Fix an invalid default value cause bootstrap failed

dbms/src/Storages/Transaction/TiDB.cpp

@@ -26,6 +26,8 @@
 #include <Storages/Transaction/SchemaNameMapper.h>
 #include <Storages/Transaction/TiDB.h>
 
+#include <cmath>
+
 namespace DB
 {
 namespace ErrorCodes
@@ -110,14 +112,28 @@ Field ColumnInfo::defaultValueToField() const
     }
     switch (tp)
     {
-    // TODO: Consider unsigned?
     // Integer Type.
     case TypeTiny:
     case TypeShort:
     case TypeLong:
     case TypeLongLong:
     case TypeInt24:
-        return value.convert<Int64>();
+    {
+        // In c++, cast a unsigned integer to signed integer will not change the value.
+        // like 9223372036854775808 which is larger than the maximum value of Int64,
+        // static_cast<UInt64>(static_cast<Int64>(9223372036854775808)) == 9223372036854775808
+        // so we don't need consider unsigned here.
+        try
+        {
+            return value.convert<Int64>();
+        }
+        catch (...)
+        {
+            // due to https://github.com/pingcap/tidb/issues/34881
+            // we do this to avoid exception in older version of TiDB.
+            return static_cast<Int64>(std::llround(value.convert<double>()));
+        }
+    }
     case TypeBit:
     {
         // TODO: We shall use something like `orig_default_bit`, which will never change once created,
@@ -615,6 +631,8 @@ catch (const Poco::Exception & e)
 ///////////////////////
 
 IndexColumnInfo::IndexColumnInfo(Poco::JSON::Object::Ptr json)
+    : offset()
+    , length()
 {
     deserialize(json);
 }
@@ -664,6 +682,13 @@ catch (const Poco::Exception & e)
 ///////////////////////
 
 IndexInfo::IndexInfo(Poco::JSON::Object::Ptr json)
+    : id()
+    , state()
+    , index_type()
+    , is_unique()
+    , is_primary()
+    , is_invisible()
+    , is_global()
 {
     deserialize(json);
 }