[Xamarin.Android.Build.Tasks] fix enormous string expansion

[jonathanpeppers]

Context: dotnet/msbuild#5553
Context: dotnet/msbuild#5315

I have seen some comically long log messages such as:

Task "GetDependsOnNETStandard" skipped, due to false condition; ('$(_HasReferenceToSystemRuntime)' != 'true' and '$(_IsXBuild)' != 'true' and '$(DependsOnNETStandard)' == '' and '@(_XACandidateNETStandardReferences)' != '') was evaluated as ('true' != 'true' and 'true' != 'true' and '' == '' and 'C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\Microsoft.CSharp.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\Microsoft.VisualBasic.Core.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\Microsoft.VisualBasic.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\Microsoft.Win32.Primitives.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.AppContext.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Buffers.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Collections.Concurrent.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Collections.Immutable.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Collections.NonGeneric.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Collections.Specialized.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Collections.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.ComponentModel.Annotations.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.ComponentModel.DataAnnotations.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.ComponentModel.EventBasedAsync.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.ComponentModel.Primitives.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.ComponentModel.TypeConverter.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.ComponentModel.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Configuration.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Console.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Core.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Data.Common.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Data.DataSetExtensions.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Data.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Diagnostics.Contracts.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Diagnostics.Debug.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Diagnostics.DiagnosticSource.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Diagnostics.FileVersionInfo.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Diagnostics.Process.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Diagnostics.StackTrace.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Diagnostics.TextWriterTraceListener.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Diagnostics.Tools.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Diagnostics.TraceSource.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Diagnostics.Tracing.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Drawing.Primitives.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Drawing.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Dynamic.Runtime.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Formats.Asn1.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Globalization.Calendars.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Globalization.Extensions.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Globalization.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.Compression.Brotli.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.Compression.FileSystem.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.Compression.ZipFile.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.Compression.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.FileSystem.DriveInfo.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.FileSystem.Primitives.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.FileSystem.Watcher.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.FileSystem.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.IsolatedStorage.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.MemoryMappedFiles.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.Pipes.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.UnmanagedMemoryStream.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.IO.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Linq.Expressions.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Linq.Parallel.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Linq.Queryable.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Linq.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Memory.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.Http.Json.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.Http.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.HttpListener.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.Mail.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.NameResolution.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.NetworkInformation.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.Ping.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.Primitives.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.Requests.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.Security.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.ServicePoint.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.Sockets.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.WebClient.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.WebHeaderCollection.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.WebProxy.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.WebSockets.Client.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.WebSockets.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Net.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Numerics.Vectors.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Numerics.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.ObjectModel.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Reflection.DispatchProxy.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Reflection.Emit.ILGeneration.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Reflection.Emit.Lightweight.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Reflection.Emit.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Reflection.Extensions.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Reflection.Metadata.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Reflection.Primitives.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Reflection.TypeExtensions.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Reflection.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Resources.Reader.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Resources.ResourceManager.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Resources.Writer.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.CompilerServices.Unsafe.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.CompilerServices.VisualC.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.Extensions.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.Handles.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.InteropServices.JavaScript.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.InteropServices.RuntimeInformation.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.InteropServices.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.Intrinsics.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.Loader.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.Numerics.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.Serialization.Formatters.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.Serialization.Json.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.Serialization.Primitives.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.Serialization.Xml.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.Serialization.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Runtime.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Security.Claims.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Security.Cryptography.Algorithms.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Security.Cryptography.Csp.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Security.Cryptography.Encoding.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Security.Cryptography.Primitives.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Security.Cryptography.X509Certificates.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Security.Principal.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Security.SecureString.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Security.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.ServiceModel.Web.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.ServiceProcess.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Text.Encoding.CodePages.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Text.Encoding.Extensions.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Text.Encoding.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Text.Encodings.Web.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Text.Json.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Text.RegularExpressions.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Threading.Channels.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Threading.Overlapped.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Threading.Tasks.Dataflow.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Threading.Tasks.Extensions.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Threading.Tasks.Parallel.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Threading.Tasks.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Threading.Thread.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Threading.ThreadPool.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Threading.Timer.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Threading.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Transactions.Local.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Transactions.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.ValueTuple.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Web.HttpUtility.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Web.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Windows.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Xml.Linq.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Xml.ReaderWriter.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Xml.Serialization.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Xml.XDocument.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Xml.XPath.XDocument.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Xml.XPath.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Xml.XmlDocument.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Xml.XmlSerializer.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.Xml.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\System.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\WindowsBase.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\mscorlib.dll;C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0-rc.1.20371.13\ref\net5.0\netstandard.dll;C:\src\net5-samples\packages\microsoft.android.ref\11.0.100-ci.master.11\ref\net5.0\Java.Interop.dll;C:\src\net5-samples\packages\microsoft.android.ref\11.0.100-ci.master.11\ref\net5.0\Mono.Android.Export.dll;C:\src\net5-samples\packages\microsoft.android.ref\11.0.100-ci.master.11\ref\net5.0\Mono.Android.dll' != '').

This message is ~18K characters long.

This particular example has been around since PCL support was added
for Xamarin.Android.

There is a "fast path" in MSBuild that actually evaluating the
Condition will not expand the string when you compare against ''.
However, the string gets expanded anyway to produce the above log
message! At least it's not getting expanded twice?

The fix is to use ->Count() instead:

'@(_XACandidateNETStandardReferences->Count())' != '0'

Which prints a much shorter log message:

Task "GetDependsOnNETStandard" skipped, due to false condition; ('$(_HasReferenceToSystemRuntime)' != 'true' and '$(_IsXBuild)' != 'true' and '$(DependsOnNETStandard)' == '' and '@(_XACandidateNETStandardReferences->Count())' != '0') was evaluated as ('true' != 'true' and 'true' != 'true' and '' == '' and '156' != '0')

I fixed a similar message in Roslyn:

dotnet/roslyn#46445

Results

In a build with no changes:

> dotnet build .\HelloAndroid\HelloAndroid.csproj -bl -v:quiet

I could see a difference:

Project "HelloAndroid.csproj" (default targets): (1.024s)
Project "HelloAndroid.csproj" (default targets): (968ms)

The <GetDependsOnNETStandard/> MSBuild task runs 4 times in this
project because it is building for multiple $(RuntimeIdentifiers).

This saved ~56ms in one example, but it might not be noticeable at all
in "legacy" Xamarin.Android.

Down the road I will see if we can drop
Xamarin.Android.PCLSupport.targets completely for .NET 6 projects.

I went ahead and fixed any cases of '@(Foo)' != '' and updated
MSBuildBestPractices.md. The others would not likely be checking
against large item groups, but they could be.

[dellis1972]

We are using this '@(xxxx)' != '' construct allot.

git grep " != ''" | grep "@"
MSBuild/Xamarin/Android/Xamarin.Android.Aapt2.targets:    Condition=" '$(_AndroidUseAapt2)' == 'True' And '@(_ProcessedCustomViews)' != '' ">
MSBuild/Xamarin/Android/Xamarin.Android.Aapt2.targets:      Condition=" '$(AndroidUseAapt2)' == 'True' And '@(_ItemsToFixup)' != '' "
MSBuild/Xamarin/Android/Xamarin.Android.Aapt2.targets:  <Touch Files="$(_AndroidResgenFlagFile)" AlwaysCreate="True" Condition=" '@(_UpdatedFlatFiles)' != '' " />
MSBuild/Xamarin/Android/Xamarin.Android.Bindings.Core.targets:      Condition=" '$(UsingAndroidNETSdk)' != 'true' Or '@(InputJar)' != '' Or '@(EmbeddedJar)' != '' ">
MSBuild/Xamarin/Android/Xamarin.Android.Bindings.Core.targets:      Condition=" '$(UsingAndroidNETSdk)' != 'true' Or '@(InputJar)' != '' Or '@(EmbeddedJar)' != '' "
MSBuild/Xamarin/Android/Xamarin.Android.Bindings.Documentation.targets:      Condition=" '@(JavaDocIndex)' != '' And '$(_JavadocSupported)' == 'True' "
MSBuild/Xamarin/Android/Xamarin.Android.Common/ImportAfter/Microsoft.Cpp.Android.targets:               Condition="'$(BuildingSolutionFile)' == '' and '@(_NativeAndroidProjectReferenceWithoutConfiguration)' != ''" />
MSBuild/Xamarin/Android/Xamarin.Android.Common/ImportAfter/Microsoft.Cpp.Android.targets:               Condition="'@(_NativeAndroidProjectReferenceWithoutConfiguration)' != ''" />-->
MSBuild/Xamarin/Android/Xamarin.Android.Common/ImportAfter/Microsoft.Cpp.Android.targets:                 Condition="'@(_NativeAndroidProjectReferenceWithConfiguration)' != ''">
MSBuild/Xamarin/Android/Xamarin.Android.Common/ImportAfter/Microsoft.Cpp.Android.targets:        <MergeApkRecipelists RecipeFiles="%(_NativeAndroidRecipeFiles.Identity)" Condition="'@(_NativeAndroidRecipeFiles)' != '' And Exists('%(_NativeAndroidRecipeFiles.Identity)')">
MSBuild/Xamarin/Android/Xamarin.Android.Common/ImportAfter/Microsoft.Cpp.Android.targets:        <ItemGroup Condition="'@(NativeLibraryPaths)' != ''">
MSBuild/Xamarin/Android/Xamarin.Android.Wear.targets:      Condition=" $(AndroidApplication) And '@(_AppExtensionReference)' != '' "
Xamarin.Android.Common.targets:		<Compile Remove="@(CorrectCasedItem)" Condition=" '$(AndroidResgenFile)' != '' "/>
Xamarin.Android.Common.targets:		Condition=" '@(Content)' != '' "
Xamarin.Android.Common.targets:		<Compile Remove="@(CorrectCasedItem)" Condition=" '$(ManagedDesignTimeBuild)' == 'True' And '%(CorrectCasedItem.Identity)' != '' "/>
Xamarin.Android.Common.targets:	<Touch Files="$(_AndroidResFlagFile)" AlwaysCreate="True" Condition=" !Exists ('$(_AndroidResFlagFile)') Or  '@(_ModifiedResources)' != '' Or '@(_AndroidResourceDestRemovedFiles)' != '' " />
Xamarin.Android.Common.targets:    Condition=" '$(Language)' == 'C#' And ('$(AndroidGenerateLayoutBindings)' == 'True' Or '@(AndroidBoundLayout)' != '') ">
Xamarin.Android.Common.targets:	<ItemGroup Condition=" '@(_LayoutForBinding)' != '' ">
Xamarin.Android.Common.targets:	<ItemGroup Condition=" '@(_LayoutForBinding)' != '' ">
Xamarin.Android.Common.targets:	<ItemGroup Condition=" '@(_LayoutPartialClass)' != '' ">
Xamarin.Android.Common.targets:	Condition="@(AndroidInterfaceDescription) != ''"
Xamarin.Android.EmbeddedResource.targets:      Condition=" '$(AndroidApplication)' != 'true' And '@(EmbeddedNativeLibrary)' != '' "
Xamarin.Android.PCLSupport.targets:				Condition="'$(_HasReferenceToSystemRuntime)' != 'true' and '$(_IsXBuild)' != 'true' and '$(DependsOnNETStandard)' == '' and '@(_XACandidateNETStandardReferences)' != ''"
Xamarin.Android.Tooling.targets:      <_ResolveSdksFrameworkRefAssemblyPaths Include="@(ResolvedTargetingPack->'%(Path)\ref\%(TargetFramework)')" Condition=" '@(ResolvedTargetingPack)' == '@(FrameworkReference)' and '%(Identity)' != '' " />

might be worth cleaning that all up to use the faster option?

[jonathanpeppers]

I should go ahead fix them all.

The one I fixed here was the only one I found generating a huge string. Doing something like:

> dotnet build HelloAndroid\HelloAndroid.csproj -v:diag | grep 'skipped, due to false condition' | code -

Then I scrolled through the list in VS Code and looked at the extremely long lines.

There might be others you can hit in large projects, or using different settings.

[dellis1972]

We can do it in another PR if you want. I don't mind

[jonathanpeppers]

I fixed them all except for the ones in Microsoft.Cpp.Android.targets. I'm not sure we have great testing around those targets, so I'd rather not change them.