[fix](coalesce) fix 'heap-use-after-free' of function coalesce (#42666)

apache · Oct 29, 2024 · 58cf980 · 58cf980
1 parent d5c43c5
commit 58cf980
Showing 1 changed file with 9 additions and 11 deletions.
diff --git a/be/src/vec/functions/function_coalesce.cpp b/be/src/vec/functions/function_coalesce.cpp
@@ -56,7 +56,6 @@ class FunctionCoalesce : public IFunction {
 public:
     static constexpr auto name = "coalesce";
 
-    mutable DataTypePtr result_type;
     mutable FunctionBasePtr func_is_not_null;
 
     static FunctionPtr create() { return std::make_shared<FunctionCoalesce>(); }
@@ -70,26 +69,25 @@ class FunctionCoalesce : public IFunction {
     size_t get_number_of_arguments() const override { return 0; }
 
     DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {
+        DataTypePtr res;
         for (const auto& arg : arguments) {
             if (!arg->is_nullable()) {
-                result_type = arg;
+                res = arg;
                 break;
             }
         }
 
-        result_type = result_type ? result_type : arguments[0];
-        return result_type;
+        res = res ? res : arguments[0];
+
+        const ColumnsWithTypeAndName is_not_null_col {{nullptr, make_nullable(res), ""}};
+        func_is_not_null = SimpleFunctionFactory::instance().get_function(
+                "is_not_null_pred", is_not_null_col, std::make_shared<DataTypeUInt8>());
+
+        return res;
     }
 
     Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,
                         size_t result, size_t input_rows_count) const override {
-        if (!func_is_not_null) [[unlikely]] {
-            const ColumnsWithTypeAndName is_not_null_col {
-                    {nullptr, make_nullable(result_type), ""}};
-            func_is_not_null = SimpleFunctionFactory::instance().get_function(
-                    "is_not_null_pred", is_not_null_col, std::make_shared<DataTypeUInt8>(),
-                    {.enable_decimal256 = context->state()->enable_decimal256()});
-        }
         DCHECK_GE(arguments.size(), 1);
         DataTypePtr result_type = block.get_by_position(result).type;
         ColumnNumbers filtered_args;