Api diff

[danwalmsley]

What does the pull request do?

This ensures binary compatibility with a specified version (currently 0.10.0-preview1)

Binary api changes will cause an error.

used this guide: https://stu.dev/check-for-breaking-changes-with-apicompat/

There are ApiCompatBaseLine.txt files next to csproj with breaking changes since the specified release.
i.e.

Compat issues with assembly Avalonia.Base:
MembersMustExist : Member 'public void Avalonia.Threading.AvaloniaSynchronizationContext..ctor()' does not exist in the implementation but it does exist in the contract.
Total Issues: 1

Those files allow breaking changes to be allowed.

These files can be generated when a breaking change occurs using... dotnet build /p:BaselineAllAPICompatError=true
They can then be checked in.

My suggestion is these are all removed after 0.10.0 release and 0.10.0 becomes our api promise more or less.

We will also need to do an api review...

We can generate a report comparing to 0.9.11 at the time to help us work out if some stuff was made public that shouldnt and if some apis need fixing.

What is the current behavior?

What is the updated/expected behavior with this PR?

If you make an api change you will get a build error i.e.:

C:\Users\danwa\.nuget\packages\microsoft.dotnet.apicompat\5.0.0-beta.20364.3\build\Microsoft.DotNet.ApiCompat.targets(82,5): error : MembersMustExist : Member 'public void Avalonia.Controls.Button..ctor()' does not exist in the implementation but it does exist in the contract. 

example can be seen here:
https://dev.azure.com/AvaloniaUI/AvaloniaUI/_build/results?buildId=9466&view=results

How was the solution implemented (if it's not obvious)?

Checklist

• Added unit tests (if possible)?
• Added XML documentation to any related classes?
• Consider submitting a PR to https://github.com/AvaloniaUI/Avaloniaui.net with user documentation

Breaking changes

Fixed issues

[danwalmsley]

In future we can exclude certain types, methods and classes from api checks with attributes and have a single baseline file for the entire solution... however this is currently blocked by:

dotnet/arcade#5826