Handle edge cases in export

**Problem**
When working with parsers, 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 issue does not name files, tests, or an entry point. Start by locating the parser export and error-handling paths, then reproduce the reported edge cases; done means export failures have more descriptive error messages and coverage for the relevant cases.

Written by the indexing model from the issue text.