More validations for code that generates invalid SQL

src/Query/Sql/Base.php

@@ -25,6 +25,16 @@ class Base extends BaseQuery
      */
     protected $table = null;
 
+    /**
+     * Function to check if sub queries have been generated correctly, to avoid translation errors
+     *
+     * @return bool
+     */
+    protected function isValid()
+    {
+        return (bool)!empty($this->table);
+    }
+
     /**
      * Inherit property values from parent query
      * 
@@ -42,7 +52,27 @@ protected function inheritFromParent(BaseQuery $parent)
             $this->table = $parent->table;
         }
     }
-
+
+    /**
+     * Process a subquery generator callback
+     *
+     * @param callable             $generator
+     * @return void
+     */
+    protected function generateSubQuery($generator, $object = null)
+    {
+        // create new query object
+        $subquery = is_null($object)? new Select : $object;
+
+        // run the closure callback on the sub query
+        $generator($subquery);
+        if (!$subquery->isValid()) {
+            throw new Exception('Subquery generator did not generate a valid subquery.');
+        }
+
+        return $subquery;
+    }
+
     /**
      * Create a new select query builder
      *      
@@ -57,6 +87,11 @@ protected function inheritFromParent(BaseQuery $parent)
      */
     public function table($table, $alias = null)
     {
+        if (empty($table) && !is_numeric($table))
+        {
+            throw new Exception('Table name cannot be empty.');
+        }
+
         $database = null;
 
         // Check if the table is an object, this means
@@ -81,11 +116,7 @@ public function table($table, $alias = null)
             $alias = key($table);
             $table = reset($table);
 
-            // create new query object
-            $subquery = new Select;
-
-            // run the closure callback on the sub query
-            call_user_func_array($table, array(&$subquery));
+            $subquery = $this->generateSubQuery($table);
 
             // set the table 
             // IMPORTANT: Only if we have a closure as table

src/Query/Sql/Select.php

@@ -64,9 +64,19 @@ class Select extends SelectBase implements FetchableInterface
      */
     protected $forwardKey = false;
 
+    /**
+     * Function to check if sub queries have been generated correctly, to avoid translation errors
+     *
+     * @return bool
+     */
+    protected function isValid()
+    {
+        return (bool)!empty($this->table);
+    }
+
     /**
      * Inherit property values from parent query
-     * 
+     *
      * @param BaseQuery             $parent
      * @return void
      */
@@ -340,18 +350,22 @@ public function join($table, $localKey, $operator = null, $referenceKey = null,
             throw new Exception('Invalid join type "'.$type.'" given. Available type: inner, left, right, outer');
         }
 
-        // to make nested joins possible you can pass an closure
-        // wich will create a new query where you can add your nested wheres
-        if (is_object($localKey) && ($localKey instanceof \Closure)) 
-        {
-            // create new query object
-            $subquery = new SelectJoin;
-
-            // run the closure callback on the sub query
-            call_user_func_array($localKey, array(&$subquery));
-
-            // add the join
-            $this->joins[] = array($type, $table, $subquery); return $this;
+        if (is_object($localKey)) {
+            // to make nested joins possible you can pass a closure
+            // which will create a new query where you can add your nested wheres
+            if ($localKey instanceof \Closure) {
+                $localKey = $this->generateSubQuery($localKey, new SelectJoin);
+            }
+            // also allow using a manually constructed SelectJoin object
+            if ($localKey instanceof SelectJoin) {
+                $this->joins[] = [$type, $table, $localKey];
+                return $this;
+            }
+            // continue, because localKey could be an expression object
+        }
+
+        if (is_null($operator) || is_null($referenceKey)) {
+            throw new Exception('When using non nested join conditions, an operator and a reference key is required.');
         }
 
         $this->joins[] = array($type, $table, $localKey, $operator, $referenceKey); return $this;

src/Query/Sql/SelectBase.php

@@ -35,6 +35,16 @@ class SelectBase extends Base
      */
     protected $limit = null;
 
+    /**
+     * Function to check if sub queries have been generated correctly, to avoid translation errors
+     *
+     * @return bool
+     */
+    protected function isValid()
+    {
+        return (bool)!empty($this->wheres);
+    }
+
     /**
      * Returns an string argument as parsed array if possible
      * 
@@ -126,17 +136,12 @@ public function where($column, $param1 = null, $param2 = null, $type = 'and')
             $this->wheres[] = array($type, $subquery); return $this;
         }
 
-        // to make nested wheres possible you can pass an closure
-        // wich will create a new query where you can add your nested wheres
-        if (is_object($column) && ($column instanceof \Closure)) 
-        {
-            // create new query object
-            $subquery = new SelectBase;
-
-            // run the closure callback on the sub query
-            call_user_func_array($column, array( &$subquery ));
-
-            $this->wheres[] = array($type, $subquery); return $this;
+        // to make nested wheres possible you can pass a closure
+        // which will create a new query where you can add your nested wheres
+        if (is_object($column) && ($column instanceof \Closure)) {
+            $subquery = $this->generateSubQuery($column, new SelectBase);
+            $this->wheres[] = [$type, $subquery];
+            return $this;
         }
 
         // when param2 is null we replace param2 with param one as the

src/Query/Sql/SelectJoin.php

@@ -27,6 +27,16 @@ class SelectJoin extends SelectBase
      */
     protected $wheres = array();
 
+    /**
+     * Function to check if sub queries have been generated correctly, to avoid translation errors
+     *
+     * @return bool
+     */
+    protected function isValid()
+    {
+        return (bool)!empty($this->ons);
+    }
+
     /**
      * Add an on condition to the join object
      * 

src/Translator/Mysql.php

@@ -38,18 +38,6 @@ class Mysql implements TranslatorInterface
      */
     protected $attributes = array();
 
-    /**
-     * Function to escape identifier names (columns and tables)
-     * Doubles backticks, removes null bytes
-     * https://dev.mysql.com/doc/refman/8.0/en/identifiers.html
-     *
-     * @var string
-     */
-    public function escapeIdentifier($identifier)
-    {
-        return '`'.str_replace(['`',"\0"],['``',''],$identifier).'`';
-    }
-
     /**
      * Translate the given query object and return the results as
      * argument array
@@ -243,6 +231,18 @@ protected function escape($string)
         return $this->escapeIdentifier($string);
     }
 
+    /**
+     * Function to escape identifier names (columns and tables)
+     * Doubles backticks, removes null bytes
+     * https://dev.mysql.com/doc/refman/8.0/en/identifiers.html
+     *
+     * @var string
+     */
+    public function escapeIdentifier($identifier)
+    {
+        return '`' . str_replace(['`', "\0"], ['``',''], $identifier) . '`';
+    }
+
     /**
      * Escapes an sql function object
      *