Serious perf regression between 0.22.0 and 0.23.0

[AArnott]

I recently upgraded Nerdbank.GitVersioning from libgit2sharp 0.22.0 to 0.23.0-pre20160803182831 because it fixed #1338. But after running my tests, I found there was a huge perf regression in the newer version.

Before, with 0.22.0:

After, with 0.23.0-pre20160803182831:

Repro instructions:

git clone https://github.com/AArnott/Nerdbank.GitVersioning.git
cd Nerdbank.GitVersioning
git checkout 4613c2516787
.\init.ps1
src\Nerdbank.GitVersioning.sln

In VS, build the solution.
In Test Explorer set "_roundtrip" to be your test filter and run tests.

[AArnott]

I ran an ETL trace on the regression. It seems very clearly due to an added new StackTrace(int, bool) call made from the Libgit2Object constructor:

Name                                                                        Inc %         Inc
 libgit2sharp!LibGit2Sharp.Core.Handles.Libgit2Object..ctor(void*,bool)      60.8      18,112
+ mscorlib.ni!System.Diagnostics.StackTrace..ctor(Int32, Boolean)$##6003121  58.9      17,563

[AArnott]

It looks like LEAKS_TRACKING was defined for the build that released to nuget. :(

[ethomson]

Ouch. Thanks for digging in. I can merge #1357 and spin a new prerelease build.

[biyimaks]

@ethomson when will a new build be created?

[ethomson]

Please see https://www.nuget.org/packages/LibGit2Sharp/0.23.0-pre20160922233542

Thanks again @AArnott for reporting this, and thanks @biyimaks for the ping.