The nuget package: https://www.nuget.org/api/v2/package/System.Buffers/4.5.1 has mismatched assembly versions.

[KevinRansom]

The nuget package: https://www.nuget.org/api/v2/package/System.Buffers/4.5.1 has mismatched assembly versions.

Which requires binding redirects on the desktop to successfully bind.

Download the nuget package : https://www.nuget.org/api/v2/package/System.Buffers/4.5.1

Extract the files:
use ildasm or some other mechanism to examine the assembly version numbers.

ref\net45\System.Buffers.dll                      Version:   4.0.3.0
ref\netstandard1.1\System.Buffers.dll       Version:   4.0.2.0
ref\netstandard2.0\System.Buffers.dll       Version:   4.0.2.0

lib\net461\System.Buffers.dll                    Version:   4.0.3.0

This is an issue because if I build a library for netstandard2.0, and reference it from an app built for net472 the app needs a binding redirect to correctly execute.

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Issue Details

---

The nuget package: https://www.nuget.org/api/v2/package/System.Buffers/4.5.1 has mismatched assembly versions.

Which requires binding redirects on the desktop to successfully bind.

Download the nuget package : https://www.nuget.org/api/v2/package/System.Buffers/4.5.1

Extract the files:
use ildasm or some other mechanism to examine the assembly version numbers.

ref\net45\System.Buffers.dll                      Version:   4.0.3.0
ref\netstandard1.1\System.Buffers.dll       Version:   4.0.2.0
ref\netstandard2.0\System.Buffers.dll       Version:   4.0.2.0

lib\net461\System.Buffers.dll                    Version:   4.0.3.0

This is an issue because if I build a library for netstandard2.0, and reference it from an app built for net472 the app needs a binding redirect to correctly execute.

Author:	KevinRansom
Assignees:	-
Labels:	area-System.Buffers, untriaged
Milestone:	-

[huoyaoyuan]

#45921

[danmoseley]

@Anipik

[saucecontrol]

Not a direct fix, but if you're targeting .NET Standard and intend compatibility with .NET Framework, your users will have a better experience in general if you multi-target your library for both net461 and netstandard2.0. That will fix your issue with System.Buffers as a side effect, but there are other benefits as well.

Rick Strahl has a good writeup on that here, and the same recommendation is given in Microsoft's guidance for library developers here.

✔️ CONSIDER adding a target for net461 when you're offering a netstandard2.0 target.

Using .NET Standard 2.0 from .NET Framework has some issues that were addressed in .NET Framework 4.7.2. You can improve the experience for developers that are still on .NET Framework 4.6.1 - 4.7.1 by offering them a binary that is built for .NET Framework 4.6.1.

[KevinRansom]

@saucecontrol ,
If I build and reference ref/netstandard2.0 and the assembly verision is 4.0.2.0 and The corresponding lib/netstandard2.0 has an assembly version of 4.0.3.0 then on the desktop a binding redirect is necessary.

For developers building software that is a plugin, it is very hard to get an app to add the necessary binding redirect. I would suggest that having different version numbers for ref and lib in the same nuget package is just broken.

[saucecontrol]

Correct, if the ref/lib versions don't match, the binding redirect is necessary on desktop. However, if you multi-target, the net461 version of your library in the package would pick up the reference to 4.0.3 while the netstandard2.0 copy of your library would reference 4.0.2 (this doesn't matter since netfx is the only that one won't load without an exact version match). I've been through this in my own libraries, and multi-targeting, along with careful selection of dependency versions has solved the issue for my users.

having different version numbers for ref and lib in the same nuget package is just broken.

I couldn't agree more, and I said as much over on #26370. You might find that issue informative, if only so you can get a picture of how/why the current broken state came to be ;)