[DO NOT MERGE] Restore ability for users to consume the containers package easily (#43794)

Co-authored-by: Chet Husk <[email protected]>

Author: surayya-MS

src/Containers/Microsoft.NET.Build.Containers/KnownStrings.cs

@@ -48,8 +48,14 @@ public static class Items
 
     public static class ErrorCodes
     {
+        // current version doesn't support containerization
         public static readonly string CONTAINER002 = nameof(CONTAINER002);
+        // containerimagename rename
         public static readonly string CONTAINER003 = nameof(CONTAINER003);
+        // generic http error
+        public static readonly string CONTAINER004 = nameof(CONTAINER004);
+        // don't use the containers package
+        public static readonly string CONTAINER005 = nameof(CONTAINER005);
         public static readonly string CONTAINER1011 = nameof(CONTAINER1011);
         public static readonly string CONTAINER1012 = nameof(CONTAINER1012);
         public static readonly string CONTAINER1013 = nameof(CONTAINER1013);

src/Containers/packaging/build/Microsoft.NET.Build.Containers.targets

@@ -222,6 +222,7 @@
           ($(_SdkCanPublishWorker) and $(_IsWorkerProject)) or
           ($(_SdkCanPublishConsole) and '$(EnableSdkContainerSupport)' == 'true')
         )"
+      Code="CONTAINER005"
       Text="The $(_ContainersPackageIdentity) NuGet package is explicitly referenced but the current SDK can natively publish the project as a container. Consider removing the package reference to $(_ContainersPackageIdentity) because it is no longer needed." />
 
     <PropertyGroup>

src/Tasks/Microsoft.NET.Build.Tasks/sdk/Sdk.targets

@@ -55,12 +55,14 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <!-- Import targets from Microdoft.NET.Build.Container.targets -->
   <PropertyGroup>
-    <_ContainersTargetsDir Condition=" '$(_ContainersTargetsDir)'=='' ">$(MSBuildThisFileDirectory)..\..\..\Containers\build\</_ContainersTargetsDir>
+    <_IsNotSetContainersTargetsDir>false</_IsNotSetContainersTargetsDir>
+    <_IsNotSetContainersTargetsDir Condition=" '$(_ContainersTargetsDir)'=='' ">true</_IsNotSetContainersTargetsDir>
+    <_ContainersTargetsDir Condition="$(_IsNotSetContainersTargetsDir)">$(MSBuildThisFileDirectory)..\..\..\Containers\build\</_ContainersTargetsDir>
   </PropertyGroup>
 
   <Import Project="$(MSBuildThisFileDirectory)..\..\..\Containers\build\Microsoft.NET.Build.Containers.props"
           Condition="Exists('$(MSBuildThisFileDirectory)..\..\..\Containers\build\Microsoft.NET.Build.Containers.props')" />
 
   <Import Project="$(_ContainersTargetsDir)Microsoft.NET.Build.Containers.targets"
-    Condition="Exists('$(_ContainersTargetsDir)Microsoft.NET.Build.Containers.targets') AND '$(TargetFramework)' != ''" />
+    Condition="$(_IsNotSetContainersTargetsDir) AND Exists('$(_ContainersTargetsDir)Microsoft.NET.Build.Containers.targets') AND '$(TargetFramework)' != ''" />
 </Project>

src/Tests/Microsoft.NET.Build.Containers.IntegrationTests/EndToEndTests.cs

@@ -369,7 +369,7 @@ public async Task EndToEnd_NoAPI_ProjectType(string projectType, bool addPackage
 
         if (addPackageReference)
         {
-            commandResult.Should().HaveStdOutContaining("warning : The Microsoft.NET.Build.Containers NuGet package is explicitly referenced but the current SDK can natively publish the project as a container. Consider removing the package reference to Microsoft.NET.Build.Containers because it is no longer needed.");
+            commandResult.Should().HaveStdOutContaining("warning CONTAINER005: The Microsoft.NET.Build.Containers NuGet package is explicitly referenced but the current SDK can natively publish the project as a container. Consider removing the package reference to Microsoft.NET.Build.Containers because it is no longer needed.");
         }
         else
         {