SERVER-56585 replace MONGO_COMPILER_VARIABLE_UNUSED with c++17 attribute maybe_unused (.cpp files only)

11 files changed, 21 insertions, 25 deletions

diff --git a/src/mongo/base/initializer.cpp b/src/mongo/base/initializer.cpp
index 633067784f7..c64e5770049 100644
--- a/src/mongo/base/initializer.cpp
+++ b/src/mongo/base/initializer.cpp
@@ -227,7 +227,7 @@ namespace {
 // Make sure that getGlobalInitializer() is called at least once before main(), and so at least
 // once in a single-threaded context.  Otherwise, static initialization inside
 // getGlobalInitializer() won't be thread-safe.
-MONGO_COMPILER_VARIABLE_UNUSED const auto earlyCaller = [] {
+[[maybe_unused]] const auto earlyCaller = [] {
     getGlobalInitializer();
     return 0;
 }();
diff --git a/src/mongo/bson/mutable/document.cpp b/src/mongo/bson/mutable/document.cpp
index 3e7853146a1..b72b9d8f326 100644
--- a/src/mongo/bson/mutable/document.cpp
+++ b/src/mongo/bson/mutable/document.cpp
@@ -2277,14 +2277,14 @@ Document::Document(const BSONObj& value, InPlaceMode inPlaceMode)
 
 void Document::reset() {
     _impl->reset(Document::kInPlaceDisabled);
-    MONGO_COMPILER_VARIABLE_UNUSED const Element newRoot = makeRootElement();
+    [[maybe_unused]] const Element newRoot = makeRootElement();
     dassert(newRoot._repIdx == _root._repIdx);
     dassert(_root._repIdx == kRootRepIdx);
 }
 
 void Document::reset(const BSONObj& value, InPlaceMode inPlaceMode) {
     _impl->reset(inPlaceMode);
-    MONGO_COMPILER_VARIABLE_UNUSED const Element newRoot = makeRootElement(value);
+    [[maybe_unused]] const Element newRoot = makeRootElement(value);
     dassert(newRoot._repIdx == _root._repIdx);
     dassert(_root._repIdx == kRootRepIdx);
 }
diff --git a/src/mongo/db/index/sort_key_generator_test.cpp b/src/mongo/db/index/sort_key_generator_test.cpp
index 2e6641f000d..bf5899ead53 100644
--- a/src/mongo/db/index/sort_key_generator_test.cpp
+++ b/src/mongo/db/index/sort_key_generator_test.cpp
@@ -347,7 +347,7 @@ DEATH_TEST_REGEX_F(SortKeyGeneratorWorkingSetTest,
     auto sortKeyGen = makeSortKeyGen(pattern, nullptr);
     setRecordIdAndIdx(BSON("a" << 1 << "b" << 1), BSON("" << 2 << "" << 3));
     member().metadata().setTextScore(9.9);
-    MONGO_COMPILER_VARIABLE_UNUSED auto ignored = sortKeyGen->computeSortKey(member());
+    [[maybe_unused]] auto ignored = sortKeyGen->computeSortKey(member());
 }
 
 }  // namespace
diff --git a/src/mongo/db/index_builds_coordinator.cpp b/src/mongo/db/index_builds_coordinator.cpp
index 732dd8fc237..9e3a9a8f059 100644
--- a/src/mongo/db/index_builds_coordinator.cpp
+++ b/src/mongo/db/index_builds_coordinator.cpp
@@ -1400,7 +1400,7 @@ void IndexBuildsCoordinator::restartIndexBuildsForRecovery(
         try {
             // This spawns a new thread and returns immediately. These index builds will resume and
             // wait for a commit or abort to be replicated.
-            MONGO_COMPILER_VARIABLE_UNUSED auto fut = uassertStatusOK(resumeIndexBuild(
+            [[maybe_unused]] auto fut = uassertStatusOK(resumeIndexBuild(
                 opCtx, nss->db().toString(), collUUID, indexSpecs, buildUUID, resumeInfo));
             successfullyResumed.insert(buildUUID);
         } catch (const DBException& e) {
@@ -1462,14 +1462,13 @@ void IndexBuildsCoordinator::restartIndexBuildsForRecovery(
         indexBuildOptions.applicationMode = ApplicationMode::kStartupRepair;
         // This spawns a new thread and returns immediately. These index builds will start and wait
         // for a commit or abort to be replicated.
-        MONGO_COMPILER_VARIABLE_UNUSED auto fut =
-            uassertStatusOK(startIndexBuild(opCtx,
-                                            nss->db().toString(),
-                                            build.collUUID,
-                                            build.indexSpecs,
-                                            buildUUID,
-                                            IndexBuildProtocol::kTwoPhase,
-                                            indexBuildOptions));
+        [[maybe_unused]] auto fut = uassertStatusOK(startIndexBuild(opCtx,
+                                                                    nss->db().toString(),
+                                                                    build.collUUID,
+                                                                    build.indexSpecs,
+                                                                    buildUUID,
+                                                                    IndexBuildProtocol::kTwoPhase,
+                                                                    indexBuildOptions));
     }
 }
 
diff --git a/src/mongo/db/repl/rollback_impl.cpp b/src/mongo/db/repl/rollback_impl.cpp
index 14be427c59c..faa97126788 100644
--- a/src/mongo/db/repl/rollback_impl.cpp
+++ b/src/mongo/db/repl/rollback_impl.cpp
@@ -347,7 +347,7 @@ void RollbackImpl::_stopAndWaitForIndexBuilds(OperationContext* opCtx) {
     invariant(opCtx);
 
     // Aborts all active, two-phase index builds.
-    MONGO_COMPILER_VARIABLE_UNUSED auto stoppedIndexBuilds =
+    [[maybe_unused]] auto stoppedIndexBuilds =
         IndexBuildsCoordinator::get(opCtx)->stopIndexBuildsForRollback(opCtx);
 
     // Get a list of all databases.
diff --git a/src/mongo/db/storage/ephemeral_for_test/ephemeral_for_test_init.cpp b/src/mongo/db/storage/ephemeral_for_test/ephemeral_for_test_init.cpp
index c2deace9fba..d0256805cea 100644
--- a/src/mongo/db/storage/ephemeral_for_test/ephemeral_for_test_init.cpp
+++ b/src/mongo/db/storage/ephemeral_for_test/ephemeral_for_test_init.cpp
@@ -59,7 +59,7 @@ public:
             ++setupCountForUnitTests;
 
             // Intentionally leaked.
-            MONGO_COMPILER_VARIABLE_UNUSED auto leakedSection = new ServerStatusSection(kv.get());
+            [[maybe_unused]] auto leakedSection = new ServerStatusSection(kv.get());
 
             // This allows unit tests to run this code without encountering memory leaks
 #if __has_feature(address_sanitizer)
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_init.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_init.cpp
index c6c40aaec25..ba3b5894ae8 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_init.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_init.cpp
@@ -121,8 +121,7 @@ public:
             ++setupCountForUnitTests;
 
             // Intentionally leaked.
-            MONGO_COMPILER_VARIABLE_UNUSED auto leakedSection =
-                new WiredTigerServerStatusSection(kv.get());
+            [[maybe_unused]] auto leakedSection = new WiredTigerServerStatusSection(kv.get());
 
             // This allows unit tests to run this code without encountering memory leaks
 #if __has_feature(address_sanitizer)
diff --git a/src/mongo/db/timeseries/bucket_catalog.cpp b/src/mongo/db/timeseries/bucket_catalog.cpp
index 6daf97c95e5..162b98aed97 100644
--- a/src/mongo/db/timeseries/bucket_catalog.cpp
+++ b/src/mongo/db/timeseries/bucket_catalog.cpp
@@ -1237,7 +1237,7 @@ BSONObj BucketCatalog::MinMax::minUpdates() {
 
     BSONObjBuilder builder;
     // Return constructed document even if empty.
-    MONGO_COMPILER_VARIABLE_UNUSED auto appended = _appendUpdates(&builder, GetMin());
+    [[maybe_unused]] auto appended = _appendUpdates(&builder, GetMin());
     return builder.obj();
 }
 
@@ -1246,7 +1246,7 @@ BSONObj BucketCatalog::MinMax::maxUpdates() {
 
     BSONObjBuilder builder;
     // Return constructed document even if empty.
-    MONGO_COMPILER_VARIABLE_UNUSED auto appended = _appendUpdates(&builder, GetMax());
+    [[maybe_unused]] auto appended = _appendUpdates(&builder, GetMax());
     return builder.obj();
 }
 
diff --git a/src/mongo/db/update/push_node.cpp b/src/mongo/db/update/push_node.cpp
index 46b44daa01a..e236f2e9124 100644
--- a/src/mongo/db/update/push_node.cpp
+++ b/src/mongo/db/update/push_node.cpp
@@ -270,7 +270,7 @@ ModifierNode::ModifyResult PushNode::insertElementsWithPosition(
     // TODO: The use of std::accumulate here is maybe questionable
     // given that we are ignoring the return value. MSVC flagged this,
     // and we worked around by tagging the result as unused.
-    MONGO_COMPILER_VARIABLE_UNUSED auto ignored =
+    [[maybe_unused]] auto ignored =
         std::accumulate(std::next(valuesToPush.begin()),
                         valuesToPush.end(),
                         firstElementToInsert,
diff --git a/src/mongo/scripting/mozjs/session.cpp b/src/mongo/scripting/mozjs/session.cpp
index 6aa805ff425..a73e267356d 100644
--- a/src/mongo/scripting/mozjs/session.cpp
+++ b/src/mongo/scripting/mozjs/session.cpp
@@ -124,16 +124,14 @@ void endSession(SessionHolder* holder) {
         BSONObj abortObj = BSON("abortTransaction" << 1 << "lsid" << holder->lsid << "txnNumber"
                                                    << holder->txnNumber << "autocommit" << false);
 
-        MONGO_COMPILER_VARIABLE_UNUSED auto ignored =
-            holder->client->runCommand("admin", abortObj, out);
+        [[maybe_unused]] auto ignored = holder->client->runCommand("admin", abortObj, out);
     }
 
     EndSessions es;
 
     es.setEndSessions({holder->lsid});
 
-    MONGO_COMPILER_VARIABLE_UNUSED auto ignored =
-        holder->client->runCommand("admin", es.toBSON(), out);
+    [[maybe_unused]] auto ignored = holder->client->runCommand("admin", es.toBSON(), out);
 
     holder->client.reset();
 }
diff --git a/src/mongo/util/signal_handlers_synchronous.cpp b/src/mongo/util/signal_handlers_synchronous.cpp
index b197107c210..8f052ea134b 100644
--- a/src/mongo/util/signal_handlers_synchronous.cpp
+++ b/src/mongo/util/signal_handlers_synchronous.cpp
@@ -268,7 +268,7 @@ extern "C" void abruptQuitAction(int signalNum, siginfo_t*, void*) {
 
 extern "C" void abruptQuitWithAddrSignal(int signalNum, siginfo_t* siginfo, void* ucontext_erased) {
     // For convenient debugger access.
-    MONGO_COMPILER_VARIABLE_UNUSED auto ucontext = static_cast<const ucontext_t*>(ucontext_erased);
+    [[maybe_unused]] auto ucontext = static_cast<const ucontext_t*>(ucontext_erased);
 
     MallocFreeOStreamGuard lk{};