From 25672336f92accfa8d24823d11d0bb5528c9ad4d Mon Sep 17 00:00:00 2001
From: Doug Bunting <6431421+dougbu@users.noreply.github.com>
Date: Sun, 2 Jun 2019 22:09:42 -0700
Subject: [PATCH] Add more properties controlling service reference code
 generation (#10641)

- `$(OpenApiGenerateCodeOnBuild)` controls if targets run before compile targets
  - #4924
  - also correct multiple invocations when project has multiple target frameworks
- `$(OpenApiBuildReferencedProjects)` controls whether `@(OpenApiProjectReference)` items build automatically
  - #6582
- rename a few other properties and targets

also:
- add symbols for Microsoft.Extensions.ApiDescription.Client task assembly
  - #10508
- unconditionally run `OpenApiGetDocuments` target in referenced projects
  - corrects compilation in design-time builds
  - no longer uses `@(ProjectReferenceWithConfiguration)`; referenced project chooses all property values

nits:
- consolidate into a single `$(GenerateOpenApiCodeDependsOn)` property
- rename task assembly and namespaces in Microsoft.Extensions.ApiDesription.Client to match the project
- allow `OpenApiGetDocuments` targets to run in parallel if `$(BuildInParallel)` is enabled
- remove `$(OpenApiCodeDirectory)` normalization; never concatenated with anything else
---
 eng/ProjectReferences.props                   |  2 +-
 .../src/CSharpIdentifier.cs                   |  2 +-
 .../src/GetCurrentItems.cs                    |  2 +-
 .../src/GetFileReferenceMetadata.cs           |  2 +-
 .../src/MetadataSerializer.cs                 |  2 +-
 ...ft.Extensions.ApiDescription.Client.csproj |  4 +-
 ...ft.Extensions.ApiDescription.Client.nuspec |  4 +-
 .../src/Properties/Resources.Designer.cs      |  4 +-
 ...oft.Extensions.ApiDescription.Client.props | 69 +++++++++++++------
 ...t.Extensions.ApiDescription.Client.targets | 60 ++++++++--------
 ...oft.Extensions.ApiDescription.Client.props |  4 ++
 ...t.Extensions.ApiDescription.Client.targets | 13 ++--
 12 files changed, 103 insertions(+), 65 deletions(-)
 create mode 100644 src/Mvc/Extensions.ApiDescription.Client/src/buildMultiTargeting/Microsoft.Extensions.ApiDescription.Client.props

diff --git a/eng/ProjectReferences.props b/eng/ProjectReferences.props
index 9f037c669a..d7b785a06f 100644
--- a/eng/ProjectReferences.props
+++ b/eng/ProjectReferences.props
@@ -8,7 +8,7 @@
     <ProjectReferenceProvider Include="Microsoft.AspNetCore.Identity.Specification.Tests" ProjectPath="$(RepoRoot)src\Identity\Specification.Tests\src\Microsoft.AspNetCore.Identity.Specification.Tests.csproj"  />
     <ProjectReferenceProvider Include="Microsoft.Web.Xdt.Extensions" ProjectPath="$(RepoRoot)src\SiteExtensions\Microsoft.Web.Xdt.Extensions\src\Microsoft.Web.Xdt.Extensions.csproj"  />
     <ProjectReferenceProvider Include="Microsoft.AspNetCore.DeveloperCertificates.XPlat" ProjectPath="$(RepoRoot)src\Tools\FirstRunCertGenerator\src\Microsoft.AspNetCore.DeveloperCertificates.XPlat.csproj"  />
-    <ProjectReferenceProvider Include="Microsoft.Extensions.ApiDescription.Tasks" ProjectPath="$(RepoRoot)src\Mvc\Extensions.ApiDescription.Client\src\Microsoft.Extensions.ApiDescription.Client.csproj"  />
+    <ProjectReferenceProvider Include="Microsoft.Extensions.ApiDescription.Client" ProjectPath="$(RepoRoot)src\Mvc\Extensions.ApiDescription.Client\src\Microsoft.Extensions.ApiDescription.Client.csproj"  />
     <ProjectReferenceProvider Include="Microsoft.AspNetCore.SignalR.Specification.Tests" ProjectPath="$(RepoRoot)src\SignalR\server\Specification.Tests\src\Microsoft.AspNetCore.SignalR.Specification.Tests.csproj"  />
     <ProjectReferenceProvider Include="Microsoft.AspNetCore.Blazor.Build" ProjectPath="$(RepoRoot)src\Components\Blazor\Build\src\Microsoft.AspNetCore.Blazor.Build.csproj"  />
     <ProjectReferenceProvider Include="Microsoft.AspNetCore" ProjectPath="$(RepoRoot)src\DefaultBuilder\src\Microsoft.AspNetCore.csproj" RefProjectPath="$(RepoRoot)src\DefaultBuilder\ref\Microsoft.AspNetCore.csproj" />
diff --git a/src/Mvc/Extensions.ApiDescription.Client/src/CSharpIdentifier.cs b/src/Mvc/Extensions.ApiDescription.Client/src/CSharpIdentifier.cs
index 33d0b0e9eb..b1ee4f7c0c 100644
--- a/src/Mvc/Extensions.ApiDescription.Client/src/CSharpIdentifier.cs
+++ b/src/Mvc/Extensions.ApiDescription.Client/src/CSharpIdentifier.cs
@@ -6,7 +6,7 @@ using System.Text;
 
 // Copied from
 // https://github.com/aspnet/AspNetCore-Tooling/blob/master/src/Razor/src/Microsoft.AspNetCore.Razor.Language/CSharpIdentifier.cs
-namespace Microsoft.Extensions.ApiDescription.Tasks
+namespace Microsoft.Extensions.ApiDescription.Client
 {
     internal static class CSharpIdentifier
     {
diff --git a/src/Mvc/Extensions.ApiDescription.Client/src/GetCurrentItems.cs b/src/Mvc/Extensions.ApiDescription.Client/src/GetCurrentItems.cs
index 97ea236f2c..975e716d64 100644
--- a/src/Mvc/Extensions.ApiDescription.Client/src/GetCurrentItems.cs
+++ b/src/Mvc/Extensions.ApiDescription.Client/src/GetCurrentItems.cs
@@ -4,7 +4,7 @@
 using Microsoft.Build.Framework;
 using Microsoft.Build.Utilities;
 
-namespace Microsoft.Extensions.ApiDescription.Tasks
+namespace Microsoft.Extensions.ApiDescription.Client
 {
     /// <summary>
     /// Restore <see cref="ITaskItem"/>s from given property value.
diff --git a/src/Mvc/Extensions.ApiDescription.Client/src/GetFileReferenceMetadata.cs b/src/Mvc/Extensions.ApiDescription.Client/src/GetFileReferenceMetadata.cs
index 73f8d01495..2b0447c590 100644
--- a/src/Mvc/Extensions.ApiDescription.Client/src/GetFileReferenceMetadata.cs
+++ b/src/Mvc/Extensions.ApiDescription.Client/src/GetFileReferenceMetadata.cs
@@ -7,7 +7,7 @@ using System.IO;
 using Microsoft.Build.Framework;
 using Microsoft.Build.Utilities;
 
-namespace Microsoft.Extensions.ApiDescription.Tasks
+namespace Microsoft.Extensions.ApiDescription.Client
 {
     /// <summary>
     /// Adds or corrects ClassName, FirstForGenerator, Namespace, and OutputPath metadata in OpenApiReference items.
diff --git a/src/Mvc/Extensions.ApiDescription.Client/src/MetadataSerializer.cs b/src/Mvc/Extensions.ApiDescription.Client/src/MetadataSerializer.cs
index 32f7fbf832..eeff4170fc 100644
--- a/src/Mvc/Extensions.ApiDescription.Client/src/MetadataSerializer.cs
+++ b/src/Mvc/Extensions.ApiDescription.Client/src/MetadataSerializer.cs
@@ -6,7 +6,7 @@ using System.Text;
 using Microsoft.Build.Framework;
 using Microsoft.Build.Utilities;
 
-namespace Microsoft.Extensions.ApiDescription.Tasks
+namespace Microsoft.Extensions.ApiDescription.Client
 {
     /// <summary>
     /// Utility methods to serialize and deserialize <see cref="ITaskItem"/> metadata.
diff --git a/src/Mvc/Extensions.ApiDescription.Client/src/Microsoft.Extensions.ApiDescription.Client.csproj b/src/Mvc/Extensions.ApiDescription.Client/src/Microsoft.Extensions.ApiDescription.Client.csproj
index 2edaf7b68c..2029ac0a25 100644
--- a/src/Mvc/Extensions.ApiDescription.Client/src/Microsoft.Extensions.ApiDescription.Client.csproj
+++ b/src/Mvc/Extensions.ApiDescription.Client/src/Microsoft.Extensions.ApiDescription.Client.csproj
@@ -6,21 +6,19 @@
     <!-- Do not complain about lack of lib folder. -->
     <NoPackageAnalysis>true</NoPackageAnalysis>
 
-    <AssemblyName>Microsoft.Extensions.ApiDescription.Tasks</AssemblyName>
     <Description>MSBuild tasks and targets for code generation</Description>
     <IncludeBuildOutput>false</IncludeBuildOutput>
     <IncludeSource>false</IncludeSource>
-    <IncludeSymbols>false</IncludeSymbols>
     <NuspecFile>$(MSBuildProjectName).nuspec</NuspecFile>
     <PackageId>$(MSBuildProjectName)</PackageId>
     <PackageTags>Build Tasks;MSBuild;Swagger;Open API;code generation; Web API client</PackageTags>
     <IsShippingPackage>true</IsShippingPackage>
     <PackageVersion>$(ExperimentalPackageVersion)</PackageVersion>
-    <RootNamespace>$(AssemblyName)</RootNamespace>
     <TargetFrameworks>netstandard2.0;net461</TargetFrameworks>
     <VerifyVersion>false</VerifyVersion>
     <VersionPrefix>$(ExperimentalVersionPrefix)</VersionPrefix>
     <VersionSuffix>$(ExperimentalVersionSuffix)</VersionSuffix>
+
     <HasReferenceAssembly>false</HasReferenceAssembly>
   </PropertyGroup>
 
diff --git a/src/Mvc/Extensions.ApiDescription.Client/src/Microsoft.Extensions.ApiDescription.Client.nuspec b/src/Mvc/Extensions.ApiDescription.Client/src/Microsoft.Extensions.ApiDescription.Client.nuspec
index f04380cfe4..cc49fd1c56 100644
--- a/src/Mvc/Extensions.ApiDescription.Client/src/Microsoft.Extensions.ApiDescription.Client.nuspec
+++ b/src/Mvc/Extensions.ApiDescription.Client/src/Microsoft.Extensions.ApiDescription.Client.nuspec
@@ -19,7 +19,7 @@
   <files>
     <file src="build\*" target="build" />
     <file src="buildMultiTargeting\*" target="buildMultiTargeting" />
-    <file src="$baseOutputPath$\$configuration$\net461\Microsoft.Extensions.ApiDescription.Tasks.*" target="tasks\net461" />
-    <file src="$baseOutputPath$\$configuration$\netstandard2.0\Microsoft.Extensions.ApiDescription.Tasks.*" target="tasks\netstandard2.0" />
+    <file src="$baseOutputPath$\$configuration$\net461\Microsoft.Extensions.ApiDescription.Client.*" target="tasks\net461" />
+    <file src="$baseOutputPath$\$configuration$\netstandard2.0\Microsoft.Extensions.ApiDescription.Client.*" target="tasks\netstandard2.0" />
   </files>
 </package>
diff --git a/src/Mvc/Extensions.ApiDescription.Client/src/Properties/Resources.Designer.cs b/src/Mvc/Extensions.ApiDescription.Client/src/Properties/Resources.Designer.cs
index 3e16c26c41..f1b61f00ac 100644
--- a/src/Mvc/Extensions.ApiDescription.Client/src/Properties/Resources.Designer.cs
+++ b/src/Mvc/Extensions.ApiDescription.Client/src/Properties/Resources.Designer.cs
@@ -1,5 +1,5 @@
 // <auto-generated />
-namespace Microsoft.Extensions.ApiDescription.Tasks
+namespace Microsoft.Extensions.ApiDescription.Client
 {
     using System.Globalization;
     using System.Reflection;
@@ -8,7 +8,7 @@ namespace Microsoft.Extensions.ApiDescription.Tasks
     internal static class Resources
     {
         private static readonly ResourceManager _resourceManager
-            = new ResourceManager("Microsoft.Extensions.ApiDescription.Tasks.Resources", typeof(Resources).GetTypeInfo().Assembly);
+            = new ResourceManager("Microsoft.Extensions.ApiDescription.Client.Resources", typeof(Resources).GetTypeInfo().Assembly);
 
         /// <summary>
         /// Multiple items have OutputPath='{0}'. All OpenApiReference items must have unique OutputPath metadata.
diff --git a/src/Mvc/Extensions.ApiDescription.Client/src/build/Microsoft.Extensions.ApiDescription.Client.props b/src/Mvc/Extensions.ApiDescription.Client/src/build/Microsoft.Extensions.ApiDescription.Client.props
index 5f5640bfd3..dd5e8dd9e8 100644
--- a/src/Mvc/Extensions.ApiDescription.Client/src/build/Microsoft.Extensions.ApiDescription.Client.props
+++ b/src/Mvc/Extensions.ApiDescription.Client/src/build/Microsoft.Extensions.ApiDescription.Client.props
@@ -1,35 +1,60 @@
 <?xml version="1.0" encoding="utf-8" standalone="no"?>
 <Project>
   <PropertyGroup>
-    <_ApiDescriptionTasksAssemblyTarget
-        Condition="'$(MSBuildRuntimeType)' == 'Core'">netstandard2.0</_ApiDescriptionTasksAssemblyTarget>
-    <_ApiDescriptionTasksAssemblyTarget
-        Condition="'$(MSBuildRuntimeType)' != 'Core'">net461</_ApiDescriptionTasksAssemblyTarget>
-    <_ApiDescriptionTasksAssemblyPath>$(MSBuildThisFileDirectory)/../tasks/$(_ApiDescriptionTasksAssemblyTarget)/Microsoft.Extensions.ApiDescription.Tasks.dll</_ApiDescriptionTasksAssemblyPath>
-    <_ApiDescriptionTasksAssemblyTarget />
+    <_ApiDescriptionClientAssemblyTarget
+        Condition="'$(MSBuildRuntimeType)' == 'Core'">netstandard2.0</_ApiDescriptionClientAssemblyTarget>
+    <_ApiDescriptionClientAssemblyTarget
+        Condition="'$(MSBuildRuntimeType)' != 'Core'">net461</_ApiDescriptionClientAssemblyTarget>
+    <_ApiDescriptionClientAssemblyPath>$(MSBuildThisFileDirectory)/../tasks/$(_ApiDescriptionClientAssemblyTarget)/Microsoft.Extensions.ApiDescription.Client.dll</_ApiDescriptionClientAssemblyPath>
+    <_ApiDescriptionClientAssemblyTarget />
   </PropertyGroup>
-  <UsingTask TaskName="GetCurrentItems" AssemblyFile="$(_ApiDescriptionTasksAssemblyPath)" />
-  <UsingTask TaskName="GetFileReferenceMetadata" AssemblyFile="$(_ApiDescriptionTasksAssemblyPath)" />
+  <UsingTask TaskName="GetCurrentItems" AssemblyFile="$(_ApiDescriptionClientAssemblyPath)" />
+  <UsingTask TaskName="GetFileReferenceMetadata" AssemblyFile="$(_ApiDescriptionClientAssemblyPath)" />
 
   <!--
     Settings users may update as they see fit.
   -->
   <PropertyGroup>
-    <OpenApiDefaultGeneratorOptions Condition="'$(OpenApiDefaultGeneratorOptions)' == ''"></OpenApiDefaultGeneratorOptions>
+    <!--
+      Options added to the code generator command line by default. Provides the default %(Options) metadata of
+      @(OpenApiReference) and @(OpenApiProjectReference) items.
+    -->
+    <OpenApiGenerateCodeOptions Condition="'$(OpenApiGenerateCodeOptions)' == ''"></OpenApiGenerateCodeOptions>
 
     <!--
-      If 'true', will generate code for OpenApiReference items during design-time builds. Otherwise, generate code only
-      for output files that do not yet exist during design-time builds.
+      If 'true' (the default), generate code for @(OpenApiReference) and @(OpenApiProjectReference) items before the
+      BeforeCompile target.
+
+      If 'false', the 'GenerateOpenApiCode' target is not part of the build (by default) but can run when explicitly
+      referenced. That is, the target may be invoked from the command line or tied in through another target.
     -->
-    <OpenApiGenerateAtDesignTime Condition="'$(OpenApiGenerateAtDesignTime)' == ''">true</OpenApiGenerateAtDesignTime>
+    <OpenApiGenerateCodeOnBuild Condition="'$(OpenApiGenerateCodeOnBuild)' == ''">true</OpenApiGenerateCodeOnBuild>
 
     <!--
-      $(OpenApiDefaultOutputDirectory) value is interpreted relative to the project folder, unless already an
-      absolute path.
+      If 'true' (the default), generate code for @(OpenApiReference) and @(OpenApiProjectReference) items during
+      design-time builds. Otherwise, generate code only during a full build.
     -->
-    <OpenApiDefaultOutputDirectory
-        Condition="'$(OpenApiDefaultOutputDirectory)' == ''">$(BaseIntermediateOutputPath)</OpenApiDefaultOutputDirectory>
-    <OpenApiDefaultOutputDirectory>$([MSBuild]::EnsureTrailingSlash('$(OpenApiDefaultOutputDirectory)'))</OpenApiDefaultOutputDirectory>
+    <OpenApiGenerateCodeAtDesignTime
+        Condition="'$(OpenApiGenerateCodeAtDesignTime)' == ''">true</OpenApiGenerateCodeAtDesignTime>
+
+    <!--
+      If 'true' (the default), build projects referenced in @(OpenApiProjectReference) items before retrieving that
+      project's Open API documents list (or generating code). Recommend setting this to 'false' when the referenced
+      projects do not share target framework values (avoiding build errors and / or warnings).
+
+      If 'false', ensure the referenced projects build before this one in the solution or through other means. IDEs may
+      be confused about the project dependency graph in this case.
+    -->
+    <OpenApiBuildReferencedProjects
+        Condition="'$(OpenApiBuildReferencedProjects)' == ''">true</OpenApiBuildReferencedProjects>
+
+    <!--
+      Default folder to place code generated from Open API documents. Value is interpreted relative to the project
+      folder, unless already an absolute path. Part of the default %(OutputPath) metadata of @(OpenApiReference) and
+      @(OpenApiProjectReference) items.
+    -->
+    <OpenApiCodeDirectory
+        Condition="'$(OpenApiCodeDirectory)' == ''">$(BaseIntermediateOutputPath)</OpenApiCodeDirectory>
   </PropertyGroup>
 
   <!--
@@ -42,24 +67,28 @@
     <OpenApiReference>
       <!-- Name of the class to generate. Defaults to match filename in %(OutputPath). -->
       <ClassName />
+
       <!--
         Code generator to use. Required and must end with "CSharp" or "TypeScript" (the currently-supported target
         languages) unless %(OutputPath) is set. Builds will invoke a target named "Generate%(CodeGenerator)" to do
         actual code generation.
       -->
       <CodeGenerator>NSwagCSharp</CodeGenerator>
+
       <!-- Namespace to contain generated class. Default is $(RootNamespace). -->
       <Namespace />
+
       <!--
         Options to pass to the code generator target then (likely) added to a tool's command line. Value is passed
         along to the code generator but otherwise unused in this package.
       -->
-      <Options>$(OpenApiDefaultGeneratorOptions)</Options>
+      <Options>$(OpenApiGenerateCodeOptions)</Options>
+
       <!--
         Path to place generated code. Code generator may interpret path as a filename or directory. Default filename or
         folder name is %(Filename)Client.[cs|ts]. Filenames and relative paths (if explicitly set) are combined with
-        $(OpenApiDefaultOutputDirectory). Final value (depending on $(OpenApiDefaultOutputDirectory)) is likely to be
-        a path relative to the client project.
+        $(OpenApiCodeDirectory). Final value (depending on $(OpenApiCodeDirectory)) is likely to be a path relative to
+        the client project.
       -->
       <OutputPath />
     </OpenApiReference>
diff --git a/src/Mvc/Extensions.ApiDescription.Client/src/build/Microsoft.Extensions.ApiDescription.Client.targets b/src/Mvc/Extensions.ApiDescription.Client/src/build/Microsoft.Extensions.ApiDescription.Client.targets
index bd7006fc36..b10277a696 100644
--- a/src/Mvc/Extensions.ApiDescription.Client/src/build/Microsoft.Extensions.ApiDescription.Client.targets
+++ b/src/Mvc/Extensions.ApiDescription.Client/src/build/Microsoft.Extensions.ApiDescription.Client.targets
@@ -2,21 +2,18 @@
 <Project>
   <!-- Internal settings. Not intended for customization. -->
   <PropertyGroup>
-    <GenerateOpenApiReferenceCodeDependsOn>
-      _GetMetadataForOpenApiReferences;
-      _GenerateOpenApiReferenceCode;
-      _CreateCompileItemsForOpenApiReferences
-    </GenerateOpenApiReferenceCodeDependsOn>
-    <GenerateServiceFileReferenceCodeDependsOn>
+    <GenerateOpenApiCodeDependsOn>
       _GenerateErrorsForOldItems;
       _CreateOpenApiReferenceItemsForOpenApiProjectReferences;
-      GenerateOpenApiReferenceCode
-    </GenerateServiceFileReferenceCodeDependsOn>
+      _GetMetadataForOpenApiReferences;
+      _GenerateOpenApiCode;
+      _CreateCompileItemsForOpenApiReferences
+    </GenerateOpenApiCodeDependsOn>
   </PropertyGroup>
 
   <!-- OpenApiProjectReference support. -->
 
-  <ItemGroup>
+  <ItemGroup Condition=" '$(OpenApiBuildReferencedProjects)' == 'true' ">
     <!--
       Do not change %(ReferenceOutputAssembly) if project contains duplicate @(ProjectReference) and
       @(OpenApiProjectReference) items.
@@ -30,19 +27,16 @@
     </ProjectReference>
   </ItemGroup>
 
-  <Target Name="_CreateOpenApiReferenceItemsForOpenApiProjectReferences"
-      AfterTargets="ResolveProjectReferences"
-      Condition="'$(DesignTimeBuild)' != 'true' AND '$(BuildingProject)' == 'true'">
+  <Target Name="_CreateOpenApiReferenceItemsForOpenApiProjectReferences" DependsOnTargets="ResolveProjectReferences">
     <ItemGroup>
       <_Temporary Remove="@(_Temporary)" />
     </ItemGroup>
 
     <MSBuild Targets="OpenApiGetDocuments"
-        Projects="@(ProjectReferenceWithConfiguration)"
-        Condition="'%(ProjectReferenceWithConfiguration.OpenApiReference)' == 'true'"
-        Properties="%(ProjectReferenceWithConfiguration.SetConfiguration); %(ProjectReferenceWithConfiguration.SetPlatform); %(ProjectReferenceWithConfiguration.SetTargetFramework)"
+        BuildInParallel="$(BuildInParallel)"
+        Projects="@(OpenApiProjectReference)"
         RebaseOutputs="true"
-        RemoveProperties="%(ProjectReferenceWithConfiguration.GlobalPropertiesToRemove);TargetFrameworks;RuntimeIdentifier">
+        RemoveProperties="Configuration;Platform;RuntimeIdentifier;TargetFramework;TargetFrameworks">
       <Output TaskParameter="TargetOutputs" ItemName="_Temporary" />
     </MSBuild>
 
@@ -62,7 +56,7 @@
     <GetFileReferenceMetadata Inputs="@(OpenApiReference)"
         Extension="$(DefaultLanguageSourceExtension)"
         Namespace="$(RootNamespace)"
-        OutputDirectory="$(OpenApiDefaultOutputDirectory)">
+        OutputDirectory="$(OpenApiCodeDirectory)">
       <Output TaskParameter="Outputs" ItemName="_Temporary" />
     </GetFileReferenceMetadata>
 
@@ -79,17 +73,16 @@
     </GetCurrentItems>
   </Target>
 
-  <Target Name="_InnerGenerateOpenApiReferenceCode" DependsOnTargets="_GetCurrentOpenApiReference;$(GeneratorTarget)" />
+  <Target Name="_InnerGenerateOpenApiCode" DependsOnTargets="_GetCurrentOpenApiReference;$(GeneratorTarget)" />
 
-  <Target Name="_GenerateOpenApiReferenceCode"
-      Condition="$(OpenApiGenerateAtDesignTime) OR ('$(DesignTimeBuild)' != 'true' AND '$(BuildingProject)' == 'true')"
+  <Target Name="_GenerateOpenApiCode"
+      Condition="$(OpenApiGenerateCodeAtDesignTime) OR ('$(DesignTimeBuild)' != 'true' AND '$(BuildingProject)' == 'true')"
       Inputs="@(OpenApiReference)"
       Outputs="%(OutputPath)">
-    <MSBuild BuildInParallel="$(BuildInParallel)"
-        Projects="$(MSBuildProjectFullPath)"
+    <MSBuild Projects="$(MSBuildProjectFullPath)"
+        BuildInParallel="$(BuildInParallel)"
         Properties="GeneratorTargetPath=%(OpenApiReference.OutputPath);GeneratorTarget=Generate%(CodeGenerator);GeneratorMetadata=%(SerializedMetadata)"
-        RemoveProperties="TargetFrameworks"
-        Targets="_InnerGenerateOpenApiReferenceCode" />
+        Targets="_InnerGenerateOpenApiCode" />
   </Target>
 
   <Target Name="_CreateCompileItemsForOpenApiReferences" Condition="'@(OpenApiReference)' != ''">
@@ -133,9 +126,7 @@
     </ItemGroup>
   </Target>
 
-  <Target Name="GenerateOpenApiReferenceCode" DependsOnTargets="$(GenerateOpenApiReferenceCodeDependsOn)" />
-
-  <!-- Tie above code generation steps into the build.  -->
+  <!-- Inform users of breaking changes in this file and Microsoft.Extensions.ApiDescription.Client.props. -->
 
   <Target Name="_GenerateErrorsForOldItems">
     <Error Condition="'@(ServiceProjectReference)' != ''" Text="ServiceProjectReference items are no longer supported." />
@@ -143,7 +134,18 @@
     <Error Condition="'@(ServiceFileReference)' != ''" Text="ServiceFileReference items are no longer supported." />
   </Target>
 
-  <Target Name="GenerateServiceFileReferenceCode"
+  <!-- Main code generation entry point. -->
+
+  <Target Name="GenerateOpenApiCode" DependsOnTargets="$(GenerateOpenApiCodeDependsOn)" />
+
+  <!--
+    Unless this is an inner build or default timing is disabled, tie code generation into the build. Separate from
+    GenerateOpenApiCode and not invoked from the ../buildMultiTargeting targets to prevent repeated code generation
+    when multi-targeting.
+  -->
+
+  <Target Name="_TieInGenerateOpenApiCode"
       BeforeTargets="BeforeCompile"
-      DependsOnTargets="$(GenerateServiceFileReferenceCodeDependsOn)" />
+      Condition=" '$(OpenApiGenerateCodeOnBuild)' == 'true' AND ('$(TargetFramework)' == '' OR '$(TargetFrameworks)' == '') "
+      DependsOnTargets="GenerateOpenApiCode" />
 </Project>
diff --git a/src/Mvc/Extensions.ApiDescription.Client/src/buildMultiTargeting/Microsoft.Extensions.ApiDescription.Client.props b/src/Mvc/Extensions.ApiDescription.Client/src/buildMultiTargeting/Microsoft.Extensions.ApiDescription.Client.props
new file mode 100644
index 0000000000..9ce9d3e259
--- /dev/null
+++ b/src/Mvc/Extensions.ApiDescription.Client/src/buildMultiTargeting/Microsoft.Extensions.ApiDescription.Client.props
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8" standalone="no"?>
+<Project>
+  <Import Project="../build/Microsoft.Extensions.ApiDescription.Client.props" />
+</Project>
diff --git a/src/Mvc/Extensions.ApiDescription.Client/src/buildMultiTargeting/Microsoft.Extensions.ApiDescription.Client.targets b/src/Mvc/Extensions.ApiDescription.Client/src/buildMultiTargeting/Microsoft.Extensions.ApiDescription.Client.targets
index d085051f06..b264baa9df 100644
--- a/src/Mvc/Extensions.ApiDescription.Client/src/buildMultiTargeting/Microsoft.Extensions.ApiDescription.Client.targets
+++ b/src/Mvc/Extensions.ApiDescription.Client/src/buildMultiTargeting/Microsoft.Extensions.ApiDescription.Client.targets
@@ -1,9 +1,14 @@
 <?xml version="1.0" encoding="utf-8" standalone="no"?>
 <Project>
-  <Target Name="GenerateServiceFileReferenceCode" BeforeTargets="BeforeCompile">
-    <MsBuild Projects="$(MSBuildProjectFile)"
-        Targets="GenerateServiceFileReferenceCode"
+  <Target Name="GenerateOpenApiCode">
+    <MSBuild Projects="$(MSBuildProjectFile)"
+        Targets="GenerateOpenApiCode"
         Properties="TargetFramework=$(TargetFrameworks.Split(';')[0])"
-        RemoveProperties="TargetFrameworks;RuntimeIdentifier" />
+        RemoveProperties="RuntimeIdentifier" />
   </Target>
+
+  <Target Name="_GenerateOpenApiCode"
+      BeforeTargets="BeforeCompile"
+      Condition=" ''$(OpenApiGenerateCodeOnBuild)' == 'true' "
+      DependsOnTargets="GenerateOpenApiCode" />
 </Project>