[BUG] install.ps1 prints "✅ Installation complete!" even when claude.exe install fails in Windows Powershell -

irm https://claude.ai/install.ps1 | iex
Setting up Claude Code...
× Installation failed
Checksum mismatch: expected b29dca8880f7bcd8820909cb630f0bace6e8a4a126caa7aafdd5ca2dbd13c497, got
e677b695c8418c687d5084cd88012d36be9695e8db59510531023601e4a0deeb
Try running with --force to override checks
✅ Installation complete!

Bug Description

The PowerShell installer (install.ps1) prints ✅ Installation complete! even when the installation subprocess fails.

Root cause: The script calls & $binaryPath install $Target (an external process) inside a try/finally block but never checks $LASTEXITCODE after it. In PowerShell, $ErrorActionPreference = "Stop" only applies to cmdlets — it does not throw on non-zero exit codes from external executables. So when claude.exe install fails and exits with a non-zero code, PowerShell silently continues and executes the success message on the next line.

Relevant code in install.ps1:

try {
    & $binaryPath install $Target   # ← fails, exits non-zero
}
finally {
    Remove-Item -Force $binaryPath  # ← cleanup runs (correct)
}

Write-Output "✅ Installation complete!"  # ← BUG: always runs regardless of exit code

Proposed fix:

try {
    if ($Target) {
        & $binaryPath install $Target
    } else {
        & $binaryPath install
    }

    # $ErrorActionPreference = "Stop" does NOT cover external processes.
    # Must check $LASTEXITCODE explicitly for any executable called with &
    if ($LASTEXITCODE -ne 0) {
        Write-Error "Installation failed (claude.exe exited with code $LASTEXITCODE)"
        exit $LASTEXITCODE
    }
}
finally {
    try {
        Start-Sleep -Seconds 1
        Remove-Item -Force $binaryPath
    }
    catch {
        Write-Warning "Could not remove temporary file: $binaryPath"
    }
}

# Only reached if $LASTEXITCODE -eq 0
Write-Output ""
Write-Output "$([char]0x2705) Installation complete!"
Write-Output ""