Fix msbuild.exe on Windows

Author: AArnott

src/Nerdbank.GitVersioning.NuGet/build/Nerdbank.GitVersioning.targets

@@ -32,7 +32,9 @@
     <GenerateAssemblyVersionAttribute>false</GenerateAssemblyVersionAttribute>
     <GenerateAssemblyFileVersionAttribute>false</GenerateAssemblyFileVersionAttribute>
 
-    <NerdbankGitVersioningTasksPath Condition=" '$(NerdbankGitVersioningTasksPath)' == '' ">$(MSBuildThisFileDirectory)</NerdbankGitVersioningTasksPath>
+    <_NBGV_PlatformSuffix Condition=" '$(_NBGV_PlatformSuffix)' == '' and '$(MSBuildRuntimeType)' == 'Core' ">MSBuildCore/</_NBGV_PlatformSuffix>
+    <_NBGV_PlatformSuffix Condition=" '$(_NBGV_PlatformSuffix)' == '' ">MSBuildFull/</_NBGV_PlatformSuffix>
+    <NerdbankGitVersioningTasksPath Condition=" '$(NerdbankGitVersioningTasksPath)' == '' ">$(MSBuildThisFileDirectory)$(_NBGV_PlatformSuffix)</NerdbankGitVersioningTasksPath>
   </PropertyGroup>
 
   <UsingTask AssemblyFile="$(NerdbankGitVersioningTasksPath)Nerdbank.GitVersioning.Tasks.dll" TaskName="Nerdbank.GitVersioning.Tasks.AssemblyVersionInfo"/>
@@ -52,7 +54,7 @@
       BuildMetadata="@(BuildMetadata)"
       DefaultPublicRelease="$(PublicRelease)"
       GitRepoRoot="$(GitRepoRoot)"
-      TaskAssemblyPath="$(NerdbankGitVersioningTasksPath)">
+      TargetsPath="$(MSBuildThisFileDirectory)">
 
       <Output TaskParameter="Version" PropertyName="BuildVersion" />
       <Output TaskParameter="AssemblyInformationalVersion" PropertyName="AssemblyInformationalVersion" />

src/Nerdbank.GitVersioning.Tasks/GetBuildVersion.cs

@@ -15,12 +15,10 @@
 
     public class GetBuildVersion : Task
     {
-#if !NET45
         /// <summary>
         /// An AppDomain-wide variable used on 
         /// </summary>
         private static bool libgit2PathInitialized;
-#endif
 
         /// <summary>
         /// Initializes a new instance of the <see cref="GetBuildVersion"/> class.
@@ -52,13 +50,14 @@ public GetBuildVersion()
         public string GitRepoRoot { get; set; }
 
         /// <summary>
-        /// Gets or sets the path to the folder that contains this task's assembly.
+        /// Gets or sets the path to the folder that contains the NB.GV .targets file.
         /// </summary>
         /// <remarks>
         /// This is particularly useful in .NET Core where discovering one's own assembly path
         /// is not allowed before .NETStandard 2.0.
         /// </remarks>
-        public string TaskAssemblyPath { get; set; }
+        [Required]
+        public string TargetsPath { get; set; }
 
         /// <summary>
         /// Gets or sets a value indicating whether the project is building
@@ -163,10 +162,7 @@ public override bool Execute()
         {
             try
             {
-                if (!this.HelpFindLibGit2NativeBinaries())
-                {
-                    return false;
-                }
+                this.HelpFindLibGit2NativeBinaries();
 
                 var cloudBuild = CloudBuild.Active;
                 var oracle = VersionOracle.Create(Directory.GetCurrentDirectory(), this.GitRepoRoot, cloudBuild);
@@ -213,24 +209,25 @@ public override bool Execute()
             return true;
         }
 
-        private bool HelpFindLibGit2NativeBinaries()
+        private void HelpFindLibGit2NativeBinaries()
         {
-#if !NET45
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && !libgit2PathInitialized)
+            if (!libgit2PathInitialized)
             {
-                if (string.IsNullOrWhiteSpace(this.TaskAssemblyPath))
+                string nativeDllPath = null;
+#if !NET45
+                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+#endif
                 {
-                    this.Log.LogError("The TaskAssemblyPath parameter is required on .NET Core running on Windows.");
-                    return false;
+                    nativeDllPath = Path.Combine(this.TargetsPath, "lib", "win32", IntPtr.Size == 4 ? "x86" : "x64");
+                }
+
+                if (nativeDllPath != null)
+                {
+                    Environment.SetEnvironmentVariable("PATH", Environment.GetEnvironmentVariable("PATH") + Path.PathSeparator + nativeDllPath);
                 }
 
-                string nativeDllPath = Path.Combine(this.TaskAssemblyPath, "lib", "win32", IntPtr.Size == 4 ? "x86" : "x64");
-                Environment.SetEnvironmentVariable("PATH", Environment.GetEnvironmentVariable("PATH") + Path.PathSeparator + nativeDllPath);
                 libgit2PathInitialized = true;
             }
-#endif
-
-            return true;
         }
     }
 }