fixed view fields names check and generation (changed after Trudy review: underlying field names treat as user set ones) (BUG#7448)

mysql-test/r/view.result:
  test of view field names generation
mysql-test/t/view.test:
  test of view field names generation
sql/item.cc:
  add a flag that indicates that the name of the item was an auto-generated one and so can be changed in a view
sql/item.h:
  add a flag that indicates that the name of the item was an auto-generated one and so can be changed in a view
  layout fixed
sql/item_func.cc:
  line made less then 80 columns
sql/sql_view.cc:
  fixed checking of duplicates of view fields:
  1) case-insensitive system charset/collation is used now to compare view filds
  2) in case if the duplicate field name was of an auto-generated one, we create another unique name for it
sql/sql_yacc.yy:
  add a flag that indicates that the name of the item was an auto-generated one and so can be changed in a view

7 files changed, 196 insertions, 11 deletions

diff --git a/mysql-test/r/view.result b/mysql-test/r/view.result
index b178af1bb1c..99bf11ef9d8 100644
--- a/mysql-test/r/view.result
+++ b/mysql-test/r/view.result
@@ -1743,3 +1743,58 @@ select * from v1;
 cast(1 as decimal)
 1.00
 drop view v1;
+create view v1 as select '\\','\\shazam';
+select * from v1;
+\	\shazam
+\	\shazam
+drop view v1;
+create view v1 as select '\'','\shazam';
+select * from v1;
+'	shazam
+'	shazam
+drop view v1;
+create view v1 as select 'k','K';
+select * from v1;
+k	My_exp_K
+k	K
+drop view v1;
+create table t1 (s1 int);
+create view v1 as select s1, 's1' from t1;
+select * from v1;
+s1	My_exp_s1
+drop view v1;
+create view v1 as select 's1', s1 from t1;
+select * from v1;
+My_exp_s1	s1
+drop view v1;
+create view v1 as select 's1', s1, 1 as My_exp_s1 from t1;
+select * from v1;
+My_exp_1_s1	s1	My_exp_s1
+drop view v1;
+create view v1 as select 1 as My_exp_s1, 's1', s1  from t1;
+select * from v1;
+My_exp_s1	My_exp_1_s1	s1
+drop view v1;
+create view v1 as select 1 as s1, 's1', 's1' from t1;
+select * from v1;
+s1	My_exp_s1	My_exp_1_s1
+drop view v1;
+create view v1 as select 's1', 's1', 1 as s1 from t1;
+select * from v1;
+My_exp_1_s1	My_exp_s1	s1
+drop view v1;
+create view v1 as select s1, 's1', 's1' from t1;
+select * from v1;
+s1	My_exp_s1	My_exp_1_s1
+drop view v1;
+create view v1 as select 's1', 's1', s1 from t1;
+select * from v1;
+My_exp_1_s1	My_exp_s1	s1
+drop view v1;
+create view v1 as select 1 as s1, 's1', s1 from t1;
+ERROR 42S21: Duplicate column name 's1'
+create view v1 as select 's1', s1, 1 as s1 from t1;
+ERROR 42S21: Duplicate column name 's1'
+drop table t1;
+create view v1(k, K) as select 1,2;
+ERROR 42S21: Duplicate column name 'K'
diff --git a/mysql-test/t/view.test b/mysql-test/t/view.test
index 23d482254d1..dee5c62b1fe 100644
--- a/mysql-test/t/view.test
+++ b/mysql-test/t/view.test
@@ -1587,3 +1587,56 @@ drop table t1;
 create view v1 as select cast(1 as decimal);
 select * from v1;
 drop view v1;
+
+#
+# Generation unique names for columns, and correct names check (BUG#7448)
+#
+# names with ' and \
+create view v1 as select '\\','\\shazam';
+select * from v1;
+drop view v1;
+create view v1 as select '\'','\shazam';
+select * from v1;
+drop view v1;
+# autogenerated names differ by case only
+create view v1 as select 'k','K';
+select * from v1;
+drop view v1;
+create table t1 (s1 int);
+# same autogenerated names
+create view v1 as select s1, 's1' from t1;
+select * from v1;
+drop view v1;
+create view v1 as select 's1', s1 from t1;
+select * from v1;
+drop view v1;
+# set name as one of expected autogenerated
+create view v1 as select 's1', s1, 1 as My_exp_s1 from t1;
+select * from v1;
+drop view v1;
+create view v1 as select 1 as My_exp_s1, 's1', s1  from t1;
+select * from v1;
+drop view v1;
+# set name conflict with autogenerated names
+create view v1 as select 1 as s1, 's1', 's1' from t1;
+select * from v1;
+drop view v1;
+create view v1 as select 's1', 's1', 1 as s1 from t1;
+select * from v1;
+drop view v1;
+# underlying field name conflict with autogenerated names
+create view v1 as select s1, 's1', 's1' from t1;
+select * from v1;
+drop view v1;
+create view v1 as select 's1', 's1', s1 from t1;
+select * from v1;
+drop view v1;
+# underlying field name conflict with set name
+-- error 1060
+create view v1 as select 1 as s1, 's1', s1 from t1;
+-- error 1060
+create view v1 as select 's1', s1, 1 as s1 from t1;
+drop table t1;
+# set names differ by case only
+-- error 1060
+create view v1(k, K) as select 1,2;
diff --git a/sql/item.cc b/sql/item.cc
index e7feeaa4289..2276758e284 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -314,6 +314,7 @@ void *Item::operator new(size_t size, Item *reuse, uint *rsize)
 
 Item::Item():
   rsize(0), name(0), orig_name(0), name_length(0), fixed(0),
+  is_autogenerated_name(TRUE),
   collation(&my_charset_bin, DERIVATION_COERCIBLE)
 {
   marker= 0;
diff --git a/sql/item.h b/sql/item.h
index 6a1490a19d5..afaefe9a096 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -269,6 +269,8 @@ public:
   my_bool unsigned_flag;
   my_bool with_sum_func;
   my_bool fixed;                        /* If item fixed with fix_fields */
+  my_bool is_autogenerated_name;        /* indicate was name of this Item
+                                           autogenerated or set by user */
   DTCollation collation;
 
   // alloc & destruct is done as start of select using sql_alloc
@@ -288,7 +290,7 @@ public:
     name=0;
 #endif
   }		/*lint -e1509 */
-  void set_name(const char *str,uint length, CHARSET_INFO *cs);
+  void set_name(const char *str, uint length, CHARSET_INFO *cs);
   void rename(char *new_name);
   void init_make_field(Send_field *tmp_field,enum enum_field_types type);
   virtual void cleanup();
@@ -1170,7 +1172,7 @@ public:
     collation.set(cs, dv);
     str_value.set_or_copy_aligned(str,length,cs);
     max_length= str_value.numchars()*cs->mbmaxlen;
-    set_name(name_par,0,cs);
+    set_name(name_par, 0, cs);
     decimals=NOT_FIXED_DEC;
     // it is constant => can be used without fix_fields (and frequently used)
     fixed= 1;
diff --git a/sql/item_func.cc b/sql/item_func.cc
index 4166605ae11..57f68bbc2a0 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -4620,7 +4620,7 @@ Item *get_system_var(THD *thd, enum_var_type var_type, const char *var_name,
   if (!(item=var->item(thd, var_type, &null_lex_string)))
     return 0;						// Impossible
   thd->lex->uncacheable(UNCACHEABLE_SIDEEFFECT);
-  item->set_name(item_name, 0, system_charset_info);	// Will use original name
+  item->set_name(item_name, 0, system_charset_info);  // Will use original name
   return item;
 }
 
diff --git a/sql/sql_view.cc b/sql/sql_view.cc
index 5152619fd85..0b351407c13 100644
--- a/sql/sql_view.cc
+++ b/sql/sql_view.cc
@@ -36,6 +36,61 @@ TYPELIB updatable_views_with_limit_typelib=
 
 
 /*
+  Make a unique name for an anonymous view column
+  SYNOPSIS
+    target        reference to the item for which a new name has to be made
+    item_list     list of items within which we should check uniqueness of
+                  the created name
+    last_element  the last element of the list above
+
+  NOTE
+    Unique names are generated by adding 'My_exp_' to the old name of the
+    column. In case the name that was created this way already exists, we
+    add a numeric postfix to its end (i.e. "1") and increase the number
+    until the name becomes unique. If the generated name is longer than
+    NAME_LEN, it is truncated.
+*/
+
+static void make_unique_view_field_name(Item *target,
+                                        List<Item> &item_list,
+                                        Item *last_element)
+{
+  char *name= (target->orig_name ?
+               target->orig_name :
+               target->name);
+  uint name_len;
+  uint attempt= 0;
+  char buff[NAME_LEN+1];
+  for (;; attempt++)
+  {
+    Item *check;
+    List_iterator_fast<Item> itc(item_list);
+    bool ok= TRUE;
+
+    if (attempt)
+      name_len= my_snprintf(buff, NAME_LEN, "My_exp_%d_%s", attempt, name);
+    else
+      name_len= my_snprintf(buff, NAME_LEN, "My_exp_%s", name);
+
+    do
+    {
+      check= itc++;
+      if (check != target &&
+          my_strcasecmp(system_charset_info, buff, check->name) == 0)
+      {
+        ok= FALSE;
+        break;
+      }
+    } while (check != last_element);
+    if (ok)
+      break;
+  }
+
+  target->orig_name= target->name;
+  target->set_name(buff, name_len, system_charset_info);
+}
+
+/*
   Creating/altering VIEW procedure
 
   SYNOPSIS
@@ -240,24 +295,36 @@ bool mysql_create_view(THD *thd,
       goto err;
     }
     while ((item= it++, name= nm++))
+    {
       item->set_name(name->str, name->length, system_charset_info);
+      item->is_autogenerated_name= FALSE;
+    }
   }
 
   /* Test absence of duplicates names */
   {
     Item *item;
     List_iterator_fast<Item> it(select_lex->item_list);
-    it++;
     while ((item= it++))
     {
       Item *check;
       List_iterator_fast<Item> itc(select_lex->item_list);
+      /* treat underlying fields like set by user names */
+      if (item->real_item()->type() == Item::FIELD_ITEM)
+        item->is_autogenerated_name= FALSE;
       while ((check= itc++) && check != item)
       {
-        if (strcmp(item->name, check->name) == 0)
+        if (my_strcasecmp(system_charset_info, item->name, check->name) == 0)
         {
-          my_error(ER_DUP_FIELDNAME, MYF(0), item->name);
-          DBUG_RETURN(TRUE);
+          if (item->is_autogenerated_name)
+            make_unique_view_field_name(item, select_lex->item_list, item);
+          else if (check->is_autogenerated_name)
+            make_unique_view_field_name(check, select_lex->item_list, item);
+          else
+          {
+            my_error(ER_DUP_FIELDNAME, MYF(0), item->name);
+            DBUG_RETURN(TRUE);
+          }
         }
       }
     }
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 00ef8b581f1..1b9176e2744 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -4107,7 +4107,10 @@ select_item:
 	    if (add_item_to_list(YYTHD, $2))
 	      YYABORT;
 	    if ($4.str)
-	      $2->set_name($4.str,$4.length,system_charset_info);
+            {
+	      $2->set_name($4.str, $4.length, system_charset_info);
+              $2->is_autogenerated_name= FALSE;
+            }
 	    else if (!$2->name) {
 	      char *str = $1;
 	      if (str[-1] == '`')
@@ -4913,9 +4916,12 @@ udf_expr:
 	remember_name expr remember_end select_alias
 	{
 	  if ($4.str)
-	    $2->set_name($4.str,$4.length,system_charset_info);
+          {
+	    $2->set_name($4.str, $4.length, system_charset_info);
+            $2->is_autogenerated_name= FALSE;
+          }
 	  else
-	    $2->set_name($1,(uint) ($3 - $1), YYTHD->charset());
+	    $2->set_name($1, (uint) ($3 - $1), YYTHD->charset());
 	  $$= $2;
 	}
 	;
@@ -5691,7 +5697,8 @@ procedure_item:
 	    if (add_proc_to_list(lex->thd, $2))
 	      YYABORT;
 	    if (!$2->name)
-	      $2->set_name($1,(uint) ((char*) lex->tok_end - $1), YYTHD->charset());
+	      $2->set_name($1,(uint) ((char*) lex->tok_end - $1),
+                           YYTHD->charset());
 	  }
           ;