Feature: Has one of many support (#141)

* Added support for hasOne()->ofMany()

* Improved tests; Added additional check:

Author: luisdalmolin

.gitignore

@@ -5,3 +5,4 @@ vendor
 coverage
 .phpunit.result.cache
 .php_cs.cache
+.envrc

src/Mixins/RelationshipsExtraMethods.php

@@ -14,8 +14,33 @@
 use Illuminate\Database\Eloquent\Relations\MorphToMany;
 
 /**
- * @method getModel
+ * @method \Illuminate\Database\Eloquent\Model getModel()
+ * @method string getTable()
+ * @method string getForeignPivotKeyName()
+ * @method string getRelatedPivotKeyName()
+ * @method bool isOneOfMany()
+ * @method \Illuminate\Database\Eloquent\Builder|void getOneOfManySubQuery()
+ * @method \Illuminate\Database\Eloquent\Builder getQuery()
+ * @method \Illuminate\Database\Eloquent\Model getThroughParent()
+ * @method string getForeignKeyName()
+ * @method string getMorphType()
+ * @method string getMorphClass()
+ * @method string getFirstKeyName()
+ * @method string getQualifiedLocalKeyName()
+ * @method string getExistenceCompareKey()
  * @mixin \Illuminate\Database\Eloquent\Relations\Relation
+ * @mixin \Illuminate\Database\Eloquent\Relations\HasOneOrMany
+ * @mixin \Illuminate\Database\Eloquent\Relations\BelongsToMany
+ * @property \Illuminate\Database\Eloquent\Builder $query
+ * @property \Illuminate\Database\Eloquent\Model $parent
+ * @property \Illuminate\Database\Eloquent\Model $throughParent
+ * @property string $foreignKey
+ * @property string $parentKey
+ * @property string $ownerKey
+ * @property string $localKey
+ * @property string $secondKey
+ * @property string $secondLocalKey
+ * @property \Illuminate\Database\Eloquent\Model $farParent
  */
 class RelationshipsExtraMethods
 {
@@ -226,6 +251,15 @@ protected function performJoinForEloquentPowerJoinsForHasMany()
         return function ($builder, $joinType, $callback = null, $alias = null, bool $disableExtraConditions = false) {
             $joinedTable = $alias ?: $this->query->getModel()->getTable();
             $parentTable = StaticCache::getTableOrAliasForModel($this->parent);
+            $isOneOfMany = method_exists($this, 'isOneOfMany') ? $this->isOneOfMany() : false;
+
+            if ($isOneOfMany) {
+                foreach ($this->getOneOfManySubQuery()->getQuery()->columns as $column) {
+                    $builder->addSelect($column);
+                }
+
+                $builder->take(1);
+            }
 
             $builder->{$joinType}($this->query->getModel()->getTable(), function ($join) use ($callback, $joinedTable, $parentTable, $alias, $disableExtraConditions) {
                 if ($alias) {

tests/JoinRelationshipTest.php

@@ -727,4 +727,45 @@ public function test_it_can_alias_belongs_to_many()
             $sql
         );
     }
+
+    public function test_has_one_of_many()
+    {
+        $post = factory(Post::class)->create();
+        $bestComment = factory(Comment::class)->state('approved')->create(['body' => 'best comment', 'votes' => 2]);
+        $lastComment = factory(Comment::class)->state('approved')->create(['body' => 'worst comment', 'votes' => 0]);
+
+        $bestCommentSql = Post::query()
+            ->select('posts.*', 'comments.body')
+            ->joinRelationship('bestComment')
+            ->toSql();
+
+        $bestCommentPost = Post::query()
+            ->select('posts.*', 'comments.body')
+            ->joinRelationship('bestComment')
+            ->first();
+
+        $this->assertStringContainsString(
+            'max("comments"."votes") as "votes_aggregate"',
+            $bestCommentSql
+        );
+
+        $this->assertEquals($bestComment->body, $bestCommentPost->body);
+
+        $lastCommentSql = Post::query()
+            ->select('posts.*', 'comments.body')
+            ->joinRelationship('lastComment')
+            ->toSql();
+
+        $lastCommentPost = Post::query()
+            ->select('posts.*', 'comments.body')
+            ->joinRelationship('lastComment')
+            ->first();
+
+        $this->assertStringContainsString(
+            'max("comments"."id") as "id_aggregate"',
+            strtolower($lastCommentSql)
+        );
+
+        $this->assertEquals($lastComment->body, $lastCommentPost->body);
+    }
 }

tests/Models/Post.php

@@ -4,6 +4,8 @@
 
 use Kirschbaum\PowerJoins\PowerJoins;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Relations\HasOne;
 use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Database\Eloquent\Relations\MorphMany;
@@ -36,6 +38,20 @@ public function comments(): HasMany
         return $this->hasMany(Comment::class);
     }
 
+    public function lastComment(): HasOne
+    {
+        return $this
+            ->hasOne(Comment::class)
+            ->ofMany();
+    }
+
+    public function bestComment(): HasOne
+    {
+        return $this
+            ->hasOne(Comment::class)
+            ->ofMany('votes', 'max');
+    }
+
     public function images(): MorphMany
     {
         return $this->morphMany(Image::class, 'imageable');