uri_builder crash

[opottone]

This minimal program crashes:

#include "cpprest/uri.h"

int main()
{
    web::uri uri(U("http://127.0.0.1:34568/"));
}

The crash happens when the program is compiled with Visual Studio 2017 in Debug mode with Runtime Library set to "Multi-Threaded Debug (/MTd)" (Project properties -> C/C++ -> Code Generation -> Runtime Library)

The program crashes with error message

Debug Assertion Failed!
File: minkernel/crts/ucrt/src/appcrt/heap/debug_heap.cpp
Line: 996
Expression: __acrt_first_block == header

[BillyONeal]

I just tried this under address sanitizer and it passes. What version are you looking at?

[opottone]

I'm using 2.10.8 (the version you get when you just run vcpkg install).

[BillyONeal]

Oh, I see what happened. You built vcpkg in the default (x86-windows) mode which builds cpprestsdk under /MD and /MDd, but then created a project referencing it that used /MT and /MTd. That explodes because you try to allocate memory from one debug CRT and free on a different debug CRT.

If you install targeting the x86-windows-static triplet that should get you a compatible cpprestsdk build (and will also automatically make you statically link to the bits so you don't need to deploy an extra dll)

/cc @ras0219-msft

[opottone]

Yes that makes sense. Thank you @BillyONeal.

[opottone]

Though in neither case did I actively chose the wrong option, I just went with the defaults. What if static build were the default in vcpgk installation?

[BillyONeal]

The default when you make a new project in VS is to use the DLL variant of the CRT, which is also vcpkg's default. They both need to be changed at the same time. That said, it would be better if you got some kind of message from vcpkg that explained badness was happening rather than just deploying incorrect bits. At that point though, it becomes a vcpkg bug; there's nothing cpprestsdk can do here.