Module join 

PatchSet join — CRDT merge of two patch-sets sharing the same base epoch.

The join operation combines two PatchSets into one by unioning their path maps. When both patch-sets touch the same path, we resolve:

1. Identical — same PatchValue: idempotent, keep one copy.
2. Compatible — mergeable edits on the same path (e.g. both Add the same blob via different FileIds would conflict, but identical Adds are idempotent per case 1).
3. Conflicting — incompatible edits: emit a PathConflict.

CRDT properties

join is:

• Commutative: join(a, b) == join(b, a)
• Associative: join(join(a, b), c) == join(a, join(b, c))
• Idempotent: join(a, a) == a

These hold because:

• BTreeMap iteration is deterministic.
• Identical entries collapse (idempotent).
• Conflict detection is symmetric (both sides produce the same PathConflict regardless of argument order because sides are sorted).

Structs

EpochMismatch

Error that occurs if join is called on patch-sets with different base epochs.

JoinResult

The result of joining two PatchSets.

PathConflict

A conflict on a single path during join.

Enums

ConflictReason

Why two PatchValues on the same path could not be merged.

Functions

join

Join (CRDT merge) two PatchSets that share the same base epoch.