NET8 Android binding library generated sources are deleted when app resources are updated

[uholeschak]

Android application type

.NET Android (net7.0-android, net8.0-android, etc.)

Affected platform version

VS2022 17.8.5

Description

The NET8 Android binding library generates it sources files at obj\$(Configuration)\$(TargetFramework)\generated\src.
When the resources of the corresponding app are updated by MSBuild:UpdateGeneratedFiles the msbuild target PrepareResources is called, which deletes the generated sources.
When debugging this causes problems, because the source has changed.
Building the application fails if resources files are open.

Steps to Reproduce

1. Create NET8 Android binding library for an .AAR file
2. Use the binding library in a application as project reference
3. Build the application
4. Check the binding library generated source at obj\$(Configuration)\$(TargetFramework)\generated\src
5. Open the app Android resource and change it
6. Watch obj\$(Configuration)\$(TargetFramework)\generated\src, the source will be deleted after some delay.
7. While debugging (hitting a break point) the hot reload window is displayed, because the source files have been deleted.

Did you find any workaround?

Create a file Directory.Build.targets in the Android binding library project directory

<Project>
    <Target Name="PrepareResources" DependsOnTargets="$(PrepareResourcesDependsOn)" Condition="'$(DesignTimeBuild)'!='true'">
        <Message Text="PrepareResources modified" Importance="High" />
    </Target>
</Project>

Add to all projects in the solution:

    <DisableFastUpToDateCheck>true</DisableFastUpToDateCheck>

This disables the resource update in the Android binding library

Relevant log output

No response

[dellis1972]

@uholeschak

Are you able to provide binlogs which demonstrates the issue?
You can follow the instrucitons at https://github.com/dotnet/msbuild/blob/main/documentation/wiki/Providing-Binary-Logs.md#capturing-binary-logs-through-visual-studio. This will capture ALL data including the design time builds, it will allow us to see what is happening. Note it is important that we do get the design time build logs, as from what you describe the problem is with one of those.

[uholeschak]

Ich have created some log files with Project System Tools 2022 in design mode when opening an Android resource:
VSLogFiles.zip
The interesting files are the 3 log files from the NetBinding projects.
The generated sources are deleted in this case.

[dellis1972]

@uholeschak

Cam you share the csproj for one of those files? Usually I'd extract it from the binlog but I cannot open it on the mac as the https://live.msbuildlog.com/ site has not been updated it seems :(.

Looks like the problem is the _ClearGeneratedManagedBindings target. Its currently using the following condition
'@(InputJar->Count())' == '0' And '@(EmbeddedJar->Count())' == '0' And '@(LibraryProjectZip->Count())' == '0' And '@(_JavaBindingSource->Count())' == '0'.

All of which are evaluating to 0. Something is missing from the conditon on this target it seems.

[uholeschak]

Here is one of the binding project files.
UsbSerialNetBinding.zip
It also contains a pre build step, that is irrelevant in this case. It only tries to force a regeneration of the source if the source is missing ...
The input file is an .aar that is auto detected by the project.