Improve "first run" build & run time inside VS

[jonathanpeppers]

Android application type

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

Affected platform version

.NET 7,8,9

Description

When you build an Android project, we have logic that "finds" the property $(RuntimeIdentifier) for the attached device:

https://github.com/xamarin/monodroid/blob/867ef5e9ead84e407419e6a1f5d64a3d6583f6d5/tools/msbuild/Xamarin.Android.Common.Debugging.targets#L451-L475

If you have no device attached, it just builds all 4 $(RuntimeIdentifiers).

Problem

This can slow down the 1st time experience for MAUI on Android, as there would be no emulators running or Android devices attached. This builds 4 architectures for no reason.

Solution 1

The IDE passes $(RuntimeIdentifier) to builds. This could be problematic as right now project defaults are:

<RuntimeIdentifier></RuntimeIdentifier>
<RuntimeIdentifiers>android-arm;android-arm64;android-x86;android-x64</RuntimeIdentifiers>
<AppendRuntimeIdentifierToOutputPath>true</AppendRuntimeIdentifierToOutputPath>
<AppendRuntimeIdentifierToIntermediateOutputPath>true</AppendRuntimeIdentifierToIntermediateOutputPath>

This could have unforseen consequences, in trying to use RID for this. There are many general issues about RIDs in multi-targeted projects:

• Make it possible to choose a different default RuntimeIdentifier between build and publish for SDKs sdk#27253
• Specifying both -f ... and -r ... to dotnet build fails to restore if multiple frameworks are present in the project file sdk#21877

Solution 2

Invent a new property that would skip the <GetPrimaryCpu/> task and just set appropriate properties instead.

Steps to Reproduce

1. File > New MAUI project
2. Run in VS without an emulator running or device attached

Did you find any workaround?

No response

Relevant log output

No response

[jonathanpeppers]

This scenario is also improved by:

• [Xamarin.Android.Build.Tasks] default to only 64-bit targets #9179

[jonathanpeppers]

The current proposal is:

• The IDE sets a new value -p:AdbTargetArchitecture
• At this time, the emulator is closed, adb devices doesn't report anything
• The IDE doesn't have the value for -p:AdbTarget at this time either

So, the build could:

• Skip _GetPrimaryCpuAbi if $(AdbTargetArchitecture) is set
• Set appropriate values for $(RuntimeIdentifiers), etc.

By the time the IDE Deploys, or runs the Install target:

• Build is complete
• Emulator is running
• Install will be passed -p:AdbTarget as before, and passed -p:AdbTargetArchitecture for completeness (this way _GetPrimaryCpu is skipped).