Ensure Repeatable Results by Preserving Insert Order in Unique Array Generation Methods

[Jason5Lee]

Context:

The methods ArrayOfUniqueValues and ArrayOfUniqueStrings aim to generate repeatable sequences of unique values or strings. The repeatability is achieved using a fixed Seed (as noted in the comment on line 16). However, the current implementation relies on the traversal order of HashSet, which does not guarantee a consistent order.

Issue:

The assumption that a fixed insertion sequence into a HashSet ensures a repeatable traversal order is flawed:

1. HashSet does not provide any guarantees about order semantics in its documentation.
2. Some standard libraries in other programming languages, or even future implementations of .NET, may introduce variations in Set behavior where traversal order is inconsistent even with a fixed insertion sequence.

This discrepancy could lead to non-repeatable results, breaking the method's intended behavior.

Solution:

• Instead of relying on HashSet.CopyTo for transferring elements to the result array, we now directly assign values to the array in the order they are added to the HashSet. This ensures the output matches the insertion order and remains repeatable with a fixed seed.
• Updated both ArrayOfUniqueValues and ArrayOfUniqueStrings methods to reflect this approach.

Changes:

1. Modified ArrayOfUniqueValues:
   • Removed reliance on HashSet.CopyTo.
   • Assigned values to the result array during insertion to preserve order.
2. Modified ArrayOfUniqueStrings:
   • Similarly, ensured the assignment to the array occurs during insertion into the HashSet.

Benefits:

• Guarantees repeatable results consistent with the fixed seed.
• Eliminates reliance on undocumented behavior of HashSet traversal.