[rel/17.14] Fix setting DOTNET_ROOT (#15252)

nohwnd · web-flow · commit 4ac9f0d4d2df · 2025-08-11T13:46:30.000Z
* Handle dotnet_root in testhost version aware way (#15184) * Handle dotnet_root in testhost version aware way * Fix unit tests * Fixes * Fixes * Fixes * Apply suggestion from @nohwnd * Apply suggestion from @nohwnd * Revert changes to playground * Only apply architecture when it is the same (#15250)
diff --git a/docs/contribute.md b/docs/contribute.md
@@ -147,7 +147,7 @@ default, `Debug` configuration is run.
 If you want to run a particular test. Eg: Test Name that contains Blame in Acceptance test
 
 ```shell
-> test.cmd -p accept -f net451 -filter blame
+> .\test.cmd -bl -c release /p:TestRunnerAdditionalArguments="'--filter Blame'" -Integration
 ```
 
 ## Deployment
diff --git a/playground/TestPlatform.Playground/TestPlatform.Playground.csproj b/playground/TestPlatform.Playground/TestPlatform.Playground.csproj
@@ -56,8 +56,8 @@
 
     <ItemGroup>
       <!-- .NET Framework console -->
-      <FileToCopy Include="$(SourcePath)bin\vstest.console\$(Configuration)\$(NetFrameworkMinimum)\win7-x64\**\*.*" SubFolder="netfx" />
-      <FileToCopy Include="$(SourcePath)bin\Microsoft.TestPlatform.TestHostProvider\$(Configuration)\$(NetFrameworkMinimum)\**\*.*" SubFolder="netfx\Extensions\" />
+      <FileToCopy Include="$(SourcePath)bin\vstest.console\$(Configuration)\$(NetFrameworkRunnerTargetFramework)\win7-x64\**\*.*" SubFolder="netfx" />
+      <FileToCopy Include="$(SourcePath)bin\Microsoft.TestPlatform.TestHostProvider\$(Configuration)\$(NetFrameworkRunnerTargetFramework)\**\*.*" SubFolder="netfx\Extensions\" />
 
       <!-- copy net462, net47, net471, net472, net48 and net481 testhosts -->
       <FileToCopy Include="$(SourcePath)bin\testhost.x86\$(Configuration)\$(NetFrameworkMinimum)\win-x86\**\*.*" SubFolder="netfx\TestHostNetFramework\" />
diff --git a/src/Microsoft.TestPlatform.TestHostProvider/Hosting/DotnetTestHostManager.cs b/src/Microsoft.TestPlatform.TestHostProvider/Hosting/DotnetTestHostManager.cs
@@ -513,23 +513,119 @@ public virtual TestProcessStartInfo GetTestHostProcessStartInfo(
         // i.e. I've got only private install and no global installation, in this case apphost needs to use env var to locate runtime.
         if (testHostExeFound)
         {
-            string prefix = "VSTEST_WINAPPHOST_";
-            string dotnetRootEnvName = $"{prefix}DOTNET_ROOT(x86)";
-            var dotnetRoot = _environmentVariableHelper.GetEnvironmentVariable(dotnetRootEnvName);
-            if (dotnetRoot is null)
+            // This change needs to happen first on vstest side, and then on dotnet/sdk, so prefer this approach and fallback to the old one.
+            // VSTEST_DOTNET_ROOT v2
+            string? dotnetRootPath = _environmentVariableHelper.GetEnvironmentVariable("VSTEST_DOTNET_ROOT_PATH");
+            if (!StringUtils.IsNullOrWhiteSpace(dotnetRootPath))
             {
-                dotnetRootEnvName = $"{prefix}DOTNET_ROOT";
-                dotnetRoot = _environmentVariableHelper.GetEnvironmentVariable(dotnetRootEnvName);
-            }
+                // This is v2 of the environment variables that we are passing, we are in new dotnet sdk. So also grab the architecture.
+                string? dotnetRootArchitecture = _environmentVariableHelper.GetEnvironmentVariable("VSTEST_DOTNET_ROOT_ARCHITECTURE");
 
-            if (dotnetRoot != null)
-            {
-                EqtTrace.Verbose($"DotnetTestHostmanager.LaunchTestHostAsync: Found '{dotnetRootEnvName}' in env variables, value '{dotnetRoot}', forwarding to '{dotnetRootEnvName.Replace(prefix, string.Empty)}'");
-                startInfo.EnvironmentVariables.Add(dotnetRootEnvName.Replace(prefix, string.Empty), dotnetRoot);
+                if (StringUtils.IsNullOrWhiteSpace(dotnetRootArchitecture))
+                {
+                    throw new InvalidOperationException("'VSTEST_DOTNET_ROOT_PATH' and 'VSTEST_DOTNET_ROOT_ARCHITECTURE' must be both always set. If you are seeing this error, this is a bug in dotnet SDK that sets those variables.");
+                }
+
+                EqtTrace.Verbose($"DotnetTestHostmanager.LaunchTestHostAsync: VSTEST_DOTNET_ROOT_PATH={dotnetRootPath}");
+                EqtTrace.Verbose($"DotnetTestHostmanager.LaunchTestHostAsync: VSTEST_DOTNET_ROOT_ARCHITECTURE={dotnetRootArchitecture}");
+
+                // The parent process is passing to us the path in which the dotnet.exe is and is passing the architecture of the dotnet.exe,
+                // so if the child process (testhost) is the same architecture it can pick up that dotnet.exe location and run. This is to allow
+                // local installations of dotnet/sdk to work with testhost.
+                //
+                // There are 2 complications in this process:
+                // 1) There are differences between how .NET Apphosts are handling DOTNET_ROOT, versions pre-net6 are only looking at
+                //    DOTNET_ROOT(x86) and then DOTNET_ROOT. This makes is really easy to set DOTNET_ROOT to point at x64 dotnet installation
+                //    and have that picked up by x86 testhost and fail.
+                //    Unfortunately vstest.console has to support both new (17.14+) testhosts that are built against net8, and old (pre 17.14)
+                //    testhosts that are built using netcoreapp3.1 apphost, and so their approach to resolving DOTNET_ROOT differ.
+                //
+                //    /!\ The apphost version does not align with the targeted framework (tfm), an older testhost is built against netcoreapp3.1
+                //        but can be used to run net8 tests. The only way to tell is the version of the testhost.
+                //
+                //    netcoreapp3.1 hosts only support DOTNET_ROOT and DOTNET_ROOT(x86) env variables.
+                //    net8          hosts, support also DOTNET_ROOT_<ARCH> variables, which is what we should prefer to set the location of dotnet
+                //                  in a more architecture specific way.
+                //
+                // 2) The surrounding environment might already have the environment variables set, most likely by setting DOTNET_ROOT, which is
+                //    a universal way of setting where the dotnet is, that works across all different architectures of the .NET apphost.
+                //    By setting our (hopefully more specific variable) we might overwrite what user specified, and in case of DOTNET_ROOT it is probably
+                //    preferable when we can set the DOTNET_ROOT_<ARCH> variable.
+                var testhostDllPath = Path.ChangeExtension(startInfo.FileName, ".dll");
+                // This file check is for unit tests, we expect the file to always be there. Otherwise testhost.exe would not be able to run.
+                var testhostVersionInfo = _fileHelper.Exists(testhostDllPath) ? FileVersionInfo.GetVersionInfo(testhostDllPath) : null;
+                if (testhostVersionInfo != null && testhostVersionInfo.ProductMajorPart >= 17 && testhostVersionInfo.ProductMinorPart >= 14)
+                {
+                    // This is a new testhost that builds at least against net8 we should set the architecture specific DOTNET_ROOT_<ARCH>.
+                    //
+                    // We ship just testhost.exe and testhost.x86.exe if the architecture is different we won't find the testhost*.exe and
+                    // won't reach this code, but let's write this in a generic way anyway, to avoid breaking if we add more variants of testhost*.exe.
+                    var environmentVariableName = $"DOTNET_ROOT_{_architecture.ToString().ToUpperInvariant()}";
+
+                    var existingDotnetRoot = _environmentVariableHelper.GetEnvironmentVariable(environmentVariableName);
+                    if (!StringUtilities.IsNullOrWhiteSpace(existingDotnetRoot))
+                    {
+                        // The variable is already set in the surrounding environment, don't set it, because we want to keep what user provided.
+                    }
+                    else
+                    {
+                        var architectureFromEnv = (Architecture)Enum.Parse(typeof(Architecture), dotnetRootArchitecture, ignoreCase: true);
+                        if (architectureFromEnv == _architecture)
+                        {
+                            // Set the architecture specific variable to the environment of the process so it is picked up.
+                            startInfo.EnvironmentVariables.Add(environmentVariableName, dotnetRootPath);
+                        }
+                    }
+                }
+                else
+                {
+                    // This is an old testhost that built against netcoreapp3.1, it does not understand architecture specific DOTNET_ROOT_<ARCH>, we have to set it more carefully
+                    // to avoid setting DOTNET_ROOT that points to x64 but is picked up by x86 host.
+                    //
+                    // Also avoid setting it if we are already getting it from the surrounding environment.
+                    var architectureFromEnv = (Architecture)Enum.Parse(typeof(Architecture), dotnetRootArchitecture, ignoreCase: true);
+                    if (architectureFromEnv == _architecture)
+                    {
+                        if (_architecture == Architecture.X86)
+                        {
+                            const string dotnetRootX86 = "DOTNET_ROOT(x86)";
+                            if (StringUtils.IsNullOrWhiteSpace(_environmentVariableHelper.GetEnvironmentVariable(dotnetRootX86)))
+                            {
+                                startInfo.EnvironmentVariables.Add(dotnetRootX86, dotnetRootPath);
+                            }
+                        }
+                        else
+                        {
+                            const string dotnetRoot = "DOTNET_ROOT";
+                            if (StringUtils.IsNullOrWhiteSpace(_environmentVariableHelper.GetEnvironmentVariable(dotnetRoot)))
+                            {
+                                startInfo.EnvironmentVariables.Add(dotnetRoot, dotnetRootPath);
+                            }
+                        }
+                    }
+                }
             }
             else
             {
-                EqtTrace.Verbose($"DotnetTestHostmanager.LaunchTestHostAsync: Prefix '{prefix}*' not found in env variables");
+                // Fallback, can delete this once the change is in dotnet sdk. because they are always used together.
+                string prefix = "VSTEST_WINAPPHOST_";
+                string dotnetRootEnvName = $"{prefix}DOTNET_ROOT(x86)";
+                var dotnetRoot = _environmentVariableHelper.GetEnvironmentVariable(dotnetRootEnvName);
+                if (dotnetRoot is null)
+                {
+                    dotnetRootEnvName = $"{prefix}DOTNET_ROOT";
+                    dotnetRoot = _environmentVariableHelper.GetEnvironmentVariable(dotnetRootEnvName);
+                }
+
+                if (dotnetRoot != null)
+                {
+                    EqtTrace.Verbose($"DotnetTestHostmanager.LaunchTestHostAsync: Found '{dotnetRootEnvName}' in env variables, value '{dotnetRoot}', forwarding to '{dotnetRootEnvName.Replace(prefix, string.Empty)}'");
+                    startInfo.EnvironmentVariables.Add(dotnetRootEnvName.Replace(prefix, string.Empty), dotnetRoot);
+                }
+                else
+                {
+                    EqtTrace.Verbose($"DotnetTestHostmanager.LaunchTestHostAsync: Prefix '{prefix}*' not found in env variables");
+                }
             }
         }
 
diff --git a/src/Microsoft.TestPlatform.VsTestConsole.TranslationLayer/VsTestConsoleRequestSender.cs b/src/Microsoft.TestPlatform.VsTestConsole.TranslationLayer/VsTestConsoleRequestSender.cs
@@ -1197,7 +1197,7 @@ private void SendMessageAndListenAndReportTestResults(
             EqtTrace.Error("Aborting Test Run Operation: {0}", exception);
             eventHandler.HandleLogMessage(
                 TestMessageLevel.Error,
-                TranslationLayerResources.AbortedTestsRun);
+                TranslationLayerResources.AbortedTestsRun + " " + exception.ToString());
             var completeArgs = new TestRunCompleteEventArgs(
                 null, false, true, exception, null, null, TimeSpan.Zero);
             eventHandler.HandleTestRunComplete(completeArgs, null, null, null);
@@ -1282,7 +1282,7 @@ private async Task SendMessageAndListenAndReportTestResultsAsync(
             EqtTrace.Error("Aborting Test Run Operation: {0}", exception);
             eventHandler.HandleLogMessage(
                 TestMessageLevel.Error,
-                TranslationLayerResources.AbortedTestsRun);
+                TranslationLayerResources.AbortedTestsRun + " " + exception.ToString());
             var completeArgs = new TestRunCompleteEventArgs(
                 null, false, true, exception, null, null, TimeSpan.Zero);
             eventHandler.HandleTestRunComplete(completeArgs, null, null, null);
diff --git a/test/Microsoft.TestPlatform.Acceptance.IntegrationTests/Build.cs b/test/Microsoft.TestPlatform.Acceptance.IntegrationTests/Build.cs
@@ -62,7 +62,17 @@ private static void CopyAndPatchDotnet()
         // e.g. artifacts\tmp\.dotnet\sdk\
         var sdkDirectory = Path.Combine(patchedDotnetDir, "sdk");
         // e.g. artifacts\tmp\.dotnet\sdk\8.0.100-preview.6.23330.14
-        var dotnetSdkDirectory = Directory.GetDirectories(sdkDirectory).Single();
+        var dotnetSdkDirectories = Directory.GetDirectories(sdkDirectory);
+        if (dotnetSdkDirectories.Length == 0)
+        {
+            throw new InvalidOperationException($"No .NET SDK directories found in '{sdkDirectory}'.");
+        }
+        if (dotnetSdkDirectories.Length > 1)
+        {
+            throw new InvalidOperationException($"More than 1 .NET SDK directories found in '{sdkDirectory}': {string.Join(", ", dotnetSdkDirectories)}.");
+        }
+
+        var dotnetSdkDirectory = dotnetSdkDirectories.Single();
         DirectoryUtils.CopyDirectory(Path.Combine(packagePath, "lib", "netstandard2.0"), dotnetSdkDirectory);
         DirectoryUtils.CopyDirectory(Path.Combine(packagePath, "runtimes", "any", "native"), dotnetSdkDirectory);
     }
diff --git a/test/Microsoft.TestPlatform.TestHostProvider.UnitTests/Hosting/DotnetTestHostManagerTests.cs b/test/Microsoft.TestPlatform.TestHostProvider.UnitTests/Hosting/DotnetTestHostManagerTests.cs
@@ -86,7 +86,6 @@ public DotnetTestHostManagerTests()
         _mockProcessHelper.Setup(ph => ph.GetCurrentProcessFileName()).Returns(DefaultDotnetPath);
         _mockProcessHelper.Setup(ph => ph.GetTestEngineDirectory()).Returns(DefaultDotnetPath);
         _mockProcessHelper.Setup(ph => ph.GetCurrentProcessArchitecture()).Returns(PlatformArchitecture.X64);
-        _mockEnvironmentVariable.Setup(ev => ev.GetEnvironmentVariable(It.IsAny<string>())).Returns(Path.GetDirectoryName(DefaultDotnetPath)!);
         _mockFileHelper.Setup(ph => ph.Exists(_defaultTestHostPath)).Returns(true);
         _mockFileHelper.Setup(ph => ph.Exists(DefaultDotnetPath)).Returns(true);
 
