SERVER-28507 Centralize ignored fields in command implementations

22 files changed, 136 insertions, 147 deletions

diff --git a/src/mongo/db/auth/user_management_commands_parser.cpp b/src/mongo/db/auth/user_management_commands_parser.cpp
index 35c37020c0e..d480e7bc271 100644
--- a/src/mongo/db/auth/user_management_commands_parser.cpp
+++ b/src/mongo/db/auth/user_management_commands_parser.cpp
@@ -42,6 +42,7 @@
 #include "mongo/db/auth/privilege_parser.h"
 #include "mongo/db/auth/user_document_parser.h"
 #include "mongo/db/auth/user_name.h"
+#include "mongo/db/commands.h"
 #include "mongo/db/jsobj.h"
 #include "mongo/platform/unordered_set.h"
 #include "mongo/util/mongoutils/str.h"
@@ -60,7 +61,8 @@ Status _checkNoExtraFields(const BSONObj& cmdObj,
     // ones.
     for (BSONObjIterator iter(cmdObj); iter.more(); iter.next()) {
         StringData fieldName = (*iter).fieldNameStringData();
-        if (!validFieldNames.count(fieldName.toString())) {
+        if (!Command::isGenericArgument(fieldName) &&
+            !validFieldNames.count(fieldName.toString())) {
             return Status(ErrorCodes::BadValue,
                           mongoutils::str::stream() << "\"" << fieldName << "\" is not "
                                                                             "a valid argument to "
@@ -149,8 +151,6 @@ Status parseRolePossessionManipulationCommands(const BSONObj& cmdObj,
     unordered_set<std::string> validFieldNames;
     validFieldNames.insert(cmdName.toString());
     validFieldNames.insert("roles");
-    validFieldNames.insert("writeConcern");
-    validFieldNames.insert("maxTimeMS");
 
     Status status = _checkNoExtraFields(cmdObj, cmdName, validFieldNames);
     if (!status.isOK()) {
@@ -191,8 +191,6 @@ Status parseCreateOrUpdateUserCommands(const BSONObj& cmdObj,
     validFieldNames.insert("digestPassword");
     validFieldNames.insert("pwd");
     validFieldNames.insert("roles");
-    validFieldNames.insert("writeConcern");
-    validFieldNames.insert("maxTimeMS");
 
     Status status = _checkNoExtraFields(cmdObj, cmdName, validFieldNames);
     if (!status.isOK()) {
@@ -273,8 +271,6 @@ Status parseAndValidateDropUserCommand(const BSONObj& cmdObj,
                                        UserName* parsedUserName) {
     unordered_set<std::string> validFieldNames;
     validFieldNames.insert("dropUser");
-    validFieldNames.insert("writeConcern");
-    validFieldNames.insert("maxTimeMS");
 
     Status status = _checkNoExtraFields(cmdObj, "dropUser", validFieldNames);
     if (!status.isOK()) {
@@ -296,8 +292,6 @@ Status parseFromDatabaseCommand(const BSONObj& cmdObj,
                                 std::string command) {
     unordered_set<std::string> validFieldNames;
     validFieldNames.insert(command);
-    validFieldNames.insert("writeConcern");
-    validFieldNames.insert("maxTimeMS");
 
     Status status = _checkNoExtraFields(cmdObj, command, validFieldNames);
     if (!status.isOK()) {
@@ -316,7 +310,6 @@ Status parseUsersInfoCommand(const BSONObj& cmdObj, StringData dbname, UsersInfo
     validFieldNames.insert("usersInfo");
     validFieldNames.insert("showPrivileges");
     validFieldNames.insert("showCredentials");
-    validFieldNames.insert("maxTimeMS");
 
     Status status = _checkNoExtraFields(cmdObj, "usersInfo", validFieldNames);
     if (!status.isOK()) {
@@ -364,7 +357,6 @@ Status parseRolesInfoCommand(const BSONObj& cmdObj, StringData dbname, RolesInfo
     validFieldNames.insert("rolesInfo");
     validFieldNames.insert("showPrivileges");
     validFieldNames.insert("showBuiltinRoles");
-    validFieldNames.insert("maxTimeMS");
 
     Status status = _checkNoExtraFields(cmdObj, "rolesInfo", validFieldNames);
     if (!status.isOK()) {
@@ -467,8 +459,6 @@ Status parseCreateOrUpdateRoleCommands(const BSONObj& cmdObj,
     validFieldNames.insert(cmdName.toString());
     validFieldNames.insert("privileges");
     validFieldNames.insert("roles");
-    validFieldNames.insert("writeConcern");
-    validFieldNames.insert("maxTimeMS");
 
     Status status = _checkNoExtraFields(cmdObj, cmdName, validFieldNames);
     if (!status.isOK()) {
@@ -527,8 +517,6 @@ Status parseAndValidateRolePrivilegeManipulationCommands(const BSONObj& cmdObj,
     unordered_set<std::string> validFieldNames;
     validFieldNames.insert(cmdName.toString());
     validFieldNames.insert("privileges");
-    validFieldNames.insert("writeConcern");
-    validFieldNames.insert("maxTimeMS");
 
     Status status = _checkNoExtraFields(cmdObj, cmdName, validFieldNames);
     if (!status.isOK()) {
@@ -569,8 +557,6 @@ Status parseDropRoleCommand(const BSONObj& cmdObj,
                             RoleName* parsedRoleName) {
     unordered_set<std::string> validFieldNames;
     validFieldNames.insert("dropRole");
-    validFieldNames.insert("writeConcern");
-    validFieldNames.insert("maxTimeMS");
 
     Status status = _checkNoExtraFields(cmdObj, "dropRole", validFieldNames);
     if (!status.isOK()) {
@@ -599,8 +585,6 @@ Status parseMergeAuthzCollectionsCommand(const BSONObj& cmdObj,
     validFieldNames.insert("tempRolesCollection");
     validFieldNames.insert("db");
     validFieldNames.insert("drop");
-    validFieldNames.insert("writeConcern");
-    validFieldNames.insert("maxTimeMS");
 
     Status status = _checkNoExtraFields(cmdObj, "_mergeAuthzCollections", validFieldNames);
     if (!status.isOK()) {
@@ -648,8 +632,6 @@ Status parseAuthSchemaUpgradeCommand(const BSONObj& cmdObj,
     validFieldNames.insert("authSchemaUpgrade");
     validFieldNames.insert("maxSteps");
     validFieldNames.insert("upgradeShards");
-    validFieldNames.insert("writeConcern");
-    validFieldNames.insert("maxTimeMS");
 
     Status status = _checkNoExtraFields(cmdObj, "authSchemaUpgrade", validFieldNames);
     if (!status.isOK()) {
diff --git a/src/mongo/db/catalog/coll_mod.cpp b/src/mongo/db/catalog/coll_mod.cpp
index 93abe72214c..5e6ec1af9e4 100644
--- a/src/mongo/db/catalog/coll_mod.cpp
+++ b/src/mongo/db/catalog/coll_mod.cpp
@@ -63,22 +63,20 @@ struct CollModRequest {
 StatusWith<CollModRequest> parseCollModRequest(OperationContext* opCtx,
                                                const NamespaceString& nss,
                                                Collection* coll,
-                                               const BSONObj& cmdObj) {
+                                               const BSONObj& cmdObj,
+                                               BSONObjBuilder* oplogEntryBuilder) {
 
     bool isView = !coll;
 
     CollModRequest cmr;
 
     BSONForEach(e, cmdObj) {
-        if (str::equals("collMod", e.fieldName())) {
+        const auto fieldName = e.fieldNameStringData();
+        if (Command::isGenericArgument(fieldName)) {
+            continue;  // Don't add to oplog builder.
+        } else if (fieldName == "collMod") {
             // no-op
-        } else if (str::startsWith(e.fieldName(), "$")) {
-            // no-op ignore top-level fields prefixed with $. They are for the command processor
-        } else if (QueryRequest::cmdOptionMaxTimeMS == e.fieldNameStringData()) {
-            // no-op
-        } else if (str::equals("shardVersion", e.fieldName())) {
-            // no-op
-        } else if (str::equals("index", e.fieldName()) && !isView) {
+        } else if (fieldName == "index" && !isView) {
             BSONObj indexObj = e.Obj();
             StringData indexName;
             BSONObj keyPattern;
@@ -158,25 +156,25 @@ StatusWith<CollModRequest> parseCollModRequest(OperationContext* opCtx,
                               "existing expireAfterSeconds field is not a number");
             }
 
-        } else if (str::equals("validator", e.fieldName()) && !isView) {
+        } else if (fieldName == "validator" && !isView) {
             auto statusW = coll->parseValidator(e.Obj());
             if (!statusW.isOK())
                 return statusW.getStatus();
 
             cmr.collValidator = e;
-        } else if (str::equals("validationLevel", e.fieldName()) && !isView) {
+        } else if (fieldName == "validationLevel" && !isView) {
             auto statusW = coll->parseValidationLevel(e.String());
             if (!statusW.isOK())
                 return statusW.getStatus();
 
             cmr.collValidationLevel = e.String();
-        } else if (str::equals("validationAction", e.fieldName()) && !isView) {
+        } else if (fieldName == "validationAction" && !isView) {
             auto statusW = coll->parseValidationAction(e.String());
             if (!statusW.isOK())
                 statusW.getStatus();
 
             cmr.collValidationAction = e.String();
-        } else if (str::equals("pipeline", e.fieldName())) {
+        } else if (fieldName == "pipeline") {
             if (!isView) {
                 return Status(ErrorCodes::InvalidOptions,
                               "'pipeline' option only supported on a view");
@@ -185,7 +183,7 @@ StatusWith<CollModRequest> parseCollModRequest(OperationContext* opCtx,
                 return Status(ErrorCodes::InvalidOptions, "not a valid aggregation pipeline");
             }
             cmr.viewPipeLine = e;
-        } else if (str::equals("viewOn", e.fieldName())) {
+        } else if (fieldName == "viewOn") {
             if (!isView) {
                 return Status(ErrorCodes::InvalidOptions,
                               "'viewOn' option only supported on a view");
@@ -195,23 +193,24 @@ StatusWith<CollModRequest> parseCollModRequest(OperationContext* opCtx,
             }
             cmr.viewOn = e.str();
         } else {
-            const StringData name = e.fieldNameStringData();
             if (isView) {
                 return Status(ErrorCodes::InvalidOptions,
-                              str::stream() << "option not supported on a view: " << name);
+                              str::stream() << "option not supported on a view: " << fieldName);
             }
             // As of SERVER-17312 we only support these two options. When SERVER-17320 is
             // resolved this will need to be enhanced to handle other options.
             typedef CollectionOptions CO;
 
-            if (name == "usePowerOf2Sizes")
+            if (fieldName == "usePowerOf2Sizes")
                 cmr.usePowerOf2Sizes = e;
-            else if (name == "noPadding")
+            else if (fieldName == "noPadding")
                 cmr.noPadding = e;
             else
                 return Status(ErrorCodes::InvalidOptions,
-                              str::stream() << "unknown option to collMod: " << name);
+                              str::stream() << "unknown option to collMod: " << fieldName);
         }
+
+        oplogEntryBuilder->append(e);
     }
 
     return {std::move(cmr)};
@@ -256,7 +255,8 @@ Status collMod(OperationContext* opCtx,
                                     << nss.ns());
     }
 
-    auto statusW = parseCollModRequest(opCtx, nss, coll, cmdObj);
+    BSONObjBuilder oplogEntryBuilder;
+    auto statusW = parseCollModRequest(opCtx, nss, coll, cmdObj, &oplogEntryBuilder);
     if (!statusW.isOK()) {
         return statusW.getStatus();
     }
@@ -347,7 +347,7 @@ Status collMod(OperationContext* opCtx,
 
         // Only observe non-view collMods, as view operations are observed as operations on the
         // system.views collection.
-        getGlobalServiceContext()->getOpObserver()->onCollMod(opCtx, nss, cmdObj);
+        getGlobalServiceContext()->getOpObserver()->onCollMod(opCtx, nss, oplogEntryBuilder.obj());
     }
 
     wunit.commit();
diff --git a/src/mongo/db/catalog/coll_mod.h b/src/mongo/db/catalog/coll_mod.h
index 9442fc7d82e..2ae6e0cb33b 100644
--- a/src/mongo/db/catalog/coll_mod.h
+++ b/src/mongo/db/catalog/coll_mod.h
@@ -38,11 +38,6 @@ class OperationContext;
 
 struct CollModRequest;
 
-StatusWith<CollModRequest> parseCollModRequest(OperationContext* opCtx,
-                                               const NamespaceString& nss,
-                                               Collection* coll,
-                                               const BSONObj& cmdObj);
-
 /**
  * Performs the collection modification described in "cmdObj" on the collection "ns".
  */
diff --git a/src/mongo/db/catalog/collection_options.cpp b/src/mongo/db/catalog/collection_options.cpp
index 8825bdca62b..72431637574 100644
--- a/src/mongo/db/catalog/collection_options.cpp
+++ b/src/mongo/db/catalog/collection_options.cpp
@@ -31,6 +31,7 @@
 #include "mongo/db/catalog/collection_options.h"
 
 #include "mongo/base/string_data.h"
+#include "mongo/db/commands.h"
 #include "mongo/db/server_parameters.h"
 #include "mongo/util/mongoutils/str.h"
 
@@ -91,13 +92,6 @@ Status checkStorageEngineOptions(const BSONElement& elem) {
     return Status::OK();
 }
 
-// These are collection creation options which are handled elsewhere. If we encounter a field which
-// CollectionOptions doesn't know about, parsing the options should fail unless we find the field
-// name in this whitelist.
-const std::set<StringData> collectionOptionsWhitelist{
-    "maxTimeMS"_sd, "writeConcern"_sd,
-};
-
 }  // namespace
 
 bool CollectionOptions::isView() const {
@@ -249,8 +243,7 @@ Status CollectionOptions::parse(const BSONObj& options, ParseKind kind) {
             }
 
             pipeline = e.Obj().getOwned();
-        } else if (!createdOn24OrEarlier &&
-                   collectionOptionsWhitelist.find(fieldName) == collectionOptionsWhitelist.end()) {
+        } else if (!createdOn24OrEarlier && !Command::isGenericArgument(fieldName)) {
             return Status(ErrorCodes::InvalidOptions,
                           str::stream() << "The field '" << fieldName
                                         << "' is not a valid collection option. Options: "
diff --git a/src/mongo/db/catalog/create_collection.cpp b/src/mongo/db/catalog/create_collection.cpp
index f8a39c20350..19e32cb9b96 100644
--- a/src/mongo/db/catalog/create_collection.cpp
+++ b/src/mongo/db/catalog/create_collection.cpp
@@ -63,7 +63,9 @@ Status createCollection(OperationContext* opCtx,
     // Build options object from remaining cmdObj elements.
     BSONObjBuilder optionsBuilder;
     while (it.more()) {
-        optionsBuilder.append(it.next());
+        const auto elem = it.next();
+        if (!Command::isGenericArgument(elem.fieldNameStringData()))
+            optionsBuilder.append(elem);
     }
 
     BSONObj options = optionsBuilder.obj();
diff --git a/src/mongo/db/commands.h b/src/mongo/db/commands.h
index 0c9ffca316b..02e9f125e95 100644
--- a/src/mongo/db/commands.h
+++ b/src/mongo/db/commands.h
@@ -472,6 +472,22 @@ public:
                                      const std::string& dbname,
                                      const BSONObj& cmdObj);
 
+    /**
+     * Returns true if the provided argument is one that is handled by the command processing layer
+     * and should generally be ignored by individual command implementations. In particular,
+     * commands that fail on unrecognized arguments must not fail for any of these.
+     */
+    static bool isGenericArgument(StringData arg) {
+        // Not including "help" since we don't pass help requests through to the command parser.
+        // If that changes, it should be added.
+        return arg == "maxTimeMS" ||   //
+            arg == "$queryOptions" ||  //
+            arg == "shardVersion" ||   //
+            arg == "writeConcern" ||   //
+            arg == "readConcern" ||    //
+            false;  // These comments tell clang-format to keep this line-oriented.
+    }
+
 private:
     /**
      * Checks if the given client is authorized to run this command on database "dbname"
diff --git a/src/mongo/db/commands/create_indexes.cpp b/src/mongo/db/commands/create_indexes.cpp
index 189ec8e78f1..8dfca9ed9cc 100644
--- a/src/mongo/db/commands/create_indexes.cpp
+++ b/src/mongo/db/commands/create_indexes.cpp
@@ -66,9 +66,6 @@ namespace {
 
 const StringData kIndexesFieldName = "indexes"_sd;
 const StringData kCommandName = "createIndexes"_sd;
-const StringData kWriteConcern = "writeConcern"_sd;
-const StringData kMaxTimeMS = "maxTimeMS"_sd;
-const StringData kShardVersion = "shardVersion"_sd;
 
 /**
  * Parses the index specifications from 'cmdObj', validates them, and returns equivalent index
@@ -125,8 +122,8 @@ StatusWith<std::vector<BSONObj>> parseAndValidateIndexSpecs(
             }
 
             hasIndexesField = true;
-        } else if (kCommandName == cmdElemFieldName || kWriteConcern == cmdElemFieldName ||
-                   kMaxTimeMS == cmdElemFieldName || kShardVersion == cmdElemFieldName) {
+        } else if (kCommandName == cmdElemFieldName ||
+                   Command::isGenericArgument(cmdElemFieldName)) {
             continue;
         } else {
             return {ErrorCodes::BadValue,
diff --git a/src/mongo/db/commands/current_op.cpp b/src/mongo/db/commands/current_op.cpp
index c5f05e314ae..ebb4c15d207 100644
--- a/src/mongo/db/commands/current_op.cpp
+++ b/src/mongo/db/commands/current_op.cpp
@@ -103,9 +103,12 @@ public:
             i.next();  // skip {currentOp: 1} which is required to be the first element
             while (i.more()) {
                 BSONElement e = i.next();
-                if (str::equals("$all", e.fieldName())) {
+                const auto fieldName = e.fieldNameStringData();
+                if (fieldName == "$all") {
                     continue;
-                } else if (str::equals("$ownOps", e.fieldName())) {
+                } else if (fieldName == "$ownOps") {
+                    continue;
+                } else if (Command::isGenericArgument(fieldName)) {
                     continue;
                 }
 
diff --git a/src/mongo/db/commands/feature_compatibility_version_command_parser.cpp b/src/mongo/db/commands/feature_compatibility_version_command_parser.cpp
index e8536e88db2..551ac40a758 100644
--- a/src/mongo/db/commands/feature_compatibility_version_command_parser.cpp
+++ b/src/mongo/db/commands/feature_compatibility_version_command_parser.cpp
@@ -32,6 +32,7 @@
 
 #include "mongo/base/status_with.h"
 #include "mongo/bson/bsonobj.h"
+#include "mongo/db/commands.h"
 #include "mongo/db/query/query_request.h"
 #include "mongo/util/version.h"
 
@@ -62,8 +63,8 @@ StatusWith<std::string> FeatureCompatibilityVersionCommandParser::extractVersion
 
     // Ensure that the command does not contain any unrecognized parameters
     for (const auto& cmdElem : cmdObj) {
-        if (cmdElem.fieldNameStringData() == commandName ||
-            cmdElem.fieldNameStringData() == QueryRequest::cmdOptionMaxTimeMS) {
+        const auto fieldName = cmdElem.fieldNameStringData();
+        if (fieldName == commandName || Command::isGenericArgument(fieldName)) {
             continue;
         }
 
diff --git a/src/mongo/db/commands/get_last_error.cpp b/src/mongo/db/commands/get_last_error.cpp
index 0340a01139b..c5d8ff9b519 100644
--- a/src/mongo/db/commands/get_last_error.cpp
+++ b/src/mongo/db/commands/get_last_error.cpp
@@ -203,9 +203,17 @@ public:
             }
         }
 
-        BSONObj writeConcernDoc = cmdObj;
+        BSONObj writeConcernDoc = ([&] {
+            BSONObjBuilder bob;
+            for (auto&& elem : cmdObj) {
+                if (!Command::isGenericArgument(elem.fieldNameStringData()))
+                    bob.append(elem);
+            }
+            return bob.obj();
+        }());
+
         // Use the default options if we have no gle options aside from wOpTime/wElectionId
-        const int nFields = cmdObj.nFields();
+        const int nFields = writeConcernDoc.nFields();
         bool useDefaultGLEOptions = (nFields == 1) || (nFields == 2 && lastOpTimePresent) ||
             (nFields == 3 && lastOpTimePresent && electionIdPresent);
 
diff --git a/src/mongo/db/commands/parameters.cpp b/src/mongo/db/commands/parameters.cpp
index f2e10dac2b5..c908edb3390 100644
--- a/src/mongo/db/commands/parameters.cpp
+++ b/src/mongo/db/commands/parameters.cpp
@@ -164,6 +164,8 @@ public:
         while (parameterCheckIterator.more()) {
             BSONElement parameter = parameterCheckIterator.next();
             std::string parameterName = parameter.fieldName();
+            if (Command::isGenericArgument(parameterName))
+                continue;
 
             ServerParameter::Map::const_iterator foundParameter = parameterMap.find(parameterName);
 
diff --git a/src/mongo/db/ops/write_ops_parsers.cpp b/src/mongo/db/ops/write_ops_parsers.cpp
index 1cbe9dea328..f45af99d00e 100644
--- a/src/mongo/db/ops/write_ops_parsers.cpp
+++ b/src/mongo/db/ops/write_ops_parsers.cpp
@@ -33,6 +33,7 @@
 #include "mongo/bson/util/bson_check.h"
 #include "mongo/client/dbclientinterface.h"
 #include "mongo/db/catalog/document_validation.h"
+#include "mongo/db/commands.h"
 #include "mongo/db/dbmessage.h"
 #include "mongo/util/assert_util.h"
 #include "mongo/util/mongoutils/str.h"
@@ -106,15 +107,11 @@ void parseWriteCommand(StringData dbName,
         } else if (fieldName == uniqueFieldName) {
             haveUniqueField = true;
             *uniqueField = field;
-        } else if (fieldName[0] != '$') {
-            std::initializer_list<StringData> ignoredFields = {
-                "writeConcern", "maxTimeMS", "shardVersion"};
-            uassert(ErrorCodes::FailedToParse,
-                    str::stream() << "Unknown option to " << cmd.firstElementFieldName()
-                                  << " command: "
-                                  << fieldName,
-                    std::find(ignoredFields.begin(), ignoredFields.end(), fieldName) !=
-                        ignoredFields.end());
+        } else if (!Command::isGenericArgument(fieldName)) {
+            uasserted(ErrorCodes::FailedToParse,
+                      str::stream() << "Unknown option to " << cmd.firstElementFieldName()
+                                    << " command: "
+                                    << fieldName);
         }
     }
 
diff --git a/src/mongo/db/pipeline/aggregation_request.cpp b/src/mongo/db/pipeline/aggregation_request.cpp
index 43adbb213ad..163c4f288c1 100644
--- a/src/mongo/db/pipeline/aggregation_request.cpp
+++ b/src/mongo/db/pipeline/aggregation_request.cpp
@@ -83,8 +83,7 @@ StatusWith<AggregationRequest> AggregationRequest::parseFromBSON(
 
     AggregationRequest request(std::move(nss), std::move(pipeline));
 
-    const std::initializer_list<StringData> optionsParsedElseWhere = {
-        WriteConcernOptions::kWriteConcernField, kPipelineName, kCommandName};
+    const std::initializer_list<StringData> optionsParsedElseWhere = {kPipelineName, kCommandName};
 
     bool hasCursorElem = false;
     bool hasExplainElem = false;
@@ -93,24 +92,14 @@ StatusWith<AggregationRequest> AggregationRequest::parseFromBSON(
     for (auto&& elem : cmdObj) {
         auto fieldName = elem.fieldNameStringData();
 
-        // $queryOptions is the exception to our '$' filter. We expect this field to be validated
-        // elsewhere.
         if (QueryRequest::kUnwrappedReadPrefField == fieldName) {
+            // We expect this field to be validated elsewhere.
             request.setUnwrappedReadPref(elem.embeddedObject());
-        }
-
-        // Ignore top-level fields prefixed with $. They are for the command processor, not us.
-        if (fieldName[0] == '$') {
-            continue;
-        }
-
-        // Ignore options that are parsed elsewhere.
-        if (std::find(optionsParsedElseWhere.begin(), optionsParsedElseWhere.end(), fieldName) !=
-            optionsParsedElseWhere.end()) {
-            continue;
-        }
-
-        if (kCursorName == fieldName) {
+        } else if (std::find(optionsParsedElseWhere.begin(),
+                             optionsParsedElseWhere.end(),
+                             fieldName) != optionsParsedElseWhere.end()) {
+            // Ignore options that are parsed elsewhere.
+        } else if (kCursorName == fieldName) {
             long long batchSize;
             auto status =
                 CursorRequest::parseCommandCursorOptions(cmdObj, kDefaultBatchSize, &batchSize);
@@ -192,7 +181,7 @@ StatusWith<AggregationRequest> AggregationRequest::parseFromBSON(
             request.setAllowDiskUse(elem.Bool());
         } else if (bypassDocumentValidationCommandOption() == fieldName) {
             request.setBypassDocumentValidation(elem.trueValue());
-        } else {
+        } else if (!Command::isGenericArgument(fieldName)) {
             return {ErrorCodes::FailedToParse,
                     str::stream() << "unrecognized field '" << elem.fieldName() << "'"};
         }
diff --git a/src/mongo/db/pipeline/aggregation_request_test.cpp b/src/mongo/db/pipeline/aggregation_request_test.cpp
index ba036c71bf4..cb68a8af79d 100644
--- a/src/mongo/db/pipeline/aggregation_request_test.cpp
+++ b/src/mongo/db/pipeline/aggregation_request_test.cpp
@@ -368,10 +368,10 @@ TEST(AggregationRequestTest, ShouldRejectExplainExecStatsVerbosityWithWriteConce
 // Ignore fields parsed elsewhere.
 //
 
-TEST(AggregationRequestTest, ShouldIgnoreFieldsPrefixedWithDollar) {
+TEST(AggregationRequestTest, ShouldIgnoreQueryOptions) {
     NamespaceString nss("a.collection");
     const BSONObj inputBson =
-        fromjson("{pipeline: [{$match: {a: 'abc'}}], cursor: {}, $unknown: 1}");
+        fromjson("{pipeline: [{$match: {a: 'abc'}}], cursor: {}, $queryOptions: {}}");
     ASSERT_OK(AggregationRequest::parseFromBSON(nss, inputBson).getStatus());
 }
 
diff --git a/src/mongo/db/query/getmore_request.cpp b/src/mongo/db/query/getmore_request.cpp
index 48f68d338ee..6c738c4da67 100644
--- a/src/mongo/db/query/getmore_request.cpp
+++ b/src/mongo/db/query/getmore_request.cpp
@@ -34,6 +34,7 @@
 
 #include <boost/optional.hpp>
 
+#include "mongo/db/commands.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/repl/bson_extract_optime.h"
 #include "mongo/util/assert_util.h"
@@ -112,15 +113,15 @@ StatusWith<GetMoreRequest> GetMoreRequest::parseFromBSON(const std::string& dbna
     boost::optional<repl::OpTime> lastKnownCommittedOpTime;
 
     for (BSONElement el : cmdObj) {
-        const char* fieldName = el.fieldName();
-        if (str::equals(fieldName, kGetMoreCommandName)) {
+        const auto fieldName = el.fieldNameStringData();
+        if (fieldName == kGetMoreCommandName) {
             if (el.type() != BSONType::NumberLong) {
                 return {ErrorCodes::TypeMismatch,
                         str::stream() << "Field 'getMore' must be of type long in: " << cmdObj};
             }
 
             cursorid = el.Long();
-        } else if (str::equals(fieldName, kCollectionField)) {
+        } else if (fieldName == kCollectionField) {
             if (el.type() != BSONType::String) {
                 return {ErrorCodes::TypeMismatch,
                         str::stream() << "Field 'collection' must be of type string in: "
@@ -128,14 +129,14 @@ StatusWith<GetMoreRequest> GetMoreRequest::parseFromBSON(const std::string& dbna
             }
 
             nss = parseNs(dbname, cmdObj);
-        } else if (str::equals(fieldName, kBatchSizeField)) {
+        } else if (fieldName == kBatchSizeField) {
             if (!el.isNumber()) {
                 return {ErrorCodes::TypeMismatch,
                         str::stream() << "Field 'batchSize' must be a number in: " << cmdObj};
             }
 
             batchSize = el.numberLong();
-        } else if (str::equals(fieldName, kAwaitDataTimeoutField)) {
+        } else if (fieldName == kAwaitDataTimeoutField) {
             auto maxAwaitDataTime = QueryRequest::parseMaxTimeMS(el);
             if (!maxAwaitDataTime.isOK()) {
                 return maxAwaitDataTime.getStatus();
@@ -144,20 +145,20 @@ StatusWith<GetMoreRequest> GetMoreRequest::parseFromBSON(const std::string& dbna
             if (maxAwaitDataTime.getValue()) {
                 awaitDataTimeout = Milliseconds(maxAwaitDataTime.getValue());
             }
-        } else if (str::equals(fieldName, kTermField)) {
+        } else if (fieldName == kTermField) {
             if (el.type() != BSONType::NumberLong) {
                 return {ErrorCodes::TypeMismatch,
                         str::stream() << "Field 'term' must be of type NumberLong in: " << cmdObj};
             }
             term = el.Long();
-        } else if (str::equals(fieldName, kLastKnownCommittedOpTimeField)) {
+        } else if (fieldName == kLastKnownCommittedOpTimeField) {
             repl::OpTime ot;
             Status status = bsonExtractOpTimeField(el.wrap(), kLastKnownCommittedOpTimeField, &ot);
             if (!status.isOK()) {
                 return status;
             }
             lastKnownCommittedOpTime = ot;
-        } else if (!str::startsWith(fieldName, "$")) {
+        } else if (!Command::isGenericArgument(fieldName)) {
             return {ErrorCodes::FailedToParse,
                     str::stream() << "Failed to parse: " << cmdObj << ". "
                                   << "Unrecognized field '"
diff --git a/src/mongo/db/query/getmore_request_test.cpp b/src/mongo/db/query/getmore_request_test.cpp
index 828a434658d..f1be6a613bf 100644
--- a/src/mongo/db/query/getmore_request_test.cpp
+++ b/src/mongo/db/query/getmore_request_test.cpp
@@ -168,12 +168,12 @@ TEST(GetMoreRequestTest, parseFromBSONBatchSizeProvided) {
     ASSERT_EQUALS(200, *result.getValue().batchSize);
 }
 
-TEST(GetMoreRequestTest, parseFromBSONIgnoreDollarPrefixedFields) {
+TEST(GetMoreRequestTest, parseFromBSONIgnoreQueryOptions) {
     StatusWith<GetMoreRequest> result =
         GetMoreRequest::parseFromBSON("db",
                                       BSON("getMore" << CursorId(123) << "collection"
                                                      << "coll"
-                                                     << "$foo"
+                                                     << "$queryOptions"
                                                      << "bar"));
     ASSERT_OK(result.getStatus());
     ASSERT_EQUALS("db.coll", result.getValue().nss.toString());
diff --git a/src/mongo/db/query/query_request.cpp b/src/mongo/db/query/query_request.cpp
index 467f57f41f0..0b6d6e4c5c4 100644
--- a/src/mongo/db/query/query_request.cpp
+++ b/src/mongo/db/query/query_request.cpp
@@ -34,6 +34,7 @@
 #include "mongo/base/status_with.h"
 #include "mongo/bson/simple_bsonobj_comparator.h"
 #include "mongo/client/dbclientinterface.h"
+#include "mongo/db/commands.h"
 #include "mongo/db/dbmessage.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/repl/read_concern_args.h"
@@ -121,34 +122,34 @@ StatusWith<unique_ptr<QueryRequest>> QueryRequest::makeFromFindCommand(Namespace
     BSONObjIterator it(cmdObj);
     while (it.more()) {
         BSONElement el = it.next();
-        const char* fieldName = el.fieldName();
-        if (str::equals(fieldName, kFindCommandName)) {
+        const auto fieldName = el.fieldNameStringData();
+        if (fieldName == kFindCommandName) {
             Status status = checkFieldType(el, String);
             if (!status.isOK()) {
                 return status;
             }
-        } else if (str::equals(fieldName, kFilterField)) {
+        } else if (fieldName == kFilterField) {
             Status status = checkFieldType(el, Object);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_filter = el.Obj().getOwned();
-        } else if (str::equals(fieldName, kProjectionField)) {
+        } else if (fieldName == kProjectionField) {
             Status status = checkFieldType(el, Object);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_proj = el.Obj().getOwned();
-        } else if (str::equals(fieldName, kSortField)) {
+        } else if (fieldName == kSortField) {
             Status status = checkFieldType(el, Object);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_sort = el.Obj().getOwned();
-        } else if (str::equals(fieldName, kHintField)) {
+        } else if (fieldName == kHintField) {
             BSONObj hintObj;
             if (Object == el.type()) {
                 hintObj = cmdObj["hint"].Obj().getOwned();
@@ -160,7 +161,7 @@ StatusWith<unique_ptr<QueryRequest>> QueryRequest::makeFromFindCommand(Namespace
             }
 
             qr->_hint = hintObj;
-        } else if (str::equals(fieldName, repl::ReadConcernArgs::kReadConcernFieldName.c_str())) {
+        } else if (fieldName == repl::ReadConcernArgs::kReadConcernFieldName) {
             // Read concern parsing is handled elsewhere, but we store a copy here.
             Status status = checkFieldType(el, Object);
             if (!status.isOK()) {
@@ -168,7 +169,7 @@ StatusWith<unique_ptr<QueryRequest>> QueryRequest::makeFromFindCommand(Namespace
             }
 
             qr->_readConcern = el.Obj().getOwned();
-        } else if (str::equals(fieldName, QueryRequest::kUnwrappedReadPrefField.c_str())) {
+        } else if (fieldName == QueryRequest::kUnwrappedReadPrefField) {
             // Read preference parsing is handled elsewhere, but we store a copy here.
             Status status = checkFieldType(el, Object);
             if (!status.isOK()) {
@@ -176,7 +177,7 @@ StatusWith<unique_ptr<QueryRequest>> QueryRequest::makeFromFindCommand(Namespace
             }
 
             qr->setUnwrappedReadPref(el.Obj());
-        } else if (str::equals(fieldName, kCollationField)) {
+        } else if (fieldName == kCollationField) {
             // Collation parsing is handled elsewhere, but we store a copy here.
             Status status = checkFieldType(el, Object);
             if (!status.isOK()) {
@@ -184,7 +185,7 @@ StatusWith<unique_ptr<QueryRequest>> QueryRequest::makeFromFindCommand(Namespace
             }
 
             qr->_collation = el.Obj().getOwned();
-        } else if (str::equals(fieldName, kSkipField)) {
+        } else if (fieldName == kSkipField) {
             if (!el.isNumber()) {
                 str::stream ss;
                 ss << "Failed to parse: " << cmdObj.toString() << ". "
@@ -198,7 +199,7 @@ StatusWith<unique_ptr<QueryRequest>> QueryRequest::makeFromFindCommand(Namespace
             if (skip) {
                 qr->_skip = skip;
             }
-        } else if (str::equals(fieldName, kLimitField)) {
+        } else if (fieldName == kLimitField) {
             if (!el.isNumber()) {
                 str::stream ss;
                 ss << "Failed to parse: " << cmdObj.toString() << ". "
@@ -212,7 +213,7 @@ StatusWith<unique_ptr<QueryRequest>> QueryRequest::makeFromFindCommand(Namespace
             if (limit) {
                 qr->_limit = limit;
             }
-        } else if (str::equals(fieldName, kBatchSizeField)) {
+        } else if (fieldName == kBatchSizeField) {
             if (!el.isNumber()) {
                 str::stream ss;
                 ss << "Failed to parse: " << cmdObj.toString() << ". "
@@ -221,7 +222,7 @@ StatusWith<unique_ptr<QueryRequest>> QueryRequest::makeFromFindCommand(Namespace
             }
 
             qr->_batchSize = el.numberLong();
-        } else if (str::equals(fieldName, kNToReturnField)) {
+        } else if (fieldName == kNToReturnField) {
             if (!el.isNumber()) {
                 str::stream ss;
                 ss << "Failed to parse: " << cmdObj.toString() << ". "
@@ -230,21 +231,21 @@ StatusWith<unique_ptr<QueryRequest>> QueryRequest::makeFromFindCommand(Namespace
             }
 
             qr->_ntoreturn = el.numberLong();
-        } else if (str::equals(fieldName, kSingleBatchField)) {
+        } else if (fieldName == kSingleBatchField) {
             Status status = checkFieldType(el, Bool);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_wantMore = !el.boolean();
-        } else if (str::equals(fieldName, kCommentField)) {
+        } else if (fieldName == kCommentField) {
             Status status = checkFieldType(el, String);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_comment = el.str();
-        } else if (str::equals(fieldName, kMaxScanField)) {
+        } else if (fieldName == kMaxScanField) {
             if (!el.isNumber()) {
                 str::stream ss;
                 ss << "Failed to parse: " << cmdObj.toString() << ". "
@@ -253,84 +254,84 @@ StatusWith<unique_ptr<QueryRequest>> QueryRequest::makeFromFindCommand(Namespace
             }
 
             qr->_maxScan = el.numberInt();
-        } else if (str::equals(fieldName, cmdOptionMaxTimeMS)) {
+        } else if (fieldName == cmdOptionMaxTimeMS) {
             StatusWith<int> maxTimeMS = parseMaxTimeMS(el);
             if (!maxTimeMS.isOK()) {
                 return maxTimeMS.getStatus();
             }
 
             qr->_maxTimeMS = maxTimeMS.getValue();
-        } else if (str::equals(fieldName, kMinField)) {
+        } else if (fieldName == kMinField) {
             Status status = checkFieldType(el, Object);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_min = el.Obj().getOwned();
-        } else if (str::equals(fieldName, kMaxField)) {
+        } else if (fieldName == kMaxField) {
             Status status = checkFieldType(el, Object);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_max = el.Obj().getOwned();
-        } else if (str::equals(fieldName, kReturnKeyField)) {
+        } else if (fieldName == kReturnKeyField) {
             Status status = checkFieldType(el, Bool);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_returnKey = el.boolean();
-        } else if (str::equals(fieldName, kShowRecordIdField)) {
+        } else if (fieldName == kShowRecordIdField) {
             Status status = checkFieldType(el, Bool);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_showRecordId = el.boolean();
-        } else if (str::equals(fieldName, kSnapshotField)) {
+        } else if (fieldName == kSnapshotField) {
             Status status = checkFieldType(el, Bool);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_snapshot = el.boolean();
-        } else if (str::equals(fieldName, kTailableField)) {
+        } else if (fieldName == kTailableField) {
             Status status = checkFieldType(el, Bool);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_tailable = el.boolean();
-        } else if (str::equals(fieldName, kOplogReplayField)) {
+        } else if (fieldName == kOplogReplayField) {
             Status status = checkFieldType(el, Bool);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_oplogReplay = el.boolean();
-        } else if (str::equals(fieldName, kNoCursorTimeoutField)) {
+        } else if (fieldName == kNoCursorTimeoutField) {
             Status status = checkFieldType(el, Bool);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_noCursorTimeout = el.boolean();
-        } else if (str::equals(fieldName, kAwaitDataField)) {
+        } else if (fieldName == kAwaitDataField) {
             Status status = checkFieldType(el, Bool);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_awaitData = el.boolean();
-        } else if (str::equals(fieldName, kPartialResultsField)) {
+        } else if (fieldName == kPartialResultsField) {
             Status status = checkFieldType(el, Bool);
             if (!status.isOK()) {
                 return status;
             }
 
             qr->_allowPartialResults = el.boolean();
-        } else if (str::equals(fieldName, kOptionsField)) {
+        } else if (fieldName == kOptionsField) {
             // 3.0.x versions of the shell may generate an explain of a find command with an
             // 'options' field. We accept this only if the 'options' field is empty so that
             // the shell's explain implementation is forwards compatible.
@@ -353,15 +354,15 @@ StatusWith<unique_ptr<QueryRequest>> QueryRequest::makeFromFindCommand(Namespace
                               str::stream() << "Failed to parse options: " << optionsObj.toString()
                                             << ". You may need to update your shell or driver.");
             }
-        } else if (str::equals(fieldName, kShardVersionField)) {
+        } else if (fieldName == kShardVersionField) {
             // Shard version parsing is handled elsewhere.
-        } else if (str::equals(fieldName, kTermField)) {
+        } else if (fieldName == kTermField) {
             Status status = checkFieldType(el, NumberLong);
             if (!status.isOK()) {
                 return status;
             }
             qr->_replicationTerm = el._numberLong();
-        } else if (!str::startsWith(fieldName, '$')) {
+        } else if (!Command::isGenericArgument(fieldName)) {
             return Status(ErrorCodes::FailedToParse,
                           str::stream() << "Failed to parse: " << cmdObj.toString() << ". "
                                         << "Unrecognized field '"
diff --git a/src/mongo/db/repl/handshake_args.cpp b/src/mongo/db/repl/handshake_args.cpp
index 2ceae3df86e..d8ebf3c0fc7 100644
--- a/src/mongo/db/repl/handshake_args.cpp
+++ b/src/mongo/db/repl/handshake_args.cpp
@@ -53,7 +53,8 @@ const std::string kLegalHandshakeFieldNames[] = {
 HandshakeArgs::HandshakeArgs() : _hasRid(false), _hasMemberId(false), _rid(OID()), _memberId(-1) {}
 
 Status HandshakeArgs::initialize(const BSONObj& argsObj) {
-    Status status = bsonCheckOnlyHasFields("HandshakeArgs", argsObj, kLegalHandshakeFieldNames);
+    Status status =
+        bsonCheckOnlyHasFieldsForCommand("HandshakeArgs", argsObj, kLegalHandshakeFieldNames);
     if (!status.isOK())
         return status;
 
diff --git a/src/mongo/db/repl/old_update_position_args.cpp b/src/mongo/db/repl/old_update_position_args.cpp
index 92ffd74db79..e3c2f295d26 100644
--- a/src/mongo/db/repl/old_update_position_args.cpp
+++ b/src/mongo/db/repl/old_update_position_args.cpp
@@ -70,8 +70,8 @@ const std::string kLegalUpdateInfoFieldNames[] = {
 }  // namespace
 
 Status OldUpdatePositionArgs::initialize(const BSONObj& argsObj) {
-    Status status =
-        bsonCheckOnlyHasFields("OldUpdatePositionArgs", argsObj, kLegalUpdatePositionFieldNames);
+    Status status = bsonCheckOnlyHasFieldsForCommand(
+        "OldUpdatePositionArgs", argsObj, kLegalUpdatePositionFieldNames);
 
     if (!status.isOK())
         return status;
diff --git a/src/mongo/db/repl/repl_set_heartbeat_args.cpp b/src/mongo/db/repl/repl_set_heartbeat_args.cpp
index babca5a0dfa..db88f7e47b6 100644
--- a/src/mongo/db/repl/repl_set_heartbeat_args.cpp
+++ b/src/mongo/db/repl/repl_set_heartbeat_args.cpp
@@ -70,8 +70,8 @@ ReplSetHeartbeatArgs::ReplSetHeartbeatArgs()
       _senderHost(HostAndPort()) {}
 
 Status ReplSetHeartbeatArgs::initialize(const BSONObj& argsObj) {
-    Status status =
-        bsonCheckOnlyHasFields("ReplSetHeartbeatArgs", argsObj, kLegalHeartbeatFieldNames);
+    Status status = bsonCheckOnlyHasFieldsForCommand(
+        "ReplSetHeartbeatArgs", argsObj, kLegalHeartbeatFieldNames);
     if (!status.isOK())
         return status;
 
diff --git a/src/mongo/db/repl/repl_set_heartbeat_args_v1.cpp b/src/mongo/db/repl/repl_set_heartbeat_args_v1.cpp
index af6b4d69eed..39bab8cdda7 100644
--- a/src/mongo/db/repl/repl_set_heartbeat_args_v1.cpp
+++ b/src/mongo/db/repl/repl_set_heartbeat_args_v1.cpp
@@ -57,8 +57,8 @@ const std::string kLegalHeartbeatFieldNames[] = {kCheckEmptyFieldName,
 }  // namespace
 
 Status ReplSetHeartbeatArgsV1::initialize(const BSONObj& argsObj) {
-    Status status =
-        bsonCheckOnlyHasFields("ReplSetHeartbeatArgs", argsObj, kLegalHeartbeatFieldNames);
+    Status status = bsonCheckOnlyHasFieldsForCommand(
+        "ReplSetHeartbeatArgs", argsObj, kLegalHeartbeatFieldNames);
     if (!status.isOK())
         return status;
 
diff --git a/src/mongo/db/repl/repl_set_request_votes_args.cpp b/src/mongo/db/repl/repl_set_request_votes_args.cpp
index 83ded65f45f..9dbafb9c564 100644
--- a/src/mongo/db/repl/repl_set_request_votes_args.cpp
+++ b/src/mongo/db/repl/repl_set_request_votes_args.cpp
@@ -70,7 +70,8 @@ const std::string kLegalResponseFieldNames[] = {
 
 
 Status ReplSetRequestVotesArgs::initialize(const BSONObj& argsObj) {
-    Status status = bsonCheckOnlyHasFields("ReplSetRequestVotes", argsObj, kLegalArgsFieldNames);
+    Status status =
+        bsonCheckOnlyHasFieldsForCommand("ReplSetRequestVotes", argsObj, kLegalArgsFieldNames);
     if (!status.isOK())
         return status;