Do not pass /warnaserror to msbuild (#32152)

eng/build.ps1

@@ -41,7 +41,7 @@ param (
     [switch]$deployExtensions,
     [switch]$prepareMachine,
     [switch]$useGlobalNuGetCache = $true,
-    [switch]$warnAsError = $true,
+    [switch]$warnAsError = $false,
 
     # Test actions
     [switch]$test32,
@@ -91,6 +91,7 @@ function Print-Usage() {
     Write-Host "  -skipAnalyzers            Do not run analyzers during build operations"
     Write-Host "  -prepareMachine           Prepare machine for CI run, clean up processes after build"
     Write-Host "  -useGlobalNuGetCache      Use global NuGet cache."
+    Write-Host "  -warnAsError              Treat all warnings as errors"
     Write-Host ""
     Write-Host "Command line arguments starting with '/p:' are passed through to MSBuild."
 }
@@ -158,6 +159,10 @@ function BuildSolution() {
     # Do not set the property to true explicitly, since that would override value projects might set.
     $suppressExtensionDeployment = if (!$deployExtensions) { "/p:DeployExtension=false" } else { "" } 
 
+    # Setting /p:TreatWarningsAsErrors=true is a workaround for https://github.com/Microsoft/msbuild/issues/3062.
+    # We don't pass /warnaserror to msbuild ($warnAsError is set to $false by default above), but set 
+    # /p:TreatWarningsAsErrors=true so that compiler reported warnings, other than IDE0055 are treated as errors. 
+    # Warnings reported from other msbuild tasks are not treated as errors for now.
     MSBuild $toolsetBuildProj `
         $bl `
         /p:Configuration=$configuration `
@@ -177,6 +182,7 @@ function BuildSolution() {
         /p:QuietRestore=$quietRestore `
         /p:QuietRestoreBinaryLog=$binaryLog `
         /p:TestTargetFrameworks=$testTargetFrameworks `
+        /p:TreatWarningsAsErrors=true `
         $suppressExtensionDeployment `
         @properties
 }

eng/build.sh

@@ -30,6 +30,7 @@ usage()
   echo "  --bootstrap                Build using a bootstrap compilers"
   echo "  --skipAnalyzers            Do not run analyzers during build operations"
   echo "  --prepareMachine           Prepare machine for CI run, clean up processes after build"
+  echo "  --warnAsError              Treat all warnings as errors"
   echo ""
   echo "Command line arguments starting with '/p:' are passed through to MSBuild."
 }
@@ -61,6 +62,7 @@ ci=false
 bootstrap=false
 skip_analyzers=false
 prepare_machine=false
+warn_as_error=false
 properties=""
 
 docker=false
@@ -125,6 +127,9 @@ while [[ $# > 0 ]]; do
     --preparemachine)
       prepare_machine=true
       ;;
+    --warnaserror)
+      warn_as_error=true
+      ;;
     --docker)
       docker=true
       shift
@@ -245,6 +250,10 @@ function BuildSolution {
     mono_tool=""
   fi
 
+  # Setting /p:TreatWarningsAsErrors=true is a workaround for https://github.com/Microsoft/msbuild/issues/3062.
+  # We don't pass /warnaserror to msbuild (warn_as_error is set to false by default above), but set 
+  # /p:TreatWarningsAsErrors=true so that compiler reported warnings, other than IDE0055 are treated as errors. 
+  # Warnings reported from other msbuild tasks are not treated as errors for now.
   MSBuild $toolset_build_proj \
     $bl \
     /p:Configuration=$configuration \
@@ -261,6 +270,7 @@ function BuildSolution {
     /p:ContinuousIntegrationBuild=$ci \
     /p:QuietRestore=$quiet_restore \
     /p:QuietRestoreBinaryLog="$binary_log" \
+    /p:TreatWarningsAsErrors=true \
     $test_runtime \
     $mono_tool \
     $properties