Bug#40277: SHOW CREATE VIEW returns invalid SQL

The problem is that not all column names retrieved from a SELECT
statement can be used as view column names due to length and format
restrictions. The server failed to properly check the conformity
of those automatically generated column names before storing the
final view definition on disk.

Since columns retrieved from a SELECT statement can be anything
ranging from functions to constants values of any format and length,
the solution is to rewrite to a pre-defined format any names that
are not acceptable as a view column name.

The name is rewritten to "Name_exp_%u" where %u translates to the
position of the column. To avoid this conversion scheme, define
explict names for the view columns via the column_list clause.
Also, aliases are now only generated for top level statements.

mysql-test/include/view_alias.inc:
  Add test case for Bug#40277
mysql-test/r/compare.result:
  Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/group_by.result:
  Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/ps.result:
  Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/subselect.result:
  Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/subselect3.result:
  Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/type_datetime.result:
  Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/union.result:
  Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/view.result:
  Add test case result for Bug#40277
mysql-test/r/view_alias.result:
  Add test case result for Bug#40277
mysql-test/t/view_alias.test:
  Add test case for Bug#40277
sql/sql_view.cc:
  Check if auto generated column names are conforming. Also, the
  make_unique_view_field_name function is not used as it uses the
  original name to construct a new one, which does not work if the
  name is invalid.

1 files changed, 25 insertions, 0 deletions

diff --git a/mysql-test/include/view_alias.inc b/mysql-test/include/view_alias.inc
new file mode 100644
index 00000000000..17adcf5f0ab
--- /dev/null
+++ b/mysql-test/include/view_alias.inc
@@ -0,0 +1,25 @@
+# Routine to be called by t/view.inc
+#
+# The variable $after_select must be set before calling this routine.
+
+eval CREATE VIEW v1 AS SELECT $after_select;
+SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA = 'test' AND TABLE_NAME = 'v1';
+#
+# Extract the VIEW's SELECT from INFORMATION_SCHEMA.VIEWS
+let $query1 = `SELECT VIEW_DEFINITION FROM INFORMATION_SCHEMA.VIEWS WHERE TABLE_SCHEMA = 'test' AND TABLE_NAME = 'v1'`;
+#
+# Extract the VIEW's SELECT from SHOW CREATE VIEW
+# SHOW CREATE VIEW v1
+# View    Create View     character_set_client    collation_connection
+# v1      CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select '<--- .....
+let $value= query_get_value(SHOW CREATE VIEW v1, Create View, 1);
+let $query2 = `SELECT SUBSTR("$value",INSTR("$value",' as select ') + CHAR_LENGTH(' as '))`;
+DROP VIEW v1;
+
+# Recreate the view based on SELECT from INFORMATION_SCHEMA.VIEWS
+eval CREATE VIEW v1 AS $query1;
+DROP VIEW v1;
+# Recreate the view based on SHOW CREATE VIEW
+eval CREATE VIEW v1 AS $query2;
+DROP VIEW v1;
+