CODEWITHSUNDEEP
asp.net-core
jmac
jmac

Reputation: 313

Understanding ASP.NET Core Patch Version Roll Forward

I'm trying to understand how the roll-forward mechanism with Microsoft.AspNetCore.App is supposed to work along with other nuget packages.

My understanding so far is that any time I publish my app, .netcore will automatically publish the app on the latest patched version that I have installed. This doesn't sound like a good practice to me. I think the application should be deployed on the .net version that it was developed on.

I recently ran into a problem where my build server has a newer SDK installed than I have on my development machine, so it tried to publish the app with a newer .netcore version.

This caused the build to break with the following error:

error NU1605: Detected package downgrade: Microsoft.EntityFrameworkCore.Design from 2.1.8 to 2.1.4. Reference the package directly from the project to select a different version.

I have explicitly specified that I want version 2.1.4 of Microsoft.EntityFrameworkCore.Design because that was the latest version that was available when I originally developed the application.

I feel like I'm missing something here. Am I supposed to make sure that I always have the same SDK installed locally as the build server and that all of my apps are updated to the latest SDK every time I need to make a change? What if a co-worker wants to write a .netcore app targeting a newer version of the framework so they request that a new SDK be installed on the build server? Surely I shouldn't have to also update my app to the latest patch version.

Upvotes: 2

Views: 866

Answers (1)

Rutix
Rutix

Reputation: 861

You experienced the problem because when you reference the versionless Microsoft.AspNetCore.App you shouldn't reference packages which already are pulled in by the metapackage. Because the metapackage already contains Microsoft.EntityFrameworkCore.Design and you specified a hard version you got a version conflict.

This usually happens when you have one project with the metapackage in another (for example test project) have a specified version. What happens then is that when building it will determine the highest version and use that but when it gets to the test project it will need to downgrade (because of the specified version) and will throw a build error. The recommended way until 3.0 is to add <Project Sdk="Microsoft.NET.Sdk.Web"> to the test project and also use the metapackage.

As far as I know it works like this: When you reference Microsoft.AspNetCore.App it will take the lowest possible version it can. So if for example your targetframework is netcoreapp2.1 then it will take 2.1.1. When it builds it will look what the highest possible version is of the shared framework you have installed for and use that. If you have the following runtimes installed: 2.2.0, 2.1.5, 2.1.12 it will roll forward to 2.1.12. There are some additional roll forward policies having to do with the minor (if its a preview version or not ect.) but those only happen when it can't find a runtime corresponding to the major and minor version.

See also: https://github.com/aspnet/AspNetCore/issues/3292 and https://github.com/aspnet/AspNetCore.Docs/issues/6430

Upvotes: 3

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