Ark: local state stops growing forever — spent coins shed bytes, done actions shed hex.

pruneArkState runs on every manager save: a spent coin loses its signed
bytes once its spend is 30 days old and no in-flight action names it (a
spent coin can never take the exit those bytes exist for), and an action
done more than 7 days ago loses the output-vtxo hex it minted (the change /
HTLC coins live in `vtxos` in their own right). Ids, amounts, inputIds and
preimages stay for history rows and spend dedupe; failed ln-pays keep their
HTLC bytes for the refund. Selective and idempotent; unit-tested.

Measured on a live deep wallet the immediate saving is small (every recent
spend is inside the window) — what remains is the live coins' own chains,
which only a renewal shrinks. The change is a growth cap, not a diet.

Co-Authored-By: Claude Fable 5.1 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Nw1Dijik1tLVKRM1WkU7xE

1 files changed, 44 insertions, 0 deletions

diff --git a/tools/ark-prune-test.js b/tools/ark-prune-test.js
new file mode 100644
index 0000000..e12b02e
--- /dev/null
+++ b/tools/ark-prune-test.js
@@ -0,0 +1,44 @@
+// Local ark state pruning: spent coins shed bytes once their spend is old and
+// unreferenced; done actions shed output hex; nothing live is touched.
+// Run: bun tools/ark-prune-test.js
+import assert from 'node:assert/strict';
+import { pruneArkState } from '../src/ark/manager.js';
+
+const DAY = 86400_000;
+const now = 1_800_000_000_000;
+const state = {
+  vtxos: [
+    { id: 'live', state: 'spendable', bytes: 'aa' },
+    { id: 'oldspent', state: 'spent', bytes: 'bb' },        // spent 40d ago → bytes go
+    { id: 'freshspent', state: 'spent', bytes: 'cc' },      // spent yesterday → kept
+    { id: 'inflight', state: 'spent', bytes: 'dd' },        // named by a live action → kept
+    { id: 'unnamed', state: 'spent', bytes: 'ee' },         // no date known → kept
+    { id: 'pending', state: 'pending', bytes: 'ff' },
+  ],
+  actions: [
+    { id: `send-${now - 40 * DAY}`, type: 'send', step: 'done', inputIds: ['oldspent'], destBytesList: ['hex'], changeBytesList: ['hex'], amountSat: 5 },
+    { id: `ln-pay-${now - 1 * DAY}`, type: 'ln-pay', step: 'done', inputIds: ['freshspent'], htlcBytesList: ['hex'], preimage: 'p' },
+    { id: `send-${now - 3 * DAY}`, type: 'send', step: 'submitted', inputIds: ['inflight'], changeBytesList: ['hex'] },
+    { id: `board-${now - 30 * DAY}`, type: 'board', step: 'done', fundingTxHex: 'ff', outputVtxos: ['hex'], fundingTxid: 'x' },
+    { id: `ln-pay-${now - 10 * DAY}`, type: 'ln-pay', step: 'failed', htlcBytesList: ['hex'] },
+  ],
+  movements: [{ id: 'm1', type: 'send', status: 'complete', ts: now - 40 * DAY, inputIds: ['oldspent'] }],
+};
+const before = JSON.stringify(state).length;
+pruneArkState(state, now);
+const v = (id) => state.vtxos.find((x) => x.id === id);
+assert.equal(v('live').bytes, 'aa');
+assert.equal(v('pending').bytes, 'ff');
+assert.equal(v('oldspent').bytes, undefined, 'old spend sheds its bytes');
+assert.equal(v('freshspent').bytes, 'cc', 'a recent spend keeps them');
+assert.equal(v('inflight').bytes, 'dd', 'an in-flight action pins them');
+assert.equal(v('unnamed').bytes, 'ee', 'no known spend date → keep');
+const a = (i) => state.actions[i];
+assert.ok(!('destBytesList' in a(0)) && !('changeBytesList' in a(0)) && a(0).amountSat === 5 && a(0).inputIds[0] === 'oldspent', 'old done action loses hex, keeps ids');
+assert.equal(a(1).htlcBytesList[0], 'hex', 'a day-old done action still has its hex');
+assert.equal(a(2).changeBytesList[0], 'hex', 'in-flight action untouched');
+assert.ok(!('fundingTxHex' in a(3)) && !('outputVtxos' in a(3)) && a(3).fundingTxid === 'x');
+assert.equal(a(4).htlcBytesList[0], 'hex', 'a failed ln-pay keeps its HTLC bytes for the refund');
+assert.ok(JSON.stringify(state).length < before);
+pruneArkState(state, now);
+console.log('✓ ark state pruning is selective and idempotent');