registry/trie

What the trie refuses for an edge, read off the trie itself (#177, #183).

Responsibility

The named refusals a fold raises when the leaf an edge needs is not the leaf the trie binds: terminalFault for a retirement (updateTerminal), registration refuses every occupied key. Each is the one construction site of its reasons, so a test asserting a reason asserts the value the validator traces. An insert on a key the trie already binds keeps its construction site in lib (occupiedRefusal, key-exists).

Dependencies

Imports the Merkle Patricia Forestry library and lib (the edge table’s leaf bytes). Imported by registry/fold, which decides when to ask, and by the Aiken suite. It knows nothing of requests, duties or values.

Assumptions

proof is the proof the request’s action supplies for key, against the trie as the fold has advanced it so far in the batch.
The request states no leaf bytes: the leaf is what the trie binds.

Invariants

Every classification uses the library’s total checks (mpf.miss, mpf.has), which answer for any input instead of crashing, so a wrong leaf is an attributable refusal rather than a death inside mpf.update.
A key the trie does not bind at all is key-unknown for both the retirement and the read.
terminalFault answers None for an Active leaf and for a proof matching no root; the latter then fails in mpf.update exactly as on every other edge.

Functions

terminalFault(
  trie: MerklePatriciaForestry,
  key: ByteArray,
  proof: mpf.Proof,
) -> Option<String>

Why the trie refuses this updateTerminal, or None when the leaf it binds is the Active one the edge moves (#177 I177-CHAIN).

The subject is the leaf the trie ACTUALLY binds — established here, against this request’s own proof, with the MPF library’s own TOTAL checks. miss and has answer for every input instead of crashing, so a wrong leaf becomes an attributable refusal rather than a death inside mpf.update, which says only that the script died.

It is NOT a leaf the request states — edge-only requests state none: a claim by the requester says nothing about the trie.

One construction site, so a test asserting a reason asserts the value this validator traces rather than a helper nothing calls (#173 A-006, applied to this edge). The names are Lean’s, from update_terminal_transaction_row.