(0, StrEmpty(filename) ? item->name : filename); at https://github.com/OpenTTD/OpenTTD/blob/master/src/settings.cpp#L1019

In this case item->name is a std::string, file is a const char *.
The ternary's result type is std::string, so a temporary std::string is created from filename.
This goes out of scope before it is accessed from ShowErrorMessage on the next line.

While this particular one is trivial to fix, probably there are more like this in the codebase. I found it by chance when testing something else.

void SetDParamStr(uint n, const std::string &str) seems a somewhat problematic function signature in general as it can be difficult to avoid passing a temporary/rvalue.

Steps to reproduce

Use AddressSanitizer or some other heap checker, and trigger this code path using the NewGRF config window.