dotnet · dotnet-maestro · Feb 20, 2026 · Feb 24, 2026
@@ -27,7 +27,7 @@ This file should be imported by eng/Versions.props
     <MicrosoftCodeAnalysisFeaturesPackageVersion>5.0.0-2.25480.7</MicrosoftCodeAnalysisFeaturesPackageVersion>
     <MicrosoftVisualStudioLanguageServicesPackageVersion>5.0.0-2.25480.7</MicrosoftVisualStudioLanguageServicesPackageVersion>
     <!-- dotnet/arcade dependencies -->
-    <MicrosoftDotNetArcadeSdkPackageVersion>10.0.0-beta.26117.6</MicrosoftDotNetArcadeSdkPackageVersion>
+    <MicrosoftDotNetArcadeSdkPackageVersion>10.0.0-beta.26123.2</MicrosoftDotNetArcadeSdkPackageVersion>
     <!-- _git/dotnet-optimization dependencies -->
     <optimizationlinuxarm64MIBCRuntimePackageVersion>1.0.0-prerelease.26117.2</optimizationlinuxarm64MIBCRuntimePackageVersion>
     <optimizationlinuxx64MIBCRuntimePackageVersion>1.0.0-prerelease.26117.2</optimizationlinuxx64MIBCRuntimePackageVersion>

@@ -76,9 +76,9 @@
     </Dependency>
   </ProductDependencies>
   <ToolsetDependencies>
-    <Dependency Name="Microsoft.DotNet.Arcade.Sdk" Version="10.0.0-beta.26117.6">
+    <Dependency Name="Microsoft.DotNet.Arcade.Sdk" Version="10.0.0-beta.26123.2">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>eae2786f0de623ee284aea80713ec2c61531e9bd</Sha>
+      <Sha>4d898652733deb7dd274237ac06d27ee2ad85b36</Sha>
     </Dependency>
     <Dependency Name="optimization.windows_nt-x64.MIBC.Runtime" Version="1.0.0-prerelease.26117.2">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-optimization</Uri>

@@ -38,27 +38,6 @@ steps:
   displayName: Label PR commit
   workingDirectory: $(Agent.BuildDirectory)/repo
 
-- script: |
-    vmr_sha=$(grep -oP '(?<=Sha=")[^"]*' $(Agent.BuildDirectory)/repo/eng/Version.Details.xml)
-    echo "##vso[task.setvariable variable=vmr_sha]$vmr_sha"
-  displayName: Obtain the vmr sha from Version.Details.xml (Unix)
-  condition: ne(variables['Agent.OS'], 'Windows_NT')
-  workingDirectory: $(Agent.BuildDirectory)/repo
-
-- powershell: |
-    [xml]$xml = Get-Content -Path $(Agent.BuildDirectory)/repo/eng/Version.Details.xml
-    $vmr_sha = $xml.SelectSingleNode("//Source").Sha
-    Write-Output "##vso[task.setvariable variable=vmr_sha]$vmr_sha"
-  displayName: Obtain the vmr sha from Version.Details.xml (Windows)
-  condition: eq(variables['Agent.OS'], 'Windows_NT')
-  workingDirectory: $(Agent.BuildDirectory)/repo
-
-- script: |
-    git fetch --all
-    git checkout $(vmr_sha)
-  displayName: Checkout VMR at correct sha for repo flow
-  workingDirectory: ${{ parameters.vmrPath }}
-
 - script: |
     git config --global user.name "dotnet-maestro[bot]"
     git config --global user.email "dotnet-maestro[bot]@users.noreply.github.com"

@@ -34,6 +34,7 @@ resources:
     type: github
     name: dotnet/dotnet
     endpoint: dotnet
+    ref: refs/heads/main # Set to whatever VMR branch the PR build should insert into
 
 stages:
 - template: /eng/pipelines/templates/stages/vmr-build.yml@vmr

@@ -824,6 +824,11 @@ function MSBuild-Core() {
 
   $cmdArgs = "$($buildTool.Command) /m /nologo /clp:Summary /v:$verbosity /nr:$nodeReuse /p:ContinuousIntegrationBuild=$ci"
 
+  # Add -mt flag for MSBuild multithreaded mode if enabled via environment variable
+  if ($env:MSBUILD_MT_ENABLED -eq "1") {
+    $cmdArgs += ' -mt'
+  }
+
   if ($warnAsError) {
     $cmdArgs += ' /warnaserror /p:TreatWarningsAsErrors=true'
   }

@@ -526,7 +526,13 @@ function MSBuild-Core {
     }
   }
 
-  RunBuildTool "$_InitializeBuildToolCommand" /m /nologo /clp:Summary /v:$verbosity /nr:$node_reuse $warnaserror_switch /p:TreatWarningsAsErrors=$warn_as_error /p:ContinuousIntegrationBuild=$ci "$@"
+  # Add -mt flag for MSBuild multithreaded mode if enabled via environment variable
+  local mt_switch=""
+  if [[ "${MSBUILD_MT_ENABLED:-}" == "1" ]]; then
+    mt_switch="-mt"
+  fi
+
+  RunBuildTool "$_InitializeBuildToolCommand" /m /nologo /clp:Summary /v:$verbosity /nr:$node_reuse $warnaserror_switch $mt_switch /p:TreatWarningsAsErrors=$warn_as_error /p:ContinuousIntegrationBuild=$ci "$@"
 }
 
 function GetDarc {

@@ -103,12 +103,20 @@ Set-StrictMode -Version Latest
 Highlight 'Installing .NET, preparing the tooling..'
 . .\eng\common\tools.ps1
 $dotnetRoot = InitializeDotNetCli -install:$true
+$env:DOTNET_ROOT = $dotnetRoot
 $darc = Get-Darc
-$dotnet = "$dotnetRoot\dotnet.exe"
 
 Highlight "Starting the synchronization of VMR.."
 
 # Synchronize the VMR
+$versionDetailsPath = Resolve-Path (Join-Path $PSScriptRoot '..\Version.Details.xml') | Select-Object -ExpandProperty Path
+[xml]$versionDetails = Get-Content -Path $versionDetailsPath
+$repoName = $versionDetails.SelectSingleNode('//Source').Mapping
+if (-not $repoName) {
+  Fail "Failed to resolve repo mapping from $versionDetailsPath"
+  exit 1
+}
+
 $darcArgs = (
   "vmr", "forwardflow",
   "--tmp", $tmpDir,
@@ -130,9 +138,27 @@ if ($LASTEXITCODE -eq 0) {
   Highlight "Synchronization succeeded"
 }
 else {
-  Fail "Synchronization of repo to VMR failed!"
-  Fail "'$vmrDir' is left in its last state (re-run of this script will reset it)."
-  Fail "Please inspect the logs which contain path to the failing patch file (use -debugOutput to get all the details)."
-  Fail "Once you make changes to the conflicting VMR patch, commit it locally and re-run this script."
-  exit 1
+  Highlight "Failed to flow code into the local VMR. Falling back to resetting the VMR to match repo contents..."
+  git -C $vmrDir reset --hard
+
+  $resetArgs = (
+    "vmr", "reset",
+    "${repoName}:HEAD",
+    "--vmr", $vmrDir,
+    "--tmp", $tmpDir,
+    "--additional-remotes", "${repoName}:${repoRoot}"
+  )
+
+  & "$darc" $resetArgs
+
+  if ($LASTEXITCODE -eq 0) {
+    Highlight "Successfully reset the VMR using 'darc vmr reset'"
+  }
+  else {
+    Fail "Synchronization of repo to VMR failed!"
+    Fail "'$vmrDir' is left in its last state (re-run of this script will reset it)."
+    Fail "Please inspect the logs which contain path to the failing patch file (use -debugOutput to get all the details)."
+    Fail "Once you make changes to the conflicting VMR patch, commit it locally and re-run this script."
+    exit 1
+  }
 }
@@ -186,6 +186,13 @@ fi
 
 # Synchronize the VMR
 
+version_details_path=$(cd "$scriptroot/.."; pwd -P)/Version.Details.xml
+repo_name=$(grep -m 1 '<Source ' "$version_details_path" | sed -n 's/.*Mapping="\([^"]*\)".*/\1/p')
+if [[ -z "$repo_name" ]]; then
+  fail "Failed to resolve repo mapping from $version_details_path"
+  exit 1
+fi
+
 export DOTNET_ROOT="$dotnetDir"
 
 "$darc_tool" vmr forwardflow \
@@ -199,9 +206,22 @@ export DOTNET_ROOT="$dotnetDir"
 if [[ $? == 0 ]]; then
   highlight "Synchronization succeeded"
 else
-  fail "Synchronization of repo to VMR failed!"
-  fail "'$vmr_dir' is left in its last state (re-run of this script will reset it)."
-  fail "Please inspect the logs which contain path to the failing patch file (use --debug to get all the details)."
-  fail "Once you make changes to the conflicting VMR patch, commit it locally and re-run this script."
-  exit 1
+  highlight "Failed to flow code into the local VMR. Falling back to resetting the VMR to match repo contents..."
+  git -C "$vmr_dir" reset --hard
+
+  "$darc_tool" vmr reset \
+    "$repo_name:HEAD"                              \
+    --vmr "$vmr_dir"                               \
+    --tmp "$tmp_dir"                               \
+    --additional-remotes "$repo_name:$repo_root"
+
+  if [[ $? == 0 ]]; then
+    highlight "Successfully reset the VMR using 'darc vmr reset'"
+  else
+    fail "Synchronization of repo to VMR failed!"
+    fail "'$vmr_dir' is left in its last state (re-run of this script will reset it)."
+    fail "Please inspect the logs which contain path to the failing patch file (use --debug to get all the details)."
+    fail "Once you make changes to the conflicting VMR patch, commit it locally and re-run this script."
+    exit 1
+  fi
 fi
@@ -22,7 +22,7 @@
     "xcopy-msbuild": "18.0.0"
   },
   "msbuild-sdks": {
-    "Microsoft.DotNet.Arcade.Sdk": "10.0.0-beta.26117.6",
+    "Microsoft.DotNet.Arcade.Sdk": "10.0.0-beta.26123.2",
     "Microsoft.DotNet.Helix.Sdk": "8.0.0-beta.23255.2"
   }
 }