Which nuget.config am I using?

Those are my nuget usage scenarios:

• from command line
• from Visual Studio package manager
• as a post-build event in Visual Studio
• with automatic package restore in Visual Studio
• on TeamCity build server (this I consider to be a command line as well)

At some point it was vital to know - which nuget.config am I actually using?
The default location for nuget.config is C:\Users\{UserName}\AppData\Roaming\NuGet\NuGet.config

Nuget chains configuration files, if there are several. It loads default nuget.config, then searches down from drive's root to {CurrentFolder}, then adds config file specified with -ConfigFile switch. {CurrentFolder} is either the solution root directory or an invocation directory. Later located config files are "stronger" and can override settings from previously loaded.

Calling nuget from command line - loads default config and then loads all nuget.config files searching from the  drive's root and down to invocation directory. Remember - than later found than stronger. So than closer to invocation directory than better.

When working in Visual Studio package manager - placing nuget.config in the solution root directory is good enough to know that's the one being used. Basically, working in package manager is same as working from command line, having solution root directory as an invocation directory.

For using nuget.exe in a post-build event my solution is to specify location of nuget.config in a post-build event explicitely, using -ConfigFile switch. I can not know for sure from where my project will be built.

Example: nuget push $(ProjectDir)$(OutputPath)*.nupkg -ConfigFile $(SolutionDir).nuget\nuget.config

A bit different though when Visual Studio does automatic package restore. We definitely want to avoid adding packages to Source Control, and there is a nice config setting for that: 

<add key="disableSourceControlIntegration" value="true" />

But - that one will work only if you have your nuget.config file in .nuget subfolder at the Solution Root directory. 

Happy nuget-ing :)

PS: For testing I used VS 2013 Update3 and nuget 2.8

PPS: a detailed, yet not very transparent documentation can be found here.