copyRegistryTo

Copies the index registry into target, which must already be a store directory.

The half of a checkpoint rabosh-core cannot do. DocumentStore.checkpoint carries every file numbered after a live segment, which is exactly the .idx, .pst and .col sidecars and deliberately requires no knowledge of what they are — but INDEXES is named rather than numbered, and it is this catalog's file.

Leaving it behind would lose an instruction rather than derived data, which is the inversion this module's durability rule is built around: a missing .pst costs a rescan, a missing registry means the checkpoint silently has no index an operator created, with the posting files sitting beside it as orphans for the next sweep to delete. So the registry travels, and it travels whole — it is written under a temporary name, forced and moved, the same treatment it gets in a live store.

A store that has never defined an index has no registry, and this then writes nothing at all — which is the right answer and not a failure.