Problem

When the bootstrap build fails in eng/build.ps1, the script continues to clean up artifacts and proceed with the main build instead of halting. This can lead to confusing build failures and wasted build time.

Root Cause

After invoking the bootstrap build on line 391, there is no check for $lastExitCode to determine if the bootstrap build succeeded. The script unconditionally continues to the cleanup and main build stages even when the bootstrap build has failed.

Solution

Add an exit code check immediately after the bootstrap build invocation to halt the build process if the bootstrap build fails. This is consistent with how the script handles failures in the main build loop (lines 422-431).

Changes Required

In eng/build.ps1, after line 391 where the bootstrap build is invoked:

Invoke-Expression "& `"$PSScriptRoot/common/build.ps1`" $bootstrapArguments"

# ADD THIS CHECK:
if ($lastExitCode -ne 0) {
  Write-Error "Bootstrap build failed. Stopping build."
  exit 1
}

# Remove artifacts from the bootstrap build so the product build is a "clean" build.
Write-Host "Cleaning up artifacts from bootstrap build..."

This ensures that:

1. If the bootstrap build fails ($lastExitCode -ne 0), an error message is displayed
2. The script exits with code 1 (failure status)
3. The cleanup and main build stages are never reached
4. Developers get immediate, clear feedback about the bootstrap failure

File to Modify

• eng/build.ps1 - Add exit code check after bootstrap build invocation (after line 391)

Testing

To test this fix:

1. Force a bootstrap build failure (e.g., by temporarily breaking a bootstrap project)
2. Run .\build.ps1 --bootstrap
3. Verify that the build stops with an error message and doesn't proceed to cleanup or main build
4. Verify that the exit code is 1 (failure)