From 2a2cbf808a47030b3499972c97474bf0da46dcd2 Mon Sep 17 00:00:00 2001
From: Andreas Streichardt <andreas@arangodb.com>
Date: Fri, 13 Jan 2017 17:55:22 +0100
Subject: [PATCH] Do not update in endless loop

---
 js/server/modules/@arangodb/cluster.js | 79 +++++++++++---------------
 1 file changed, 34 insertions(+), 45 deletions(-)

diff --git a/js/server/modules/@arangodb/cluster.js b/js/server/modules/@arangodb/cluster.js
index 2f6b7075d8..081946b2b6 100644
--- a/js/server/modules/@arangodb/cluster.js
+++ b/js/server/modules/@arangodb/cluster.js
@@ -1624,27 +1624,36 @@ function updateCurrentForCollections(localErrors, current) {
   let localDatabases = getLocalDatabases();
   let database;
 
-  function makeAddCurrentEntryCollection(dbname, info, error, trx) {
+  function assembleLocalCollectionInfo(info, error) {
     let coll = db._collection(info.name);
-    let payload = {indexes: coll.getIndexes()};
-    // Fix up the IDs of the indexes:
-    for (let i = 0; i < payload.indexes.length; ++i) {
-      let pos = payload.indexes[i].id.indexOf("/");
+    let payload = {
+      error: error.error,
+      errorMessage: error.errorMessage,
+      errorNum: error.errorNum,
+    };
+    payload.indexes = coll.getIndexes().map(index => {
+      let agencyIndex = {};
+      Object.assign(agencyIndex, index);
+      // Fix up the IDs of the indexes:
+      let pos = index.id.indexOf("/");
       if (pos >= 0) {
-        payload.indexes[i].id = payload.indexes[i].id.slice(pos+1);
+        agencyIndex.id = index.id.slice(pos+1);
+      } else {
+        agencyIndex.id = index.id;
       }
-    }
-    Object.keys(error.indexes).forEach(id => {
-      payload.indexes.push(error.indexes[id]);
+
+      if (error.indexes[agencyIndex.id] !== undefined) {
+        Object.assign(agencyIndex, error.indexes[agencyIndex.id]);
+        delete error.indexes[agencyIndex.id];
+      }
+      return agencyIndex;
+    });
+    // add the remaining errors which do not have a local id
+    Object.keys(error.indexes).forEach(indexId => {
+      payload.indexes.push(error.indexes[indexId]);
     });
-    if (error !== undefined && error.error) {
-      _.assign(payload, error);
-    } else {
-      _.assign(payload, { error: false, errorNum: 0, errorMessage: "" });
-    }
     payload.servers = [ourselves].concat(coll.getFollowers());
-    trx[0][curCollections + dbname + '/' + info.planId + '/' + info.name] =
-      {op: 'set', new: payload};
+    return payload;
   }
 
   function makeDropCurrentEntryCollection(dbname, col, shard, trx) {
@@ -1672,35 +1681,15 @@ function updateCurrentForCollections(localErrors, current) {
             if (localCollections.hasOwnProperty(shard)) {
               let shardInfo = localCollections[shard];
               if (shardInfo.isLeader) {
-                // It is the responsibility of the leader to update Current
-                if (!currentDBInfo.hasOwnProperty(shardInfo.planId) ||
-                    !currentDBInfo[shardInfo.planId].hasOwnProperty(shard) ||
-                    currentDBInfo[shardInfo.planId][shard].servers[0] !== 
-                    ourselves) {
-                  makeAddCurrentEntryCollection(database, shardInfo,
-                                                localErrors[shard], trx);
-                } else {
-                  // Here, the entry in current exists and we have been and
-                  // currently are the leader. So we have to update it if
-                  // changed:
-                  let inCurrent = currentDBInfo[shardInfo.planId][shard];
-                  let error = localErrors[shard];
-                  let diff = false;
-                  if (error !== undefined) {
-                    if (inCurrent.error !== error.error ||
-                        inCurrent.errorNum !== error.errorNum ||
-                        inCurrent.errorMessage !== error.errorMessage) {
-                      diff = true;
-                    }
+                let localCollectionInfo = assembleLocalCollectionInfo(shardInfo, localErrors[shard]);
+                // our local state differs from what is in the agency! => update!
+                if (typeof currentDBInfo[shardInfo.planId] != 'object'
+                  || !_.isEqual(localCollectionInfo, currentDBInfo[shardInfo.planId][shard])) {
+                    trx[0][curCollections + database + '/' + shardInfo.planId + '/' + shardInfo.name] = {
+                      op: 'set',
+                      new: localCollectionInfo,
+                    };
                   }
-                  if (!_.isEqual(inCurrent.indexes, shardInfo.indexes)) {
-                    diff = true;
-                  }
-                  if (diff) {
-                    makeAddCurrentEntryCollection(database, shardInfo, 
-                                                  error, trx);
-                  }
-                }
               }
             }
           }
@@ -1844,7 +1833,7 @@ function migratePrimary(plan, current) {
   // diff current and local and prepare agency transactions or whatever
   // to update current. Will report the errors created locally to the agency
   let trx = updateCurrentForCollections(localErrors, current);
-  if (Object.keys(trx[0]).length !== 0) {
+  if (trx.length > 0 && Object.keys(trx[0]).length !== 0) {
     trx[0][curVersion] = {op: 'increment'};
     // TODO: reduce timeout when we can:
     try {