Merge pull request ClickHouse#92133 from ClickHouse/backport/25.8/91420

Backport ClickHouse#91420 to 25.8: Fix crash in `dictGetDescendants` caused by `NULL` when dictionary type has Hierarchy support but no column is `HIERARCHICAL`

Author: clickhouse-gh[bot]

src/Functions/FunctionsExternalDictionaries.h

@@ -94,7 +94,7 @@ class FunctionDictHelper : public WithContext
         return getDictionary(dict_name_col->getValue<String>());
     }
 
-    static const DictionaryAttribute & getDictionaryHierarchicalAttribute(const std::shared_ptr<const IDictionary> & dictionary)
+    static void checkDictionaryHierarchySupport(const std::shared_ptr<const IDictionary> & dictionary)
     {
         const auto & dictionary_structure = dictionary->getStructure();
         auto hierarchical_attribute_index_optional = dictionary_structure.hierarchical_attribute_index;
@@ -103,6 +103,14 @@ class FunctionDictHelper : public WithContext
             throw Exception(ErrorCodes::UNSUPPORTED_METHOD,
                 "Dictionary {} does not support hierarchy",
                 dictionary->getFullName());
+    }
+
+    static const DictionaryAttribute & getDictionaryHierarchicalAttribute(const std::shared_ptr<const IDictionary> & dictionary)
+    {
+        checkDictionaryHierarchySupport(dictionary);
+
+        const auto & dictionary_structure = dictionary->getStructure();
+        auto hierarchical_attribute_index_optional = dictionary_structure.hierarchical_attribute_index;
 
         size_t hierarchical_attribute_index = *hierarchical_attribute_index_optional;
         const auto & hierarchical_attribute = dictionary_structure.attributes[hierarchical_attribute_index];
@@ -1316,6 +1324,9 @@ class FunctionDictGetDescendantsOverloadResolverImpl final : public IFunctionOve
     FunctionBasePtr buildImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type) const override
     {
         auto dictionary = dictionary_helper->getDictionary(arguments[0].column);
+
+        FunctionDictHelper::checkDictionaryHierarchySupport(dictionary);
+
         auto hierarchical_parent_to_child_index = dictionary->getHierarchicalIndex();
 
         size_t level = Strategy::default_level;

tests/queries/0_stateless/03749_dictionary_hierarchical_null.reference

@@ -0,0 +1,45 @@
+-- {echoOn }
+
+DROP DICTIONARY IF EXISTS d0;
+CREATE DICTIONARY d0 (c0 Int) PRIMARY KEY (c0) SOURCE(NULL()) LAYOUT(FLAT()) LIFETIME(1);
+SELECT dictGetDescendants('d0', 'c0', 1); -- { serverError UNSUPPORTED_METHOD }
+SELECT dictGetDescendants('d0', 'c0', NULL); -- { serverError UNSUPPORTED_METHOD }
+SELECT dictGetDescendants('d0', NULL, 1); -- { serverError UNSUPPORTED_METHOD }
+SELECT dictGetChildren('d0', 'c0'); -- { serverError UNSUPPORTED_METHOD }
+SELECT dictGetChildren('d0', NULL); -- { serverError UNSUPPORTED_METHOD }
+SELECT dictGetChildren(NULL, NULL); -- { serverError UNSUPPORTED_METHOD }
+DROP DICTIONARY IF EXISTS hierarchical_dictionary;
+DROP TABLE IF EXISTS hierarchy_source;
+CREATE TABLE hierarchy_source
+(
+  id UInt64,
+  parent_id UInt64,
+  name String
+) ENGINE = Memory;
+INSERT INTO hierarchy_source VALUES
+(0, 0, 'Root'),
+(1, 0, 'Level 1 - Node 1'),
+(2, 1, 'Level 2 - Node 2'),
+(3, 1, 'Level 2 - Node 3'),
+(4, 2, 'Level 3 - Node 4'),
+(5, 2, 'Level 3 - Node 5'),
+(6, 3, 'Level 3 - Node 6');
+CREATE DICTIONARY hierarchical_dictionary
+(
+    id UInt64,
+    parent_id UInt64 HIERARCHICAL,
+    name String
+)
+PRIMARY KEY id
+SOURCE(CLICKHOUSE(TABLE 'hierarchy_source'))
+LAYOUT(HASHED())
+LIFETIME(0);
+SELECT dictGetDescendants('hierarchical_dictionary', 1, 1);
+[3,2]
+SELECT dictGetDescendants('hierarchical_dictionary', NULL, 1);
+\N
+SELECT dictGetDescendants('hierarchical_dictionary', 1, NULL); -- { serverError BAD_ARGUMENTS }
+SELECT dictGetChildren('hierarchical_dictionary', 1);
+[3,2]
+SELECT dictGetChildren('hierarchical_dictionary', NULL);
+\N

tests/queries/0_stateless/03749_dictionary_hierarchical_null.sql

@@ -0,0 +1,58 @@
+-- {echoOn }
+
+DROP DICTIONARY IF EXISTS d0;
+CREATE DICTIONARY d0 (c0 Int) PRIMARY KEY (c0) SOURCE(NULL()) LAYOUT(FLAT()) LIFETIME(1);
+
+SELECT dictGetDescendants('d0', 'c0', 1); -- { serverError UNSUPPORTED_METHOD }
+
+SELECT dictGetDescendants('d0', 'c0', NULL); -- { serverError UNSUPPORTED_METHOD }
+
+SELECT dictGetDescendants('d0', NULL, 1); -- { serverError UNSUPPORTED_METHOD }
+
+SELECT dictGetChildren('d0', 'c0'); -- { serverError UNSUPPORTED_METHOD }
+
+SELECT dictGetChildren('d0', NULL); -- { serverError UNSUPPORTED_METHOD }
+
+SELECT dictGetChildren(NULL, NULL); -- { serverError UNSUPPORTED_METHOD }
+
+
+DROP DICTIONARY IF EXISTS hierarchical_dictionary;
+DROP TABLE IF EXISTS hierarchy_source;
+
+CREATE TABLE hierarchy_source
+(
+  id UInt64,
+  parent_id UInt64,
+  name String
+) ENGINE = Memory;
+
+INSERT INTO hierarchy_source VALUES
+(0, 0, 'Root'),
+(1, 0, 'Level 1 - Node 1'),
+(2, 1, 'Level 2 - Node 2'),
+(3, 1, 'Level 2 - Node 3'),
+(4, 2, 'Level 3 - Node 4'),
+(5, 2, 'Level 3 - Node 5'),
+(6, 3, 'Level 3 - Node 6');
+
+
+CREATE DICTIONARY hierarchical_dictionary
+(
+    id UInt64,
+    parent_id UInt64 HIERARCHICAL,
+    name String
+)
+PRIMARY KEY id
+SOURCE(CLICKHOUSE(TABLE 'hierarchy_source'))
+LAYOUT(HASHED())
+LIFETIME(0);
+
+SELECT dictGetDescendants('hierarchical_dictionary', 1, 1);
+
+SELECT dictGetDescendants('hierarchical_dictionary', NULL, 1);
+
+SELECT dictGetDescendants('hierarchical_dictionary', 1, NULL); -- { serverError BAD_ARGUMENTS }
+
+SELECT dictGetChildren('hierarchical_dictionary', 1);
+
+SELECT dictGetChildren('hierarchical_dictionary', NULL);