Nsubstitute: Look at restoring pre-NET46 targets for 3.x

[dtchepak]

Might be able to get back NET45, and even NET40, without much hassle:

https://www.bartwolff.com/Blog/2017/03/20/targeting-multiple-net-platforms-in-a-single-nuget-package-w

[fluffynuts]

I was just about to raise a question about this ^_^, specifically because 4.5.2 is the lowest MS-supported version (iirc), and still quite prolific "in the wild" as it were.

[dtchepak]

@fluffynuts If you have time to have a go at adding this in please let me know.

[alexandrnikitin]

I'm fine with dropping .NET 4.5 support. The official support of .NET 4.5.2 from Microsoft will end in January 2018 (together with Windows 8.1). My reasoning is that NSubstitute is a mature framework. 1.10 and 2.0.3 versions have all features that 3.0 has. The reason to have 3.0 is to catch up with Microsoft and clean up the code base. We can (possibly) introduce new major feature like mobile support but at that time .NET Core will be common.

[dtchepak]

@alexandrnikitin If we can get NET45 with next-to-no maintenance cost (as the post in the issue description suggests) then I'm happy to add it back. The previous 2.x approach of multiple projects was unsustainable though.

[alexandrnikitin]

@dtchepak I think I missed your intention at some point 😢 We had proper .NET 4.5 support with csproj style right before this commit. I thought you wanted to remove it.

[dtchepak]

@alexandrnikitin My fault, I should have been clearer, and I'm not up to date with the latest csproj/build system changes so I don't understand what is possible/supported now. :) I just wanted to simplify stuff as much as possible to get the build working again. I did File -> New Project to get a minimal csproj to work from and went from there.

If there is very little maintenance to supporting NET45 and even NET40 I would really like it in. I've been on projects where we've had to be stuck on an older framework and it was really frustrating not to be able to use particular libraries, so I don't want to subject others to that if we can avoid it. (I'd even support NET35 if we could! By AFAIK it's not supported at all by the current toolset.)

[dtchepak]

Tested this (4410509) on a net46 project, seems to work ok and also alleviates #331.

[dtchepak]

Fixed with release 3.1.0. If anyone still wants NET40 support please raise a separate issue.

[fluffynuts]

Epic! Thanks!