2 files changed, 32 insertions, 2 deletions
diff --git a/src/mongo/db/query/index_bounds_builder.cpp b/src/mongo/db/query/index_bounds_builder.cpp
index 04cf9f79b05..0896be1039f 100644
--- a/src/mongo/db/query/index_bounds_builder.cpp
+++ b/src/mongo/db/query/index_bounds_builder.cpp
@@ -496,8 +496,12 @@ void IndexBoundsBuilder::_translatePredicate(const MatchExpression* expr,
             *tightnessOut = IndexBoundsBuilder::EXACT;
         }
 
-        // If this invariant would fail, we would otherwise return incorrect query results.
-        invariant(*tightnessOut == IndexBoundsBuilder::EXACT);
+        // This disables indexed negation of array inequality.
+        // TODO: SERVER-45233 Perform correct behavior here once indexed array inequality without
+        // negation's semantics are correctly determined and implemented.
+        massert(ErrorCodes::InternalError,
+                "Indexed negation of array inequality not supported.",
+                *tightnessOut == IndexBoundsBuilder::EXACT);
 
         // If the index is multikey on this path, it doesn't matter what the tightness of the child
         // is, we must return INEXACT_FETCH. Consider a multikey index on 'a' with document
diff --git a/src/mongo/db/query/index_bounds_builder_test.cpp b/src/mongo/db/query/index_bounds_builder_test.cpp
index 2d3ca2d0ac5..7ec1beb9f37 100644
--- a/src/mongo/db/query/index_bounds_builder_test.cpp
+++ b/src/mongo/db/query/index_bounds_builder_test.cpp
@@ -492,6 +492,32 @@ TEST_F(IndexBoundsBuilderTest, TranslateGtMinKey) {
     ASSERT_EQUALS(tightness, IndexBoundsBuilder::EXACT);
 }
 
+TEST_F(IndexBoundsBuilderTest, DontCrashOnNegationOfArrayInequality) {
+    BSONObj keyPattern = BSON("a" << 1);
+    auto testIndex = IndexEntry(keyPattern,
+                                IndexNames::nameToType(IndexNames::findPluginName(keyPattern)),
+                                true,  // multikey
+                                {},
+                                {},
+                                false,  // sparse
+                                false,  // unique
+                                IndexEntry::Identifier{"test_foo"},
+                                nullptr,  // filterExpr
+                                BSONObj(),
+                                nullptr,
+                                nullptr);
+
+    BSONObj obj = fromjson("{a: {$not: {$lt: [\"here\", {}, false]}}}");
+    auto expr = MatchExpression::optimize(parseMatchExpression(obj));
+    BSONElement elt = obj.firstElement();
+    OrderedIntervalList oil;
+    IndexBoundsBuilder::BoundsTightness tightness;
+    // TODO: SERVER-45233 This should succeed rather than throwing code.
+    ASSERT_THROWS_CODE(IndexBoundsBuilder::translate(expr.get(), elt, testIndex, &oil, &tightness),
+                       DBException,
+                       ErrorCodes::InternalError);
+}
+
 // Nothing can be greater than MaxKey so the resulting index bounds would be a useless empty range.
 TEST_F(IndexBoundsBuilderTest, TranslateGtMaxKeyDoesNotGenerateBounds) {
     auto testIndex = buildSimpleIndexEntry();