BUG25614860: Fix defined_as method in the view creation

The defined_as(statement) method used to create views does not allow
SelectStatement objects, generated by Table.select().

This patch fix this issue and also prevents the select statement to
be modified after passed to the defined_as() method.

Test were added for regression.

Author: nmariz

lib/mysqlx/statement.py

@@ -1,5 +1,5 @@
 # MySQL Connector/Python - MySQL driver written in Python.
-# Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved.
 
 # MySQL Connector/Python is licensed under the terms of the GPLv2
 # <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most
@@ -23,6 +23,7 @@
 
 """Implementation of Statements."""
 
+import copy
 import json
 import re
 
@@ -580,8 +581,7 @@ def get_sql(self):
             self._limit_offset) if self._has_limit else ""
 
         stmt = ("SELECT {select} FROM {schema}.{table}{where}{group}{having}"
-                "{order}{limit}".format(
-                select=getattr(self, '_projection_str', "*"),
+                "{order}{limit}".format(select=self._projection_str or "*",
                 schema=self.schema.name, table=self.target.name, limit=limit,
                 where=where, group=group_by, having=having, order=order_by))
 
@@ -852,7 +852,11 @@ def defined_as(self, statement):
         Returns:
             mysqlx.CreateViewStatement: CreateViewStatement object.
         """
-        self._defined_as = statement
+        if not isinstance(statement, SelectStatement) and \
+           not isinstance(statement, STRING_TYPES):
+            raise ProgrammingError("The statement must be an instance of "
+                                   "SelectStatement or a SQL string.")
+        self._defined_as = copy.copy(statement)  # Prevent modifications
         return self
 
     def with_check_option(self, check_option):
@@ -878,6 +882,9 @@ def execute(self):
                   if self._definer else ""
         columns = " ({0})".format(", ".join(self._columns)) \
                   if self._columns else ""
+        defined_as = self._defined_as.get_sql() \
+                     if isinstance(self._defined_as, SelectStatement) \
+                     else self._defined_as
         view_name = quote_multipart_identifier((self._schema.name, self._name))
         check_option = " WITH {0} CHECK OPTION".format(self._check_option) \
                        if self._check_option else ""
@@ -887,8 +894,7 @@ def execute(self):
                "".format(replace=replace, algorithm=self._algorithm,
                          definer=definer, security=self._security,
                          view_name=view_name, columns=columns,
-                         defined_as=self._defined_as,
-                         check_option=check_option))
+                         defined_as=defined_as, check_option=check_option))
 
         self._connection.execute_nonquery("sql", sql)
         return self._view
@@ -913,6 +919,9 @@ def execute(self):
                   if self._definer else ""
         columns = " ({0})".format(", ".join(self._columns)) \
                   if self._columns else ""
+        defined_as = self._defined_as.get_sql() \
+                     if isinstance(self._defined_as, SelectStatement) \
+                     else self._defined_as
         view_name = quote_multipart_identifier((self._schema.name, self._name))
         check_option = " WITH {0} CHECK OPTION".format(self._check_option) \
                        if self._check_option else ""
@@ -921,7 +930,7 @@ def execute(self):
                "AS {defined_as}{check_option}"
                "".format(algorithm=self._algorithm, definer=definer,
                          security=self._security, view_name=view_name,
-                         columns=columns, defined_as=self._defined_as,
+                         columns=columns, defined_as=defined_as,
                          check_option=check_option))
 
         self._connection.execute_nonquery("sql", sql)

tests/test_mysqlx_crud.py

@@ -116,7 +116,7 @@ def test_create_view(self):
                           .defined_as(defined_as) \
                           .execute()
 
-        self.schema.drop_table(view_name)
+        self.schema.drop_view(view_name)
 
         # using a non-updatable view
         defined_as = ("SELECT COLUMN_TYPE, COLUMN_COMMENT FROM "
@@ -126,8 +126,30 @@ def test_create_view(self):
                           .defined_as(defined_as) \
                           .execute()
 
+        self.schema.drop_view(view_name)
+
+        # create view from Table.select()
+        table = self.schema.get_table(table_name)
+        table.insert("id").values(2).values(3).execute()
+        select = table.select()
+        view = self.schema.create_view(view_name).defined_as(select).execute()
+        self.assertEqual(3, view.count())
+
+        self.schema.drop_view(view_name)
+
+        # ensure that the object passed to defined_as() does not affect the
+        # view if changed later
+        select = table.select()
+        view = self.schema.create_view(view_name).defined_as(select)
+        select = select.where("id > 1")
+        self.assertEqual(3, view.execute().count())
+
+        # defined_as() should only accepts SelectStatement and strings
+        view = self.schema.create_view(view_name)
+        self.assertRaises(mysqlx.ProgrammingError, view.defined_as, 123)
+
+        self.schema.drop_view(view_name)
         self.schema.drop_table(table_name)
-        self.schema.drop_table(view_name)
 
     def test_alter_view(self):
         table_name = "table_test"
@@ -162,8 +184,30 @@ def test_alter_view(self):
                           .defined_as(defined_as) \
                           .execute()
 
+        self.schema.drop_view(view_name)
+
+        # create view from Table.select()
+        table = self.schema.get_table(table_name)
+        table.insert("id").values(2).values(3).execute()
+        select = table.select()
+        view = self.schema.create_view(view_name).defined_as(select).execute()
+        self.assertEqual(12, view.count())
+
+        self.schema.drop_view(view_name)
+
+        # ensure that the object passed to defined_as() does not affect the
+        # view if changed later
+        select = table.select()
+        view = self.schema.create_view(view_name).defined_as(select)
+        select = select.where("id > 1")
+        self.assertEqual(12, view.execute().count())
+
+        # defined_as() should only accepts SelectStatement and strings
+        view = self.schema.create_view(view_name)
+        self.assertRaises(mysqlx.ProgrammingError, view.defined_as, 123)
+
+        self.schema.drop_view(view_name)
         self.schema.drop_table(table_name)
-        self.schema.drop_table(view_name)
 
     def test_get_collection(self):
         collection_name = "collection_test"