Fix for bug #6008: MySQL does not create warnings when creating database and using IF NOT EXISTS

  produce warning for 'create database if not exists' if database exists
  do not update database options in this case  
  produce warning for 'create table if not exists' if table exists

mysql-test/r/create.result

@@ -9,6 +9,8 @@ NULL
 drop table if exists t1;
 create table t1 (b char(0) not null);
 create table if not exists t1 (b char(0) not null);
+Warnings:
+Note	1050	Table 't1' already exists
 insert into t1 values (""),(null);
 Warnings:
 Warning	1263	Data truncated; NULL supplied to NOT NULL column 'b' at row 2
@@ -232,9 +234,13 @@ create table t1 select x'4132';
 drop table t1;
 create table t1 select 1,2,3;
 create table if not exists t1 select 1,2;
+Warnings:
+Note	1050	Table 't1' already exists
 create table if not exists t1 select 1,2,3,4;
 ERROR 21S01: Column count doesn't match value count at row 1
 create table if not exists t1 select 1;
+Warnings:
+Note	1050	Table 't1' already exists
 select * from t1;
 1	2	3
 1	2	3
@@ -243,9 +249,13 @@ select * from t1;
 drop table t1;
 create table t1 select 1,2,3;
 create table if not exists t1 select 1,2;
+Warnings:
+Note	1050	Table 't1' already exists
 create table if not exists t1 select 1,2,3,4;
 ERROR 21S01: Column count doesn't match value count at row 1
 create table if not exists t1 select 1;
+Warnings:
+Note	1050	Table 't1' already exists
 select * from t1;
 1	2	3
 1	2	3
@@ -255,11 +265,15 @@ drop table t1;
 create table t1 (a int not null, b int, primary key (a));
 insert into t1 values (1,1);
 create table if not exists t1 select 2;
+Warnings:
+Note	1050	Table 't1' already exists
 select * from t1;
 a	b
 1	1
 0	2
 create table if not exists t1 select 3 as 'a',4 as 'b';
+Warnings:
+Note	1050	Table 't1' already exists
 create table if not exists t1 select 3 as 'a',3 as 'b';
 ERROR 23000: Duplicate entry '3' for key 1
 select * from t1;
@@ -593,3 +607,17 @@ drop database mysqltest;
 create table test.t1 like x;
 ERROR 42000: Incorrect database name 'NULL'
 drop table if exists test.t1;
+create database mysqltest;
+create database if not exists mysqltest character set latin2;
+Warnings:
+Note	1007	Can't create database 'mysqltest'; database exists
+show create database mysqltest;
+Database	Create Database
+mysqltest	CREATE DATABASE `mysqltest` /*!40100 DEFAULT CHARACTER SET latin1 */
+drop database mysqltest;
+use test;
+create table t1 (a int);
+create table if not exists t1 (a int);
+Warnings:
+Note	1050	Table 't1' already exists
+drop table t1;

mysql-test/r/temp_table.result

@@ -23,6 +23,8 @@ a	b
 6	g
 create TEMPORARY TABLE t2 engine=heap select * from t1;
 create TEMPORARY TABLE IF NOT EXISTS t2 (a int) engine=heap;
+Warnings:
+Note	1050	Table 't2' already exists
 CREATE TEMPORARY TABLE t1 (a int not null, b char (10) not null);
 ERROR 42S01: Table 't1' already exists
 ALTER TABLE t1 RENAME t2;

mysql-test/r/warnings.result

@@ -63,9 +63,11 @@ show count(*) warnings;
 1
 create table t1(id int);
 create table if not exists t1(id int);
+Warnings:
+Note	1050	Table 't1' already exists
 select @@warning_count;
 @@warning_count
-0
+1
 drop table t1;
 create table t1(a tinyint, b int not null, c date, d char(5));
 load data infile '../../std_data/warnings_loaddata.dat' into table t1 fields terminated by ',';

mysql-test/t/create.test

@@ -513,4 +513,17 @@ create table test.t1 like x;
 drop table if exists test.t1;
 --enable_warnings
 
+#
+# Bug #6008 MySQL does not create warnings when
+# creating database and using IF NOT EXISTS
+#
+create database mysqltest;
+create database if not exists mysqltest character set latin2;
+show create database mysqltest;
+drop database mysqltest;
+use test;
+create table t1 (a int);
+create table if not exists t1 (a int);
+drop table t1;
+
 # End of 4.1 tests

sql/sql_db.cc

@@ -427,7 +427,11 @@ int mysql_create_db(THD *thd, char *db, HA_CREATE_INFO *create_info,
       error= -1;
       goto exit;
     }
-    result= 0;
+    push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
+                        ER_DB_CREATE_EXISTS, ER(ER_DB_CREATE_EXISTS), db);
+    error= 0;
+    send_ok(thd);
+    goto exit;
   }
   else
   {

sql/sql_table.cc

@@ -1360,6 +1360,9 @@ int mysql_create_table(THD *thd,const char *db, const char *table_name,
     if (create_info->options & HA_LEX_CREATE_IF_NOT_EXISTS)
     {
       create_info->table_existed= 1;		// Mark that table existed
+      push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
+                          ER_TABLE_EXISTS_ERROR, ER(ER_TABLE_EXISTS_ERROR),
+                          alias);
       DBUG_RETURN(0);
     }
     my_error(ER_TABLE_EXISTS_ERROR, MYF(0), alias);
@@ -1373,12 +1376,8 @@ int mysql_create_table(THD *thd,const char *db, const char *table_name,
     if (!access(path,F_OK))
     {
       if (create_info->options & HA_LEX_CREATE_IF_NOT_EXISTS)
-      {
-	create_info->table_existed= 1;		// Mark that table existed
-	error= 0;
-      }
-      else
-	my_error(ER_TABLE_EXISTS_ERROR,MYF(0),table_name);
+        goto warn;
+      my_error(ER_TABLE_EXISTS_ERROR,MYF(0),table_name);
       goto end;
     }
   }
@@ -1401,12 +1400,8 @@ int mysql_create_table(THD *thd,const char *db, const char *table_name,
       DBUG_PRINT("info", ("Table with same name already existed in handler"));
 
       if (create_if_not_exists)
-      {
-        create_info->table_existed= 1;   // Mark that table existed
-        error= 0;
-      }
-      else
-       my_error(ER_TABLE_EXISTS_ERROR,MYF(0),table_name);
+        goto warn;
+      my_error(ER_TABLE_EXISTS_ERROR,MYF(0),table_name);
       goto end;
     }
   }
@@ -1447,6 +1442,15 @@ int mysql_create_table(THD *thd,const char *db, const char *table_name,
     }
   }
   error=0;
+  goto end;
+
+warn:
+  error= 0;
+  push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
+                      ER_TABLE_EXISTS_ERROR, ER(ER_TABLE_EXISTS_ERROR),
+                      alias);
+  create_info->table_existed= 1;		// Mark that table existed
+
 end:
   VOID(pthread_mutex_unlock(&LOCK_open));
   start_waiting_global_read_lock(thd);