From 1121201a36c1bc8d657bd57a2b44923f4e92580c Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Sun, 14 May 2023 17:54:38 +0200
Subject: [PATCH 1/4] Add warning when using packages.config for MVVM Toolkit

---
 .../CommunityToolkit.Mvvm.targets                   | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets b/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets
index 958c2c2e5..d481f5efe 100644
--- a/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets
+++ b/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets
@@ -99,4 +99,17 @@
     </ItemGroup>
   </Target>
 
+  <!-- Remove the analyzer if packages.config is used -->
+  <Target Name="MVVMToolkitWarnForPackagesConfigUse"
+          AfterTargets="ResolvePackageDependenciesForBuild;ResolveNuGetPackageAssets"
+          DependsOnTargets="MVVMToolkitGatherAnalyzers">
+
+    <!--
+      Emit a warning in case packages.config is used, by reading the associated MSBuild property.
+      This happens when either the project style is using packages.config, or when explicitly requested.
+      See https://learn.microsoft.com/en-us/nuget/reference/msbuild-targets#restoring-packagereference-and-packagesconfig-projects-with-msbuild.
+    -->
+    <Warning Condition ="'$(RestorePackagesConfig)' == 'true' OR '$(RestoreProjectStyle)' == 'PackagesConfig'" Text="The MVVM Toolkit source generators might not be loaded correctly, as the current project is using the packages.config setup to restore NuGet packages. Source generators require PackageReference to be used (either in a legacy-style or SDK-style .csproj project, both are supported as long as PackageReference is used)."/>
+  </Target>
+
 </Project>
\ No newline at end of file

From 9a671aa8fc2cf4a1e01018434a0792dae7d92946 Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Sun, 14 May 2023 18:34:04 +0200
Subject: [PATCH 2/4] Add error code and help link for .targets warnings

---
 .../CommunityToolkit.Mvvm.targets                      | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets b/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets
index d481f5efe..d90ab9d8f 100644
--- a/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets
+++ b/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets
@@ -54,7 +54,10 @@
       emitting this manually lets us customize the message to inform developers as to why exactly the generators have been
       disabled, and that the rest of the MVVM Toolkit will still keep working as intended, just without additional features.
     -->
-    <Warning Condition ="'$(MVVMToolkitCurrentCompilerVersionIsNotNewEnough)' == 'true'" Text="The MVVM Toolkit source generators have been disabled on the current configuration, as they need Roslyn 4.x in order to work. The MVVM Toolkit will work just fine, but features relying on the source generators will not be available."/>
+    <Warning Condition ="'$(MVVMToolkitCurrentCompilerVersionIsNotNewEnough)' == 'true'"
+             Code="MVVMTKCFG0001"
+             HelpLink="https://aka.ms/mvvmtoolkit/errors/mvvmtkcfg0001"
+             Text="The MVVM Toolkit source generators have been disabled on the current configuration, as they need Roslyn 4.x in order to work. The MVVM Toolkit will work just fine, but features relying on the source generators will not be available."/>
   
     <PropertyGroup>
 
@@ -109,7 +112,10 @@
       This happens when either the project style is using packages.config, or when explicitly requested.
       See https://learn.microsoft.com/en-us/nuget/reference/msbuild-targets#restoring-packagereference-and-packagesconfig-projects-with-msbuild.
     -->
-    <Warning Condition ="'$(RestorePackagesConfig)' == 'true' OR '$(RestoreProjectStyle)' == 'PackagesConfig'" Text="The MVVM Toolkit source generators might not be loaded correctly, as the current project is using the packages.config setup to restore NuGet packages. Source generators require PackageReference to be used (either in a legacy-style or SDK-style .csproj project, both are supported as long as PackageReference is used)."/>
+    <Warning Condition ="'$(RestorePackagesConfig)' == 'true' OR '$(RestoreProjectStyle)' == 'PackagesConfig'"
+             Code="MVVMTKCFG0002"
+             HelpLink="https://aka.ms/mvvmtoolkit/errors/mvvmtkcfg0002"
+             Text="The MVVM Toolkit source generators might not be loaded correctly, as the current project is using the packages.config setup to restore NuGet packages. Source generators require PackageReference to be used (either in a legacy-style or SDK-style .csproj project, both are supported as long as PackageReference is used)."/>
   </Target>
 
 </Project>
\ No newline at end of file

From 14b7672d20557ac5036251ae1c57f2ae571e312a Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Sun, 14 May 2023 19:51:47 +0200
Subject: [PATCH 3/4] Manually look for a packages.config file in builds

---
 .../CommunityToolkit.Mvvm.targets             | 28 +++++++++++++++++--
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets b/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets
index d90ab9d8f..b135d50d3 100644
--- a/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets
+++ b/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets
@@ -106,13 +106,35 @@
   <Target Name="MVVMToolkitWarnForPackagesConfigUse"
           AfterTargets="ResolvePackageDependenciesForBuild;ResolveNuGetPackageAssets"
           DependsOnTargets="MVVMToolkitGatherAnalyzers">
-
+    
     <!--
-      Emit a warning in case packages.config is used, by reading the associated MSBuild property.
+      Check whether packages are being restored via packages.config, by reading the associated MSBuild property.
       This happens when either the project style is using packages.config, or when explicitly requested.
       See https://learn.microsoft.com/en-us/nuget/reference/msbuild-targets#restoring-packagereference-and-packagesconfig-projects-with-msbuild.
     -->
-    <Warning Condition ="'$(RestorePackagesConfig)' == 'true' OR '$(RestoreProjectStyle)' == 'PackagesConfig'"
+    <PropertyGroup>
+      <MVVMToolkitIsTargetProjectUsingPackagesConfig Condition ="'$(RestorePackagesConfig)' == 'true' OR '$(RestoreProjectStyle)' == 'PackagesConfig'">true</MVVMToolkitIsTargetProjectUsingPackagesConfig>
+    </PropertyGroup>
+
+    <!--
+      If no packages.config properties are set, also try to manually find the packages.config file.
+      This will be in the @(None) elements, if present. Doing so makes sure this works in builds as
+      well, since the implicit targets populating the properties above only run when restoring.
+    -->
+    <FindInList ItemSpecToFind="packages.config"
+                List="@(None)"
+                MatchFileNameOnly="false"
+                Condition="'$(MVVMToolkitIsTargetProjectUsingPackagesConfig)' != 'true'">
+      <Output TaskParameter="ItemFound" PropertyName="MVVMToolkitPackagesConfigFile"/>
+    </FindInList>
+
+    <!-- Make sure to update the MSBuild property if the above task did find something -->
+    <PropertyGroup>
+      <MVVMToolkitIsTargetProjectUsingPackagesConfig Condition ="'$(MVVMToolkitPackagesConfigFile)' == 'packages.config'">true</MVVMToolkitIsTargetProjectUsingPackagesConfig>
+    </PropertyGroup>
+
+    <!-- Emit a warning in case packages.config is used -->
+    <Warning Condition ="'$(MVVMToolkitIsTargetProjectUsingPackagesConfig)' == 'true'"
              Code="MVVMTKCFG0002"
              HelpLink="https://aka.ms/mvvmtoolkit/errors/mvvmtkcfg0002"
              Text="The MVVM Toolkit source generators might not be loaded correctly, as the current project is using the packages.config setup to restore NuGet packages. Source generators require PackageReference to be used (either in a legacy-style or SDK-style .csproj project, both are supported as long as PackageReference is used)."/>

From 0071d6a912689dbc322b97809b8d7c74eb7febca Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Sun, 14 May 2023 21:01:48 +0200
Subject: [PATCH 4/4] Skip checking for packages.config in SDK-style projects

---
 .../CommunityToolkit.Mvvm.targets                    | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets b/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets
index b135d50d3..aa4b8966f 100644
--- a/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets
+++ b/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.targets
@@ -102,15 +102,19 @@
     </ItemGroup>
   </Target>
 
-  <!-- Remove the analyzer if packages.config is used -->
+  <!--
+    Inform the user if packages.config is used (as the analyzers and the source generators
+    won't work at all). Since packages.config can only be used with legacy-style projects,
+    the entire package can be skipped if an SDK-style project is used.
+  -->
   <Target Name="MVVMToolkitWarnForPackagesConfigUse"
           AfterTargets="ResolvePackageDependenciesForBuild;ResolveNuGetPackageAssets"
-          DependsOnTargets="MVVMToolkitGatherAnalyzers">
+          Condition="'$(UsingMicrosoftNetSDK)' != 'true'">
     
     <!--
       Check whether packages are being restored via packages.config, by reading the associated MSBuild property.
       This happens when either the project style is using packages.config, or when explicitly requested.
-      See https://learn.microsoft.com/en-us/nuget/reference/msbuild-targets#restoring-packagereference-and-packagesconfig-projects-with-msbuild.
+      See https://learn.microsoft.com/nuget/reference/msbuild-targets#restoring-packagereference-and-packagesconfig-projects-with-msbuild.
     -->
     <PropertyGroup>
       <MVVMToolkitIsTargetProjectUsingPackagesConfig Condition ="'$(RestorePackagesConfig)' == 'true' OR '$(RestoreProjectStyle)' == 'PackagesConfig'">true</MVVMToolkitIsTargetProjectUsingPackagesConfig>
@@ -120,6 +124,8 @@
       If no packages.config properties are set, also try to manually find the packages.config file.
       This will be in the @(None) elements, if present. Doing so makes sure this works in builds as
       well, since the implicit targets populating the properties above only run when restoring.
+      Since the packages.config file will always be in the root of the project, if present, we will
+      match with the full item spec (see https://learn.microsoft.com/nuget/reference/packages-config).
     -->
     <FindInList ItemSpecToFind="packages.config"
                 List="@(None)"