Possible In-memory repository regression?

So I'm trying to get my branch updated with master https://github.com/Zoxive/libgit2sharp/tree/zoxive/refdb/ which revives the pluggable RefDb backend (#1226)

I've gotten through all the compile issues rebasing it up to the latest with dotnet core, and the codegen stuff. (Took a while to figure out that I had to change all the NativeMethod funcs to use the new custom marshaler)

Anyways all compiles and stuff now.. but testing my changes im running into an error that appears to be coming straight from libgit2.

LibGit2SharpException: path cannot exist in repository

It happens when i have an in memory repository and an OdbBackend.

Heres a sample unit test that shows the problem.
https://github.com/Zoxive/libgit2sharp/commit/7957581353134c17deaa71714ffd24a0a6130c5e

I did see that libgit2 had a regression (https://github.com/libgit2/libgit2/pull/4263) @ethomson fixed.
I'm guessing its related?

首先，使用内存中的 repository 和 OdbBackend 运行提交 7957581353134c17deaa71714ffd24a0a6130c5e 中的示例单元测试。将该失败与 libgit2 pull request 4263 进行比较，并追踪“path cannot exist in repository”异常在哪里被抛出。完成的标准是复现成功，且不会导致其他 repository backend 出现回归。