[YQL-14732] Use Optional at top level in type string

ref:74fed2bdc1cd02ecef9478d2898b8fce0cec00d7

3 files changed, 32 insertions, 6 deletions

diff --git a/ydb/library/yql/ast/yql_type_string.cpp b/ydb/library/yql/ast/yql_type_string.cpp
index 898e19c80b5..928aecacdb6 100644
--- a/ydb/library/yql/ast/yql_type_string.cpp
+++ b/ydb/library/yql/ast/yql_type_string.cpp
@@ -1139,11 +1139,13 @@ public:
 
 private:
     void Visit(const TUnitExprType& type) final {
+        TopLevel = false;
         Y_UNUSED(type);
         Out_ << TStringBuf("Unit");
     }
 
     void Visit(const TMultiExprType& type) final {
+        TopLevel = false;
         Out_ << TStringBuf("Multi<");
         const auto& items = type.GetItems();
         for (ui32 i = 0; i < items.size(); ++i) {
@@ -1156,6 +1158,7 @@ private:
     }
 
     void Visit(const TTupleExprType& type) final {
+        TopLevel = false;
         Out_ << TStringBuf("Tuple<");
         const auto& items = type.GetItems();
         for (ui32 i = 0; i < items.size(); ++i) {
@@ -1168,6 +1171,7 @@ private:
     }
 
     void Visit(const TStructExprType& type) final {
+        TopLevel = false;
         Out_ << TStringBuf("Struct<");
         const auto& items = type.GetItems();
         for (ui32 i = 0; i < items.size(); ++i) {
@@ -1180,30 +1184,35 @@ private:
     }
 
     void Visit(const TItemExprType& type) final {
+        TopLevel = false;
         EscapeArbitraryAtom(type.GetName(), '\'', &Out_);
         Out_ << ':';
         type.GetItemType()->Accept(*this);
     }
 
     void Visit(const TListExprType& type) final {
+        TopLevel = false;
         Out_ << TStringBuf("List<");
         type.GetItemType()->Accept(*this);
         Out_ << '>';
     }
 
     void Visit(const TStreamExprType& type) final {
+        TopLevel = false;
         Out_ << TStringBuf("Stream<");
         type.GetItemType()->Accept(*this);
         Out_ << '>';
     }
 
     void Visit(const TFlowExprType& type) final {
+        TopLevel = false;
         Out_ << TStringBuf("Flow<");
         type.GetItemType()->Accept(*this);
         Out_ << '>';
     }
 
     void Visit(const TDataExprType& type) final {
+        TopLevel = false;
         Out_ << type.GetName();
         if (const auto dataExprParamsType = dynamic_cast<const TDataExprParamsType*>(&type)) {
             Out_ << '(' << dataExprParamsType->GetParamOne() << ',' << dataExprParamsType->GetParamTwo() << ')';
@@ -1211,6 +1220,7 @@ private:
     }
 
     void Visit(const TPgExprType& type) final {
+        TopLevel = false;
         TStringBuf name = type.GetName();
         if (!name.SkipPrefix("_")) {
             Out_ << "pg" << name;
@@ -1221,22 +1231,26 @@ private:
 
     void Visit(const TWorldExprType& type) final {
         Y_UNUSED(type);
+        TopLevel = false;
         Out_ << TStringBuf("World");
     }
 
     void Visit(const TOptionalExprType& type) final {
         const TTypeAnnotationNode* itemType = type.GetItemType();
-        if (itemType->GetKind() == ETypeAnnotationKind::Callable) {
+        if (TopLevel || itemType->GetKind() == ETypeAnnotationKind::Callable) {
+            TopLevel = false;
             Out_ << TStringBuf("Optional<");
             itemType->Accept(*this);
             Out_ << '>';
         } else {
+            TopLevel = false;
             itemType->Accept(*this);
             Out_ << '?';
         }
     }
 
     void Visit(const TCallableExprType& type) final {
+        TopLevel = false;
         const auto& args = type.GetArguments();
         ui32 argsCount = type.GetArgumentsSize();
         ui32 optArgsCount =
@@ -1278,18 +1292,21 @@ private:
     }
 
     void Visit(const TResourceExprType& type) final {
+        TopLevel = false;
         Out_ << TStringBuf("Resource<");
         EscapeArbitraryAtom(type.GetTag(), '\'', &Out_);
         Out_ << '>';
     }
 
     void Visit(const TTypeExprType& type) final {
+        TopLevel = false;
         Out_ << TStringBuf("Type<");
         type.GetType()->Accept(*this);
         Out_ << '>';
     }
 
     void Visit(const TDictExprType& type) final {
+        TopLevel = false;
         if (type.GetPayloadType()->GetKind() == ETypeAnnotationKind::Void) {
             Out_ << TStringBuf("Set<");
             type.GetKeyType()->Accept(*this);
@@ -1305,30 +1322,36 @@ private:
 
     void Visit(const TVoidExprType& type) final {
         Y_UNUSED(type);
+        TopLevel = false;
         Out_ << TStringBuf("Void");
     }
 
     void Visit(const TNullExprType& type) final {
         Y_UNUSED(type);
+        TopLevel = false;
         Out_ << TStringBuf("Null");
     }
 
     void Visit(const TEmptyListExprType& type) final {
         Y_UNUSED(type);
+        TopLevel = false;
         Out_ << TStringBuf("EmptyList");
     }
 
     void Visit(const TEmptyDictExprType& type) final {
         Y_UNUSED(type);
+        TopLevel = false;
         Out_ << TStringBuf("EmptyDict");
     }
 
     void Visit(const TGenericExprType& type) final {
         Y_UNUSED(type);
+        TopLevel = false;
         Out_ << TStringBuf("Generic");
     }
 
     void Visit(const TTaggedExprType& type) final {
+        TopLevel = false;
         Out_ << TStringBuf("Tagged<");
         type.GetBaseType()->Accept(*this);
         Out_ << ',';
@@ -1337,6 +1360,7 @@ private:
     }
 
     void Visit(const TErrorExprType& type) final {
+        TopLevel = false;
         Out_ << TStringBuf("Error<");
         auto pos = type.GetError().Position;
         EscapeArbitraryAtom(pos.File.empty() ? "<main>" : pos.File, '\'', &Out_);
@@ -1350,6 +1374,7 @@ private:
     }
 
     void Visit(const TVariantExprType& type) final {
+        TopLevel = false;
         auto underlyingType = type.GetUnderlyingType();
         if (underlyingType->GetKind() == ETypeAnnotationKind::Tuple) {
             Out_ << TStringBuf("Variant<");
@@ -1388,6 +1413,7 @@ private:
 
 private:
     IOutputStream& Out_;
+    bool TopLevel = true;
 };
 
 } // namespace
diff --git a/ydb/library/yql/ast/yql_type_string_ut.cpp b/ydb/library/yql/ast/yql_type_string_ut.cpp
index 1ef629067f8..abeee1fec37 100644
--- a/ydb/library/yql/ast/yql_type_string_ut.cpp
+++ b/ydb/library/yql/ast/yql_type_string_ut.cpp
@@ -568,7 +568,7 @@ Y_UNIT_TEST_SUITE(TTypeString)
     }
 
     Y_UNIT_TEST(FormatOptional) {
-        TestFormat("((Optional (Data Uint32)))", "Uint32?");
+        TestFormat("((Optional (Data Uint32)))", "Optional<Uint32>");
         TestFormat("((List (Optional (Data Uint32))))", "List<Uint32?>");
     }
 
@@ -628,7 +628,7 @@ Y_UNIT_TEST_SUITE(TTypeString)
                    "    ((Data String))"
                    "    ((Optional (Data Uint8)))"
                    "))))",
-                   "Optional<Callable<(Uint8?)->String>>?");
+                   "Optional<Optional<Callable<(Uint8?)->String>>>");
     }
 
     Y_UNIT_TEST(FormatCallableWithNamedArgs) {
@@ -657,7 +657,7 @@ Y_UNIT_TEST_SUITE(TTypeString)
         TestFormat("((Resource aaa))", "Resource<'aaa'>");
         TestFormat("((Resource \"a b\"))", "Resource<'a b'>");
         TestFormat("((Resource \"a\\t\\n\\x01b\"))", "Resource<'a\\t\\n\\x01b'>");
-        TestFormat("((Optional (Resource aaa)))", "Resource<'aaa'>?");
+        TestFormat("((Optional (Resource aaa)))", "Optional<Resource<'aaa'>>");
     }
 
     Y_UNIT_TEST(FormatTagged) {
diff --git a/ydb/tests/functional/canonical/canondata/test_sql.TestCanonicalFolder1.test_case_json_json_query.sql-result_sets_/json_json_query.sql.results b/ydb/tests/functional/canonical/canondata/test_sql.TestCanonicalFolder1.test_case_json_json_query.sql-result_sets_/json_json_query.sql.results
index 9c46b5be480..8c379570532 100644
--- a/ydb/tests/functional/canonical/canondata/test_sql.TestCanonicalFolder1.test_case_json_json_query.sql-result_sets_/json_json_query.sql.results
+++ b/ydb/tests/functional/canonical/canondata/test_sql.TestCanonicalFolder1.test_case_json_json_query.sql-result_sets_/json_json_query.sql.results
@@ -1,9 +1,9 @@
 [
     [
         {
-            "column0": "JsonDocument?",
+            "column0": "Optional<JsonDocument>",
             "column1": "[1,2,3,4]",
-            "column2": "JsonDocument?",
+            "column2": "Optional<JsonDocument>",
             "column3": "{\"key\":\"value\"}"
         }
     ]