Add checks to tasks instead of targets

Author: emaf

dotnet/targets/Xamarin.Shared.Sdk.targets

@@ -856,7 +856,7 @@
 		<!-- Figure out which frameworks are really dynamic libraries, and only publish those -->
 		<FilterStaticFrameworks
 			SessionId="$(BuildSessionId)"
-			Condition="'$(IsMacEnabled)' == 'true' And '@(_FrameworkToPublish)' != ''"
+			Condition="'$(IsMacEnabled)' == 'true'"
 			FrameworkToPublish="@(_FrameworkToPublish)"
 		>
 			<Output TaskParameter="FrameworkToPublish" ItemName="_FilteredFrameworkToPublish" />
@@ -873,7 +873,7 @@
 
 		 -->
 		<GetFullPaths
-			Condition="'$(IsMacEnabled)' == 'true' And '@(_FilteredFrameworkToPublish)' != ''"
+			Condition="'$(IsMacEnabled)' == 'true'"
 			SessionId="$(BuildSessionId)"
 			Items="@(_FilteredFrameworkToPublish)"
 			Metadata="Identity;SourceDirectory"
@@ -2620,7 +2620,6 @@ global using nfloat = global::System.Runtime.InteropServices.NFloat%3B
 
 		-->
 		<GetFileSystemEntries
-			Condition="'@(_BindingPackagesFromReferencedAssembliesDirectoriesExists)' != ''"
 			SessionId="$(BuildSessionIdIfConnected)"
 			DirectoryPath="@(_BindingPackagesFromReferencedAssembliesDirectoriesExists)"
 			Pattern="*"

msbuild/Xamarin.Localization.MSBuild/MSBStrings.resx

@@ -1621,4 +1621,12 @@
             {2} and {3}: the different LogicalName metadata
         </comment>
     </data>
+
+    <data name="M7159" xml:space="preserve">
+        <value>Skipping {0} - {1} is empty.</value>
+        <comment>
+            {0}: the name of the MSBuild task that's being skipped (Copy, GetFullPaths, FilterStaticFrameworks, etc.).
+            {1}: the name of the property that is empty (SourceFiles, Items, FrameworkToPublish, etc.).
+        </comment>
+    </data>
 </root>

msbuild/Xamarin.MacDev.Tasks/MsBuildTasks/Copy.cs

@@ -1,18 +1,22 @@
 extern alias Microsoft_Build_Tasks_Core;
 
-using System;
-using System.IO;
 using System.Linq;
 
 using Microsoft.Build.Framework;
 
+using Xamarin.Localization.MSBuild;
 using Xamarin.Messaging.Build.Client;
 
 namespace Microsoft.Build.Tasks {
 	public class Copy : Microsoft_Build_Tasks_Core::Microsoft.Build.Tasks.Copy {
 		public string SessionId { get; set; } = string.Empty;
 		public override bool Execute ()
 		{
+			if (SourceFiles?.Any () != true) {
+				Log.LogMessage (MessageImportance.Low, MSBStrings.M7159 /* Skipping {0} - {1} is empty. */, nameof(Copy), nameof(SourceFiles));
+				return true;
+			}
+
 			if (!this.ShouldExecuteRemotely (SessionId))
 				return base.Execute ();
 

msbuild/Xamarin.MacDev.Tasks/Tasks/FilterStaticFrameworks.cs

@@ -22,6 +22,11 @@ public class FilterStaticFrameworks : XamarinTask, ITaskCallback {
 
 		public override bool Execute ()
 		{
+			if (FrameworkToPublish?.Any () != true) {
+				Log.LogMessage (MessageImportance.Low, MSBStrings.M7159 /* Skipping {0} - {1} is empty. */, nameof(FilterStaticFrameworks), nameof(FrameworkToPublish));
+				return true;
+			}
+
 			if (ShouldExecuteRemotely ())
 				return new TaskRunner (SessionId, BuildEngine4).RunAsync (this).Result;
 

msbuild/Xamarin.MacDev.Tasks/Tasks/GetFileSystemEntries.cs

@@ -43,6 +43,11 @@ public class GetFileSystemEntries : XamarinTask, ICancelableTask, ITaskCallback
 
 		public override bool Execute ()
 		{
+			if (DirectoryPath?.Any () != true) {
+				Log.LogMessage (MessageImportance.Low, MSBStrings.M7159 /* Skipping {0} - {1} is empty. */, nameof(GetFileSystemEntries), nameof(DirectoryPath));
+				return true;
+			}
+
 			if (ShouldExecuteRemotely ())
 				return new TaskRunner (SessionId, BuildEngine4).RunAsync (this).Result;
 

msbuild/Xamarin.MacDev.Tasks/Tasks/GetFullPaths.cs

@@ -6,7 +6,7 @@
 using Microsoft.Build.Framework;
 using Microsoft.Build.Utilities;
 
-using Xamarin.MacDev.Tasks;
+using Xamarin.Localization.MSBuild;
 using Xamarin.Messaging.Build.Client;
 
 #nullable enable
@@ -23,6 +23,11 @@ public class GetFullPaths : XamarinTask, ICancelableTask, ITaskCallback {
 
 		public override bool Execute ()
 		{
+			if (Items?.Any () != true) {
+				Log.LogMessage (MessageImportance.Low, MSBStrings.M7159 /* Skipping {0} - {1} is empty. */, nameof(GetFullPaths), nameof(Items));
+				return true;
+			}
+
 			if (ShouldExecuteRemotely ())
 				return new TaskRunner (SessionId, BuildEngine4).RunAsync (this).Result;
 

msbuild/Xamarin.iOS.Tasks.Windows/Xamarin.iOS.Common.After.targets

@@ -306,7 +306,7 @@ Copyright (C) 2011-2013 Xamarin. All rights reserved.
 		destination doesn't exist, the source is newer than the destination, or if the source and
 		destination differ by file size.
 		-->
-		<Copy Condition="'$(IsMacEnabled)' == 'true' And '@(_ResolvedFileToPublishAlways)' != ''"
+		<Copy Condition="'$(IsMacEnabled)' == 'true'"
 			SessionId="$(BuildSessionId)"
 			SourceFiles = "@(_ResolvedFileToPublishAlways)"
 			DestinationFiles="@(_ResolvedFileToPublishAlways->'$(PublishDir)%(RelativePath)')"