From 2f335b00e557d5621969bad53f9bc1af387f00a1 Mon Sep 17 00:00:00 2001
From: Nirmal Guru <Nirmal4G@gmail.com>
Date: Fri, 3 Apr 2020 22:00:10 +0530
Subject: [PATCH 1/7] Add BaseOutputPath to common targets

While this is not officially supported on non-sdk projects,
 NuGet Pack targets need a common output path
 to put '.nupkg' across both type of projects
---
 .../Microsoft.Common.CurrentVersion.targets   | 69 +++++++++++--------
 1 file changed, 41 insertions(+), 28 deletions(-)

diff --git a/src/Tasks/Microsoft.Common.CurrentVersion.targets b/src/Tasks/Microsoft.Common.CurrentVersion.targets
index a006a2f3083..08670d74d9f 100644
--- a/src/Tasks/Microsoft.Common.CurrentVersion.targets
+++ b/src/Tasks/Microsoft.Common.CurrentVersion.targets
@@ -68,6 +68,8 @@ Copyright (C) Microsoft Corporation. All rights reserved.
   <Import Project="Microsoft.NET.props" Condition="'$(TargetFrameworkIdentifier)' == '.NETStandard' or '$(TargetFrameworkIdentifier)' == '.NETCoreApp'"/>
 
   <PropertyGroup>
+    <!-- Generates full paths for the 'File' property in errors, warnings and messages in many targets -->
+    <GenerateFullPaths Condition="'$(GenerateFullPaths)' == ''">true</GenerateFullPaths>
     <!-- Yield optimization properties -->
     <YieldDuringToolExecution Condition="'$(YieldDuringToolExecution)' == ''">true</YieldDuringToolExecution>
   </PropertyGroup>
@@ -109,7 +111,15 @@ Copyright (C) Microsoft Corporation. All rights reserved.
     OutDir can be used to gather multiple project outputs in one location. In addition,
     OutDir is included in AssemblySearchPaths used for resolving references.
 
+    BaseOutputPath:
+    This is the top level folder where all configuration specific output folders will be created.
+    Default value is bin\
+
     OutputPath:
+    This is the full Output Path, and is derived from BaseOutputPath, if none specified
+    (eg. bin\Debug). If this property is overridden, then setting BaseOutputPath has no effect.
+
+    For projects loaded with MPFProj (Legacy project system):
     This property is usually specified in the project file and is used to initialize OutDir.
     OutDir and OutputPath are distinguished for legacy reasons, and OutDir should be used if at all possible.
 
@@ -119,26 +129,37 @@ Copyright (C) Microsoft Corporation. All rights reserved.
 
     IntermediateOutputPath:
     This is the full intermediate Output Path, and is derived from BaseIntermediateOutputPath, if none specified
-    (eg. obj\debug). If this property is overridden, then setting BaseIntermediateOutputPath has no effect.
+    (eg. obj\Debug). If this property is overridden, then setting BaseIntermediateOutputPath has no effect.
+
+    Ensure any and all path property has a trailing slash, so it can be concatenated.
     -->
 
   <PropertyGroup>
-    <GenerateFullPaths Condition="'$(GenerateFullPaths)' == ''">true</GenerateFullPaths>
-    <!-- Ensure any OutputPath has a trailing slash, so it can be concatenated -->
-    <OutputPath Condition="'$(OutputPath)' != '' and !HasTrailingSlash('$(OutputPath)')">$(OutputPath)\</OutputPath>
-    <AssemblyName Condition=" '$(AssemblyName)'=='' ">$(MSBuildProjectName)</AssemblyName>
-    <!--
-        Be careful not to give OutputPath a default value in the case of an invalid Configuration/Platform.
-        We use OutputPath specifically to check for invalid configurations/platforms.
-        -->
-    <OutputPath Condition=" '$(Platform)'=='' and '$(Configuration)'=='' and '$(OutputPath)'=='' ">bin\Debug\</OutputPath>
-    <_OriginalConfiguration>$(Configuration)</_OriginalConfiguration>
+    <!-- Example, AnyCPU -->
     <_OriginalPlatform>$(Platform)</_OriginalPlatform>
-    <Configuration Condition=" '$(Configuration)'=='' ">Debug</Configuration>
-    <ConfigurationName Condition=" '$(ConfigurationName)' == '' ">$(Configuration)</ConfigurationName>
+    <Platform Condition="'$(Platform)' == ''">AnyCPU</Platform>
+    <PlatformName Condition="'$(PlatformName)' == ''">$(Platform)</PlatformName>
     <!-- Example, Debug -->
-    <Platform Condition=" '$(Platform)'=='' ">AnyCPU</Platform>
+    <_OriginalConfiguration>$(Configuration)</_OriginalConfiguration>
+    <Configuration Condition="'$(Configuration)' == ''">Debug</Configuration>
+    <ConfigurationName Condition="'$(ConfigurationName)' == ''">$(Configuration)</ConfigurationName>
+
+    <BaseOutputPath Condition="'$(BaseOutputPath)' == ''">bin\</BaseOutputPath>
+    <BaseOutputPath Condition="!HasTrailingSlash('$(BaseOutputPath)')">$(BaseOutputPath)\</BaseOutputPath>
+    <OutputPath Condition="'$(OutputPath)' == '' and '$(PlatformName)' == 'AnyCPU'">$(BaseOutputPath)$(Configuration)\</OutputPath>
+    <OutputPath Condition="'$(OutputPath)' == '' and '$(PlatformName)' != 'AnyCPU'">$(BaseOutputPath)$(PlatformName)\$(Configuration)\</OutputPath>
+    <OutputPath Condition="!HasTrailingSlash('$(OutputPath)')">$(OutputPath)\</OutputPath>
 
+    <BaseIntermediateOutputPath Condition="'$(BaseIntermediateOutputPath)' == ''">obj\</BaseIntermediateOutputPath>
+    <BaseIntermediateOutputPath Condition="!HasTrailingSlash('$(BaseIntermediateOutputPath)')">$(BaseIntermediateOutputPath)\</BaseIntermediateOutputPath>
+    <IntermediateOutputPath Condition="'$(IntermediateOutputPath)' == '' and '$(PlatformName)' == 'AnyCPU'">$(BaseIntermediateOutputPath)$(Configuration)\</IntermediateOutputPath>
+    <IntermediateOutputPath Condition="'$(IntermediateOutputPath)' == '' and '$(PlatformName)' != 'AnyCPU'">$(BaseIntermediateOutputPath)$(PlatformName)\$(Configuration)\</IntermediateOutputPath>
+    <IntermediateOutputPath Condition="!HasTrailingSlash('$(IntermediateOutputPath)')">$(IntermediateOutputPath)\</IntermediateOutputPath>
+  </PropertyGroup>
+
+  <PropertyGroup>
+
+    <!-- Determine OutputType property from the legacy TargetType property -->
     <OutputType Condition=" '$(TargetType)' != ''">$(TargetType)</OutputType>
     <OutputType Condition=" '$(TargetType)' == 'Container' or '$(TargetType)' == 'DocumentContainer' ">library</OutputType>
     <OutputType Condition=" '$(OutputType)' == '' ">exe</OutputType>
@@ -201,6 +222,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
     <!-- For projects that generate app packages or ones that want a per-project output directory, update OutDir to include the project name -->
     <OutDir Condition="'$(OutDir)' != '' and '$(OutDirWasSpecified)' == 'true' and (('$(WindowsAppContainer)' == 'true' and '$(GenerateProjectSpecificOutputFolder)' != 'false') or '$(GenerateProjectSpecificOutputFolder)' == 'true')">$(OutDir)$(ProjectName)\</OutDir>
 
+    <AssemblyName Condition=" '$(AssemblyName)'=='' ">$(MSBuildProjectName)</AssemblyName>
     <TargetName Condition="'$(TargetName)' == '' and '$(OutputType)' == 'winmdobj' and '$(RootNamespace)' != ''">$(RootNamespace)</TargetName>
     <TargetName Condition=" '$(TargetName)' == '' ">$(AssemblyName)</TargetName>
     <!-- Example, MyAssembly -->
@@ -279,26 +301,23 @@ Copyright (C) Microsoft Corporation. All rights reserved.
   </ItemGroup>
 
   <PropertyGroup>
-    <!-- Example, c:\MyProjects\MyProject\bin\debug\ -->
+    <!-- Example, C:\MyProjects\MyProject\bin\Debug\ -->
     <!--
         Condition intentionally omitted on this one, because it causes problems
         when we pick up the value of an environment variable named TargetDir
         -->
     <TargetDir Condition="'$(OutDir)' != ''">$([MSBuild]::Escape($([System.IO.Path]::GetFullPath(`$([System.IO.Path]::Combine(`$(MSBuildProjectDirectory)`, `$(OutDir)`))`))))</TargetDir>
 
-    <!-- Example, c:\MyProjects\MyProject\bin\debug\MyAssembly.dll -->
+    <!-- Example, C:\MyProjects\MyProject\bin\Debug\MyAssembly.dll -->
     <TargetPath Condition=" '$(TargetPath)' == '' ">$(TargetDir)$(TargetFileName)</TargetPath>
 
     <TargetRefPath Condition=" '$(TargetRefPath)' == '' and '$(ProduceReferenceAssembly)' == 'true' ">$([MSBuild]::NormalizePath($(TargetDir), 'ref', $(TargetFileName)))</TargetRefPath>
 
-    <!-- Example, c:\MyProjects\MyProject\ -->
-    <ProjectDir Condition=" '$(ProjectDir)' == '' ">$(MSBuildProjectDirectory)\</ProjectDir>
+    <!-- Example, C:\MyProjects\MyProject\ -->
+    <ProjectDir Condition=" '$(ProjectDir)' == '' ">$([MSBuild]::EnsureTrailingSlash($(MSBuildProjectDirectory))</ProjectDir>
 
-    <!-- Example, c:\MyProjects\MyProject\MyProject.csproj -->
+    <!-- Example, C:\MyProjects\MyProject\MyProject.csproj -->
     <ProjectPath Condition=" '$(ProjectPath)' == '' ">$(ProjectDir)$(ProjectFileName)</ProjectPath>
-
-    <!-- Example, AnyCPU -->
-    <PlatformName Condition=" '$(PlatformName)' == '' ">$(Platform)</PlatformName>
   </PropertyGroup>
 
   <ItemGroup>
@@ -336,7 +355,6 @@ Copyright (C) Microsoft Corporation. All rights reserved.
     <AutoUnifyAssemblyReferences Condition="'$(GenerateBindingRedirectsOutputType)' == 'true' and '$(AutoGenerateBindingRedirects)' != 'true'">false</AutoUnifyAssemblyReferences>
   </PropertyGroup>
   <PropertyGroup>
-    <BaseIntermediateOutputPath Condition="!HasTrailingSlash('$(BaseIntermediateOutputPath)')">$(BaseIntermediateOutputPath)\</BaseIntermediateOutputPath>
     <CleanFile Condition="'$(CleanFile)'==''">$(MSBuildProjectFile).FileListAbsolute.txt</CleanFile>
     <!-- During DesignTime Builds, skip project reference build as Design time is only queueing information.-->
     <BuildProjectReferences Condition="'$(BuildProjectReferences)' == '' and '$(DesignTimeBuild)' == 'true'">false</BuildProjectReferences>
@@ -349,12 +367,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
     <ComReferenceNoClassMembers Condition="'$(ComReferenceNoClassMembers)' == ''">false</ComReferenceNoClassMembers>
   </PropertyGroup>
 
-  <PropertyGroup Condition=" $(IntermediateOutputPath) == '' ">
-    <IntermediateOutputPath Condition=" '$(PlatformName)' == 'AnyCPU' ">$(BaseIntermediateOutputPath)$(Configuration)\</IntermediateOutputPath>
-    <IntermediateOutputPath Condition=" '$(PlatformName)' != 'AnyCPU' ">$(BaseIntermediateOutputPath)$(PlatformName)\$(Configuration)\</IntermediateOutputPath>
-  </PropertyGroup>
   <PropertyGroup>
-    <IntermediateOutputPath Condition="!HasTrailingSlash('$(IntermediateOutputPath)')">$(IntermediateOutputPath)\</IntermediateOutputPath>
     <_GenerateBindingRedirectsIntermediateAppConfig>$(IntermediateOutputPath)$(TargetFileName).config</_GenerateBindingRedirectsIntermediateAppConfig>
   </PropertyGroup>
   <ItemGroup>

From 1e779a59014c21fe3dadbb99956c437b1e080ccf Mon Sep 17 00:00:00 2001
From: Nirmal Guru <Nirmal4G@gmail.com>
Date: Fri, 3 Apr 2020 22:00:13 +0530
Subject: [PATCH 2/7] Use property functions within MSBuild namespace, wherever
 possible

Replace 'HasTrailingSlash' conditional function with '[MSBuild]::EnsureTrailingSlash' property function
Replace '[System.IO.Path]::Combine' property function with '[MSBuild]::NormalizePath' and '[MSBuild]::NormalizeDirectory' property functions
---
 .../Microsoft.Common.CrossTargeting.targets   |  2 +-
 .../Microsoft.Common.CurrentVersion.targets   | 28 ++++++++-----------
 src/Tasks/Microsoft.Common.props              | 10 +++----
 src/Tasks/Microsoft.Common.targets            |  2 +-
 4 files changed, 18 insertions(+), 24 deletions(-)

diff --git a/src/Tasks/Microsoft.Common.CrossTargeting.targets b/src/Tasks/Microsoft.Common.CrossTargeting.targets
index 51ef08021b0..c7023d3cca6 100644
--- a/src/Tasks/Microsoft.Common.CrossTargeting.targets
+++ b/src/Tasks/Microsoft.Common.CrossTargeting.targets
@@ -201,7 +201,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
   <PropertyGroup Condition="'$(ImportDirectoryBuildTargets)' == 'true' and '$(DirectoryBuildTargetsPath)' == ''">
     <_DirectoryBuildTargetsFile Condition="'$(_DirectoryBuildTargetsFile)' == ''">Directory.Build.targets</_DirectoryBuildTargetsFile>
     <_DirectoryBuildTargetsBasePath Condition="'$(_DirectoryBuildTargetsBasePath)' == ''">$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildProjectDirectory), '$(_DirectoryBuildTargetsFile)'))</_DirectoryBuildTargetsBasePath>
-    <DirectoryBuildTargetsPath Condition="'$(_DirectoryBuildTargetsBasePath)' != '' and '$(_DirectoryBuildTargetsFile)' != ''">$([System.IO.Path]::Combine('$(_DirectoryBuildTargetsBasePath)', '$(_DirectoryBuildTargetsFile)'))</DirectoryBuildTargetsPath>
+    <DirectoryBuildTargetsPath Condition="'$(_DirectoryBuildTargetsBasePath)' != '' and '$(_DirectoryBuildTargetsFile)' != ''">$([MSBuild]::NormalizePath('$(_DirectoryBuildTargetsBasePath)', '$(_DirectoryBuildTargetsFile)'))</DirectoryBuildTargetsPath>
   </PropertyGroup>
 
   <Import Project="$(DirectoryBuildTargetsPath)" Condition="'$(ImportDirectoryBuildTargets)' == 'true' and exists('$(DirectoryBuildTargetsPath)')"/>
diff --git a/src/Tasks/Microsoft.Common.CurrentVersion.targets b/src/Tasks/Microsoft.Common.CurrentVersion.targets
index 08670d74d9f..1522bdfaabb 100644
--- a/src/Tasks/Microsoft.Common.CurrentVersion.targets
+++ b/src/Tasks/Microsoft.Common.CurrentVersion.targets
@@ -144,17 +144,15 @@ Copyright (C) Microsoft Corporation. All rights reserved.
     <Configuration Condition="'$(Configuration)' == ''">Debug</Configuration>
     <ConfigurationName Condition="'$(ConfigurationName)' == ''">$(Configuration)</ConfigurationName>
 
-    <BaseOutputPath Condition="'$(BaseOutputPath)' == ''">bin\</BaseOutputPath>
-    <BaseOutputPath Condition="!HasTrailingSlash('$(BaseOutputPath)')">$(BaseOutputPath)\</BaseOutputPath>
+    <BaseOutputPath>$([MSBuild]::EnsureTrailingSlash($([MSBuild]::ValueOrDefault('$(BaseOutputPath)', 'bin'))))</BaseOutputPath>
     <OutputPath Condition="'$(OutputPath)' == '' and '$(PlatformName)' == 'AnyCPU'">$(BaseOutputPath)$(Configuration)\</OutputPath>
     <OutputPath Condition="'$(OutputPath)' == '' and '$(PlatformName)' != 'AnyCPU'">$(BaseOutputPath)$(PlatformName)\$(Configuration)\</OutputPath>
-    <OutputPath Condition="!HasTrailingSlash('$(OutputPath)')">$(OutputPath)\</OutputPath>
+    <OutputPath>$([MSBuild]::EnsureTrailingSlash('$(OutputPath)'))</OutputPath>
 
-    <BaseIntermediateOutputPath Condition="'$(BaseIntermediateOutputPath)' == ''">obj\</BaseIntermediateOutputPath>
-    <BaseIntermediateOutputPath Condition="!HasTrailingSlash('$(BaseIntermediateOutputPath)')">$(BaseIntermediateOutputPath)\</BaseIntermediateOutputPath>
+    <BaseIntermediateOutputPath>$([MSBuild]::EnsureTrailingSlash($([MSBuild]::ValueOrDefault('$(BaseIntermediateOutputPath)', 'obj'))))</BaseIntermediateOutputPath>
     <IntermediateOutputPath Condition="'$(IntermediateOutputPath)' == '' and '$(PlatformName)' == 'AnyCPU'">$(BaseIntermediateOutputPath)$(Configuration)\</IntermediateOutputPath>
     <IntermediateOutputPath Condition="'$(IntermediateOutputPath)' == '' and '$(PlatformName)' != 'AnyCPU'">$(BaseIntermediateOutputPath)$(PlatformName)\$(Configuration)\</IntermediateOutputPath>
-    <IntermediateOutputPath Condition="!HasTrailingSlash('$(IntermediateOutputPath)')">$(IntermediateOutputPath)\</IntermediateOutputPath>
+    <IntermediateOutputPath>$([MSBuild]::EnsureTrailingSlash('$(IntermediateOutputPath)'))</IntermediateOutputPath>
   </PropertyGroup>
 
   <PropertyGroup>
@@ -212,15 +210,14 @@ Copyright (C) Microsoft Corporation. All rights reserved.
     <!-- Required for enabling Team Build for packaging app package-generating projects -->
     <OutDirWasSpecified Condition=" '$(OutDir)'!='' and '$(OutDirWasSpecified)'=='' ">true</OutDirWasSpecified>
 
-    <OutDir Condition=" '$(OutDir)' == '' ">$(OutputPath)</OutDir>
     <!-- Example, bin\Debug\ -->
     <!-- Ensure OutDir has a trailing slash, so it can be concatenated -->
-    <OutDir Condition="'$(OutDir)' != '' and !HasTrailingSlash('$(OutDir)')">$(OutDir)\</OutDir>
+    <OutDir>$([MSBuild]::EnsureTrailingSlash($([MSBuild]::ValueOrDefault('$(OutDir)', '$(OutputPath)'))))</OutDir>
     <ProjectName Condition=" '$(ProjectName)' == '' ">$(MSBuildProjectName)</ProjectName>
     <!-- Example, MyProject -->
 
     <!-- For projects that generate app packages or ones that want a per-project output directory, update OutDir to include the project name -->
-    <OutDir Condition="'$(OutDir)' != '' and '$(OutDirWasSpecified)' == 'true' and (('$(WindowsAppContainer)' == 'true' and '$(GenerateProjectSpecificOutputFolder)' != 'false') or '$(GenerateProjectSpecificOutputFolder)' == 'true')">$(OutDir)$(ProjectName)\</OutDir>
+    <OutDir Condition="'$(OutDir)' != '' and '$(OutDirWasSpecified)' == 'true' and (('$(WindowsAppContainer)' == 'true' and '$(GenerateProjectSpecificOutputFolder)' != 'false') or '$(GenerateProjectSpecificOutputFolder)' == 'true')">$([MSBuild]::EnsureTrailingSlash('$(OutDir)$(ProjectName)'))</OutDir>
 
     <AssemblyName Condition=" '$(AssemblyName)'=='' ">$(MSBuildProjectName)</AssemblyName>
     <TargetName Condition="'$(TargetName)' == '' and '$(OutputType)' == 'winmdobj' and '$(RootNamespace)' != ''">$(RootNamespace)</TargetName>
@@ -306,7 +303,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
         Condition intentionally omitted on this one, because it causes problems
         when we pick up the value of an environment variable named TargetDir
         -->
-    <TargetDir Condition="'$(OutDir)' != ''">$([MSBuild]::Escape($([System.IO.Path]::GetFullPath(`$([System.IO.Path]::Combine(`$(MSBuildProjectDirectory)`, `$(OutDir)`))`))))</TargetDir>
+    <TargetDir Condition="'$(OutDir)' != ''">$([MSBuild]::NormalizeDirectory('$(MSBuildProjectDirectory)', '$(OutDir)'))</TargetDir>
 
     <!-- Example, C:\MyProjects\MyProject\bin\Debug\MyAssembly.dll -->
     <TargetPath Condition=" '$(TargetPath)' == '' ">$(TargetDir)$(TargetFileName)</TargetPath>
@@ -390,12 +387,12 @@ Copyright (C) Microsoft Corporation. All rights reserved.
 
   <PropertyGroup Condition="'$(_DebugSymbolsProduced)' == 'true' and '$(OutputType)' == 'winmdobj'">
     <WinMDExpOutputPdb Condition="'$(WinMDExpOutputPdb)' == ''">$(IntermediateOutputPath)$(TargetName).pdb</WinMDExpOutputPdb>
-    <_WinMDDebugSymbolsOutputPath>$([System.IO.Path]::Combine('$(OutDir)', $([System.IO.Path]::GetFileName('$(WinMDExpOutputPdb)'))))</_WinMDDebugSymbolsOutputPath>
+    <_WinMDDebugSymbolsOutputPath>$(OutDir)$([System.IO.Path]::GetFileName('$(WinMDExpOutputPdb)'))</_WinMDDebugSymbolsOutputPath>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(OutputType)' == 'winmdobj' and '$(DocumentationFile)'!=''">
     <WinMDOutputDocumentationFile Condition="'$(WinMDOutputDocumentationFile)' == ''">$(IntermediateOutputPath)$(TargetName).xml</WinMDOutputDocumentationFile>
-    <_WinMDDocFileOutputPath>$([System.IO.Path]::Combine('$(OutDir)', $([System.IO.Path]::GetFileName('$(WinMDOutputDocumentationFile)'))))</_WinMDDocFileOutputPath>
+    <_WinMDDocFileOutputPath>$(OutDir)$([System.IO.Path]::GetFileName('$(WinMDOutputDocumentationFile)'))</_WinMDDocFileOutputPath>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(WinMDExpOutputWindowsMetadataFilename)' != ''">
@@ -467,8 +464,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
 
   <!-- Output location for publish target. -->
   <PropertyGroup>
-    <PublishDir Condition="'$(PublishDir)' != '' and !HasTrailingSlash('$(PublishDir)')">$(PublishDir)\</PublishDir>
-    <PublishDir Condition="'$(PublishDir)'==''">$(OutputPath)app.publish\</PublishDir>
+    <PublishDir>$([MSBuild]::EnsureTrailingSlash($([MSBuild]::ValueOrDefault('$(PublishDir)', '$(OutputPath)app.publish'))))</PublishDir>
   </PropertyGroup>
 
   <!--
@@ -3376,7 +3372,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
   <PropertyGroup Condition="'$(TargetFrameworkMoniker)' != ''">
     <!-- Do not clean if we are going to default the path to the temp directory -->
     <TargetFrameworkMonikerAssemblyAttributesFileClean Condition="'$(TargetFrameworkMonikerAssemblyAttributesFileClean)' == '' and '$(TargetFrameworkMonikerAssemblyAttributesPath)' != ''">true</TargetFrameworkMonikerAssemblyAttributesFileClean>
-    <TargetFrameworkMonikerAssemblyAttributesPath Condition="'$(TargetFrameworkMonikerAssemblyAttributesPath)' == ''">$([System.IO.Path]::Combine('$(IntermediateOutputPath)','$(TargetFrameworkMoniker).AssemblyAttributes$(DefaultLanguageSourceExtension)'))</TargetFrameworkMonikerAssemblyAttributesPath>
+    <TargetFrameworkMonikerAssemblyAttributesPath Condition="'$(TargetFrameworkMonikerAssemblyAttributesPath)' == ''">$(IntermediateOutputPath)$(TargetFrameworkMoniker).AssemblyAttributes$(DefaultLanguageSourceExtension)</TargetFrameworkMonikerAssemblyAttributesPath>
   </PropertyGroup>
 
   <PropertyGroup>
@@ -4581,7 +4577,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
       <Output TaskParameter="DestinationFiles" ItemName="FinalWinmdExpArtifacts" />
     </Copy>
 
-    <Message Importance="High" Text="$(MSBuildProjectName) -&gt; $([System.IO.Path]::GetFullPath('$(_WindowsMetadataOutputPath)'))" Condition="'$(SkipCopyWinMDArtifact)' != 'true' and '$(_WindowsMetadataOutputPath)' != ''" />
+    <Message Importance="High" Text="$(MSBuildProjectName) -&gt; $([MSBuild]::NormalizePath('$(_WindowsMetadataOutputPath)'))" Condition="'$(SkipCopyWinMDArtifact)' != 'true' and '$(_WindowsMetadataOutputPath)' != ''" />
 
   </Target>
 
diff --git a/src/Tasks/Microsoft.Common.props b/src/Tasks/Microsoft.Common.props
index 89e402b0582..942daa68814 100644
--- a/src/Tasks/Microsoft.Common.props
+++ b/src/Tasks/Microsoft.Common.props
@@ -26,7 +26,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
   <PropertyGroup Condition="'$(ImportDirectoryBuildProps)' == 'true' and '$(DirectoryBuildPropsPath)' == ''">
     <_DirectoryBuildPropsFile Condition="'$(_DirectoryBuildPropsFile)' == ''">Directory.Build.props</_DirectoryBuildPropsFile>
     <_DirectoryBuildPropsBasePath Condition="'$(_DirectoryBuildPropsBasePath)' == ''">$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildProjectDirectory), '$(_DirectoryBuildPropsFile)'))</_DirectoryBuildPropsBasePath>
-    <DirectoryBuildPropsPath Condition="'$(_DirectoryBuildPropsBasePath)' != '' and '$(_DirectoryBuildPropsFile)' != ''">$([System.IO.Path]::Combine('$(_DirectoryBuildPropsBasePath)', '$(_DirectoryBuildPropsFile)'))</DirectoryBuildPropsPath>
+    <DirectoryBuildPropsPath Condition="'$(_DirectoryBuildPropsBasePath)' != '' and '$(_DirectoryBuildPropsFile)' != ''">$([MSBuild]::NormalizePath('$(_DirectoryBuildPropsBasePath)', '$(_DirectoryBuildPropsFile)'))</DirectoryBuildPropsPath>
   </PropertyGroup>
 
   <Import Project="$(DirectoryBuildPropsPath)" Condition="'$(ImportDirectoryBuildProps)' == 'true' and exists('$(DirectoryBuildPropsPath)')"/>
@@ -43,18 +43,16 @@ Copyright (C) Microsoft Corporation. All rights reserved.
             The declaration of $(BaseIntermediateOutputPath) had to be moved up from Microsoft.Common.CurrentVersion.targets
             in order for the $(MSBuildProjectExtensionsPath) to use it as a default.
         -->
-    <BaseIntermediateOutputPath Condition="'$(BaseIntermediateOutputPath)'=='' ">obj\</BaseIntermediateOutputPath>
-    <BaseIntermediateOutputPath Condition="!HasTrailingSlash('$(BaseIntermediateOutputPath)')">$(BaseIntermediateOutputPath)\</BaseIntermediateOutputPath>
+    <BaseIntermediateOutputPath>$([MSBuild]::EnsureTrailingSlash($([MSBuild]::ValueOrDefault('$(BaseIntermediateOutputPath)', 'obj'))))</BaseIntermediateOutputPath>
     <_InitialBaseIntermediateOutputPath>$(BaseIntermediateOutputPath)</_InitialBaseIntermediateOutputPath>
 
-    <MSBuildProjectExtensionsPath Condition="'$(MSBuildProjectExtensionsPath)' == '' ">$(BaseIntermediateOutputPath)</MSBuildProjectExtensionsPath>
+    <MSBuildProjectExtensionsPath>$([MSBuild]::EnsureTrailingSlash($([MSBuild]::ValueOrDefault('$(MSBuildProjectExtensionsPath)', '$(BaseIntermediateOutputPath)'))))</MSBuildProjectExtensionsPath>
     <!--
         Import paths that are relative default to be relative to the importing file.  However, since MSBuildExtensionsPath
         defaults to BaseIntermediateOutputPath we expect it to be relative to the project directory.  So if the path is relative
         it needs to be made absolute based on the project directory.
       -->
-    <MSBuildProjectExtensionsPath Condition="'$([System.IO.Path]::IsPathRooted($(MSBuildProjectExtensionsPath)))' == 'false'">$([System.IO.Path]::Combine('$(MSBuildProjectDirectory)', '$(MSBuildProjectExtensionsPath)'))</MSBuildProjectExtensionsPath>
-    <MSBuildProjectExtensionsPath Condition="!HasTrailingSlash('$(MSBuildProjectExtensionsPath)')">$(MSBuildProjectExtensionsPath)\</MSBuildProjectExtensionsPath>
+    <MSBuildProjectExtensionsPath Condition="!$([System.IO.Path]::IsPathRooted('$(MSBuildProjectExtensionsPath)'))">$([MSBuild]::NormalizeDirectory('$(MSBuildProjectDirectory)', '$(MSBuildProjectExtensionsPath)'))</MSBuildProjectExtensionsPath>
     <ImportProjectExtensionProps Condition="'$(ImportProjectExtensionProps)' == ''">true</ImportProjectExtensionProps>
     <_InitialMSBuildProjectExtensionsPath Condition=" '$(ImportProjectExtensionProps)' == 'true' ">$(MSBuildProjectExtensionsPath)</_InitialMSBuildProjectExtensionsPath>
   </PropertyGroup>
diff --git a/src/Tasks/Microsoft.Common.targets b/src/Tasks/Microsoft.Common.targets
index d88e7eb9221..b3e9be1fa09 100644
--- a/src/Tasks/Microsoft.Common.targets
+++ b/src/Tasks/Microsoft.Common.targets
@@ -137,7 +137,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
   <PropertyGroup Condition="'$(ImportDirectoryBuildTargets)' == 'true' and '$(DirectoryBuildTargetsPath)' == ''">
     <_DirectoryBuildTargetsFile Condition="'$(_DirectoryBuildTargetsFile)' == ''">Directory.Build.targets</_DirectoryBuildTargetsFile>
     <_DirectoryBuildTargetsBasePath Condition="'$(_DirectoryBuildTargetsBasePath)' == ''">$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildProjectDirectory), '$(_DirectoryBuildTargetsFile)'))</_DirectoryBuildTargetsBasePath>
-    <DirectoryBuildTargetsPath Condition="'$(_DirectoryBuildTargetsBasePath)' != '' and '$(_DirectoryBuildTargetsFile)' != ''">$([System.IO.Path]::Combine('$(_DirectoryBuildTargetsBasePath)', '$(_DirectoryBuildTargetsFile)'))</DirectoryBuildTargetsPath>
+    <DirectoryBuildTargetsPath Condition="'$(_DirectoryBuildTargetsBasePath)' != '' and '$(_DirectoryBuildTargetsFile)' != ''">$([MSBuild]::NormalizePath('$(_DirectoryBuildTargetsBasePath)', '$(_DirectoryBuildTargetsFile)'))</DirectoryBuildTargetsPath>
   </PropertyGroup>
 
   <Import Project="$(DirectoryBuildTargetsPath)" Condition="'$(ImportDirectoryBuildTargets)' == 'true' and exists('$(DirectoryBuildTargetsPath)')"/>

From 9a7012e744ae376cb278f10c90eef7d42dba4971 Mon Sep 17 00:00:00 2001
From: Nirmal Guru <Nirmal4G@gmail.com>
Date: Fri, 8 May 2020 14:12:16 +0530
Subject: [PATCH 3/7] Fallback to legacy behavior for Configuration/Platform
 validation

when using OutputPath without BaseOutputPath
---
 .../Microsoft.Common.CurrentVersion.targets   | 36 +++++++++++++------
 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/src/Tasks/Microsoft.Common.CurrentVersion.targets b/src/Tasks/Microsoft.Common.CurrentVersion.targets
index 1522bdfaabb..4d1c2f5ad11 100644
--- a/src/Tasks/Microsoft.Common.CurrentVersion.targets
+++ b/src/Tasks/Microsoft.Common.CurrentVersion.targets
@@ -137,10 +137,17 @@ Copyright (C) Microsoft Corporation. All rights reserved.
   <PropertyGroup>
     <!-- Example, AnyCPU -->
     <_OriginalPlatform>$(Platform)</_OriginalPlatform>
-    <Platform Condition="'$(Platform)' == ''">AnyCPU</Platform>
-    <PlatformName Condition="'$(PlatformName)' == ''">$(Platform)</PlatformName>
     <!-- Example, Debug -->
     <_OriginalConfiguration>$(Configuration)</_OriginalConfiguration>
+    <!-- Check whether OutputPath was specified for valid Configuration/Platform combination -->
+    <_OutputPathWasMissing Condition="'$(_OriginalPlatform)' != '' and '$(_OriginalConfiguration)' != '' and '$(OutputPath)' == ''">true</_OutputPathWasMissing>
+    <!-- Check whether BaseOutputPath was specified -->
+    <BaseOutputPathWasSpecified Condition="'$(BaseOutputPath)' != ''">true</BaseOutputPathWasSpecified>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <Platform Condition="'$(Platform)' == ''">AnyCPU</Platform>
+    <PlatformName Condition="'$(PlatformName)' == ''">$(Platform)</PlatformName>
     <Configuration Condition="'$(Configuration)' == ''">Debug</Configuration>
     <ConfigurationName Condition="'$(ConfigurationName)' == ''">$(Configuration)</ConfigurationName>
 
@@ -181,12 +188,19 @@ Copyright (C) Microsoft Corporation. All rights reserved.
     <ProduceReferenceAssembly Condition="'$(ProduceReferenceAssembly)' == ''">false</ProduceReferenceAssembly>
   </PropertyGroup>
 
-  <PropertyGroup Condition=" '$(OutputPath)' == '' ">
+  <!--
+    For projects loaded with MPFProj (Legacy project system) that defines the properties per Configuration/Platform
+    combination by the IDE itself, the validation of an invalid Configuration/Platform is determined by the non-empty
+    value of the 'OutputPath' property specified under the IDE generated Configuration/Platform 'PropertyGroup' section.
+
+    If 'BaseOutputPath' is not specified, then, we should fallback to the existing behavior, as described above.
+  -->
+  <PropertyGroup Condition="'$(BaseOutputPathWasSpecified)' != 'true' and '$(_OutputPathWasMissing)' == 'true'">
     <!--
-        A blank OutputPath at this point means that the user passed in an invalid Configuration/Platform
-        combination.  Whether this is considered an error or a warning depends on the value of
-        $(SkipInvalidConfigurations).
-        -->
+        When 'OutputPath' is missing or empty (along with non-existent 'BaseOutputPath') at this point means that
+        we're in legacy mode and we should assume the current Configuration/Platform combination as invalid.
+        Whether this is considered an error or a warning depends on the value of $(SkipInvalidConfigurations).
+    -->
     <_InvalidConfigurationError Condition=" '$(SkipInvalidConfigurations)' != 'true' ">true</_InvalidConfigurationError>
     <_InvalidConfigurationWarning Condition=" '$(SkipInvalidConfigurations)' == 'true' ">true</_InvalidConfigurationWarning>
   </PropertyGroup>
@@ -195,7 +209,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
     IDE Macros available from both integrated builds and from command line builds.
     The following properties are 'macros' that are available via IDE for
     pre and post build steps.
-    -->
+  -->
   <PropertyGroup>
     <TargetExt Condition="'$(TargetExt)' == '' and '$(OutputType)'=='exe'">.exe</TargetExt>
     <TargetExt Condition="'$(TargetExt)' == '' and '$(OutputType)'=='winexe'">.exe</TargetExt>
@@ -793,7 +807,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
       BeforeTargets="$(BuildDependsOn);Build;$(RebuildDependsOn);Rebuild;$(CleanDependsOn);Clean">
 
     <PropertyGroup>
-      <_InvalidConfigurationMessageText>The OutputPath property is not set for project '$(MSBuildProjectFile)'.  Please check to make sure that you have specified a valid combination of Configuration and Platform for this project.  Configuration='$(_OriginalConfiguration)'  Platform='$(_OriginalPlatform)'.</_InvalidConfigurationMessageText>
+      <_InvalidConfigurationMessageText>The BaseOutputPath/OutputPath property is not set for project '$(MSBuildProjectFile)'.  Please check to make sure that you have specified a valid combination of Configuration and Platform for this project.  Configuration='$(_OriginalConfiguration)'  Platform='$(_OriginalPlatform)'.</_InvalidConfigurationMessageText>
       <_InvalidConfigurationMessageText Condition="'$(BuildingInsideVisualStudio)' == 'true'">$(_InvalidConfigurationMessageText)  This error may also appear if some other project is trying to follow a project-to-project reference to this project, this project has been unloaded or is not included in the solution, and the referencing project does not build using the same or an equivalent Configuration or Platform.</_InvalidConfigurationMessageText>
       <_InvalidConfigurationMessageText Condition="'$(BuildingInsideVisualStudio)' != 'true'">$(_InvalidConfigurationMessageText)  You may be seeing this message because you are trying to build a project without a solution file, and have specified a non-default Configuration or Platform that doesn't exist for this project.</_InvalidConfigurationMessageText>
     </PropertyGroup>
@@ -806,8 +820,10 @@ Copyright (C) Microsoft Corporation. All rights reserved.
 
     <!-- Although we try to ensure a trailing slash, it's possible to circumvent this if the property is set on the command line -->
     <Error Condition="'$(OutDir)' != '' and !HasTrailingSlash('$(OutDir)')" Text="The OutDir property must end with a trailing slash." />
-    <Error Condition="'$(BaseIntermediateOutputPath)' != '' and !HasTrailingSlash('$(BaseIntermediateOutputPath)')" Text="The BaseIntermediateOutputPath must end with a trailing slash." />
+    <Error Condition="'$(OutputPath)' != '' and !HasTrailingSlash('$(OutputPath)')" Text="The OutputPath must end with a trailing slash." />
+    <Error Condition="'$(BaseOutputPath)' != '' and !HasTrailingSlash('$(BaseOutputPath)')" Text="The BaseOutputPath must end with a trailing slash." />
     <Error Condition="'$(IntermediateOutputPath)' != '' and !HasTrailingSlash('$(IntermediateOutputPath)')" Text="The IntermediateOutputPath must end with a trailing slash." />
+    <Error Condition="'$(BaseIntermediateOutputPath)' != '' and !HasTrailingSlash('$(BaseIntermediateOutputPath)')" Text="The BaseIntermediateOutputPath must end with a trailing slash." />
 
     <!-- Also update the value of PlatformTargetAsMSBuildArchitecture per the value of Prefer32Bit.  We are doing
          this here because Prefer32Bit may be set anywhere in the targets, so we can't depend on it having the

From 601ed385483533657ea120c7d880effce7b4c0cf Mon Sep 17 00:00:00 2001
From: Nirmal Guru <Nirmal4G@gmail.com>
Date: Wed, 5 Aug 2020 21:02:16 +0530
Subject: [PATCH 4/7] Use 'Path.Combine' property function in place of using
 slashes to combine paths

Usually, either '[MSBuild]::NormalizePath' or '[MSBuild]::NormalizeDirectory' property functions would be preferred for these cases.
But, there's a bug (on Windows) which occurs when a drive relative path like 'C:Projects' is specified and it fails to return to the project directory.

Usually, '[System.IO.Path]::Join' would be most preferred in this context. But, it's not available in NETFX. So, '[System.IO.Path]::Combine' is used instead.
---
 src/Tasks/Microsoft.Common.CurrentVersion.targets | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/Tasks/Microsoft.Common.CurrentVersion.targets b/src/Tasks/Microsoft.Common.CurrentVersion.targets
index 4d1c2f5ad11..6df1e3a4a7b 100644
--- a/src/Tasks/Microsoft.Common.CurrentVersion.targets
+++ b/src/Tasks/Microsoft.Common.CurrentVersion.targets
@@ -152,13 +152,13 @@ Copyright (C) Microsoft Corporation. All rights reserved.
     <ConfigurationName Condition="'$(ConfigurationName)' == ''">$(Configuration)</ConfigurationName>
 
     <BaseOutputPath>$([MSBuild]::EnsureTrailingSlash($([MSBuild]::ValueOrDefault('$(BaseOutputPath)', 'bin'))))</BaseOutputPath>
-    <OutputPath Condition="'$(OutputPath)' == '' and '$(PlatformName)' == 'AnyCPU'">$(BaseOutputPath)$(Configuration)\</OutputPath>
-    <OutputPath Condition="'$(OutputPath)' == '' and '$(PlatformName)' != 'AnyCPU'">$(BaseOutputPath)$(PlatformName)\$(Configuration)\</OutputPath>
+    <OutputPath Condition="'$(OutputPath)' == '' and '$(PlatformName)' == 'AnyCPU'">$([System.IO.Path]::Combine('$(BaseOutputPath)', '$(Configuration)'))</OutputPath>
+    <OutputPath Condition="'$(OutputPath)' == '' and '$(PlatformName)' != 'AnyCPU'">$([System.IO.Path]::Combine('$(BaseOutputPath)', '$(PlatformName)', '$(Configuration)'))</OutputPath>
     <OutputPath>$([MSBuild]::EnsureTrailingSlash('$(OutputPath)'))</OutputPath>
 
     <BaseIntermediateOutputPath>$([MSBuild]::EnsureTrailingSlash($([MSBuild]::ValueOrDefault('$(BaseIntermediateOutputPath)', 'obj'))))</BaseIntermediateOutputPath>
-    <IntermediateOutputPath Condition="'$(IntermediateOutputPath)' == '' and '$(PlatformName)' == 'AnyCPU'">$(BaseIntermediateOutputPath)$(Configuration)\</IntermediateOutputPath>
-    <IntermediateOutputPath Condition="'$(IntermediateOutputPath)' == '' and '$(PlatformName)' != 'AnyCPU'">$(BaseIntermediateOutputPath)$(PlatformName)\$(Configuration)\</IntermediateOutputPath>
+    <IntermediateOutputPath Condition="'$(IntermediateOutputPath)' == '' and '$(PlatformName)' == 'AnyCPU'">$([System.IO.Path]::Combine('$(BaseIntermediateOutputPath)', '$(Configuration)'))</IntermediateOutputPath>
+    <IntermediateOutputPath Condition="'$(IntermediateOutputPath)' == '' and '$(PlatformName)' != 'AnyCPU'">$([System.IO.Path]::Combine('$(BaseIntermediateOutputPath)', '$(PlatformName)', '$(Configuration)'))</IntermediateOutputPath>
     <IntermediateOutputPath>$([MSBuild]::EnsureTrailingSlash('$(IntermediateOutputPath)'))</IntermediateOutputPath>
   </PropertyGroup>
 

From 97bc2b5ff08b864c7fe606394abfd698d5a1f4e1 Mon Sep 17 00:00:00 2001
From: Nirmal Guru <Nirmal4G@gmail.com>
Date: Wed, 5 Aug 2020 21:04:19 +0530
Subject: [PATCH 5/7] Add tests for checking 'OutputPath' properties

Making sure that existing 'OutputPath' scenarios work, while allowing the use of 'BaseOutputPath' property
---
 src/Tasks.UnitTests/OutputPathTests.cs | 186 +++++++++++++++++++++++++
 1 file changed, 186 insertions(+)
 create mode 100644 src/Tasks.UnitTests/OutputPathTests.cs

diff --git a/src/Tasks.UnitTests/OutputPathTests.cs b/src/Tasks.UnitTests/OutputPathTests.cs
new file mode 100644
index 00000000000..f2bc410bbbd
--- /dev/null
+++ b/src/Tasks.UnitTests/OutputPathTests.cs
@@ -0,0 +1,186 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.IO;
+
+using Microsoft.Build.Evaluation;
+using Microsoft.Build.Shared;
+using Microsoft.Build.UnitTests;
+
+using Shouldly;
+
+using Xunit;
+using Xunit.Abstractions;
+
+namespace Microsoft.Build.Tasks.UnitTests
+{
+    public sealed class OutputPathTests : IDisposable
+    {
+        private readonly ITestOutputHelper _output;
+        private readonly string _projectRelativePath = Path.Combine("src", "test", "test.csproj");
+
+        public OutputPathTests(ITestOutputHelper output)
+        {
+            _output = output;
+            ObjectModelHelpers.DeleteTempProjectDirectory();
+        }
+
+        public void Dispose()
+        {
+            ObjectModelHelpers.DeleteTempProjectDirectory();
+        }
+
+        /// <summary>
+        /// Test when both BaseOutputPath and OutputPath are not specified.
+        /// </summary>
+        [Fact]
+        public void BothBaseOutputPathAndOutputPathWereNotSpecified()
+        {
+            // Arrange
+            var baseOutputPath = "bin";
+
+            var projectFilePath = ObjectModelHelpers.CreateFileInTempProjectDirectory(_projectRelativePath,
+$@"<Project DefaultTargets=`Build` xmlns=`msbuildnamespace` ToolsVersion=`msbuilddefaulttoolsversion`>
+
+    <Import Project=`$(MSBuildToolsPath)\Microsoft.Common.props`/>
+
+    <PropertyGroup>
+        <Platform>AnyCPU</Platform>
+        <Configuration>Debug</Configuration>
+    </PropertyGroup>
+
+    <Import Project=`$(MSBuildToolsPath)\Microsoft.Common.targets`/>
+    <Target Name=`Build`/>
+
+</Project>");
+
+            // Act
+            Project project = ObjectModelHelpers.LoadProjectFileInTempProjectDirectory(projectFilePath, touchProject: false);
+
+            project.Build(new MockLogger(_output)).ShouldBeFalse();
+
+            // Assert
+            project.GetPropertyValue("BaseOutputPath").ShouldBe(baseOutputPath.WithTrailingSlash());
+            project.GetPropertyValue("BaseOutputPathWasSpecified").ShouldBe(string.Empty);
+            project.GetPropertyValue("_OutputPathWasMissing").ShouldBe("true");
+        }
+
+        /// <summary>
+        /// Test when BaseOutputPath is specified without the OutputPath.
+        /// </summary>
+        [Fact]
+        public void BaseOutputPathWasSpecifiedAndIsOverridable()
+        {
+            // Arrange
+            var baseOutputPath = Path.Combine("build", "bin");
+
+            var projectFilePath = ObjectModelHelpers.CreateFileInTempProjectDirectory(_projectRelativePath,
+$@"<Project DefaultTargets=`Build` xmlns=`msbuildnamespace` ToolsVersion=`msbuilddefaulttoolsversion`>
+
+    <Import Project=`$(MSBuildToolsPath)\Microsoft.Common.props`/>
+
+    <PropertyGroup>
+        <Platform>AnyCPU</Platform>
+        <Configuration>Debug</Configuration>
+        <BaseOutputPath>{baseOutputPath}</BaseOutputPath>
+    </PropertyGroup>
+
+    <Import Project=`$(MSBuildToolsPath)\Microsoft.Common.targets`/>
+    <Target Name=`Build`/>
+
+</Project>");
+
+            // Act
+            Project project = ObjectModelHelpers.LoadProjectFileInTempProjectDirectory(projectFilePath, touchProject: false);
+
+            project.Build(new MockLogger(_output)).ShouldBeTrue();
+
+            // Assert
+            project.GetPropertyValue("BaseOutputPath").ShouldBe(baseOutputPath.WithTrailingSlash());
+            project.GetPropertyValue("BaseOutputPathWasSpecified").ShouldBe("true");
+            project.GetPropertyValue("_OutputPathWasMissing").ShouldBe("true");
+        }
+
+        /// <summary>
+        /// Test when both BaseOutputPath and OutputPath are specified.
+        /// </summary>
+        [Fact]
+        public void BothBaseOutputPathAndOutputPathWereSpecified()
+        {
+            // Arrange
+            var baseOutputPath = Path.Combine("build", "bin");
+            var outputPath = Path.Combine("bin", "Debug");
+            var outputPathAlt = Path.Combine("bin", "Release");
+
+            var projectFilePath = ObjectModelHelpers.CreateFileInTempProjectDirectory(_projectRelativePath,
+$@"<Project DefaultTargets=`Build` xmlns=`msbuildnamespace` ToolsVersion=`msbuilddefaulttoolsversion`>
+
+    <Import Project=`$(MSBuildToolsPath)\Microsoft.Common.props`/>
+
+    <PropertyGroup>
+        <Platform>AnyCPU</Platform>
+        <Configuration>Debug</Configuration>
+    </PropertyGroup>
+
+    <PropertyGroup>
+        <BaseOutputPath>{baseOutputPath}</BaseOutputPath>
+        <OutputPath Condition=`'$(Platform)|$(Configuration)' == 'AnyCPU|Debug'`>{outputPath}</OutputPath>
+        <OutputPath Condition=`'$(Platform)|$(Configuration)' == 'AnyCPU|Release'`>{outputPathAlt}</OutputPath>
+    </PropertyGroup>
+
+    <Import Project=`$(MSBuildToolsPath)\Microsoft.Common.targets`/>
+    <Target Name=`Build`/>
+
+</Project>");
+
+            // Act
+            Project project = ObjectModelHelpers.LoadProjectFileInTempProjectDirectory(projectFilePath, touchProject: false);
+
+            project.Build(new MockLogger(_output)).ShouldBeTrue();
+
+            // Assert
+            project.GetPropertyValue("BaseOutputPath").ShouldBe(baseOutputPath.WithTrailingSlash());
+            project.GetPropertyValue("OutputPath").ShouldBe(outputPath.WithTrailingSlash());
+            project.GetPropertyValue("BaseOutputPathWasSpecified").ShouldBe("true");
+            project.GetPropertyValue("_OutputPathWasMissing").ShouldBe(string.Empty);
+        }
+
+        /// <summary>
+        /// Test for [MSBuild]::NormalizePath and [MSBuild]::NormalizeDirectory returning current directory instead of current Project directory.
+        /// </summary>
+        [ConditionalFact(typeof(NativeMethodsShared), nameof(NativeMethodsShared.IsWindows), Skip = "Skipping this test for now until we have a consensus about this issue.")]
+        public void MSBuildNormalizePathShouldReturnProjectDirectory()
+        {
+            // Arrange
+            var configuration = "Debug";
+            var baseOutputPath = "bin";
+
+            var projectFilePath = ObjectModelHelpers.CreateFileInTempProjectDirectory(_projectRelativePath,
+$@"<Project DefaultTargets=`Build` xmlns=`msbuildnamespace` ToolsVersion=`msbuilddefaulttoolsversion`>
+
+    <Import Project=`$(MSBuildToolsPath)\Microsoft.Common.props`/>
+
+    <PropertyGroup Condition=`'$(OutputPath)' == ''`>
+        <OutputPath>$([MSBuild]::NormalizeDirectory('{baseOutputPath}', '{configuration}'))</OutputPath>
+    </PropertyGroup>
+
+    <Import Project=`$(MSBuildToolsPath)\Microsoft.Common.targets`/>
+    <Target Name=`Build`/>
+
+</Project>");
+
+            // Act
+            Project project = ObjectModelHelpers.LoadProjectFileInTempProjectDirectory(projectFilePath, touchProject: false);
+
+            project.Build(new MockLogger(_output)).ShouldBeTrue();
+
+            // Assert
+            project.GetPropertyValue("Configuration").ShouldBe(configuration);
+            project.GetPropertyValue("BaseOutputPath").ShouldBe(baseOutputPath.WithTrailingSlash());
+
+            var expectedOutputPath = FileUtilities.CombinePaths(project.DirectoryPath, baseOutputPath, configuration).WithTrailingSlash();
+            project.GetPropertyValue("OutputPath").ShouldBe(expectedOutputPath);
+        }
+    }
+}

From 17c4944991fd23fda3e4ec2ec40e4ce86107cd1d Mon Sep 17 00:00:00 2001
From: Nirmal Guru <Nirmal4G@gmail.com>
Date: Wed, 2 Dec 2020 09:28:55 +0530
Subject: [PATCH 6/7] Update comments on legacy Configuration/Platform check

Adjust the wording to make it simple, brief and clear.

Co-Authored-By: Rainer Sigwald <raines@microsoft.com>

> Fixup with original commit when this patch is approved.
---
 .../Microsoft.Common.CurrentVersion.targets     | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/src/Tasks/Microsoft.Common.CurrentVersion.targets b/src/Tasks/Microsoft.Common.CurrentVersion.targets
index 6df1e3a4a7b..da26d36c313 100644
--- a/src/Tasks/Microsoft.Common.CurrentVersion.targets
+++ b/src/Tasks/Microsoft.Common.CurrentVersion.targets
@@ -119,8 +119,8 @@ Copyright (C) Microsoft Corporation. All rights reserved.
     This is the full Output Path, and is derived from BaseOutputPath, if none specified
     (eg. bin\Debug). If this property is overridden, then setting BaseOutputPath has no effect.
 
-    For projects loaded with MPFProj (Legacy project system):
-    This property is usually specified in the project file and is used to initialize OutDir.
+    For Legacy projects using only Common targets, this property is usually specified in the project file
+    and is used to initialize OutDir. Some SDKs including the .NET SDK derive this automatically.
     OutDir and OutputPath are distinguished for legacy reasons, and OutDir should be used if at all possible.
 
     BaseIntermediateOutputPath:
@@ -189,16 +189,17 @@ Copyright (C) Microsoft Corporation. All rights reserved.
   </PropertyGroup>
 
   <!--
-    For projects loaded with MPFProj (Legacy project system) that defines the properties per Configuration/Platform
-    combination by the IDE itself, the validation of an invalid Configuration/Platform is determined by the non-empty
-    value of the 'OutputPath' property specified under the IDE generated Configuration/Platform 'PropertyGroup' section.
+    For Legacy projects that define properties per Configuration/Platform combination, the validity of an
+    invalid combination is determined by the non-empty value of the 'OutputPath' property specified under
+    the IDE generated Configuration/Platform specific 'PropertyGroup' section.
 
-    If 'BaseOutputPath' is not specified, then, we should fallback to the existing behavior, as described above.
+    If 'BaseOutputPath' is specified, we can skip the validation, since, we assume the 'OutputPath' property
+    will be derived (e.g.: from the 'BaseOutputPath' property).
   -->
   <PropertyGroup Condition="'$(BaseOutputPathWasSpecified)' != 'true' and '$(_OutputPathWasMissing)' == 'true'">
     <!--
-        When 'OutputPath' is missing or empty (along with non-existent 'BaseOutputPath') at this point means that
-        we're in legacy mode and we should assume the current Configuration/Platform combination as invalid.
+        When 'OutputPath' is missing or empty (along with non-existent 'BaseOutputPath') at this point means,
+        we're in legacy mode and we shall assume the current Configuration/Platform combination as invalid.
         Whether this is considered an error or a warning depends on the value of $(SkipInvalidConfigurations).
     -->
     <_InvalidConfigurationError Condition=" '$(SkipInvalidConfigurations)' != 'true' ">true</_InvalidConfigurationError>

From f7e97bd6f3f929440d709bc7474a3a59a2ba4f33 Mon Sep 17 00:00:00 2001
From: Nirmal Guru <Nirmal4G@gmail.com>
Date: Wed, 2 Dec 2020 10:05:52 +0530
Subject: [PATCH 7/7] Add a missing bracket

Silly ME!

There were a lot of build errors from the Fakes targets.
I was banging my head on which change caused this but finally found it.
Guess being sick has its perks.
---
 src/Tasks/Microsoft.Common.CurrentVersion.targets | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/Tasks/Microsoft.Common.CurrentVersion.targets b/src/Tasks/Microsoft.Common.CurrentVersion.targets
index da26d36c313..c7c94603ad1 100644
--- a/src/Tasks/Microsoft.Common.CurrentVersion.targets
+++ b/src/Tasks/Microsoft.Common.CurrentVersion.targets
@@ -326,7 +326,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
     <TargetRefPath Condition=" '$(TargetRefPath)' == '' and '$(ProduceReferenceAssembly)' == 'true' ">$([MSBuild]::NormalizePath($(TargetDir), 'ref', $(TargetFileName)))</TargetRefPath>
 
     <!-- Example, C:\MyProjects\MyProject\ -->
-    <ProjectDir Condition=" '$(ProjectDir)' == '' ">$([MSBuild]::EnsureTrailingSlash($(MSBuildProjectDirectory))</ProjectDir>
+    <ProjectDir Condition=" '$(ProjectDir)' == '' ">$([MSBuild]::EnsureTrailingSlash($(MSBuildProjectDirectory)))</ProjectDir>
 
     <!-- Example, C:\MyProjects\MyProject\MyProject.csproj -->
     <ProjectPath Condition=" '$(ProjectPath)' == '' ">$(ProjectDir)$(ProjectFileName)</ProjectPath>
@@ -1718,7 +1718,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
 
     <!-- Pass the CurrentProjectTargetPlatform parameter to the task only if GetReferenceNearestTargetFrameworkTaskSupportsTargetPlatformParameter is true.  This means
          that we are using a version of NuGet which supports that parameter on this task. -->
-    
+
     <GetReferenceNearestTargetFrameworkTask AnnotatedProjectReferences="@(_ProjectReferenceTargetFrameworkPossibilities)"
                                             CurrentProjectTargetFramework="$(ReferringTargetFrameworkForProjectReferences)"
                                             CurrentProjectTargetPlatform="$(TargetPlatformMoniker)"
@@ -1787,7 +1787,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
         <TargetPlatformMonikers>@(_TargetFrameworkInfo->'%(TargetPlatformMonikers)')</TargetPlatformMonikers>
 
         <HasSingleTargetFramework>true</HasSingleTargetFramework>
-        
+
         <!-- indicate to caller that project is RID agnostic so that a global property RuntimeIdentifier value can be removed -->
         <IsRidAgnostic>false</IsRidAgnostic>
         <IsRidAgnostic Condition=" '$(RuntimeIdentifier)' == '' and '$(RuntimeIdentifiers)' == '' ">true</IsRidAgnostic>
@@ -4029,7 +4029,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.
       Name="_DeploymentGenerateLauncher"
       Condition="'$(GenerateClickOnceManifests)'=='true' and '$(_DeploymentLauncherBased)' == 'true'">
 
-    <!-- 
+    <!--
       If apphost based built EXE is found, use that as the Launcher.exe's entry point otherwise
       use the built DLL as the entry point
     -->