feat: Sdk and Tool usage validation (#209)

* feat: Plugin.Sdk inserts check into Plugin targets

This checks whether CodeGeneration.Roslyn.Tool targets are imported,
and raises a warning when they're not.

* feat: Inform/warn on Tool used with older packages

Author: amis92

src/CodeGeneration.Roslyn.Plugin.Sdk/build/BuildPluginPackage.targets

@@ -59,12 +59,24 @@
 </Project>
 ]]>
       </PackagePropsContent>
+      <PackageTargetsContent>
+        <![CDATA[
+<?xml version="1.0" encoding="utf-8" ?>
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Target Name="CheckCgrToolUsed" BeforeTargets="Build">
+    <Warning Condition=" '%24(UsingCodeGenerationRoslynToolTargets)' != 'true' " Text="CodeGeneration.Roslyn.Tool build targets weren't detected. CG.R Plugins (generators) won't be run without importing targets from the CodeGeneration.Roslyn.Tool package (v$(PackageVersion))." />
+  </Target>
+</Project>
+]]>
+      </PackageTargetsContent>
       <PackagePropsPath>$(IntermediateOutputPath)$(PackageId).props</PackagePropsPath>
+      <PackageTargetsPath>$(IntermediateOutputPath)$(PackageId).targets</PackageTargetsPath>
     </PropertyGroup>
     <WriteLinesToFile File="$(PackagePropsPath)" Lines="$(PackagePropsContent)" Overwrite="true" />
+    <WriteLinesToFile File="$(PackageTargetsPath)" Lines="$(PackageTargetsContent)" Overwrite="true" />
     <ItemGroup>
-      <TfmSpecificPackageFile Include="$(PackagePropsPath)" Pack="true" PackagePath="build/" BuildAction="None" />
-      <FileWrites Include="$(PackagePropsPath)" />
+      <TfmSpecificPackageFile Include="$(PackagePropsPath);$(PackageTargetsPath)" Pack="true" PackagePath="build/" BuildAction="None" />
+      <FileWrites Include="$(PackagePropsPath);$(PackageTargetsPath)" />
     </ItemGroup>
   </Target>
 

src/CodeGeneration.Roslyn.PluginMetapackage.Sdk/build/CodeGeneration.Roslyn.PluginMetapackage.Sdk.targets

@@ -101,7 +101,7 @@
           Condition=" '%(Identity)' == 'CodeGeneration.Roslyn.Tool' " />
     </ItemGroup>
     <Warning
-        Condition=" @(_CgrToolRef->WithMetadataValue('Version', '$(CodeGenerationRoslynPluginMetapackageSdkVersion)')->WithMetadataValue('PrivateAssets', 'none')->Count()) == 0 "
+        Condition=" '@(_CgrToolRef->WithMetadataValue('Version', '$(CodeGenerationRoslynPluginMetapackageSdkVersion)')->WithMetadataValue('PrivateAssets', 'none'))' == '' "
         Code="CGR2001"
         Text="$(_CheckCgrToolReferenceExistsWarning.Trim())" />
   </Target>

src/CodeGeneration.Roslyn.Tool/build/CodeGeneration.Roslyn.Tool.props

@@ -1,5 +1,13 @@
 <?xml version="1.0" encoding="utf-8" ?>
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+
+  <PropertyGroup>
+    <!--
+      Announce this Tool's build artifacts are being used.
+      Plugins can validate whether the Tool is available to use on this property.
+    -->
+    <UsingCodeGenerationRoslynToolTargets>true</UsingCodeGenerationRoslynToolTargets>
+  </PropertyGroup>
 
   <ItemDefinitionGroup>
     <Compile>

src/CodeGeneration.Roslyn.Tool/build/CodeGeneration.Roslyn.Tool.targets

@@ -40,6 +40,21 @@
       Code="CGR1002"
       Text="Using GeneratorAssemblySearchPaths is deprecated, please use CodeGenerationRoslynPlugin ItemGroup. See $(CgrUrl) for more info. Suppress this warning by adding CGR1002 to MSBuildWarningsAsMessages PropertyGroup."
       Condition=" '@(GeneratorAssemblySearchPaths)' != '' " />
+    <!-- Warning for when the BuildTime package is referenced. -->
+    <Warning
+      Code="CGR1003"
+      Condition=" '@(PackageReference->AnyHaveMetadataValue('Identity', 'CodeGeneration.Roslyn.BuildTime'))' == 'true' "
+      Text="Using both CodeGeneration.Roslyn.Tool and CodeGeneration.Roslyn.BuildTime is unsupported. Please either remove reference to the BuildTime package, or add an explicit reference and mark it as ExcludeAssets=&quot;all&quot;. See $(CgrUrl) for more info." />
+    <!-- Inform the user there are no generators so the Tool won't be run. -->
+    <Message
+      Condition=" '@(CodeGenerationRoslynPlugin)' != '' " 
+      Text="There are no registered Plugins (generators) for the CodeGeneration.Roslyn.Tool to run. The tool won't run." 
+      Importance="high" />
+    <!-- Inform the user DotNetCliToolReference is deprecated and unnecessary since v0.7. -->
+    <Message
+      Condition=" '@(DotNetCliToolReference->AnyHaveMetadataValue('Identity', 'dotnet-codegen'))' == 'true' " 
+      Text="DotNetCliToolReference of 'dotnet-codegen' is deprecated and can be removed since CodeGeneration.Roslyn v0.7." 
+      Importance="high" />
     <PropertyGroup>
       <CodeGenerationRoslynToolPath
         Condition="'$(GenerateCodeFromAttributesToolPathOverride)' != ''">$(GenerateCodeFromAttributesToolPathOverride)</CodeGenerationRoslynToolPath>
@@ -101,10 +116,13 @@
     and just read the existing file in ReadGenerateCodeFromAttributesResults target.
   -->
   <Target Name="GenerateCodeFromAttributesCore"
-    Condition=" '@(_CodeGenToolInputs_Compile)' != '' AND '$(_CodeGenToolVersionExitCode)' == '0' "
+    Condition=" '@(_CodeGenToolInputs_Compile)' != '' AND '$(_CodeGenToolVersionExitCode)' == '0' AND '@(CodeGenerationRoslynPlugin)' != '' "
     Inputs="$(_CodeGenToolResponseFileFullPath);@(CodeGenerationRoslynPlugin);@(_CodeGenToolInputs_Compile)"
     Outputs="$(_CodeGenToolGeneratedFileListFullPath)">
-    <!--Run the tool and raise an error when failed-->
+    <!--
+      Run the tool and raise an error when failed:
+      dotnet "path/to/CodeGeneration.Roslyn.Tool" "@path/to/responseFile.rsp"
+    -->
     <Exec
       Command="dotnet &quot;$(CodeGenerationRoslynToolPath)&quot; &quot;%40$(_CodeGenToolResponseFileFullPath)&quot;"
       StandardOutputImportance="normal" />