[XABT] Create separate assembly preparation tasks.

[jpobst]

Break down the CollectAssemblyFilesForArchive task further into individual tasks.

These tasks each handle a separate concern about preparing the assemblies for the apk:

• CompressAssemblies - Compresses assemblies using LZ4 compression (independent of ZIP compression).
• CreateAssemblyStore - Bundles assemblies into a single .blob file.
• WrapAssembliesAsSharedLibraries - Wraps the assemblies as shared libraries so they can go in the lib directory of the APK.

This should allow them to be moved to separate incremental targets in the future. For example, we do not need to compress all assemblies on every build if they haven't changed since the previous build.

[dellis1972]

This throws https://learn.microsoft.com/en-us/dotnet/api/system.convert.changetype?view=net-9.0. We should handle that case? and return the default.

[jpobst]

I think this only throws if the input cannot be converted to the requested type, like say you passed in "tru" and T is bool.

Passing in an invalid input is a bug that should be fixed, and it feels like we should indeed throw an exception here rather than silently swallow the error and return the default.

[jonpryor]

Recording what was mentioned on an earlier call:

We need to simplify our build system (and related) to reduce maintenance costs, up to and including removing infrequently/rarely used features.

While we need to continue to support $(EmbedAssembliesIntoApk)=True, that does not meant that we need to continue to support "one file per assembly within the .apk" (86260ed), which is Yet Another Codepath that we need to support for minimal gain. $(EmbedAssembliesIntoApk)=True should instead be an Assembly Store, even for Debug builds.

The appropriate fix for #9455 is not to "make $(EmbedAssembliesIntoApk)=True faster"; it is instead to make Fast Deployment more reliable. If Fast Deployment is only successful 40% of the time, we need more information (adb logcat output, MSBuild .binlog files around dotnet build -t:Install) so that we can fix those reliability issues.

[jpobst]

$(EmbedAssembliesIntoApk)=True should instead be an Assembly Store, even for Debug builds.

One caveat with this today is that assembly stores do not contain .pdb files, so you can't debug when using assembly stores. I would assume this is fixable but may require runtime loader changes. 🤷

android/src/Xamarin.Android.Build.Tasks/Tasks/CollectAssemblyFilesForArchive.cs

Lines 118 to 153 in 0475a60

	void DoAddAssembliesFromArchCollection (TaskLoggingHelper log, AndroidTargetArch arch, ITaskItem assembly, DSOWrapperGenerator.Config dsoWrapperConfig, PackageFileListBuilder files, bool debug, bool compress, IDictionary<AndroidTargetArch, Dictionary<string, CompressedAssemblyInfo>>? compressedAssembliesInfo, string compressedOutputDir, AssemblyStoreBuilder? storeBuilder)
	{
	// In the "all assemblies are per-RID" world, assemblies, pdb and config are disguised as shared libraries (that is,
	// their names end with the .so extension) so that Android allows us to put them in the `lib/{ARCH}` directory.
	// For this reason, they have to be treated just like other .so files, as far as compression rules are concerned.
	// Thus, we no longer just store them in the apk but we call the `GetCompressionMethod` method to find out whether
	// or not we're supposed to compress .so files.
	var sourcePath = CompressAssembly (assembly, compress, compressedAssembliesInfo, compressedOutputDir);
	if (UseAssemblyStore) {
	storeBuilder!.AddAssembly (sourcePath, assembly, includeDebugSymbols: debug);
	return;
	}
	// Add assembly
	(string assemblyPath, string assemblyDirectory) = GetInArchiveAssemblyPath (assembly);
	string wrappedSourcePath = DSOWrapperGenerator.WrapIt (Log, dsoWrapperConfig, arch, sourcePath, Path.GetFileName (assemblyPath));
	files.AddItem (wrappedSourcePath, assemblyPath);
	// Try to add config if exists
	var config = Path.ChangeExtension (assembly.ItemSpec, "dll.config");
	AddAssemblyConfigEntry (dsoWrapperConfig, files, arch, assemblyDirectory, config);
	// Try to add symbols if Debug
	if (!debug) {
	return;
	}
	string symbols = Path.ChangeExtension (assembly.ItemSpec, "pdb");
	if (!File.Exists (symbols)) {
	return;
	}
	string archiveSymbolsPath = assemblyDirectory + MonoAndroidHelper.MakeDiscreteAssembliesEntryName (Path.GetFileName (symbols));
	string wrappedSymbolsPath = DSOWrapperGenerator.WrapIt (Log, dsoWrapperConfig, arch, symbols, Path.GetFileName (archiveSymbolsPath));
	files.AddItem (wrappedSymbolsPath, archiveSymbolsPath);
	}

We default assembly stores to false if using debug symbols:

android/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets

Lines 328 to 329 in 0475a60

	<AndroidUseAssemblyStore Condition=" '$(AndroidUseAssemblyStore)' == '' and ('$(EmbedAssembliesIntoApk)' != 'true' or '$(AndroidIncludeDebugSymbols)' == 'true') ">false</AndroidUseAssemblyStore>
	<AndroidUseAssemblyStore Condition=" '$(AndroidUseAssemblyStore)' == '' ">true</AndroidUseAssemblyStore>

Copilot reviewed 5 out of 8 changed files in this pull request and generated no comments.

Files not reviewed (3)

• src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets: Language not supported
• src/Xamarin.Android.Build.Tasks/Tasks/CollectAssemblyFilesForArchive.cs: Evaluated as low risk
• src/Xamarin.Android.Build.Tasks/Tasks/CompressAssemblies.cs: Evaluated as low risk

Comments suppressed due to low confidence (1)

src/Xamarin.Android.Build.Tasks/Tasks/CreateAssemblyStore.cs:79

• The metadata value may not be a valid boolean. Consider using bool.TryParse to ensure the metadata value is a valid boolean.

var should_skip = asm.GetMetadataOrDefault ("AndroidSkipAddToPackage", false);