Support enum with index 0 (pingcap#8533) (pingcap#8549)

close pingcap#8311
ti-chi-bot · Dec 19, 2023 · a03e16f · a03e16f
1 parent a5a9e99
commit a03e16f
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Showing 3 changed files with 30 additions and 2 deletions.
diff --git a/dbms/src/DataTypes/DataTypeEnum.h b/dbms/src/DataTypes/DataTypeEnum.h
@@ -81,11 +81,15 @@ class DataTypeEnum final : public IDataTypeEnum
     std::string getName() const override { return name; }
     const char * getFamilyName() const override;
 
-    const StringRef & getNameForValue(const FieldType & value) const
+    StringRef getNameForValue(const FieldType & value) const
     {
         const auto it = value_to_name_map.find(value);
         if (it == std::end(value_to_name_map))
+        {
+            if (!value)
+                return {};
             throw Exception{"Unexpected value " + toString(value) + " for type " + getName(), ErrorCodes::LOGICAL_ERROR};
+        }
 
         return it->second;
     }

diff --git a/dbms/src/Flash/Coprocessor/ArrowColCodec.cpp b/dbms/src/Flash/Coprocessor/ArrowColCodec.cpp
@@ -280,7 +280,7 @@ void flashEnumColToArrowCol(
             }
         }
         auto enum_value = static_cast<UInt64>(flash_col->getElement(i));
-        if (enum_value == 0 || enum_value > enum_value_size)
+        if (enum_value > enum_value_size)
             throw TiFlashException("number of enum overflow enum boundary", Errors::Coprocessor::Internal);
         TiDBEnum ti_enum(enum_value, enum_type->getNameForValue(static_cast<const DataTypeEnum16::FieldType>(enum_value)));
         dag_column.append(ti_enum);

diff --git a/tests/fullstack-test2/ddl/alter_column_enum.test b/tests/fullstack-test2/ddl/alter_column_enum.test
@@ -41,4 +41,28 @@ mysql> set session tidb_isolation_read_engines='tiflash'; select * from test.a1
 |  4 | D    |
 +----+------+
 
+mysql> SET SESSION SQL_MODE = ''; insert into test.a1 values (5,'');
+
+mysql> set session tidb_isolation_read_engines='tiflash'; select * from test.a1 order by id;
++----+------+
+| id | name |
++----+------+
+|  1 | A    |
+|  2 | B    |
+|  3 | C    |
+|  4 | D    |
+|  5 |      |
++----+------+
+
+mysql> set session tidb_isolation_read_engines='tiflash'; select name+0 from test.a1 order by id;
++--------+
+| name+0 |
++--------+
+|      1 |
+|      2 |
+|      3 |
+|      4 |
+|      0 |
++--------+
+
 mysql> drop table if exists test.a1