2 files changed, 28 insertions, 2 deletions
diff --git a/src/mongo/db/pipeline/expression.cpp b/src/mongo/db/pipeline/expression.cpp
index 8db17f3152a..2ce8b92cbbb 100644
--- a/src/mongo/db/pipeline/expression.cpp
+++ b/src/mongo/db/pipeline/expression.cpp
@@ -1321,7 +1321,6 @@ void ExpressionObject::addToDocument(MutableDocument& out,
         if (dynamic_cast<ExpressionObject*>(it->second.get()) && pValue.getDocument().empty())
             continue;
 
-
         out.addField(fieldName, pValue);
     }
 }
@@ -2407,7 +2406,6 @@ intrusive_ptr<Expression> ExpressionSetIsSubset::optimize() {
 
         return new Optimized(arrayToSet(rhs), vpOperand);
     }
-
     return optimized;
 }
 
@@ -2470,6 +2468,30 @@ const char* ExpressionSize::getOpName() const {
     return "$size";
 }
 
+/* ----------------------- ExpressionSqrt ---------------------------- */
+
+Value ExpressionSqrt::evaluateInternal(Variables* vars) const {
+    Value argVal = vpOperand[0]->evaluateInternal(vars);
+    if (argVal.nullish())
+        return Value(BSONNULL);
+
+    uassert(28715,
+            str::stream() << "$sqrt only supports numeric types, not "
+                          << typeName(argVal.getType()),
+            argVal.numeric());
+
+    double argDouble = argVal.coerceToDouble();
+    uassert(28714,
+            "$sqrt's argument must be greater than or equal to 0",
+            argDouble >= 0 || std::isnan(argDouble));
+    return Value(sqrt(argDouble));
+}
+
+REGISTER_EXPRESSION("$sqrt", ExpressionSqrt::parse);
+const char* ExpressionSqrt::getOpName() const {
+    return "$sqrt";
+}
+
 /* ----------------------- ExpressionStrcasecmp ---------------------------- */
 
 Value ExpressionStrcasecmp::evaluateInternal(Variables* vars) const {
diff --git a/src/mongo/db/pipeline/expression.h b/src/mongo/db/pipeline/expression.h
index 3650efc6655..330487b4342 100644
--- a/src/mongo/db/pipeline/expression.h
+++ b/src/mongo/db/pipeline/expression.h
@@ -989,6 +989,10 @@ public:
     const char* getOpName() const final;
 };
 
+class ExpressionSqrt final : public ExpressionFixedArity<ExpressionSqrt, 1> {
+    Value evaluateInternal(Variables* vars) const final;
+    const char* getOpName() const final;
+};
 
 class ExpressionStrcasecmp final : public ExpressionFixedArity<ExpressionStrcasecmp, 2> {
 public: