SERVER-32903 Ambiguous field name error should be ignored during initial sync

 create mode 100644 jstests/replsets/initial_sync_ambiguous_index.js

 create mode 100644 jstests/replsets/initial_sync_ambiguous_index.js

1 files changed, 74 insertions, 0 deletions

diff --git a/jstests/replsets/initial_sync_ambiguous_index.js b/jstests/replsets/initial_sync_ambiguous_index.js
new file mode 100644
index 00000000000..2b5a1291a00
--- /dev/null
+++ b/jstests/replsets/initial_sync_ambiguous_index.js
@@ -0,0 +1,74 @@
+/**
+ * Asserts that inserting a document like `{a:[{"0":1}]}` on the
+ * primary doesn't cause initial-sync to fail if there was index
+ * on `a.0` at the beginning of initial-sync but the `dropIndex`
+ * hasn't yet been applied on the secondary prior to cloning the
+ * insert oplog entry.
+ */
+
+(function() {
+"use strict";
+
+load("jstests/libs/fail_point_util.js");
+
+const dbName = 'test';
+const collectionName = 'coll';
+
+// How many documents to insert on the primary prior to
+// starting initial-sync.
+const initialDocs = 10;
+// Batch-size used for cloning.
+// Used as a fail-point parameter as detailed below.
+const clonerBatchSize = 1;
+
+// Setting initialDocs larger than clonerBatchSize causes
+// the fail-point to be hit because we fetch
+// multiple batches in the InitialSyncer.
+
+// Start one-node repl-set.
+const rst = new ReplSetTest({name: "apply_ops_ambiguous_index", nodes: 1});
+rst.startSet();
+rst.initiate();
+const primaryColl = rst.getPrimary().getDB(dbName).getCollection(collectionName);
+
+// Create the index.
+primaryColl.ensureIndex({"a.0": 1});
+
+// Insert the initial document set.
+for (let i = 0; i < initialDocs; ++i) {
+    primaryColl.insertOne({_id: i, a: i});
+}
+
+// Add a secondary.
+const secondary = rst.add(
+    {setParameter: {"numInitialSyncAttempts": 1, 'collectionClonerBatchSize': clonerBatchSize}});
+secondary.setSlaveOk();
+const secondaryColl = secondary.getDB(dbName).getCollection(collectionName);
+
+// We set the collectionClonerBatchSize low above, so we will definitely hit
+// this fail-point and hang after the first batch is applied. While the
+// secondary is hung we clone the problematic document.
+const failPoint = configureFailPoint(secondary,
+                                     "initialSyncHangCollectionClonerAfterHandlingBatchResponse",
+                                     {nss: secondaryColl.getFullName()});
+rst.reInitiate();
+failPoint.wait();
+
+// Primary no longer has the problematic index so the insert succeeds on the primary.
+// The collection-cloner will resume when the failpoint is turned off.
+primaryColl.dropIndex({"a.0": 1});
+primaryColl.insertOne({_id: 200, a: [{"0": 1}]});
+
+// Resume initial sync. The "bad" document will be applied; the dropIndex will
+// be applied later.
+failPoint.off();
+
+// Wait for initial sync to finish.
+rst.awaitSecondaryNodes();
+
+// Check document count on secondary.
+// initialDocs from the initial `for` loop and the 1 "bad" document.
+assert.eq(initialDocs + 1, secondaryColl.find().itcount());
+
+rst.stopSet();
+})();