Handle edge cases in sorting

**Problem**
When working with controllers, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

The payload names no files, tests, or entry points. Start by locating the controller sorting and error-handling code, reproduce the reported edge cases, and define done as descriptive errors for the affected cases with regression coverage.

Written by the indexing model from the issue text.