SERVER-56877 add js test for validating multikey compound index after restarting

This test checks that the multikey paths for a compound index remain consistent
despite some failed writes. The test uses a compound index with two indexed fields
that are updated separately by different write operations. A hashed index provides
an easy way to fail a write operation due to a constraint on field values in a hashed
index.

This initial version of the test characterizes a defect in multikey tracking that shows
up as validation errors after the server restarts.

(cherry picked from commit 54f015ab1bc386b61c8011d5d8e3267bb4e181bf)

1 files changed, 78 insertions, 0 deletions

diff --git a/jstests/noPassthrough/validate_multikey_compound.js b/jstests/noPassthrough/validate_multikey_compound.js
new file mode 100644
index 00000000000..11e2a0a551a
--- /dev/null
+++ b/jstests/noPassthrough/validate_multikey_compound.js
@@ -0,0 +1,78 @@
+/**
+ * Validates multikey compound index in a collection that also contains a hashed index.
+ * The scenario tested here involves restarting the node after a failed insert due
+ * to contraints imposed by the hashed index. The validation behavior observed after
+ * restarting is that, even though we inserted documents that contain arrays in every
+ * indexed field in the compound index, we fail to save all the multikey path information
+ * in the catalog.
+ * @tags: [
+ *     requires_replication,
+ *     requires_persistence,
+ * ]
+ */
+(function() {
+'use strict';
+
+const rst = new ReplSetTest({nodes: 1});
+rst.startSet();
+rst.initiate();
+
+let primary = rst.getPrimary();
+let testColl = primary.getCollection('test.validate_multikey_restart');
+
+assert.commandWorked(testColl.getDB().createCollection(testColl.getName()));
+
+assert.commandWorked(testColl.createIndex({a: 1, b: 1}));
+assert.commandWorked(testColl.createIndex({c: 'hashed'}));
+
+// Insert 3 documents. Only the first and last documents are valid.
+assert.commandWorked(testColl.insert({_id: 0, a: [1, 2, 3], b: 'abc', c: 'valid_hash_0'}));
+
+// 16766 is the error code returned by ExpressionKeysPrivate::getHashKeys() for
+// "hashed indexes do not currently support array values".
+assert.commandFailedWithCode(
+    testColl.insert({_id: 1, a: 456, b: ['d', 'e', 'f'], c: ['invalid', 'hash']}), 16766);
+
+assert.commandWorked(testColl.insert({_id: 2, a: 789, b: ['g', 'h', ' i'], c: 'valid_hash_2'}));
+
+jsTestLog('Checking documents in collection before restart');
+let docs = testColl.find().sort({_id: 1}).toArray();
+assert.eq(2, docs.length, 'too many docs in collection: ' + tojson(docs));
+assert.eq(0, docs[0]._id, 'unexpected document content in collection: ' + tojson(docs));
+assert.eq(2, docs[1]._id, 'unexpected document content in collection: ' + tojson(docs));
+
+// For the purpose of reproducing the validation error in a_1, it is important to skip validation
+// when restarting the primary node. Enabling validation here has an effect on the validate
+// command's behavior after restarting.
+primary = rst.restart(primary, {skipValidation: true}, /*signal=*/undefined, /*wait=*/true);
+testColl = primary.getCollection(testColl.getFullName());
+
+jsTestLog('Checking documents in collection after restart');
+docs = testColl.find().sort({_id: 1}).toArray();
+assert.eq(2, docs.length, 'too many docs in collection: ' + tojson(docs));
+assert.eq(0, docs[0]._id, 'unexpected document content in collection: ' + tojson(docs));
+assert.eq(2, docs[1]._id, 'unexpected document content in collection: ' + tojson(docs));
+
+jsTestLog('Validating collection after restart');
+const result = assert.commandWorked(testColl.validate({full: true}));
+
+jsTestLog('Validation result: ' + tojson(result));
+assert.eq(testColl.getFullName(), result.ns, tojson(result));
+assert.eq(0, result.nInvalidDocuments, tojson(result));
+assert.eq(2, result.nrecords, tojson(result));
+assert.eq(3, result.nIndexes, tojson(result));
+
+// Check non-multikey indexes.
+assert.eq(2, result.keysPerIndex._id_, tojson(result));
+assert.eq(2, result.keysPerIndex.c_hashed, tojson(result));
+assert(result.indexDetails._id_.valid, tojson(result));
+assert(result.indexDetails.c_hashed.valid, tojson(result));
+
+// Check multikey index.
+assert.eq(6, result.keysPerIndex.a_1_b_1, tojson(result));
+assert(!result.indexDetails.a_1_b_1.valid, tojson(result));
+
+assert(!result.valid, tojson(result));
+
+rst.stopSet(/*signal=*/undefined, /*forRestart=*/undefined, {skipValidation: true});
+})();