SERVER-73822 Time-series $group rewrite ignores certain accumulators

(cherry picked from commit f9fd648140b48de6af36f1b96bd66b5b54d5deb7)

4 files changed, 38 insertions, 2 deletions

diff --git a/etc/backports_required_for_multiversion_tests.yml b/etc/backports_required_for_multiversion_tests.yml
index 744c67e1e65..c66453c204b 100644
--- a/etc/backports_required_for_multiversion_tests.yml
+++ b/etc/backports_required_for_multiversion_tests.yml
@@ -306,6 +306,8 @@ last-continuous:
     ticket: SERVER-72620
   - test_file: jstests/core/timeseries/bucket_unpacking_with_sort_extended_range.js
     ticket: SERVER-73110
+  - test_file: jstests/core/timeseries/timeseries_groupby_reorder.js
+    ticket: SERVER-73822
   suites: null
 last-lts:
   all:
@@ -687,4 +689,6 @@ last-lts:
     ticket: SERVER-72620
   - test_file: jstests/core/timeseries/bucket_unpacking_with_sort_extended_range.js
     ticket: SERVER-73110
+  - test_file: jstests/core/timeseries/timeseries_groupby_reorder.js
+    ticket: SERVER-73822
   suites: null
diff --git a/jstests/core/timeseries/timeseries_groupby_reorder.js b/jstests/core/timeseries/timeseries_groupby_reorder.js
index 0f6ee2aef6d..c4c34bc1249 100644
--- a/jstests/core/timeseries/timeseries_groupby_reorder.js
+++ b/jstests/core/timeseries/timeseries_groupby_reorder.js
@@ -38,7 +38,18 @@ if (!isMongos(db)) {
                  res.stages[1]);
 }
 
-const res = coll.aggregate([{$group: {_id: '$meta', accmin: {$min: '$b'}, accmax: {$max: '$c'}}}])
-                .toArray();
+let res = coll.aggregate([{$group: {_id: '$meta', accmin: {$min: '$b'}, accmax: {$max: '$c'}}}])
+              .toArray();
 assert.docEq([{"_id": null, "accmin": 1, "accmax": 3}], res);
+
+// Test SERVER-73822 fix: complex $min and $max (i.e. not just straight field refs) work correctly.
+res = coll.aggregate([{
+              $group: {
+                  _id: '$meta',
+                  accmin: {$min: {$add: ["$b", "$c"]}},
+                  accmax: {$max: {$add: ["$b", "$c"]}}
+              }
+          }])
+          .toArray();
+assert.docEq([{"_id": null, "accmin": 2, "accmax": 6}], res);
 })();
diff --git a/src/mongo/db/pipeline/document_source_internal_unpack_bucket.cpp b/src/mongo/db/pipeline/document_source_internal_unpack_bucket.cpp
index 256804b978f..0da1d9d1f75 100644
--- a/src/mongo/db/pipeline/document_source_internal_unpack_bucket.cpp
+++ b/src/mongo/db/pipeline/document_source_internal_unpack_bucket.cpp
@@ -815,6 +815,8 @@ DocumentSourceInternalUnpackBucket::rewriteGroupByMinMax(Pipeline::SourceContain
             AccumulationExpression accExpr = stmt.expr;
             accExpr.argument = newExpr;
             accumulationStatements.emplace_back(stmt.fieldName, std::move(accExpr));
+        } else {
+            return {};
         }
     }
 
diff --git a/src/mongo/db/pipeline/document_source_internal_unpack_bucket_test/group_reorder_test.cpp b/src/mongo/db/pipeline/document_source_internal_unpack_bucket_test/group_reorder_test.cpp
index 6100897fd79..749c8c33a02 100644
--- a/src/mongo/db/pipeline/document_source_internal_unpack_bucket_test/group_reorder_test.cpp
+++ b/src/mongo/db/pipeline/document_source_internal_unpack_bucket_test/group_reorder_test.cpp
@@ -94,6 +94,25 @@ TEST_F(InternalUnpackBucketGroupReorder, MinMaxGroupOnMetadata) {
     ASSERT_BSONOBJ_EQ(optimized, serialized[0]);
 }
 
+// Test SERVER-73822 fix: complex $min and $max (i.e. not just straight field refs) work correctly.
+TEST_F(InternalUnpackBucketGroupReorder, MinMaxComplexGroupOnMetadata) {
+    auto unpackSpecObj = fromjson(
+        "{$_internalUnpackBucket: { include: ['a', 'b', 'c'], metaField: 'meta1', timeField: 't', "
+        "bucketMaxSpanSeconds: 3600}}");
+    auto groupSpecObj = fromjson(
+        "{$group: {_id: '$meta1.a.b', accmin: {$min: {$add: ['$b', {$const: 0}]}}, accmax: {$max: "
+        "{$add: [{$const: 0}, '$c']}}}}");
+
+    auto pipeline = Pipeline::parse(makeVector(unpackSpecObj, groupSpecObj), getExpCtx());
+    pipeline->optimizePipeline();
+
+    auto serialized = pipeline->serializeToBson();
+    ASSERT_EQ(2, serialized.size());
+    // Order of fields may be different between original 'unpackSpecObj' and 'serialized[0]'.
+    //   ASSERT_BSONOBJ_EQ(unpackSpecObj, serialized[0]);
+    ASSERT_BSONOBJ_EQ(groupSpecObj, serialized[1]);
+}
+
 TEST_F(InternalUnpackBucketGroupReorder, MinMaxGroupOnMetafield) {
     auto unpackSpecObj = fromjson(
         "{$_internalUnpackBucket: { include: ['a', 'b', 'c'], metaField: 'meta1', timeField: 't', "