fix(core): handle skipped testnet eras when configured for auto-upgrade

It's possible to configure when particular eras are upgraded, without an upgrade proposal, in testnet cardano-node configuration, including the specification of multiple eras in the same epoch. Era summaries therefore need to be filtered to remove eras that are being skipped, which is evidenced by a later era starting in the same slot.
input-output-hk · Sep 5, 2022 · 47fe7c1 · 47fe7c1
1 parent b5b2512
commit 47fe7c1
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Showing 2 changed files with 43 additions and 2 deletions.
diff --git a/packages/core/src/util/slotCalc.ts b/packages/core/src/util/slotCalc.ts
@@ -1,6 +1,8 @@
 import { CardanoNetworkMagic, EpochNo, Slot } from '../Cardano';
 import { CustomError } from 'ts-custom-error';
 import { EraSummary } from '../CardanoNode';
+import groupBy from 'lodash/groupBy';
+import last from 'lodash/last';
 import orderBy from 'lodash/orderBy';
 
 export interface SlotDate {
@@ -17,7 +19,7 @@ export interface EpochInfo {
 export class EraSummaryError extends CustomError {}
 
 /**
- * Were valid at 2022-05-28
+ * Valid at 2022-05-28
  */
 export const mainnetEraSummaries: EraSummary[] = [
   { parameters: { epochLength: 21_600, slotLength: 20_000 }, start: { slot: 0, time: new Date(1_506_192_291_000) } },
@@ -43,7 +45,12 @@ export const eraSummariesConfig: EraSummariesMap = {
 };
 
 const createSlotEpochCalcImpl = (eraSummaries: EraSummary[]) => {
-  const eraSummariesAsc = orderBy(eraSummaries, ({ start }) => start.slot);
+  // It's possible to configure when particular eras are upgraded, without an upgrade proposal, in
+  // testnet cardano-node configuration, including the specification of multiple eras in the same
+  // epoch. Era summaries therefore need to be filtered to remove eras that are being skipped,
+  // which is evidenced by a later era starting in the same slot.
+  const eraSummariesWithoutSkippedEras = Object.values(groupBy(eraSummaries, 'start.slot')).map(last) as EraSummary[];
+  const eraSummariesAsc = orderBy(eraSummariesWithoutSkippedEras, ({ start }) => start.slot);
   return (slotNo: Slot) => {
     const relevantEraSummariesAsc = orderBy(
       eraSummariesAsc.filter(({ start }) => start.slot <= slotNo),

diff --git a/packages/core/test/util/slotCalc.test.ts b/packages/core/test/util/slotCalc.test.ts
@@ -54,6 +54,40 @@ describe('slotCalc utils', () => {
   });
 
   describe('slotEpochCalc', () => {
+    describe('testnet with auto-upgrading eras', () => {
+      it('correctly computes epoch with multiple summaries starting from genesis', () => {
+        const eraSummaries: EraSummary[] = [
+          {
+            parameters: { epochLength: 100, slotLength: 3 },
+            start: { slot: 0, time: new Date(1_563_999_616_000) }
+          },
+          { parameters: { epochLength: 200, slotLength: 10 }, start: { slot: 0, time: new Date(1_563_999_616_000) } },
+          { parameters: { epochLength: 200, slotLength: 1 }, start: { slot: 0, time: new Date(1_563_999_616_000) } }
+        ];
+        const slotEpochCalc: SlotEpochCalc = createSlotEpochCalc(eraSummaries);
+
+        expect(slotEpochCalc(1031)).toEqual(5);
+      });
+      it('correctly computes epoch with summaries indicating an upgrade after genesis, from the same slotNo', () => {
+        const eraSummaries: EraSummary[] = [
+          {
+            parameters: { epochLength: 100, slotLength: 3 },
+            start: { slot: 0, time: new Date(1_563_999_616_000) }
+          },
+          {
+            parameters: { epochLength: 200, slotLength: 10 },
+            start: { slot: 301, time: new Date(1_563_999_716_000) }
+          },
+          {
+            parameters: { epochLength: 200, slotLength: 1 },
+            start: { slot: 301, time: new Date(1_563_999_716_000) }
+          }
+        ];
+        const slotEpochCalc: SlotEpochCalc = createSlotEpochCalc(eraSummaries);
+
+        expect(slotEpochCalc(1031)).toEqual(6);
+      });
+    });
     describe('testnet', () => {
       const slotEpochCalc: SlotEpochCalc = createSlotEpochCalc(testnetEraSummaries);