Central Package Management - warning NU1507: There are 2 package sources defined in your configuration.
A few weeks ago, I talked about a new NuGet feature, Central Package Management. This allows you to manage your dependencies at the solution level instead of at the project level.
After converting one of my projects to use Central Package Management, I noticed the following warning in Visual Studio:
warning NU1507: There are 2 package sources defined in your configuration.
When using central package management, please map your package sources with package source mapping (https://aka.ms/nuget-package-source-mapping) or specify a single package source. The following sources are defined: nuget.org, company.be.
I get this warning because I have 2 package sources defined, one at the machine level and one at the solution level in my nuget.config.
I could get rid of this warning by using a single package source.Therefore I need to update my nuget.config file to have only 1 package source defined and add a <clear /> statement to not use package sources found at other levels:
Another solution is to use Package Source Mapping as suggested in the warning.
What is Package Source Mapping?
With Package Source Mapping, you can define from which source each package in your solution should be restored. This is important to improve security when you use a mix of public and private package sources and helps you against software supply chain attacks.
To use Package Source Mapping, you need to update your nuget.config file and specify one or more package patterns:
In the example above a packageSourceMapping element was added in which we declared a packageSource element for each source in use. Per source we defined a pattern that(it can be more then one) links the package name to the correct source.
In our example, packages started with company.* will use the private company.be package source. All other packages come from the public nuget.org package source.
If you want to learn more, have a look at the documentation.