Fix using uninitialized value error. (#7131)

Author: dcherednik

ydb/core/kqp/opt/kqp_query_plan.cpp

@@ -561,9 +561,7 @@ class TxPlanSerializer {
                 }
 
                 if (auto literal = key.Maybe<TCoUuid>()) {
-                    TStringStream out;
-                    NUuid::UuidBytesToString(literal.Cast().Literal().Value().Data(), out);
-                    return out.Str();
+                    return NUuid::UuidBytesToString(literal.Cast().Literal().StringValue());
                 }
 
                 if (auto literal = key.Maybe<TCoDataCtor>()) {

ydb/library/uuid/uuid.cpp

@@ -28,6 +28,14 @@ static void WriteHex(ui16 bytes, IOutputStream& out, bool reverseBytes = false)
     }
 }
 
+TString UuidBytesToString(const TString& in) {
+    TStringStream ss;
+    
+    UuidBytesToString(in, ss);
+
+    return ss.Str();
+}
+
 void UuidBytesToString(TString in, IOutputStream& out) {
     ui16 dw[8];
     std::memcpy(dw, in.Data(), sizeof(dw));

ydb/library/uuid/uuid.h

@@ -13,6 +13,7 @@ namespace NUuid {
 
 static constexpr ui32 UUID_LEN = 16;
 
+TString UuidBytesToString(const TString& in);
 void UuidBytesToString(TString in, IOutputStream& out);
 void UuidToString(ui16 dw[8], IOutputStream& out);
 void UuidHalfsToByteString(ui64 low, ui64 hi, IOutputStream& out);