From c2bbaa6867d2cbf9dd8236bd6bd353ed6cb53ba4 Mon Sep 17 00:00:00 2001
From: prathamesh0 <42446521+prathamesh0@users.noreply.github.com>
Date: Fri, 16 Sep 2022 09:15:11 +0530
Subject: [PATCH] Update meta data verification to allow branched checkpoints
 (#183)

---
 .../src/cli/compare/compare-blocks.ts         |  4 +--
 packages/graph-node/src/cli/compare/utils.ts  | 27 ++++++++++++++-----
 2 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/packages/graph-node/src/cli/compare/compare-blocks.ts b/packages/graph-node/src/cli/compare/compare-blocks.ts
index 60b2e196..970b34e8 100644
--- a/packages/graph-node/src/cli/compare/compare-blocks.ts
+++ b/packages/graph-node/src/cli/compare/compare-blocks.ts
@@ -64,7 +64,7 @@ export const main = async (): Promise<void> => {
   let diffFound = false;
   let blockDelay = wait(0);
   let subgraphContracts: string[] = [];
-  const contractLatestStateCIDMap: Map<string, string> = new Map();
+  const contractLatestStateCIDMap: Map<string, { diff: string, checkpoint: string }> = new Map();
   let db: Database | undefined, subgraphGQLClient: GraphQLClient | undefined;
 
   if (config.watcher) {
@@ -82,7 +82,7 @@ export const main = async (): Promise<void> => {
     }
 
     subgraphContracts.forEach(subgraphContract => {
-      contractLatestStateCIDMap.set(subgraphContract, '');
+      contractLatestStateCIDMap.set(subgraphContract, { diff: '', checkpoint: '' });
     });
   }
 
diff --git a/packages/graph-node/src/cli/compare/utils.ts b/packages/graph-node/src/cli/compare/utils.ts
index c56faa65..c58363a9 100644
--- a/packages/graph-node/src/cli/compare/utils.ts
+++ b/packages/graph-node/src/cli/compare/utils.ts
@@ -211,7 +211,7 @@ export const getIPLDsByBlock = async (client: GraphQLClient, contracts: string[]
   }));
 };
 
-export const checkIPLDMetaData = (contractIPLD: {[key: string]: any}, contractLatestStateCIDMap: Map<string, string>, rawJson: boolean) => {
+export const checkIPLDMetaData = (contractIPLD: {[key: string]: any}, contractLatestStateCIDMap: Map<string, { diff: string, checkpoint: string }>, rawJson: boolean) => {
   // Return if IPLD for a contract not found
   if (!contractIPLD) {
     return;
@@ -219,22 +219,35 @@ export const checkIPLDMetaData = (contractIPLD: {[key: string]: any}, contractLa
 
   const { contractAddress, cid, kind, block } = contractIPLD;
 
-  let parentCID = contractLatestStateCIDMap.get(contractAddress);
+  const parentCIDs = contractLatestStateCIDMap.get(contractAddress);
+  assert(parentCIDs);
+
   // If CID is same as the parent CID, skip the check
-  if (cid === parentCID) {
+  if (cid === parentCIDs.diff || cid === parentCIDs.checkpoint) {
     return;
   }
 
-  // Update the parent CID in the map
-  contractLatestStateCIDMap.set(contractAddress, cid);
+  // Update the parent CIDs in the map
+  // Keep previous 'diff' if kind is 'checkpoint'
+  const nextParentCIDs = (kind === 'checkpoint')
+    ? { diff: parentCIDs.diff, checkpoint: cid as string }
+    : { diff: cid, checkpoint: '' };
+  contractLatestStateCIDMap.set(contractAddress, nextParentCIDs);
 
   // Actual meta data from the GQL result
   const data = JSON.parse(contractIPLD.data);
 
   // If parentCID not initialized (is empty at start)
   // Take the expected parentCID from the actual data itself
-  if (parentCID === '') {
-    parentCID = data.meta.parent['/'];
+  let parentCID: string;
+  const actualParentCID = data.meta.parent['/'];
+  if (parentCIDs.diff === '') {
+    parentCID = actualParentCID;
+  } else {
+    // Check if actual parent CID points to previous 'checkpoint'
+    parentCID = (parentCIDs.checkpoint !== '' && actualParentCID === parentCIDs.checkpoint)
+      ? parentCIDs.checkpoint
+      : parentCIDs.diff;
   }
 
   // Expected meta data