Throw exception instead of assert(false)

[tdrwenski]

Description of Changes

The enable asserts option has been removed from our TDS servers, so it is best that we use exceptions and not asserts for error handling.

PR Checklist

• [ ] Link to any issues that the PR addresses
• [ ] Add labels
• [ ] Open as a draft PR until ready for review
• [ ] Make sure GitHub tests pass
• [ ] Mark PR as "Ready for Review"