Query类relation支持嵌套关联

library/think/Model.php

@@ -1282,14 +1282,18 @@ abstract class Model implements \JsonSerializable, \ArrayAccess
         }
 
         foreach ($relations as $key => $relation) {
-            $closure = null;
+            $subRelation = '';
+            $closure     = null;
             if ($relation instanceof \Closure) {
                 // 支持闭包查询过滤关联条件
                 $closure  = $relation;
                 $relation = $key;
             }
+            if (strpos($relation, '.')) {
+                list($relation, $subRelation) = explode('.', $relation);
+            }
             $method                = Loader::parseName($relation, 1, false);
-            $this->data[$relation] = $this->$method()->getRelation($closure);
+            $this->data[$relation] = $this->$method()->getRelation($subRelation, $closure);
         }
         return $this;
     }

library/think/model/relation/BelongsTo.php

@@ -38,17 +38,17 @@ class BelongsTo extends OneToOne
 
     /**
      * 延迟获取关联数据
+     * @param string    $subRelation 子关联名
      * @param \Closure  $closure 闭包查询条件
      * @access public
      */
-    public function getRelation($closure = null)
+    public function getRelation($subRelation = '', $closure = null)
     {
         $foreignKey = $this->foreignKey;
-        $localKey   = $this->localKey;
         if ($closure) {
             call_user_func_array($closure, [ & $this->query]);
         }
-        return $this->query->where($localKey, $this->parent->$foreignKey)->find();
+        return $this->query->where($this->localKey, $this->parent->$foreignKey)->relation($subRelation)->find();
     }
 
     /**

library/think/model/relation/BelongsToMany.php

@@ -46,10 +46,11 @@ class BelongsToMany extends Relation
 
     /**
      * 延迟获取关联数据
+     * @param string    $subRelation 子关联名
      * @param \Closure  $closure 闭包查询条件
      * @access public
      */
-    public function getRelation($closure = null)
+    public function getRelation($subRelation = '', $closure = null)
     {
         $foreignKey = $this->foreignKey;
         $localKey   = $this->localKey;
@@ -60,7 +61,7 @@ class BelongsToMany extends Relation
         // 关联查询
         $pk                              = $this->parent->getPk();
         $condition['pivot.' . $localKey] = $this->parent->$pk;
-        $result                          = $this->belongsToManyQuery($middle, $foreignKey, $localKey, $condition)->select();
+        $result                          = $this->belongsToManyQuery($middle, $foreignKey, $localKey, $condition)->relation($subRelation)->select();
         foreach ($result as $set) {
             $pivot = [];
             foreach ($set->getData() as $key => $val) {

library/think/model/relation/HasMany.php

@@ -39,15 +39,16 @@ class HasMany extends Relation
 
     /**
      * 延迟获取关联数据
+     * @param string    $subRelation 子关联名
      * @param \Closure  $closure 闭包查询条件
      * @access public
      */
-    public function getRelation($closure = null)
+    public function getRelation($subRelation = '', $closure = null)
     {
         if ($closure) {
             call_user_func_array($closure, [ & $this->query]);
         }
-        return $this->select();
+        return $this->relation($subRelation)->select();
     }
 
     /**

library/think/model/relation/HasManyThrough.php

@@ -49,15 +49,16 @@ class HasManyThrough extends Relation
 
     /**
      * 延迟获取关联数据
+     * @param string    $subRelation 子关联名
      * @param \Closure  $closure 闭包查询条件
      * @access public
      */
-    public function getRelation($closure = null)
+    public function getRelation($subRelation = '', $closure = null)
     {
         if ($closure) {
             call_user_func_array($closure, [ & $this->query]);
         }
-        return $this->select();
+        return $this->relation($subRelation)->select();
     }
 
     /**

library/think/model/relation/HasOne.php

@@ -38,10 +38,11 @@ class HasOne extends OneToOne
 
     /**
      * 延迟获取关联数据
+     * @param string    $subRelation 子关联名
      * @param \Closure  $closure 闭包查询条件
      * @access public
      */
-    public function getRelation($colsure = null)
+    public function getRelation($subRelation = '', $colsure = null)
     {
         // 执行关联定义方法
         $localKey = $this->localKey;
@@ -49,7 +50,7 @@ class HasOne extends OneToOne
             call_user_func_array($closure, [ & $this->query]);
         }
         // 判断关联类型执行查询
-        return $this->query->where($this->foreignKey, $this->parent->$localKey)->find();
+        return $this->query->where($this->foreignKey, $this->parent->$localKey)->relation($subRelation)->find();
     }
 
     /**

library/think/model/relation/MorphMany.php

@@ -45,15 +45,16 @@ class MorphMany extends Relation
 
     /**
      * 延迟获取关联数据
+     * @param string    $subRelation 子关联名
      * @param \Closure  $closure 闭包查询条件
      * @access public
      */
-    public function getRelation($closure = null)
+    public function getRelation($subRelation = '', $closure = null)
     {
         if ($closure) {
             call_user_func_array($closure, [ & $this->query]);
         }
-        return $this->select();
+        return $this->relation($subRelation)->select();
     }
 
     /**

library/think/model/relation/MorphTo.php

@@ -39,10 +39,11 @@ class MorphTo extends Relation
 
     /**
      * 延迟获取关联数据
+     * @param string    $subRelation 子关联名
      * @param \Closure  $closure 闭包查询条件
      * @access public
      */
-    public function getRelation($closure = null)
+    public function getRelation($subRelation = '', $closure = null)
     {
         $morphKey  = $this->morphKey;
         $morphType = $this->morphType;
@@ -50,7 +51,7 @@ class MorphTo extends Relation
         $model = $this->parseModel($this->parent->$morphType);
         // 主键数据
         $pk = $this->parent->$morphKey;
-        return (new $model)->find($pk);
+        return (new $model)->relation($subRelation)->find($pk);
     }
 
     /**