SERVER-37353 Handle $slice value of LLONG_MIN gracefully

(cherry picked from commit 93fe6ccfb37d14f382abdf0e90abd013fbe8af7b)

2 files changed, 12 insertions, 4 deletions

diff --git a/src/mongo/db/update/push_node.cpp b/src/mongo/db/update/push_node.cpp
index ac235e722f9..e625eb722ed 100644
--- a/src/mongo/db/update/push_node.cpp
+++ b/src/mongo/db/update/push_node.cpp
@@ -260,7 +260,13 @@ ModifierNode::ModifyResult PushNode::performPush(mutablebson::Element* element,
         sortChildren(*element, *_sort);
     }
 
-    while (static_cast<long long>(countChildren(*element)) > std::abs(_slice)) {
+    // std::abs(LLONG_MIN) results in undefined behavior on 2's complement systems because the
+    // absolute value of LLONG_MIN cannot be represented in a 'long long'.
+    const auto sliceAbs = _slice == std::numeric_limits<decltype(_slice)>::min()
+        ? std::abs(_slice + 1)
+        : std::abs(_slice);
+
+    while (static_cast<long long>(countChildren(*element)) > sliceAbs) {
         result = ModifyResult::kNormalUpdate;
         if (_slice >= 0) {
             invariantOK(element->popBack());
diff --git a/src/mongo/db/update/push_node_test.cpp b/src/mongo/db/update/push_node_test.cpp
index 6eefb09bd53..3931bb56c4d 100644
--- a/src/mongo/db/update/push_node_test.cpp
+++ b/src/mongo/db/update/push_node_test.cpp
@@ -655,16 +655,18 @@ void checkDocumentAndResult(BSONObj updateModifier,
 
 TEST_F(PushNodeTest, ApplyToEmptyArrayWithSliceValues) {
     struct testData {
-        int sliceValue;
+        long long sliceValue;
         BSONObj resultingDoc;
     };
 
     // We repeat the same test for several different values of $slice.
-    std::vector<testData> testDataList{{-2, fromjson("{a: [1]}")},
+    std::vector<testData> testDataList{{LLONG_MIN, fromjson("{a: [1]}")},
+                                       {-2, fromjson("{a: [1]}")},
                                        {-1, fromjson("{a: [1]}")},
                                        {0, fromjson("{a: []}")},
                                        {1, fromjson("{a: [1]}")},
-                                       {2, fromjson("{a: [1]}")}};
+                                       {2, fromjson("{a: [1]}")},
+                                       {LLONG_MAX, fromjson("{a: [1]}")}};
 
     for (const auto& data : testDataList) {
         auto update = BSON(