1 files changed, 17 insertions, 18 deletions

diff --git a/src/mongo/db/pipeline/document_source_bucket_auto.cpp b/src/mongo/db/pipeline/document_source_bucket_auto.cpp
index cec0be7b847..10300e9c334 100644
--- a/src/mongo/db/pipeline/document_source_bucket_auto.cpp
+++ b/src/mongo/db/pipeline/document_source_bucket_auto.cpp
@@ -57,15 +57,15 @@ boost::intrusive_ptr<Expression> parseGroupByExpression(
         groupByField.embeddedObject().firstElementFieldName()[0] == '$') {
         return Expression::parseObject(expCtx.get(), groupByField.embeddedObject(), vps);
     } else if (groupByField.type() == BSONType::String &&
-               // Lager than 2 because we need a '$', at least one char for the field name and
-               // the final terminating 0.
-               groupByField.valuestrsize() > 2 && groupByField.valueStringData()[0] == '$') {
+               groupByField.valueStringData()[0] == '$') {
         return ExpressionFieldPath::parse(expCtx.get(), groupByField.str(), vps);
+    } else {
+        uasserted(
+            40239,
+            str::stream() << "The $bucketAuto 'groupBy' field must be defined as a $-prefixed "
+                             "path or an expression object, but found: "
+                          << groupByField.toString(false, false));
     }
-    uasserted(40239,
-              str::stream() << "The $bucketAuto 'groupBy' field must be defined as a $-prefixed "
-                               "path or an expression object, but found: "
-                            << groupByField.toString(false, false));
 }
 
 /**
@@ -221,7 +221,7 @@ void DocumentSourceBucketAuto::initializeBucketIteration() {
 
     auto& metricsCollector = ResourceConsumption::MetricsCollector::get(pExpCtx->opCtx);
     metricsCollector.incrementKeysSorted(_sorter->numSorted());
-    metricsCollector.incrementSorterSpills(_sorter->stats().spilledRanges());
+    metricsCollector.incrementSorterSpills(_sorter->numSpills());
 
     _sorter.reset();
 
@@ -372,25 +372,24 @@ void DocumentSourceBucketAuto::doDispose() {
     _sortedInput.reset();
 }
 
-Value DocumentSourceBucketAuto::serialize(const SerializationOptions& opts) const {
+Value DocumentSourceBucketAuto::serialize(
+    boost::optional<ExplainOptions::Verbosity> explain) const {
     MutableDocument insides;
 
-    insides["groupBy"] = _groupByExpression->serialize(opts);
-    insides["buckets"] = opts.serializeLiteral(_nBuckets);
+    insides["groupBy"] = _groupByExpression->serialize(static_cast<bool>(explain));
+    insides["buckets"] = Value(_nBuckets);
 
     if (_granularityRounder) {
-        //"granularity" only supports some strings, so a specific representative value is used if
-        // necessary.
-        insides["granularity"] =
-            opts.serializeLiteral(_granularityRounder->getName(), Value("R5"_sd));
+        insides["granularity"] = Value(_granularityRounder->getName());
     }
 
     MutableDocument outputSpec(_accumulatedFields.size());
     for (auto&& accumulatedField : _accumulatedFields) {
         intrusive_ptr<AccumulatorState> accum = accumulatedField.makeAccumulator();
-        outputSpec[opts.serializeFieldPathFromString(accumulatedField.fieldName)] =
-            Value(accum->serialize(
-                accumulatedField.expr.initializer, accumulatedField.expr.argument, opts));
+        outputSpec[accumulatedField.fieldName] =
+            Value(accum->serialize(accumulatedField.expr.initializer,
+                                   accumulatedField.expr.argument,
+                                   static_cast<bool>(explain)));
     }
     insides["output"] = outputSpec.freezeToValue();