Module model 

Pure collision + renumber logic. No I/O.

Structs

Collision

Located

Observation

One observation for detect_collisions.

Rename

Enums

Source

Where a version was observed.

Functions

detect_collisions

Group observations by (role, version); return only versions seen >= twice. Same version in two DIFFERENT roles is not a collision.

max_version

Highest version among files (0 if empty).

plan_renumber

Assign a contiguous block of versions strictly above floor to the topic files, preserving their relative order — but ONLY if at least one topic file is at or below the floor (i.e. actually collides). If every topic file is already above the floor, return an empty plan (idempotent no-op).