From fad7d2f5a4590c91b49115fcb68e119b60bf71bf Mon Sep 17 00:00:00 2001
From: Nate McMaster <nate.mcmaster@gmail.com>
Date: Sat, 20 Oct 2018 16:49:00 -0700
Subject: [PATCH] Fix #12 - Give base-path the lowest precedence when searching
 for managed libraries

This fixes assembly loading for System.Drawing.Common. This package was a rare case of a package with both runtime agnostic and runtime-specific versions of the managed library. This means the .NET Core SDK will dump System.Drawing.Common.dll in the plugin base path *as well as* a version in the runtimes/ folder. In this case, corehost actually treats the runtime specific asset with higher priority.

This change updates the ManagedLoadContext to imitate this behavior.
---
 .appveyor.yml                                 |  2 +-
 .vscode/launch.json                           | 11 +++++++++
 Directory.Build.props                         |  2 +-
 DotNetCorePlugins.sln                         | 15 ++++++++++++
 releasenotes.props                            |  6 +++++
 src/Plugins/Loader/ManagedLoadContext.cs      | 24 +++++++++----------
 .../Plugins.Tests/BasicAssemblyLoaderTests.cs | 19 ++++++++++++++-
 .../McMaster.NETCore.Plugins.Tests.csproj     |  1 +
 .../TestProjects/DrawingApp/DrawingApp.csproj | 11 +++++++++
 test/TestProjects/DrawingApp/Finder.cs        | 11 +++++++++
 10 files changed, 87 insertions(+), 15 deletions(-)
 create mode 100644 .vscode/launch.json
 create mode 100644 test/TestProjects/DrawingApp/DrawingApp.csproj
 create mode 100644 test/TestProjects/DrawingApp/Finder.cs

diff --git a/.appveyor.yml b/.appveyor.yml
index 555aa1f..169d7fb 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -1,4 +1,4 @@
-version: 0.2.0.{build}
+version: 0.2.1.{build}
 build_script:
   - ps: .\build.ps1 -ci
 environment:
diff --git a/.vscode/launch.json b/.vscode/launch.json
new file mode 100644
index 0000000..396e7ed
--- /dev/null
+++ b/.vscode/launch.json
@@ -0,0 +1,11 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": ".NET Core Attach",
+      "type": "coreclr",
+      "request": "attach",
+      "processId": "${command:pickProcess}"
+    }
+  ]
+}
diff --git a/Directory.Build.props b/Directory.Build.props
index a43912b..5bce517 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -26,7 +26,7 @@
     <NoWarn>$(NoWarn);NU5105</NoWarn>
 
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
-    <GenerateFullPaths Condition="'$(VSCODE_PID)' != ''">true</GenerateFullPaths>
+    <GenerateFullPaths Condition="'$(VSCODE_CWD)' != ''">true</GenerateFullPaths>
     <BaseIntermediateOutputPath>$(MSBuildThisFileDirectory).build\obj\$(MSBuildProjectName)\</BaseIntermediateOutputPath>
     <BaseOutputPath>$(MSBuildThisFileDirectory).build\bin\$(MSBuildProjectName)\</BaseOutputPath>
   </PropertyGroup>
diff --git a/DotNetCorePlugins.sln b/DotNetCorePlugins.sln
index e5b19da..1c5a9c8 100644
--- a/DotNetCorePlugins.sln
+++ b/DotNetCorePlugins.sln
@@ -57,6 +57,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Plátano", "test\TestProjects\Plátano\Plátano.csproj", "{5889B0C9-50E5-4FDC-933B-8684B9FAB8E4}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DrawingApp", "test\TestProjects\DrawingApp\DrawingApp.csproj", "{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -247,6 +249,18 @@ Global
 		{5889B0C9-50E5-4FDC-933B-8684B9FAB8E4}.Release|x64.Build.0 = Release|Any CPU
 		{5889B0C9-50E5-4FDC-933B-8684B9FAB8E4}.Release|x86.ActiveCfg = Release|Any CPU
 		{5889B0C9-50E5-4FDC-933B-8684B9FAB8E4}.Release|x86.Build.0 = Release|Any CPU
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}.Debug|x64.Build.0 = Debug|Any CPU
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}.Debug|x86.Build.0 = Debug|Any CPU
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}.Release|x64.ActiveCfg = Release|Any CPU
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}.Release|x64.Build.0 = Release|Any CPU
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}.Release|x86.ActiveCfg = Release|Any CPU
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -268,6 +282,7 @@ Global
 		{78D2B20D-B173-4CF2-A763-F2AA5347947E} = {98E964A2-55DA-4740-9F2E-B64FDF6715DB}
 		{C0BA460C-C1AC-4C54-9C88-60E4B8681E94} = {98E964A2-55DA-4740-9F2E-B64FDF6715DB}
 		{5889B0C9-50E5-4FDC-933B-8684B9FAB8E4} = {98E964A2-55DA-4740-9F2E-B64FDF6715DB}
+		{8BE0F92F-F353-4D63-9C6F-50D4A0BB7FAB} = {98E964A2-55DA-4740-9F2E-B64FDF6715DB}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {B1AF41DC-A03E-47B1-BBDB-3DC27ABD9F74}
diff --git a/releasenotes.props b/releasenotes.props
index ce47ae9..00882cb 100644
--- a/releasenotes.props
+++ b/releasenotes.props
@@ -1,5 +1,11 @@
 <Project>
   <PropertyGroup>
+    <PackageReleaseNotes Condition="'$(VersionPrefix)' == '0.2.1'">
+      <![CDATA[
+Bug fix:
+* Fix a bug in the loader which causes System.Drawing.Common to load incorrectly. This one is super
+]]>
+    </PackageReleaseNotes>
     <PackageReleaseNotes Condition="'$(VersionPrefix)' == '0.2.0'">
       <![CDATA[
 Enhancements:
diff --git a/src/Plugins/Loader/ManagedLoadContext.cs b/src/Plugins/Loader/ManagedLoadContext.cs
index b469d8b..7673e68 100644
--- a/src/Plugins/Loader/ManagedLoadContext.cs
+++ b/src/Plugins/Loader/ManagedLoadContext.cs
@@ -126,18 +126,7 @@ namespace McMaster.NETCore.Plugins.Loader
 
         private bool SearchForLibrary(ManagedLibrary library, out string path)
         {
-            // 1. Search in base path
-            foreach (var ext in PlatformInformation.ManagedAssemblyExtensions)
-            {
-                var local = Path.Combine(_basePath, library.Name.Name + ext);
-                if (File.Exists(local))
-                {
-                    path = local;
-                    return true;
-                }
-            }
-
-            // 2. Check for in _basePath + app local path
+            // 1. Check for in _basePath + app local path
             var localFile = Path.Combine(_basePath, library.AppLocalPath);
             if (File.Exists(localFile))
             {
@@ -156,6 +145,17 @@ namespace McMaster.NETCore.Plugins.Loader
                 }
             }
 
+            // 3. Search in base path
+            foreach (var ext in PlatformInformation.ManagedAssemblyExtensions)
+            {
+                var local = Path.Combine(_basePath, library.Name.Name + ext);
+                if (File.Exists(local))
+                {
+                    path = local;
+                    return true;
+                }
+            }
+
             path = null;
             return false;
         }
diff --git a/test/Plugins.Tests/BasicAssemblyLoaderTests.cs b/test/Plugins.Tests/BasicAssemblyLoaderTests.cs
index ce0f5e4..9b9aef9 100644
--- a/test/Plugins.Tests/BasicAssemblyLoaderTests.cs
+++ b/test/Plugins.Tests/BasicAssemblyLoaderTests.cs
@@ -49,6 +49,23 @@ namespace McMaster.NETCore.Plugins.Tests
             Assert.Equal("Red", method.Invoke(Activator.CreateInstance(type), Array.Empty<object>()));
         }
 
+        [Fact]
+        public void ItPrefersRuntimeSpecificManagedAssetsOverRidlessOnes()
+        {
+            // System.Drawing.Common is an example of a package which has both rid-specific and ridless versions
+            // The package has lib/netstandard2.0/System.Drawing.Common.dll, but also has runtimes/{win,unix}/lib/netcoreapp2.0/System.Drawing.Common.dll
+            // In this case, the host will pick the rid-specific version
+
+            var path = TestResources.GetTestProjectAssembly("DrawingApp");
+            var loader = PluginLoader.CreateFromConfigFile(path);
+            var assembly = loader.LoadDefaultAssembly();
+
+            var type = assembly.GetType("Finder", throwOnError: true);
+            var method = type.GetMethod("FindDrawingAssembly", BindingFlags.Static | BindingFlags.Public);
+            Assert.NotNull(method);
+            Assert.Contains("runtimes", (string)method.Invoke(null, Array.Empty<object>()));
+        }
+
         [Fact]
         [UseCulture("es")]
         public void ItLoadsSatelliteAssemblies()
@@ -71,7 +88,7 @@ namespace McMaster.NETCore.Plugins.Tests
             var loader = PluginLoader.CreateFromConfigFile(path, sharedTypes: new[] { typeof(IFruit) });
             var assembly = loader.LoadDefaultAssembly();
             var type = Assert.Single(assembly.GetTypes(), t => typeof(IFruit).IsAssignableFrom(t));
-            return (IFruit) Activator.CreateInstance(type);
+            return (IFruit)Activator.CreateInstance(type);
         }
     }
 }
diff --git a/test/Plugins.Tests/McMaster.NETCore.Plugins.Tests.csproj b/test/Plugins.Tests/McMaster.NETCore.Plugins.Tests.csproj
index d99e3dd..e0d0313 100644
--- a/test/Plugins.Tests/McMaster.NETCore.Plugins.Tests.csproj
+++ b/test/Plugins.Tests/McMaster.NETCore.Plugins.Tests.csproj
@@ -15,6 +15,7 @@
     <ProjectReference Include="..\..\src\Plugins\McMaster.NETCore.Plugins.csproj" />
     <ProjectReference Include="..\TestProjects\ReferencedLibv1\ReferencedLibv1.csproj" />
     <TestProject Include="..\TestProjects\ReferencedLibv2\ReferencedLibv2.csproj" />
+    <TestProject Include="..\TestProjects\DrawingApp\DrawingApp.csproj" />
     <TestProject Include="..\TestProjects\NetCoreApp20App\NetCoreApp20App.csproj" />
     <TestProject Include="..\TestProjects\NetStandardClassLib\NetStandardClassLib.csproj" />
     <TestProject Include="..\TestProjects\JsonNet9\JsonNet9.csproj" />
diff --git a/test/TestProjects/DrawingApp/DrawingApp.csproj b/test/TestProjects/DrawingApp/DrawingApp.csproj
new file mode 100644
index 0000000..c2630d3
--- /dev/null
+++ b/test/TestProjects/DrawingApp/DrawingApp.csproj
@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp2.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="System.Drawing.Common" Version="4.5.1" />
+  </ItemGroup>
+
+</Project>
diff --git a/test/TestProjects/DrawingApp/Finder.cs b/test/TestProjects/DrawingApp/Finder.cs
new file mode 100644
index 0000000..0bc0953
--- /dev/null
+++ b/test/TestProjects/DrawingApp/Finder.cs
@@ -0,0 +1,11 @@
+using System.Drawing.Printing;
+
+public class Finder
+{
+    public static string FindDrawingAssembly()
+    {
+        var pd = new PrintDocument();
+        return typeof(PrintDocument).Assembly.CodeBase;
+    }
+}
+