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Discuss a consistent policy for hash collisions #906
Description
Summary
Discuss whether and how Phlex should handle hash collisions consistently. This follow-up does not need to block PR #704.
Context
phlex/core/producer_catalog.cpp uses 64-bit hashes while tracking product suffixes, creator names, and types during producer selection. add_to_tracker detects distinct values that have the same hash in some cases. Other code also relies on hashed values.
Decide whether collision detection, collision-safe equality, or acceptance of the existing risk is appropriate across the project.
Scope
- Identify locations where hashes act as identity values or map keys in product selection and related logic.
- Agree on a project-wide policy for hash collisions and document the trade-offs.
- If changes are required, identify the affected code and tests.
Acceptance criteria
- The maintainers document the hash-collision policy.
- The discussion identifies any required follow-up work.
Requested by @knoepfel in #704 (comment)
Related PR: #704
Activity
knoepfel commentedon Oct 12, 2026
This issue was discussed on October 12, 2026 at a Phlex development meeting. The conclusion is that the body of code in question in
phlex/core/producer_catalog.cpp(specifically theadd_to_tracker(...)functionality) can be replaced with a simplestd::set<identifier>solution, thereby avoiding the hash-collision issue.knoepfel commentedon Oct 12, 2026
See follow-up work at #971.