C#: Encode GodotProjectDir as Base64 to prevent issues with special characters

[raulsntos]

• Fixes can_instantiate: Cannot instance script because the associated class could not be found (Project name contains invalid characters like #, ;, ') #73932.

[akien-mga]

Thanks!

[geowarin]

After this PR my build fails:

./modules/mono/build_scripts/build_assemblies.py --godot-output-dir=./bin \ --push-nupkgs-local ~/dev/LocalNugetSource

/home/geo/dev/godot/modules/mono/editor/Godot.NET.Sdk/Godot.SourceGenerators.Sample/Godot.SourceGenerators.Sample.csproj(10,5): 
error MSB4186: Invalid static method invocation syntax: "[MSBuild]::ConvertToBase64('$(GodotProjectDir)')". 
Method '[MSBuild]::ConvertToBase64' not found. Static method invocation should be of the form: $([FullTypeName]::Method()), e.g. $([System.IO.Path]::Combine(`a`, `b`)). 
Check that all parameters are defined, are of the correct type, and are specified in the right order.

dotnet --info:

.NET SDK (reflecting any global.json):
 Version:   6.0.114
 Commit:    346c0065dd

Runtime Environment:
 OS Name:     arch
 OS Version:  
 OS Platform: Linux
 RID:         arch-x64
 Base Path:   /usr/share/dotnet/sdk/6.0.114/

Host:
  Version:      7.0.3
  Architecture: x64
  Commit:       0a2bda10e8

.NET SDKs installed:
  6.0.114 [/usr/share/dotnet/sdk]

.NET runtimes installed:
  Microsoft.NETCore.App 6.0.14 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
  None

Environment variables:
  DOTNET_ROOT       [/usr/share/dotnet]

global.json file:
  Not found

[raulsntos]

Your version of MSBuild is likely outdated, what is the output of dotnet msbuild --version? I think the ConvertToBase64 method was added in 17.3.0.

[geowarin]

Indeed, I have a version < 17.3.0.

❯ dotnet msbuild --version
Microsoft (R) Build Engine version 17.0.1+b177f8fa7 for .NET
Copyright (C) Microsoft Corporation. All rights reserved.

17.0.1.11501%   

How to I update it? I think it's bundled by my distro.

[raulsntos]

MSBuild is part of the .NET SDK, can you update it? You have 6.0.114 installed, but 6.0.406 should be available.

[geowarin]

I've flag the arch packages as out-of-date.

[neikeq]

I think we should look for an alternative that doesn't require a newer MSBuild. Otherwise, we can't include it in 4.0.x as it's a breaking change. Is there a way in MSBuild to check if a method is available?

[geowarin]

I agree with @neikeq project builds are going to fail with this kind of errors:

Which is not user friendly at all.
And is a breaking change.

[YuriSizov]

Cherry-picked for 4.0.2 (alongside #74479).