Bug#31473

  "CSV does not work with NULL value in datetime fields"
  Attempting to insert a row with a NULL value for a DATETIME field
  results in a CSV file which the storage engine cannot read.
  Don't blindly assume that "0" is acceptable for all field types,
  Since CSV does not support NULL, we find out from the field the
  default non-null value.
  Do not permit the creation of a table with a nullable columns.


mysql-test/r/csv.result:
  test for bug 31473
mysql-test/r/log_tables.result:
  change in results due to bugfix 31473
mysql-test/r/system_mysql_db.result:
  change in results due to bugfix 31473
mysql-test/t/csv.test:
  test for bug 31473
mysql-test/t/log_tables.test:
  due to bug31473, all columns in CSV tables must be declared as NOT NULL
scripts/mysql_system_tables.sql:
  due to bug31473, all columns in CSV tables must be declared as NOT NULL
storage/csv/ha_tina.cc:
  bug31473
    Don't blindly assume that "0" is acceptable for all field types,
    Since CSV does not support NULL, we find out from the field the
    default non-null value.
    Do not permit the creation of a table with a nullable columns;

1 files changed, 27 insertions, 9 deletions

diff --git a/storage/csv/ha_tina.cc b/storage/csv/ha_tina.cc
index 9a7781e017d..6a87b8ecc72 100644
--- a/storage/csv/ha_tina.cc
+++ b/storage/csv/ha_tina.cc
@@ -471,22 +471,30 @@ int ha_tina::encode_quote(uchar *buf)
   {
     const char *ptr;
     const char *end_ptr;
+    const bool was_null= (*field)->is_null();
 
     /*
-      CSV does not support nulls. Write quoted 0 to the buffer. In fact,
-      (*field)->val_str(&attribute,&attribute) would usually return 0
-      in this case but we write it explicitly here.
-      Basically this is a safety check, as no one ensures that the
-      field content is cleaned up every time we use Field::set_null()
-      in the code.
+      CSV does not support nulls. ::create() prevents creation of a table
+      with nullable columns so if we encounter them here, there is a bug.
+      This may only occur if the frm was created by an older version of
+      mysqld which permitted table creation with nullable columns.
     */
-    if ((*field)->is_null())
+    DBUG_ASSERT(!(*field)->maybe_null());
+    
+    /*
+      assistance for backwards compatibility in production builds.
+      note: this will not work for ENUM columns.
+    */
+    if (was_null)
     {
-      buffer.append(STRING_WITH_LEN("\"0\","));
-      continue;
+      (*field)->set_default();
+      (*field)->set_notnull();
     }
 
     (*field)->val_str(&attribute,&attribute);
+    
+    if (was_null)
+      (*field)->set_null();
 
     if ((*field)->str_needs_quotes())
     {
@@ -1480,6 +1488,16 @@ int ha_tina::create(const char *name, TABLE *table_arg,
   File create_file;
   DBUG_ENTER("ha_tina::create");
 
+  /*
+    check columns
+  */
+  for (Field **field= table_arg->s->field; *field; field++)
+  {
+    if ((*field)->real_maybe_null())
+      DBUG_RETURN(-1);
+  }
+  
+
   if ((create_file= my_create(fn_format(name_buff, name, "", CSM_EXT,
                                         MY_REPLACE_EXT|MY_UNPACK_FILENAME), 0,
                               O_RDWR | O_TRUNC,MYF(MY_WME))) < 0)