SERVER-23945 make index builds without a collation inherit the collection default

Also ensures that the full BSON representation of the
collation spec associated with an index or with a collection
is materialized in the catalog.

5 files changed, 55 insertions, 9 deletions

diff --git a/src/mongo/db/catalog/collection_options.cpp b/src/mongo/db/catalog/collection_options.cpp
index 1595706c0e2..b2aa3da4de4 100644
--- a/src/mongo/db/catalog/collection_options.cpp
+++ b/src/mongo/db/catalog/collection_options.cpp
@@ -215,6 +215,10 @@ Status CollectionOptions::parse(const BSONObj& options) {
                 return Status(ErrorCodes::BadValue, "'collation' has to be a document.");
             }
 
+            if (e.Obj().isEmpty()) {
+                return Status(ErrorCodes::BadValue, "'collation' cannot be an empty document.");
+            }
+
             collation = e.Obj().getOwned();
         }
     }
diff --git a/src/mongo/db/catalog/collection_options_test.cpp b/src/mongo/db/catalog/collection_options_test.cpp
index 85610c6fd02..4e773f1b027 100644
--- a/src/mongo/db/catalog/collection_options_test.cpp
+++ b/src/mongo/db/catalog/collection_options_test.cpp
@@ -193,6 +193,11 @@ TEST(CollectionOptions, FailToParseCollationThatIsNotAnObject) {
     ASSERT_NOT_OK(options.parse(fromjson("{collation: 'notAnObject'}")));
 }
 
+TEST(CollectionOptions, FailToParseCollationThatIsAnEmptyObject) {
+    CollectionOptions options;
+    ASSERT_NOT_OK(options.parse(fromjson("{collation: {}}")));
+}
+
 TEST(CollectionOptions, CollationFieldParsesCorrectly) {
     CollectionOptions options;
     ASSERT_OK(options.parse(fromjson("{collation: {locale: 'en'}}")));
diff --git a/src/mongo/db/catalog/database.cpp b/src/mongo/db/catalog/database.cpp
index 06e9b8f3933..080d37e0eb8 100644
--- a/src/mongo/db/catalog/database.cpp
+++ b/src/mongo/db/catalog/database.cpp
@@ -40,27 +40,29 @@
 #include "mongo/db/audit.h"
 #include "mongo/db/auth/auth_index_d.h"
 #include "mongo/db/background.h"
-#include "mongo/db/clientcursor.h"
 #include "mongo/db/catalog/collection.h"
 #include "mongo/db/catalog/collection_catalog_entry.h"
 #include "mongo/db/catalog/collection_options.h"
 #include "mongo/db/catalog/database_catalog_entry.h"
 #include "mongo/db/catalog/database_holder.h"
+#include "mongo/db/clientcursor.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
 #include "mongo/db/dbhelpers.h"
-#include "mongo/db/service_context.h"
-#include "mongo/db/service_context_d.h"
 #include "mongo/db/index/index_access_method.h"
 #include "mongo/db/instance.h"
 #include "mongo/db/introspect.h"
 #include "mongo/db/op_observer.h"
+#include "mongo/db/query/collation/collation_serializer.h"
+#include "mongo/db/query/collation/collator_factory_interface.h"
 #include "mongo/db/repl/oplog.h"
 #include "mongo/db/repl/replication_coordinator_global.h"
 #include "mongo/db/server_parameters.h"
+#include "mongo/db/service_context.h"
+#include "mongo/db/service_context_d.h"
 #include "mongo/db/stats/top.h"
-#include "mongo/db/storage/storage_options.h"
-#include "mongo/db/storage/storage_engine.h"
 #include "mongo/db/storage/recovery_unit.h"
+#include "mongo/db/storage/storage_engine.h"
+#include "mongo/db/storage/storage_options.h"
 #include "mongo/util/log.h"
 
 namespace mongo {
@@ -618,6 +620,18 @@ Status userCreateNS(OperationContext* txn,
     if (!status.isOK())
         return status;
 
+    // Validate the collation, if there is one.
+    if (!collectionOptions.collation.isEmpty()) {
+        auto collator = CollatorFactoryInterface::get(txn->getServiceContext())
+                            ->makeFromBSON(collectionOptions.collation);
+        if (!collator.isOK()) {
+            return collator.getStatus();
+        }
+
+        collectionOptions.collation =
+            CollationSerializer::specToBSON(collator.getValue()->getSpec());
+    }
+
     status =
         validateStorageOptions(collectionOptions.storageEngine,
                                stdx::bind(&StorageEngine::Factory::validateCollectionStorageOptions,
diff --git a/src/mongo/db/catalog/index_catalog.cpp b/src/mongo/db/catalog/index_catalog.cpp
index da3d0553d9f..7887759486b 100644
--- a/src/mongo/db/catalog/index_catalog.cpp
+++ b/src/mongo/db/catalog/index_catalog.cpp
@@ -57,6 +57,7 @@
 #include "mongo/db/matcher/expression.h"
 #include "mongo/db/matcher/extensions_callback_disallow_extensions.h"
 #include "mongo/db/ops/delete.h"
+#include "mongo/db/query/collation/collation_serializer.h"
 #include "mongo/db/query/collation/collator_factory_interface.h"
 #include "mongo/db/query/internal_plans.h"
 #include "mongo/db/repl/replication_coordinator_global.h"
@@ -276,7 +277,7 @@ StatusWith<BSONObj> IndexCatalog::prepareSpecForCreate(OperationContext* txn,
     if (!status.isOK())
         return StatusWith<BSONObj>(status);
 
-    auto fixed = _fixIndexSpec(original);
+    auto fixed = _fixIndexSpec(txn, _collection, original);
     if (!fixed.isOK()) {
         return fixed;
     }
@@ -1260,7 +1261,9 @@ BSONObj IndexCatalog::fixIndexKey(const BSONObj& key) {
     return key;
 }
 
-StatusWith<BSONObj> IndexCatalog::_fixIndexSpec(const BSONObj& spec) {
+StatusWith<BSONObj> IndexCatalog::_fixIndexSpec(OperationContext* txn,
+                                                Collection* collection,
+                                                const BSONObj& spec) {
     auto statusWithSpec = IndexLegacy::adjustIndexSpecObject(spec);
     if (!statusWithSpec.isOK()) {
         return statusWithSpec;
@@ -1289,6 +1292,24 @@ StatusWith<BSONObj> IndexCatalog::_fixIndexSpec(const BSONObj& spec) {
     }
     b.append("name", name);
 
+    if (auto collationElt = spec["collation"]) {
+        // This should already have been verified by _isSpecOk().
+        invariant(collationElt.type() == BSONType::Object);
+
+        auto collator = CollatorFactoryInterface::get(txn->getServiceContext())
+                            ->makeFromBSON(collationElt.Obj());
+        if (!collator.isOK()) {
+            return collator.getStatus();
+        }
+
+        b.append("collation", CollationSerializer::specToBSON(collator.getValue()->getSpec()));
+    } else if (collection->getDefaultCollator()) {
+        // The user did not specify an explicit collation for this index and the collection has a
+        // default collator. In this case, the index inherits the collection default.
+        b.append("collation",
+                 CollationSerializer::specToBSON(collection->getDefaultCollator()->getSpec()));
+    }
+
     {
         BSONObjIterator i(o);
         while (i.more()) {
@@ -1299,7 +1320,7 @@ StatusWith<BSONObj> IndexCatalog::_fixIndexSpec(const BSONObj& spec) {
                 // skip
             } else if (s == "dropDups") {
                 // dropDups is silently ignored and removed from the spec as of SERVER-14710.
-            } else if (s == "v" || s == "unique" || s == "key" || s == "name") {
+            } else if (s == "v" || s == "unique" || s == "key" || s == "name" || s == "collation") {
                 // covered above
             } else {
                 b.append(e);
diff --git a/src/mongo/db/catalog/index_catalog.h b/src/mongo/db/catalog/index_catalog.h
index dac775501a2..a982a6e976b 100644
--- a/src/mongo/db/catalog/index_catalog.h
+++ b/src/mongo/db/catalog/index_catalog.h
@@ -364,7 +364,9 @@ private:
     // conform to the standard for insertion.  This function adds the 'v' field if it didn't
     // exist, removes the '_id' field if it exists, applies plugin-level transformations if
     // appropriate, etc.
-    static StatusWith<BSONObj> _fixIndexSpec(const BSONObj& spec);
+    static StatusWith<BSONObj> _fixIndexSpec(OperationContext* txn,
+                                             Collection* collection,
+                                             const BSONObj& spec);
 
     Status _isSpecOk(OperationContext* txn, const BSONObj& spec) const;