SERVER-34179 refactor isGenericArgument

    Remove the static tables floating around at namespace scope.

    break CommandHelpers::isGenericArgument into
    command_generic_argument library so it doesn't have to be inline.
    Some callers depend on it but would have a circularity if they
    actually added db/commands to their LIBDEPS.

27 files changed, 219 insertions, 73 deletions

diff --git a/src/mongo/bson/util/bson_check.h b/src/mongo/bson/util/bson_check.h
index 4e290024824..2c1ae510d01 100644
--- a/src/mongo/bson/util/bson_check.h
+++ b/src/mongo/bson/util/bson_check.h
@@ -29,6 +29,7 @@
 #pragma once
 
 #include "mongo/base/status.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/jsobj.h"
 #include "mongo/util/mongoutils/str.h"
@@ -91,7 +92,7 @@ Status bsonCheckOnlyHasFieldsForCommand(StringData objectName,
                                         const BSONObj& obj,
                                         const Container& allowedFields) {
     return bsonCheckOnlyHasFieldsImpl(objectName, obj, [&](StringData name) {
-        return CommandHelpers::isGenericArgument(name) ||
+        return isGenericArgument(name) ||
             (std::find(std::begin(allowedFields), std::end(allowedFields), name) !=
              std::end(allowedFields));
     });
diff --git a/src/mongo/db/SConscript b/src/mongo/db/SConscript
index 5382ff524bd..7c0d43768ef 100644
--- a/src/mongo/db/SConscript
+++ b/src/mongo/db/SConscript
@@ -536,11 +536,22 @@ env.Library(
     LIBDEPS_PRIVATE=[
         '$BUILD_DIR/mongo/rpc/rpc',
         'audit',
+        'command_generic_argument',
         'commands/server_status_core',
     ],
 )
 
 env.Library(
+    target='command_generic_argument',
+    source=[
+        'command_generic_argument.cpp',
+    ],
+    LIBDEPS=[
+        '$BUILD_DIR/mongo/base',
+    ],
+)
+
+env.Library(
     target='command_can_run_here',
     source=[
         'command_can_run_here.cpp',
diff --git a/src/mongo/db/auth/user_management_commands_parser.cpp b/src/mongo/db/auth/user_management_commands_parser.cpp
index 141b74ca07d..3785dea3cf8 100644
--- a/src/mongo/db/auth/user_management_commands_parser.cpp
+++ b/src/mongo/db/auth/user_management_commands_parser.cpp
@@ -43,6 +43,7 @@
 #include "mongo/db/auth/privilege_parser.h"
 #include "mongo/db/auth/user_document_parser.h"
 #include "mongo/db/auth/user_name.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/jsobj.h"
 #include "mongo/stdx/unordered_set.h"
@@ -61,8 +62,7 @@ Status _checkNoExtraFields(const BSONObj& cmdObj,
     // ones.
     for (BSONObjIterator iter(cmdObj); iter.more(); iter.next()) {
         StringData fieldName = (*iter).fieldNameStringData();
-        if (!CommandHelpers::isGenericArgument(fieldName) &&
-            !validFieldNames.count(fieldName.toString())) {
+        if (!isGenericArgument(fieldName) && !validFieldNames.count(fieldName.toString())) {
             return Status(ErrorCodes::BadValue,
                           mongoutils::str::stream() << "\"" << fieldName << "\" is not "
                                                                             "a valid argument to "
diff --git a/src/mongo/db/catalog/SConscript b/src/mongo/db/catalog/SConscript
index 5aa69e986c2..fecc8c6d35c 100644
--- a/src/mongo/db/catalog/SConscript
+++ b/src/mongo/db/catalog/SConscript
@@ -20,6 +20,7 @@ env.Library(
     ],
     LIBDEPS=[
         '$BUILD_DIR/mongo/base',
+        '$BUILD_DIR/mongo/db/command_generic_argument',
         '$BUILD_DIR/mongo/db/query/collation/collator_interface',
         '$BUILD_DIR/mongo/db/server_parameters',
     ],
diff --git a/src/mongo/db/catalog/coll_mod.cpp b/src/mongo/db/catalog/coll_mod.cpp
index 1bf42f508d8..35a082819fd 100644
--- a/src/mongo/db/catalog/coll_mod.cpp
+++ b/src/mongo/db/catalog/coll_mod.cpp
@@ -41,6 +41,7 @@
 #include "mongo/db/catalog/collection_options.h"
 #include "mongo/db/catalog/index_catalog.h"
 #include "mongo/db/client.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/db_raii.h"
 #include "mongo/db/index/index_descriptor.h"
 #include "mongo/db/repl/repl_client_info.h"
@@ -89,7 +90,7 @@ StatusWith<CollModRequest> parseCollModRequest(OperationContext* opCtx,
 
     BSONForEach(e, cmdObj) {
         const auto fieldName = e.fieldNameStringData();
-        if (CommandHelpers::isGenericArgument(fieldName)) {
+        if (isGenericArgument(fieldName)) {
             continue;  // Don't add to oplog builder.
         } else if (fieldName == "collMod") {
             // no-op
diff --git a/src/mongo/db/catalog/collection_options.cpp b/src/mongo/db/catalog/collection_options.cpp
index 5cedeab2302..67da1098dd0 100644
--- a/src/mongo/db/catalog/collection_options.cpp
+++ b/src/mongo/db/catalog/collection_options.cpp
@@ -33,6 +33,7 @@
 #include <algorithm>
 
 #include "mongo/base/string_data.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/query/collation/collator_factory_interface.h"
 #include "mongo/db/query/collation/collator_interface.h"
@@ -253,7 +254,7 @@ Status CollectionOptions::parse(const BSONObj& options, ParseKind kind) {
             }
 
             idIndex = std::move(tempIdIndex);
-        } else if (!createdOn24OrEarlier && !CommandHelpers::isGenericArgument(fieldName)) {
+        } else if (!createdOn24OrEarlier && !mongo::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 fa79289254b..950420fa787 100644
--- a/src/mongo/db/catalog/create_collection.cpp
+++ b/src/mongo/db/catalog/create_collection.cpp
@@ -35,6 +35,7 @@
 #include "mongo/bson/bsonobj.h"
 #include "mongo/db/catalog/database_holder.h"
 #include "mongo/db/catalog/uuid_catalog.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
 #include "mongo/db/curop.h"
@@ -72,7 +73,7 @@ Status createCollection(OperationContext* opCtx,
     BSONObjBuilder optionsBuilder;
     while (it.more()) {
         const auto elem = it.next();
-        if (!CommandHelpers::isGenericArgument(elem.fieldNameStringData()))
+        if (!isGenericArgument(elem.fieldNameStringData()))
             optionsBuilder.append(elem);
         if (elem.fieldNameStringData() == "viewOn") {
             // Views don't have UUIDs so it should always be parsed for command.
diff --git a/src/mongo/db/command_generic_argument.cpp b/src/mongo/db/command_generic_argument.cpp
new file mode 100644
index 00000000000..ef9530d1cb0
--- /dev/null
+++ b/src/mongo/db/command_generic_argument.cpp
@@ -0,0 +1,106 @@
+/**
+ *    Copyright (C) 2018 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/db/command_generic_argument.h"
+
+#include <algorithm>
+#include <array>
+#include <cstdlib>
+#include <iterator>
+
+namespace mongo {
+
+namespace {
+
+struct SpecialArgRecord {
+    StringData name;
+    bool isGeneric : 1;
+    bool stripFromRequest : 1;
+    bool stripFromReply : 1;
+};
+
+// Not including "help" since we don't pass help requests through to the command parser.
+// If that changes, it should be added. When you add to this list, consider whether you
+// should also change the filterCommandRequestForPassthrough() function.
+// clang-format off
+static constexpr std::array<SpecialArgRecord, 23> specials{{
+    //                                       /-isGeneric
+    //                                       |  /-stripFromRequest
+    //                                       |  |  /-stripFromReply
+    {"$audit"_sd,                            1, 1, 0},
+    {"$client"_sd,                           1, 1, 0},
+    {"$configServerState"_sd,                1, 1, 1},
+    {"$db"_sd,                               1, 1, 0},
+    {"allowImplicitCollectionCreation"_sd,   1, 1, 0},
+    {"$oplogQueryData"_sd,                   1, 1, 1},
+    {"$queryOptions"_sd,                     1, 0, 0},
+    {"$readPreference"_sd,                   1, 1, 0},
+    {"$replData"_sd,                         1, 1, 1},
+    {"$clusterTime"_sd,                      1, 1, 1},
+    {"maxTimeMS"_sd,                         1, 0, 0},
+    {"readConcern"_sd,                       1, 0, 0},
+    {"databaseVersion"_sd,                   1, 1, 0},
+    {"shardVersion"_sd,                      1, 1, 0},
+    {"tracking_info"_sd,                     1, 1, 0},
+    {"writeConcern"_sd,                      1, 0, 0},
+    {"lsid"_sd,                              1, 0, 0},
+    {"txnNumber"_sd,                         1, 0, 0},
+    {"autocommit"_sd,                        1, 1, 0},
+    {"stmtId"_sd,                            1, 0, 0},
+    {"$gleStats"_sd,                         0, 0, 1},
+    {"operationTime"_sd,                     0, 0, 1},
+    {"lastCommittedOpTime"_sd,               0, 0, 1}}};
+// clang-format on
+
+const SpecialArgRecord* findSpecialArg(StringData arg) {
+    for (const auto& e : specials)
+        if (e.name == arg)
+            return &e;
+    return nullptr;
+}
+
+}  // namespace
+
+bool isGenericArgument(StringData arg) {
+    auto p = findSpecialArg(arg);
+    return p && p->isGeneric;
+}
+
+bool isRequestStripArgument(StringData arg) {
+    auto p = findSpecialArg(arg);
+    return p && p->stripFromRequest;
+}
+
+bool isReplyStripArgument(StringData arg) {
+    auto p = findSpecialArg(arg);
+    return p && p->stripFromReply;
+}
+
+}  // namespace mongo
diff --git a/src/mongo/db/command_generic_argument.h b/src/mongo/db/command_generic_argument.h
new file mode 100644
index 00000000000..df3a96da578
--- /dev/null
+++ b/src/mongo/db/command_generic_argument.h
@@ -0,0 +1,55 @@
+/**
+ *    Copyright (C) 2018 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+#include "mongo/base/string_data.h"
+
+namespace mongo {
+
+/**
+ * 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.
+ */
+bool isGenericArgument(StringData arg);
+
+/**
+ * Returns true if arg must be stripped from requests that are forwarded to shards.
+ * Only generic arguments are stripped, and some of them are not.
+ * See 'CommandHelpers::filterCommandRequestForPassthrough'.
+ */
+bool isRequestStripArgument(StringData arg);
+
+/**
+ * Returns true if arg is not safe to blindly forward from shards to clients.
+ * See 'CommandHelpers::filterCommandReplyForPassthrough'.
+ */
+bool isReplyStripArgument(StringData arg);
+
+}  // namespace mongo
diff --git a/src/mongo/db/commands.cpp b/src/mongo/db/commands.cpp
index 6ebd7f38a34..103bd17dbeb 100644
--- a/src/mongo/db/commands.cpp
+++ b/src/mongo/db/commands.cpp
@@ -44,6 +44,7 @@
 #include "mongo/db/auth/authorization_session.h"
 #include "mongo/db/auth/privilege.h"
 #include "mongo/db/client.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/curop.h"
 #include "mongo/db/jsobj.h"
 #include "mongo/db/namespace_string.h"
@@ -285,18 +286,11 @@ void CommandHelpers::filterCommandRequestForPassthrough(BSONObjIterator* cmdIter
         const auto name = elem.fieldNameStringData();
         if (name == "$readPreference") {
             BSONObjBuilder(requestBuilder->subobjStart("$queryOptions")).append(elem);
-        } else if (!isGenericArgument(name) ||  //
-                   name == "$queryOptions" ||   //
-                   name == "maxTimeMS" ||       //
-                   name == "readConcern" ||     //
-                   name == "writeConcern" ||    //
-                   name == "lsid" ||            //
-                   name == "txnNumber" ||       //
-                   name == "stmtId") {
-            // This is the whitelist of generic arguments that commands can be trusted to blindly
-            // forward to the shards.
-            requestBuilder->append(elem);
+            continue;
         }
+        if (isRequestStripArgument(name))
+            continue;
+        requestBuilder->append(elem);
     }
 }
 
@@ -304,15 +298,8 @@ void CommandHelpers::filterCommandReplyForPassthrough(const BSONObj& cmdObj,
                                                       BSONObjBuilder* output) {
     for (auto elem : cmdObj) {
         const auto name = elem.fieldNameStringData();
-        if (name == "$configServerState" ||  //
-            name == "$gleStats" ||           //
-            name == "$clusterTime" ||        //
-            name == "$oplogQueryData" ||     //
-            name == "$replData" ||           //
-            name == "operationTime" ||
-            name == "lastCommittedOpTime") {
+        if (isReplyStripArgument(name))
             continue;
-        }
         output->append(elem);
     }
 }
diff --git a/src/mongo/db/commands.h b/src/mongo/db/commands.h
index 0284c852f27..cc69458f5ad 100644
--- a/src/mongo/db/commands.h
+++ b/src/mongo/db/commands.h
@@ -115,38 +115,6 @@ struct CommandHelpers {
     static BSONObj appendMajorityWriteConcern(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. When you add to this list, consider whether you
-        // should also change the filterCommandRequestForPassthrough() function.
-        return arg == "$audit" ||                        //
-            arg == "$client" ||                          //
-            arg == "$configServerState" ||               //
-            arg == "$db" ||                              //
-            arg == "allowImplicitCollectionCreation" ||  //
-            arg == "$oplogQueryData" ||                  //
-            arg == "$queryOptions" ||                    //
-            arg == "$readPreference" ||                  //
-            arg == "$replData" ||                        //
-            arg == "$clusterTime" ||                     //
-            arg == "maxTimeMS" ||                        //
-            arg == "readConcern" ||                      //
-            arg == "databaseVersion" ||                  //
-            arg == "shardVersion" ||                     //
-            arg == "tracking_info" ||                    //
-            arg == "writeConcern" ||                     //
-            arg == "lsid" ||                             //
-            arg == "txnNumber" ||                        //
-            arg == "autocommit" ||                       //
-            arg == "stmtId" ||                           //
-            false;  // These comments tell clang-format to keep this line-oriented.
-    }
-
-    /**
      * Rewrites cmdObj into a format safe to blindly forward to shards.
      *
      * This performs 2 transformations:
diff --git a/src/mongo/db/commands/SConscript b/src/mongo/db/commands/SConscript
index 52d64c426c7..206260fd7de 100644
--- a/src/mongo/db/commands/SConscript
+++ b/src/mongo/db/commands/SConscript
@@ -68,6 +68,7 @@ env.Library(
     ],
     LIBDEPS=[
         '$BUILD_DIR/mongo/base',
+        '$BUILD_DIR/mongo/db/command_generic_argument',
         '$BUILD_DIR/mongo/db/namespace_string',
     ],
 )
diff --git a/src/mongo/db/commands/create_indexes.cpp b/src/mongo/db/commands/create_indexes.cpp
index 7abb14531b7..1606db4e7c7 100644
--- a/src/mongo/db/commands/create_indexes.cpp
+++ b/src/mongo/db/commands/create_indexes.cpp
@@ -39,6 +39,7 @@
 #include "mongo/db/catalog/index_create.h"
 #include "mongo/db/catalog/index_key_validate.h"
 #include "mongo/db/client.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/concurrency/d_concurrency.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
@@ -128,8 +129,7 @@ StatusWith<std::vector<BSONObj>> parseAndValidateIndexSpecs(
             }
 
             hasIndexesField = true;
-        } else if (kCommandName == cmdElemFieldName ||
-                   CommandHelpers::isGenericArgument(cmdElemFieldName)) {
+        } else if (kCommandName == cmdElemFieldName || isGenericArgument(cmdElemFieldName)) {
             continue;
         } else {
             return {ErrorCodes::BadValue,
diff --git a/src/mongo/db/commands/current_op_common.cpp b/src/mongo/db/commands/current_op_common.cpp
index 7f85aa2952d..35bbadb32a6 100644
--- a/src/mongo/db/commands/current_op_common.cpp
+++ b/src/mongo/db/commands/current_op_common.cpp
@@ -32,6 +32,7 @@
 
 #include <string>
 
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/namespace_string.h"
 
 namespace mongo {
@@ -66,7 +67,7 @@ bool CurrentOpCommandBase::run(OperationContext* opCtx,
         const auto fieldName = elt.fieldNameStringData();
 
         if (0 == idx++ || fieldName == "$all" || fieldName == "$ownOps" ||
-            CommandHelpers::isGenericArgument(fieldName)) {
+            isGenericArgument(fieldName)) {
             continue;
         }
 
diff --git a/src/mongo/db/commands/dbcheck.cpp b/src/mongo/db/commands/dbcheck.cpp
index 2a3401a149b..8bac0ea3b4e 100644
--- a/src/mongo/db/commands/dbcheck.cpp
+++ b/src/mongo/db/commands/dbcheck.cpp
@@ -34,6 +34,7 @@
 #include "mongo/db/catalog/database.h"
 #include "mongo/db/catalog/health_log.h"
 #include "mongo/db/catalog/uuid_catalog.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/commands/test_commands_enabled.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
@@ -156,7 +157,7 @@ std::unique_ptr<DbCheckRun> getRun(OperationContext* opCtx,
 
     // Get rid of generic command fields.
     for (const auto& elem : obj) {
-        if (!CommandHelpers::isGenericArgument(elem.fieldNameStringData())) {
+        if (!isGenericArgument(elem.fieldNameStringData())) {
             builder.append(elem);
         }
     }
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 f9a66bd6f34..2e15ce22a91 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/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/commands/feature_compatibility_version_documentation.h"
 #include "mongo/db/commands/feature_compatibility_version_parser.h"
@@ -65,7 +66,7 @@ StatusWith<std::string> FeatureCompatibilityVersionCommandParser::extractVersion
     // Ensure that the command does not contain any unrecognized parameters
     for (const auto& cmdElem : cmdObj) {
         const auto fieldName = cmdElem.fieldNameStringData();
-        if (fieldName == commandName || CommandHelpers::isGenericArgument(fieldName)) {
+        if (fieldName == commandName || isGenericArgument(fieldName)) {
             continue;
         }
 
diff --git a/src/mongo/db/commands/get_last_error.cpp b/src/mongo/db/commands/get_last_error.cpp
index 900434db737..7d8b277e798 100644
--- a/src/mongo/db/commands/get_last_error.cpp
+++ b/src/mongo/db/commands/get_last_error.cpp
@@ -33,6 +33,7 @@
 #include "mongo/platform/basic.h"
 
 #include "mongo/db/client.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/curop.h"
 #include "mongo/db/field_parser.h"
@@ -213,7 +214,7 @@ public:
         BSONObj writeConcernDoc = ([&] {
             BSONObjBuilder bob;
             for (auto&& elem : cmdObj) {
-                if (!CommandHelpers::isGenericArgument(elem.fieldNameStringData()))
+                if (!isGenericArgument(elem.fieldNameStringData()))
                     bob.append(elem);
             }
             return bob.obj();
diff --git a/src/mongo/db/commands/parameters.cpp b/src/mongo/db/commands/parameters.cpp
index 29e801a72d8..f21958bfe53 100644
--- a/src/mongo/db/commands/parameters.cpp
+++ b/src/mongo/db/commands/parameters.cpp
@@ -38,6 +38,7 @@
 #include "mongo/config.h"
 #include "mongo/db/auth/authorization_manager.h"
 #include "mongo/db/auth/internal_user_auth.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/server_parameters.h"
 #include "mongo/db/storage/storage_options.h"
@@ -164,7 +165,7 @@ public:
         while (parameterCheckIterator.more()) {
             BSONElement parameter = parameterCheckIterator.next();
             std::string parameterName = parameter.fieldName();
-            if (CommandHelpers::isGenericArgument(parameterName))
+            if (isGenericArgument(parameterName))
                 continue;
 
             ServerParameter::Map::const_iterator foundParameter = parameterMap.find(parameterName);
diff --git a/src/mongo/db/pipeline/aggregation_request.cpp b/src/mongo/db/pipeline/aggregation_request.cpp
index 8eb646a7599..4f86b1c2a81 100644
--- a/src/mongo/db/pipeline/aggregation_request.cpp
+++ b/src/mongo/db/pipeline/aggregation_request.cpp
@@ -36,6 +36,7 @@
 #include "mongo/base/status_with.h"
 #include "mongo/base/string_data.h"
 #include "mongo/db/catalog/document_validation.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/pipeline/document.h"
 #include "mongo/db/pipeline/value.h"
@@ -214,7 +215,7 @@ StatusWith<AggregationRequest> AggregationRequest::parseFromBSON(
             request.setAllowDiskUse(elem.Bool());
         } else if (bypassDocumentValidationCommandOption() == fieldName) {
             request.setBypassDocumentValidation(elem.trueValue());
-        } else if (!CommandHelpers::isGenericArgument(fieldName)) {
+        } else if (!isGenericArgument(fieldName)) {
             return {ErrorCodes::FailedToParse,
                     str::stream() << "unrecognized field '" << elem.fieldName() << "'"};
         }
diff --git a/src/mongo/db/query/getmore_request.cpp b/src/mongo/db/query/getmore_request.cpp
index 21db56e4274..a6b29ea520b 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/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/repl/bson_extract_optime.h"
@@ -158,7 +159,7 @@ StatusWith<GetMoreRequest> GetMoreRequest::parseFromBSON(const std::string& dbna
                 return status;
             }
             lastKnownCommittedOpTime = ot;
-        } else if (!CommandHelpers::isGenericArgument(fieldName)) {
+        } else if (!isGenericArgument(fieldName)) {
             return {ErrorCodes::FailedToParse,
                     str::stream() << "Failed to parse: " << cmdObj << ". "
                                   << "Unrecognized field '"
diff --git a/src/mongo/db/query/query_request.cpp b/src/mongo/db/query/query_request.cpp
index 4978aad81f8..6268785c6a6 100644
--- a/src/mongo/db/query/query_request.cpp
+++ b/src/mongo/db/query/query_request.cpp
@@ -35,6 +35,7 @@
 #include "mongo/bson/simple_bsonobj_comparator.h"
 #include "mongo/client/dbclientinterface.h"
 #include "mongo/db/catalog/uuid_catalog.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/dbmessage.h"
 #include "mongo/db/namespace_string.h"
@@ -374,7 +375,7 @@ StatusWith<unique_ptr<QueryRequest>> QueryRequest::parseFromFindCommand(unique_p
                 return status;
             }
             qr->_replicationTerm = el._numberLong();
-        } else if (!CommandHelpers::isGenericArgument(fieldName)) {
+        } else if (!isGenericArgument(fieldName)) {
             return Status(ErrorCodes::FailedToParse,
                           str::stream() << "Failed to parse: " << cmdObj.toString() << ". "
                                         << "Unrecognized field '"
diff --git a/src/mongo/idl/SConscript b/src/mongo/idl/SConscript
index 87c5d3c2158..b7fdf916c29 100644
--- a/src/mongo/idl/SConscript
+++ b/src/mongo/idl/SConscript
@@ -10,6 +10,7 @@ env.Library(
     ],
     LIBDEPS=[
         '$BUILD_DIR/mongo/base',
+        '$BUILD_DIR/mongo/db/command_generic_argument',
     ]
 )
 
diff --git a/src/mongo/idl/idl_parser.cpp b/src/mongo/idl/idl_parser.cpp
index a8b591a43db..1ec3ed93459 100644
--- a/src/mongo/idl/idl_parser.cpp
+++ b/src/mongo/idl/idl_parser.cpp
@@ -33,7 +33,7 @@
 #include "mongo/idl/idl_parser.h"
 
 #include "mongo/bson/bsonobjbuilder.h"
-#include "mongo/db/commands.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/util/mongoutils/str.h"
 
 namespace mongo {
@@ -247,7 +247,7 @@ void IDLParserErrorContext::appendGenericCommandArguments(
 
         StringData name = element.fieldNameStringData();
         // Include a passthrough field as long the IDL class has not defined it.
-        if (CommandHelpers::isGenericArgument(name) &&
+        if (mongo::isGenericArgument(name) &&
             std::find(knownFields.begin(), knownFields.end(), name) == knownFields.end()) {
             builder->append(element);
         }
diff --git a/src/mongo/rpc/command_request_builder.cpp b/src/mongo/rpc/command_request_builder.cpp
index 051989015d5..68b39a460de 100644
--- a/src/mongo/rpc/command_request_builder.cpp
+++ b/src/mongo/rpc/command_request_builder.cpp
@@ -31,6 +31,7 @@
 #include "mongo/rpc/command_request_builder.h"
 
 #include "mongo/client/read_preference.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/util/assert_util.h"
 
@@ -40,7 +41,7 @@ namespace rpc {
 namespace {
 // OP_COMMAND put some generic arguments in the metadata and some in the body.
 bool fieldGoesInMetadata(StringData commandName, StringData field) {
-    if (!CommandHelpers::isGenericArgument(field))
+    if (!isGenericArgument(field))
         return false;  // All non-generic arguments go to the body.
 
     // For some reason this goes in the body only for a single command...
diff --git a/src/mongo/s/commands/cluster_explain.cpp b/src/mongo/s/commands/cluster_explain.cpp
index 3b455954ca9..1498ea9fe80 100644
--- a/src/mongo/s/commands/cluster_explain.cpp
+++ b/src/mongo/s/commands/cluster_explain.cpp
@@ -29,6 +29,7 @@
 #include "mongo/platform/basic.h"
 
 #include "mongo/bson/bsonmisc.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/rpc/get_status_from_command_result.h"
 #include "mongo/s/client/shard_registry.h"
@@ -138,7 +139,7 @@ BSONObj ClusterExplain::wrapAsExplain(const BSONObj& cmdObj, ExplainOptions::Ver
     // Propagate all generic arguments out of the inner command since the shards will only process
     // them at the top level.
     for (auto elem : filtered) {
-        if (CommandHelpers::isGenericArgument(elem.fieldNameStringData())) {
+        if (isGenericArgument(elem.fieldNameStringData())) {
             out.append(elem);
         }
     }
diff --git a/src/mongo/s/commands/cluster_explain_cmd.cpp b/src/mongo/s/commands/cluster_explain_cmd.cpp
index 4a8dfc091a6..24254f24054 100644
--- a/src/mongo/s/commands/cluster_explain_cmd.cpp
+++ b/src/mongo/s/commands/cluster_explain_cmd.cpp
@@ -29,6 +29,7 @@
 #include "mongo/platform/basic.h"
 
 #include "mongo/client/dbclientinterface.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/query/explain.h"
 #include "mongo/s/query/cluster_find.h"
@@ -194,7 +195,7 @@ std::unique_ptr<CommandInvocation> ClusterExplainCmd::parse(OperationContext* op
             // If the argument is in both the inner and outer command, we currently let the
             // inner version take precedence.
             const auto name = outerElem.fieldNameStringData();
-            if (CommandHelpers::isGenericArgument(name) && !innerObj.hasField(name)) {
+            if (isGenericArgument(name) && !innerObj.hasField(name)) {
                 bob.append(outerElem);
             }
         }
diff --git a/src/mongo/s/commands/cluster_map_reduce_cmd.cpp b/src/mongo/s/commands/cluster_map_reduce_cmd.cpp
index 6fe1d46770f..0650a073fa0 100644
--- a/src/mongo/s/commands/cluster_map_reduce_cmd.cpp
+++ b/src/mongo/s/commands/cluster_map_reduce_cmd.cpp
@@ -38,6 +38,7 @@
 #include "mongo/bson/simple_bsonobj_comparator.h"
 #include "mongo/client/connpool.h"
 #include "mongo/db/catalog/document_validation.h"
+#include "mongo/db/command_generic_argument.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/commands/mr.h"
 #include "mongo/db/query/collation/collation_spec.h"
@@ -93,7 +94,7 @@ BSONObj fixForShards(const BSONObj& orig,
             b.append(e);
         } else if (fn == "out" || fn == "finalize" || fn == "writeConcern") {
             // We don't want to copy these
-        } else if (!CommandHelpers::isGenericArgument(fn)) {
+        } else if (!isGenericArgument(fn)) {
             badShardedField = fn.toString();
             return BSONObj();
         }