Improve automatic restore support in SDK mode

.github/workflows/demos.yml

@@ -40,6 +40,13 @@ jobs:
           $version = gci bin | select -first 1 -expandproperty BaseName | %{ $_.Substring(11) }
           pushd src/Demo
           jq --arg version "$version" '.["msbuild-sdks"].SmallSharp = $version' global.json > temp.json && mv temp.json global.json
+
           # build with each top-level file as the active one
-          gci *.cs | %{ dotnet build -p:ActiveFile=$_.name }
+          foreach ($file in gci *.cs) {
+            dotnet build -p:ActiveFile=$($file.Name)
+            if ($LASTEXITCODE -ne 0) {
+              Write-Error "Build failed for $($file.Name)"
+              exit $LASTEXITCODE
+            }
+          }
 

.netconfig

@@ -91,9 +91,7 @@
 	sha = 4339749ef4b8f66def75931df09ef99c149f8421
 [file "src/kzu.snk"]
 	url = https://github.com/devlooped/oss/blob/main/src/kzu.snk
-	etag = b8d789b5b6bea017cdcc8badcea888ad78de3e34298efca922054e9fb0e7b6b9
-	weak
-	sha = 0683ee777d7d878d4bf013d7deea352685135a05
+	skip
 [file ".github/workflows/pages.yml"]
 	url = https://github.com/clarius/pages/blob/main/.github/workflows/pages.yml
 	etag = c52b3f0463b88abf696ddf2c6902675e0bc9d1e812bb317cb758221d75330b56

readme.md

@@ -62,7 +62,7 @@ modify any of the others since they automatically become *None* items.
 
 > [!TIP]
 > An initial build after selection change migh be needed to restore the packages and compile the 
-> selected file
+> selected file, unless you're using the SDK mode for SmallSharp (see below).
 
 All compile files directly under the project directory root are considered top-level programs for 
 selection and compilation purposes. If you need to share code among them, you can place additional 
@@ -93,10 +93,16 @@ and adding a couple extra properties to the project file:
 </Project>
 ```
 
-If your file-based apps use the `#:sdk` [directive](https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/preprocessor-directives#file-based-apps), 
-you need to add SmallSharp as an SDK reference instead so the SDK is picked up by the 
-generated targets/props instead of the project file. You also don't need the additional 
-properties since the SDK mode sets them automatically for you: 
+There are some limitations with this mode, however: 
+* You cannot use the `#:sdk` [directive](https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/preprocessor-directives#file-based-apps) 
+  to specify a different SDK per file, since the project file already specifies one.
+* CLI-based builds may require multiple passes to restore and build the selected file, since 
+  the package is only restored after the first build.
+* You must add ImportProjectExtensionProps/ImportProjectExtensionTargets manually, polluting the 
+  project file.
+
+So the recommended way to use SmallSharp is via the SDK mode, which results in a more streamlined 
+and seamless experience across IDE and CLI builds:
 
 ```xml
 <Project Sdk="SmallSharp/2.1.0">
@@ -109,6 +115,9 @@ properties since the SDK mode sets them automatically for you:
 </Project>
 ```
 
+The SDK mode will always produce a successful build in a single `dotnet build` pass even if you 
+change the `ActiveFile` between builds.
+
 > [!IMPORTANT]
 > If no `#:sdk` directive is provided by a specific C# file-based app, the `Microsoft.NET.SDK` will be 
 > used by default in this SDK mode.
@@ -157,19 +166,6 @@ since the "Main" file selection is performed exclusively via MSBuild item manipu
 > SDK reference, and do all project/package references in the top-level files using the `#:package` and 
 > `#:property` directives for improved isolation between the different file-based apps.
 
-```xml
-<Project Sdk="Microsoft.NET.Sdk">
-
-  <Sdk Name="SmallSharp" Version="2.0.0" />
-
-  <PropertyGroup>
-    <OutputType>Exe</OutputType>
-    <TargetFramework>net10.0</TargetFramework>
-  </PropertyGroup>
-
-</Project>
-```
-
 ![run humanizer file](https://raw.githubusercontent.com/devlooped/SmallSharp/main/assets/img/runfile1.png)
 
 ![run mcp file](https://raw.githubusercontent.com/devlooped/SmallSharp/main/assets/img/runfile2.png)

src/Demo/.gitignore

@@ -0,0 +1 @@
+Demo.sln

src/Demo/Demo.csproj

@@ -1,6 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
-
-  <Sdk Name="SmallSharp" />
+<Project Sdk="SmallSharp">
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>

src/Demo/global.json

@@ -1,5 +1,5 @@
 {
   "msbuild-sdks": {
-    "SmallSharp": "2.0.0"
+    "SmallSharp": "42.537.1166"
   }
-}
+}

src/Demo/nuget.config

@@ -2,7 +2,7 @@
 <configuration>
   <packageSources>
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
-    <add key="kzu" value="https://api.kzu.app/index.json" />
+    <add key="kzu" value="https://pkg.kzu.app/index.json" />
     <add key="local" value="../../bin/" />
   </packageSources>
   <activePackageSource>

src/SmallSharp/EmitTargets.cs

@@ -1,11 +1,13 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Text.RegularExpressions;
 using System.Xml;
 using System.Xml.Linq;
 using Microsoft.Build.Framework;
 using Microsoft.Build.Utilities;
+using static SmallSharp.TaskItemFactory;
 
 namespace SmallSharp;
 
@@ -28,7 +30,9 @@ public class EmitTargets : Task
     public required string TargetsFile { get; set; }
 
     [Required]
-    public bool UsingSmallSharpSDK { get; set; } = false;
+    public required bool UsingSDK { get; set; }
+
+    public ITaskItem[] PackageReferences { get; set; } = [];
 
     [Output]
     public ITaskItem[] Packages { get; set; } = [];
@@ -40,7 +44,7 @@ public class EmitTargets : Task
     public ITaskItem[] Properties { get; set; } = [];
 
     [Output]
-    public bool Success { get; set; } = false;
+    public bool RestoreNeeded { get; set; } = false;
 
     public override bool Execute()
     {
@@ -65,10 +69,7 @@ public override bool Execute()
                 var id = match.Groups[1].Value.Trim();
                 var version = match.Groups[2].Value.Trim();
 
-                packages.Add(new TaskItem(id, new Dictionary<string, string>
-                {
-                    { "Version", version }
-                }));
+                packages.Add(NewTaskItem(id, [("Version", version)]));
 
                 items.Add(new XElement("PackageReference",
                     new XAttribute("Include", id),
@@ -80,10 +81,7 @@ public override bool Execute()
                 var version = sdkMatch.Groups[2].Value.Trim();
                 if (!string.IsNullOrEmpty(version))
                 {
-                    sdkItems.Add(new TaskItem(name, new Dictionary<string, string>
-                    {
-                        { "Version", version }
-                    }));
+                    sdkItems.Add(NewTaskItem(name, [("Version", version)]));
                     sdks.Add([new XAttribute("Sdk", name), new XAttribute("Version", version)]);
                 }
                 else
@@ -97,10 +95,7 @@ public override bool Execute()
                 var name = propMatch.Groups[1].Value.Trim();
                 var value = propMatch.Groups[2].Value.Trim();
 
-                propItems.Add(new TaskItem(name, new Dictionary<string, string>
-                {
-                    { "Value", value }
-                }));
+                propItems.Add(NewTaskItem(name, [("Value", value)]));
                 properties.Add(new XElement(name, value));
             }
         }
@@ -109,20 +104,15 @@ public override bool Execute()
         Sdks = [.. sdkItems];
         Properties = [.. propItems];
 
-        if (sdks.Count > 0 && !UsingSmallSharpSDK)
-        {
-            Log.LogError($"When using #:sdk directive(s), you must use SmallSharp as an SDK: <Project Sdk=\"SmallSharp/{ThisAssembly.Project.Version}\">.");
-            return false;
-        }
-
         // We only emit the default SDK if the SmallSharpSDK is in use, since otherwise the 
         // project file is expected to define its own SDK and we'd be duplicating it.
         if (sdks.Count == 0)
             sdks.Add([new XAttribute("Sdk", "Microsoft.NET.Sdk")]);
 
         WriteXml(TargetsFile, new XElement("Project",
             new XElement("PropertyGroup", properties),
-            new XElement("ItemGroup", items)
+            // don't emit package references in SDK mode, since we'll add them from the SDK targets.
+            UsingSDK ? new XElement("ItemGroup") : new XElement("ItemGroup", items)
         ));
 
         WriteXml(Path.Combine(BaseIntermediateOutputPath, "SmallSharp.sdk.props"), new XElement("Project",
@@ -131,14 +121,35 @@ public override bool Execute()
         WriteXml(Path.Combine(BaseIntermediateOutputPath, "SmallSharp.sdk.targets"), new XElement("Project",
             sdks.Select(x => new XElement("Import", [new XAttribute("Project", "Sdk.targets"), .. x]))));
 
-        WriteXml(PropsFile, new XElement("Project"));
+        WriteXml(PropsFile, new XElement("Project",
+            new XElement("PropertyGroup",
+                [new XElement("SmallSharpProjectExtensionPropsImported", "true")])));
+
+        // Determine if a restore is needed: if any discovered #:package (id+version) is not already
+        // present in the incoming PackageReferences list.
+        foreach (var pkg in packages)
+        {
+            var id = pkg.ItemSpec;
+            var version = pkg.GetMetadata("Version");
+            var exists = PackageReferences?.Any(r =>
+                string.Equals(r.ItemSpec, id, StringComparison.OrdinalIgnoreCase) &&
+                string.Equals(r.GetMetadata("Version"), version, StringComparison.OrdinalIgnoreCase)) == true;
+
+            if (!exists)
+            {
+                RestoreNeeded = true;
+                break;
+            }
+        }
 
-        Success = true;
         return true;
     }
 
     void WriteXml(string path, XElement root)
     {
+        if (Path.GetDirectoryName(path) is { } dir)
+            Directory.CreateDirectory(dir);
+
         using var writer = XmlWriter.Create(path, new XmlWriterSettings { Indent = true });
         root.Save(writer);
     }

src/SmallSharp/Sdk.props

@@ -14,7 +14,7 @@
   <!-- Import Common.props explicitly we're too early here to use MSBuildProjectExtensionsPath -->
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="'$(MicrosoftCommonPropsHasBeenImported)' != 'true' and Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
 
-  <Import Project="Sdk.props" Sdk="Microsoft.NET.SDK"
+  <Import Project="Sdk.props" Sdk="Microsoft.NET.Sdk"
        Condition="!Exists('$(MSBuildProjectExtensionsPath)SmallSharp.sdks.props')" />
 
   <Import Project="$(MSBuildProjectExtensionsPath)SmallSharp.sdks.props" 

src/SmallSharp/Sdk.targets

@@ -1,16 +1,17 @@
 <Project>
 
-  <Import Project="Sdk.targets" Sdk="Microsoft.NET.SDK"
+  <Import Project="Sdk.targets" Sdk="Microsoft.NET.Sdk"
        Condition="!Exists('$(MSBuildProjectExtensionsPath)SmallSharp.sdks.targets')" />
 
   <Import Project="$(MSBuildProjectExtensionsPath)SmallSharp.sdks.targets"
        Condition="Exists('$(MSBuildProjectExtensionsPath)SmallSharp.sdks.targets')" />
 
   <Import Project="..\build\SmallSharp.targets" />
 
-  <Target Name="ImplicitPackageReferenceFromStartupFile" BeforeTargets="_GenerateProjectRestoreGraphPerFramework"
+  <Target Name="ImplicitPackageReferenceFromStartupFile" 
+          BeforeTargets="_GenerateProjectRestoreGraphPerFramework;ResolvePackageAssets;CompileDesignTime;CollectUpToDateCheckInputDesignTime"
           DependsOnTargets="StartupFile"
-          Condition="'$(StartupFile)' != '' and Exists('$(StartupFile)') and '$(RestoreNeeded)' == 'true'" >
+          Condition="'$(StartupFile)' != '' and Exists('$(StartupFile)')">
 
     <!-- Optimize for restore success on first run without previously running our targets -->
     <ReadLinesFromFile File="$(StartupFile)">

src/SmallSharp/SmallSharp.Version.props

@@ -0,0 +1,5 @@
+<Project>
+  <PropertyGroup>
+    <SmallSharpVersion>42.42.42</SmallSharpVersion>
+  </PropertyGroup>  
+</Project>

src/SmallSharp/SmallSharp.csproj

@@ -34,6 +34,8 @@
 
   <ItemGroup>
     <None Include="..\_._" PackFolder="lib\netstandard2.0" Visible="false" />
+    <None Update="SmallSharp.props" PackFolder="$(PackFolder)" CopyToOutputDirectory="PreserveNewest" />
+    <None Update="SmallSharp.Version.props" PackFolder="$(PackFolder)" CopyToOutputDirectory="PreserveNewest" />
     <None Update="SmallSharp.targets" PackFolder="$(PackFolder)" CopyToOutputDirectory="PreserveNewest" />
     <None Update="SmallSharp.Before.targets" PackFolder="$(PackFolder)" CopyToOutputDirectory="PreserveNewest" />
     <None Update="Sdk.*" PackFolder="Sdk" CopyToOutputDirectory="PreserveNewest" />
@@ -46,4 +48,11 @@
     <ProjectProperty Include="PackageVersion" />
   </ItemGroup>
 
+  <Target Name="UpdatePackagingVersion" BeforeTargets="Pack">
+    <!-- Update packaging version targets -->
+    <XmlPoke XmlInputPath="$(OutputPath)SmallSharp.Version.props"
+				 Query="/Project/PropertyGroup/SmallSharpVersion"
+				 Value="$(Version)"/>
+  </Target>
+
 </Project>

src/SmallSharp/SmallSharp.props

@@ -10,4 +10,6 @@
     <UsingSmallSharpSDK Condition="'$(UsingSmallSharpSDK)' == ''">false</UsingSmallSharpSDK>
   </PropertyGroup>
 
+  <Import Project="SmallSharp.Version.props"/>
+
 </Project>

src/SmallSharp/SmallSharp.targets

@@ -37,10 +37,12 @@
   <Target Name="StartupFile" BeforeTargets="ResolvePackageAssets;CompileDesignTime;CollectUpToDateCheckInputDesignTime" DependsOnTargets="$(StartupFileDependsOn)" />
 
   <Target Name="EnsureProperties" Condition="'$(CheckSmallSharpRequirements)' != 'false'">
-    <Error Code="SCS01" Condition="'$(_ImportProjectExtensionProps)' != 'true' or '$(_ImportProjectExtensionTargets)' != 'true'"
+    <Error Code="SCS02" Condition="'$(_ImportProjectExtensionProps)' != 'true' or '$(_ImportProjectExtensionTargets)' != 'true'"
            Text="Setting ImportProjectExtensionProps and ImportProjectExtensionTargets project properties to 'true' is required by SmallSharp to support C# package and project directives." />
-    <Error Code="SCS02" Condition="'$(ManagePackageVersionsCentrally)' == 'true'" 
+    <Error Code="SCS03" Condition="'$(ManagePackageVersionsCentrally)' == 'true'" 
            Text="Setting ManagePackageVersionsCentrally to 'true' is not supported by SmallSharp since C# program files can declare package references via #:package directives." />
+    <Warning Code="SCS04" Condition="'$(UsingSmallSharpSDK)' != 'true'"
+             Text='For maximum compatibility with file-based apps, use SmallSharp as an SDK instead of a package reference: &lt;Project Sdk="SmallSharp/$(SmallSharpVersion)"&gt;' />
   </Target>
 
   <Target Name="CollectStartupFile">
@@ -166,38 +168,19 @@
   <Target Name="EmitTargets" DependsOnTargets="CollectStartupFile;SelectTopLevelCompile;SelectStartupFile" 
           Inputs="@(Compile);$(ActiveDebugProfile);$(ActiveFile);Properties\launchSettings.json" 
           Outputs="$(SmallSharpPackagesProps);$(SmallSharpPackagesTargets)">
-    <EmitTargets StartupFile="$(StartupFile)"
+    <EmitTargets StartupFile="$(StartupFile)" 
+                 UsingSDK="$(UsingSmallSharpSDK)"
+                 PackageReferences="@(PackageReferences)"
                  PropsFile="$(SmallSharpPackagesProps)"
                  TargetsFile="$(SmallSharpPackagesTargets)"
-                 UsingSmallSharpSDK="$(UsingSmallSharpSDK)"
                  BaseIntermediateOutputPath="$(BaseIntermediateOutputPath)">
       <Output TaskParameter="Packages" ItemName="FileBasedPackage" />
       <Output TaskParameter="Properties" PropertyName="FileBasedProperty" />
       <Output TaskParameter="Sdks" PropertyName="FileBasedSdk" />
-      <Output TaskParameter="Success" PropertyName="RestoreNeeded" />
+      <Output TaskParameter="RestoreNeeded" PropertyName="RestoreNeeded" />
     </EmitTargets>
-  </Target>
-
-  <Target Name="RestoreBeforeBuild" BeforeTargets="ResolvePackageAssets" DependsOnTargets="EmitTargets" 
-          Condition="'$(RestoreNeeded)' == 'true' and '$(DesignTimeBuild)' != 'true' and '$(UsingSmallSharpSDK)' != 'true'">
-
-    <PropertyGroup>
-      <DynamicProjectAssetsFile>$(MSBuildProjectExtensionsPath)smallsharp.assets.json</DynamicProjectAssetsFile>
-    </PropertyGroup>
-
-    <MSBuild
-        Projects="$(MSBuildProjectFullPath)"
-        Targets="Restore"
-        BuildInParallel="false"
-        Properties="RestoreUseStaticGraphEvaluation=false;ImportProjectExtensionProps=true;ImportProjectExtensionTargets=true;Guid=$([System.Guid]::NewGuid().ToString())">
-    </MSBuild>
-
-    <Copy SourceFiles="$(ProjectAssetsFile)" DestinationFiles="$(DynamicProjectAssetsFile)" />
-
-    <PropertyGroup>
-      <ProjectAssetsFile>$(DynamicProjectAssetsFile)</ProjectAssetsFile>
-    </PropertyGroup>
-
+    <Error Code="SCS001" Condition="'@(FileBasedSdk)' != '' and '$(UsingSmallSharpSDK)' != 'true'"
+           Text="Using #:sdk directives requires using SmallSharp as an SDK instead of a package reference: &lt;Project Sdk='SmallSharp/$(SmallSharpVersion)'&gt;" />
   </Target>
 
   <UsingTask TaskName="SortItems" TaskFactory="RoslynCodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.Core.dll">

src/SmallSharp/TaskItemFactory.cs

@@ -0,0 +1,13 @@
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.Build.Utilities;
+
+namespace SmallSharp;
+
+static class TaskItemFactory
+{
+    public static TaskItem NewTaskItem(string itemSpec, Dictionary<string, string> metadata) => new(itemSpec, metadata);
+
+    public static TaskItem NewTaskItem(string itemSpec, params (string Key, string Value)[] metadata)
+        => new(itemSpec, metadata.ToDictionary(x => x.Key, x => x.Value));
+}