Overall the changes look good to me. But we can test this in few more scenarios or probably add test cases.
Some of which I can think of:

1. Any form of syntax errors in the powershell script
2. Certain powershell commands like Get-Item "C:\nonexistent.txt" . External programs will error out, but we can test if the powershell cmdlet also behaves the same
3. A nested try/catch scenario

Overall the changes look good to me. But we can test this in few more scenarios or probably add test cases. Some of which I can think of:

1. Any form of syntax errors in the powershell script
2. Certain powershell commands like Get-Item "C:\nonexistent.txt" . External programs will error out, but we can test if the powershell cmdlet also behaves the same
3. A nested try/catch scenario

To clarify, PowerShell errors are generally categorized into two types: terminating and non-terminating errors. The wrapper introduced here is designed to capture terminating errors and return their corresponding exit codes.

A terminating error includes:

1. Any invalid syntax.
2. CommandNotFoundException (occurs when attempting to run a non-existent command).
3. Runtime exceptions (e.g., division by zero).
4. Explicitly thrown exceptions.

Regarding the second test case, Get-Item "C:\nonexistent.txt" produces a non-terminating error by default. This means the script would continue execution without failing and return an exit status of zero. However, if users want to explicitly handle non-terminating errors and return a non-zero exit code, they can do so using the ErrorActionPreference variable. Added it in the acceptance test for reference.

There was some discussion (#6449) about whether Packer should enforce ErrorActionPreference='Stop' by default. However, since this behavior differs from PowerShell's default setting, we have opted to leave it up to the user to configure based on their needs.

Additionally, I have incorporated test cases for the nested try/catch scenario.

LGTM Also please test the case where ExecutionPolicy is set to None.

Added the test case

@kp2099 Thank very much you for this fix!

I'm going to lock this pull request because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.
If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.