Remove the CrossSchemaTableExpression

This change has caused regressions for a few folks. It also doesn't work
in all the scenarios that people need it to. Not having a problematic
feature is better than having a broken one.

There was a reasonable solution in the past that involved using
`$this->table('db.table_name')` this is a decent solution that makes the
cross db joins explicit.

Refs #9293
Refs #8679

src/Database/Connection.php

@@ -712,38 +712,6 @@ class Connection implements ConnectionInterface
     }
 
     /**
-     * Check if cross talk is supported between two connections
-     *
-     * @param ConnectionInterface $target Connection to check cross talk with
-     *
-     * @return bool
-     */
-    public function supportsCrossWith(ConnectionInterface $target)
-    {
-        $sourceConfig = $this->config();
-        $targetConfig = $target->config();
-
-        // No need to do report cross support in case the same connection is being used
-        if ($sourceConfig['name'] === $targetConfig['name']) {
-            return false;
-        }
-
-        $configToCheck = [
-            'driver',
-            'host',
-            'port'
-        ];
-
-        foreach ($configToCheck as $config) {
-            if ((isset($sourceConfig[$config])) && ($sourceConfig[$config] !== $targetConfig[$config])) {
-                return false;
-            }
-        }
-
-        return true;
-    }
-
-    /**
      * Returns a new statement object that will log the activity
      * for the passed original statement instance.
      *

src/Database/Expression/CrossSchemaTableExpression.php

@@ -1,129 +0,0 @@
-<?php
-/**
- * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
- * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
- *
- * Licensed under The MIT License
- * For full copyright and license information, please see the LICENSE.txt
- * Redistributions of files must retain the above copyright notice.
- *
- * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
- * @link          http://cakephp.org CakePHP(tm) Project
- * @since         3.3.0
- * @license       http://www.opensource.org/licenses/mit-license.php MIT License
- */
-namespace Cake\Database\Expression;
-
-use Cake\Database\ExpressionInterface;
-use Cake\Database\ValueBinder;
-
-/**
- * An expression object that represents a cross schema table name
- *
- * @internal
- */
-class CrossSchemaTableExpression implements ExpressionInterface
-{
-
-    /**
-     * Name of the schema
-     *
-     * @var \Cake\Database\ExpressionInterface|string
-     */
-    protected $_schema;
-
-    /**
-     * Name of the table
-     *
-     * @var \Cake\Database\ExpressionInterface|string
-     */
-    protected $_table;
-
-    /**
-     * @inheritDoc
-     *
-     * @param string\\Cake\Database\ExpressionInterface $schema Name of the schema
-     * @param string|\Cake\Database\ExpressionInterface $table Name of the table
-     */
-    public function __construct($schema, $table)
-    {
-        $this->_schema = $schema;
-        $this->_table = $table;
-    }
-
-    /**
-     * Get or set the schema to use
-     *
-     * @param null|string|\Cake\Database\ExpressionInterface $schema The schema to set
-     * @return $this|string|\Cake\Database\ExpressionInterface The schema that has been set
-     */
-    public function schema($schema = null)
-    {
-        if ($schema !== null) {
-            $this->_schema = $schema;
-
-            return $this;
-        }
-
-        return $this->_schema;
-    }
-
-    /**
-     * Get or set the schema to use
-     *
-     * @param null|string|\Cake\Database\ExpressionInterface $table The table to set
-     * @return $this|string|\Cake\Database\ExpressionInterface The table that has been set
-     */
-    public function table($table = null)
-    {
-        if ($table !== null) {
-            $this->_table = $table;
-
-            return $this;
-        }
-
-        return $this->_table;
-    }
-
-    /**
-     * Converts the Node into a SQL string fragment.
-     *
-     * @param \Cake\Database\ValueBinder $generator Placeholder generator object
-     * @return string
-     */
-    public function sql(ValueBinder $generator)
-    {
-        $schema = $this->_schema;
-        if ($schema instanceof ExpressionInterface) {
-            $schema = $schema->sql($generator);
-        }
-
-        $table = $this->_table;
-        if ($table instanceof ExpressionInterface) {
-            $table = $table->sql($generator);
-        }
-
-        return sprintf('%s.%s', $schema, $table);
-    }
-
-    /**
-     * Iterates over each part of the expression recursively for every
-     * level of the expressions tree and executes the $visitor callable
-     * passing as first parameter the instance of the expression currently
-     * being iterated.
-     *
-     * @param callable $visitor The callable to apply to all nodes.
-     * @return void
-     */
-    public function traverse(callable $visitor)
-    {
-        if ($this->_schema instanceof ExpressionInterface) {
-            $visitor($this->_schema);
-            $this->_schema->traverse($visitor);
-        }
-        if ($this->_table instanceof ExpressionInterface) {
-            $visitor($this->_table);
-            $this->_table->traverse($visitor);
-        }
-    }
-}

src/Database/IdentifierQuoter.php

@@ -14,7 +14,6 @@
  */
 namespace Cake\Database;
 
-use Cake\Database\Expression\CrossSchemaTableExpression;
 use Cake\Database\Expression\FieldInterface;
 use Cake\Database\Expression\IdentifierExpression;
 use Cake\Database\Expression\OrderByExpression;
@@ -95,11 +94,6 @@ class IdentifierQuoter
 
             return;
         }
-        if ($expression instanceof CrossSchemaTableExpression) {
-            $this->_quoteCrossSchemaTableExpression($expression);
-
-            return;
-        }
     }
 
     /**
@@ -267,20 +261,4 @@ class IdentifierQuoter
             $this->_driver->quoteIdentifier($expression->getIdentifier())
         );
     }
-
-    /**
-     * Quotes the cross schema table identifier
-     *
-     * @param CrossSchemaTableExpression $expression The identifier to quote
-     * @return void
-     */
-    protected function _quoteCrossSchemaTableExpression(CrossSchemaTableExpression $expression)
-    {
-        if (!$expression->schema() instanceof ExpressionInterface) {
-            $expression->schema($this->_driver->quoteIdentifier($expression->schema()));
-        }
-        if (!$expression->table() instanceof ExpressionInterface) {
-            $expression->table($this->_driver->quoteIdentifier($expression->table()));
-        }
-    }
 }

src/ORM/Association.php

@@ -16,7 +16,6 @@ namespace Cake\ORM;
 
 use Cake\Collection\Collection;
 use Cake\Core\ConventionsTrait;
-use Cake\Database\Expression\CrossSchemaTableExpression;
 use Cake\Database\Expression\IdentifierExpression;
 use Cake\Datasource\EntityInterface;
 use Cake\Datasource\ResultSetDecorator;
@@ -557,14 +556,7 @@ abstract class Association
     {
         $target = $this->target();
         $joinType = empty($options['joinType']) ? $this->joinType() : $options['joinType'];
-
         $table = $target->table();
-        if ($this->source()->connection()->supportsCrossWith($target->connection())) {
-            $table = new CrossSchemaTableExpression(
-                $target->connection()->driver()->schema(),
-                $table
-            );
-        }
 
         $options += [
             'includeFields' => true,

tests/TestCase/Database/ConnectionTest.php

@@ -987,32 +987,4 @@ class ConnectionTest extends TestCase
         $connection->schemaCollection($schema);
         $this->assertSame($schema, $connection->schemaCollection());
     }
-
-    /**
-     * Tests supportsCrossWith
-     *
-     * @return void
-     */
-    public function testSupportsCrossWith()
-    {
-        $connection = new Connection(ConnectionManager::config('test'));
-        $targetConnection = new Connection(ConnectionManager::config('test'));
-
-        $this->assertFalse($connection->supportsCrossWith($targetConnection), 'The same connection can\'t used in cross');
-
-        $connection = new Connection(ConnectionManager::config('test'));
-        $targetConnection = new Connection(['name' => 'test2'] + ConnectionManager::config('test'));
-
-        $this->assertTrue($connection->supportsCrossWith($targetConnection), 'Cross should be supported on databases on the same server');
-
-        $connection = new Connection(ConnectionManager::config('test'));
-        $targetConnection = new Connection(['port' => 999999] + ConnectionManager::config('test'));
-
-        $this->assertFalse($connection->supportsCrossWith($targetConnection), 'Cross is not supported across different server instances');
-
-        $connection = new Connection(ConnectionManager::config('test'));
-        $targetConnection = new Connection(['host' => 'db2.example.com'] + ConnectionManager::config('test'));
-
-        $this->assertFalse($connection->supportsCrossWith($targetConnection), 'Cross is not supported across different server instances');
-    }
 }

tests/TestCase/Database/Expression/CrossSchemaTableExpressionTest.php

@@ -1,71 +0,0 @@
-<?php
-/**
- * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
- * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
- *
- * Licensed under The MIT License
- * For full copyright and license information, please see the LICENSE.txt
- * Redistributions of files must retain the above copyright notice.
- *
- * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
- * @link          http://cakephp.org CakePHP(tm) Project
- * @since         3.3.0
- * @license       http://www.opensource.org/licenses/mit-license.php MIT License
- */
-namespace Cake\Test\TestCase\Database\Expression;
-
-use Cake\Database\Expression\CrossSchemaTableExpression;
-use Cake\Database\Expression\IdentifierExpression;
-use Cake\Database\ValueBinder;
-use Cake\TestSuite\TestCase;
-
-/**
- * Tests CrossSchemaTableExpression class
- */
-class CrossSchemaTableExpressionTest extends TestCase
-{
-
-    /**
-     * Test sql method with ExpressionInterfaces passed and without
-     */
-    public function testSql()
-    {
-        $expression = new CrossSchemaTableExpression(
-            new IdentifierExpression('schema'),
-            new IdentifierExpression('table')
-        );
-
-        $this->assertEquals('schema.table', $expression->sql(new ValueBinder()));
-
-        $expression = new CrossSchemaTableExpression('schema', 'table');
-
-        $this->assertEquals('schema.table', $expression->sql(new ValueBinder()));
-    }
-
-    /**
-     * Test traverse method with ExpressionInterfaces passed and without
-     */
-    public function testTraverse()
-    {
-        $expressions = [];
-
-        $collector = function ($e) use (&$expressions) {
-            $expressions[] = $e;
-        };
-
-        $expression = new CrossSchemaTableExpression(
-            new IdentifierExpression('schema'),
-            new IdentifierExpression('table')
-        );
-        $expression->traverse($collector);
-        $this->assertEquals([
-            new IdentifierExpression('schema'),
-            new IdentifierExpression('table')
-        ], $expressions);
-
-        $expressions = [];
-        $expression = new CrossSchemaTableExpression('schema', 'table');
-        $expression->traverse($collector);
-        $this->assertEquals([], $expressions);
-    }
-}