PrivateAssets="All" breaks Android apps

[Kira-NT]

Description

Hi! I'm developing a hot reload plugin for a UI framework. Well, technically, it's already done, and now I'm faced with the real challenge - packaging it.

Naturally, since my package is designed as a development-only dependency, I pack it with -p:DevelopmentDependency=true. Thus, when users install it, the following snippet is added to their project file:

<PackageReference Include="Foo" Version="...">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
</PackageReference>

which is equivalent to:

<PackageReference Include="Foo" Version="..." PrivateAssets="All" />

And everything behaves properly whenever the plugin is used with a desktop application, whether it's created via dotnet build or dotnet run.

However, the moment I try to run an Android app via dotnet run, it instantly crashes with a cryptic FileNotFoundException, signifying that the satellite library required for debug builds to function has not been included in the resulting bundle. As far as I understand after four days of digging through the best documentation I have on this topic (i.e., the sources of this repo and eight-year-old issues), this happens because dotnet run for Android builds actually uses the publish routine to generate the output that gets uploaded to the device; and the SDK by default sets Publish="false" for every PackageReference that has its PrivateAssets set to all, causing development-only dependencies to go missing, even though the intent was not to publish the app, but to create a development build for debugging purposes.

Workarounds

The ugly workaround would be to ask users to install the plugin by manually editing their project files and inserting the following snippet there:

<PackageReference Include="Foo" Version="..." PrivateAssets="All" Publish="True" />

It's "ugly" because:

1. Nobody reads documentation these days, so this will just lead to an endless stream of "No work! Crash! How fix?" issues in my repo.
2. This doesn't actually represent the proper intent of what I'm trying to achieve. I do not want my satellite library to be copied to users' published builds. It's only needed for regular debug builds, which I expect Android builds created by dotnet run to be. However, those unexpectedly differ in semantics from the desktop ones.

Sooooo... Are there any somewhat proper workarounds I can employ within the .props/.targets distributed with my nuget, so that users can simply run dotnet add package Foo and expect everything to work as intended?

Related Issues

#27211
#1019
#952

[Forgind]

I'm not sure if this is a bug in the SDK, the android workload, or something else. Would it be possible to provide a binlog? And perhaps adb logcat?

[Kira-NT]

Thanks for your response! Yup, absolutely:

• Kira-NT/HotAvalonia/samples/HotReloadDemo.Android - the project in question.
• adb.log
• msbuild.binlog

There's nothing particularly interesting in the adb logs, though. The only relevant part is:

03-12 03:01:42.687  4802  4802 W monodroid-assembly: open_from_bundles: failed to load bundled assembly HotAvalonia.Core.dll
03-12 03:01:42.687  4802  4802 W monodroid-assembly: open_from_bundles: the assembly might have been uploaded to the device with FastDev instead
03-12 03:01:42.687  4802  4802 W monodroid-assembly: open_from_update_dir: assembly file DOES NOT EXIST
03-12 03:01:42.687  4802  4802 W monodroid-assembly: open_from_bundles: failed to load bundled assembly HotAvalonia.Core.dll
03-12 03:01:42.687  4802  4802 W monodroid-assembly: open_from_bundles: the assembly might have been uploaded to the device with FastDev instead
03-12 03:01:42.707  4802  4802 W oadDemo.Android: Could not load signature of HotAvalonia.AvaloniaHotReloadExtensions:CreateHotReloadContextFactory due to: Could not load file or assembly 'HotAvalonia.Core, Version=3.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.

As generic of an error as it gets - the .dll is simply missing, and that's all there is to it.

Let me give you a bit more context. I'm developing a hot reload plugin for Avalonia and expect users to install it like any other NuGet package via:

dotnet add package HotAvalonia

which results in the following being added to their project files:

<PackageReference Include="HotAvalonia" Version="3.0.0" PrivateAssets="All" />

Note the PrivateAssets="All", which is there because the package is marked as a development-only dependency.

HotAvalonia itself is just a tooling package that orchestrates various HotAvalonia-branded bits and bobs. One of these is HotAvalonia.Core, a satellite assembly required for Debug builds of user apps to support hot reloading. HotAvalonia "depends" on it solely to ensure the SDK copies it to the output folder. And this whole ordeal works exactly as expected for desktop builds created via dotnet build or dotnet run. However, as you can see, when I try to run an Android app, HotAvalonia.Core isn't copied to the output, causing the app to immediately crash.

This can be "fixed" by adding Publish="True" to the package reference, but that requires an intervention on the user's side, and I would rather rely on a solution baked into the package itself.

So, basically, my problem can be solved in one of two ways:

1. If there were a way to control whether my package should be published to the output folder from within the package itself.
2. Or, preferably, if the peculiar mismatch between dotnet run for desktop applications (which correctly copies all referenced assemblies) and dotnet run for Android apps (which behaves like dotnet publish and omits development-only packages and their dependencies) could be resolved on the SDK's side.

[Forgind]

I'll admit that I thought I'd learn more from the binlog, but I'm still a bit lost. I found a line that said it failed to find:
/data/app/~~CMy4v3KO3gBCj3FXnwbcyA==/HotReloadDemo.Android-RgaLPgi3nhzHFvLwZULMdg==/base.dm
and I wondered if that might be required for something, but my confidence level right now is very low. I'm going to mark this for team-triage and hope someone on my team can help.

[marcpopMSFT]

Triage: @jonathanpeppers do you happen to know about hot reload plugin support in android applications?

[marcpopMSFT]

CC @nkolev92 as well since DevelopmentDependency affects the nuspec and nuget configuration so maybe he has some suggestions here as well.

[nkolev92]

I don't have any suggestions unfortunately, development dependencies have to be PrivateAssets="All".
The list of related issues captures the problem.

[Kira-NT]

So, there are no known workarounds at the moment? Will there ever be? 👉👈

[nkolev92]

So, there are no known workarounds at the moment?

I think you listed the workaround though, with Publish="True"

[Kira-NT]

Welp, it's a consumer-side workaround, so unfortunately, as a package author, I cannot employ it myself.

[jonathanpeppers]

@Kira-NT I have not seen the $(DevelopmentDependency) setting before, does it fail only on Android? What about iOS? WindowsAppSDK?

I would guess that our deployment process isn't handling $(DevelopmentDependency) packages, but I would think iOS or other platforms could have a similar issue.

[baronfel]

Here's the relevant portion from the NuGet MSBuild property documentaation, for folks that aren't aware of DevelopmentDependency or its specifications:

property	description
DevelopmentDependency	A Boolean value that specifies whether the package is marked as a development-only dependency, which prevents the package from being included as a dependency in other packages. With PackageReference (NuGet 4.8+), this flag also means that compile-time assets are excluded from compilation. For more information, see DevelopmentDependency support for PackageReference.