fix for AR case insensitive relation

framework/db/ActiveRelationTrait.php

@@ -600,7 +600,7 @@ private function normalizeModelKey($value)
             $value = $value->__toString();
         }
 
-        return $value;
+        return strtolower($value);
     }
 
     /**

tests/data/ar/Product.php

@@ -0,0 +1,29 @@
+<?php
+
+
+namespace yiiunit\data\ar;
+
+
+/**
+ * Class Product
+ * @package yiiunit\data\ar
+ *
+ * @property string $sku
+ * @property string $title
+ * @property ProductAttribute[] $productAttributes
+ */
+class Product extends ActiveRecord
+{
+    public static function tableName()
+    {
+        return 'product';
+    }
+
+    /**
+     * @return ProductAttribute[]|\yii\db\ActiveQuery
+     */
+    public function getProductAttributes()
+    {
+        return $this->hasMany(ProductAttribute::className(), ['product_sku' => 'sku']);
+    }
+}

tests/data/ar/ProductAttribute.php

@@ -0,0 +1,31 @@
+<?php
+
+
+namespace yiiunit\data\ar;
+
+
+/**
+ * Class Product
+ * @package yiiunit\data\ar
+ *
+ * @property int $id
+ * @property string $product_sku
+ * @property string $value
+ * @property Product $product
+ */
+class ProductAttribute extends ActiveRecord
+{
+    public static function tableName()
+    {
+        return 'product_attribute';
+    }
+
+    /**
+     * @return Product|\yii\db\ActiveQuery
+     */
+    public function getProduct()
+    {
+        return $this->hasOne(Product::className(), ['sku' => 'product_sku'])->inverseOf('productAttributes');
+    }
+
+}

tests/data/mysql.sql

@@ -33,6 +33,8 @@ DROP TABLE IF EXISTS `T_constraints_2` CASCADE;
 DROP TABLE IF EXISTS `T_constraints_1` CASCADE;
 DROP TABLE IF EXISTS `T_upsert` CASCADE;
 DROP TABLE IF EXISTS `T_upsert_1`;
+DROP TABLE IF EXISTS `product`;
+DROP TABLE IF EXISTS `product_attribute`;
 
 CREATE TABLE `constraints`
 (
@@ -402,3 +404,20 @@ CREATE TABLE `T_upsert_1` (
   `a` int(11) NOT NULL,
   PRIMARY KEY (`a`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
+
+CREATE TABLE `product` (
+       sku varchar(45) NOT NULL PRIMARY KEY,
+       title varchar(128) NOT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE utf8_general_ci;
+
+CREATE TABLE `product_attribute` (
+     id INTEGER NOT NULL PRIMARY KEY,
+     product_sku varchar(45),
+     value varchar(128)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE utf8_general_ci;
+
+INSERT INTO `product` (sku, title) VALUES ('ARTi01', 'Yii1');
+INSERT INTO `product` (sku, title) VALUES ('ARTI02', 'Yii2');
+INSERT INTO `product_attribute` (id, product_sku, value) VALUES (1, 'ARTI01', 'UPPERCASE');
+INSERT INTO `product_attribute` (id, product_sku, value) VALUES (2, 'ARTI01', 'UPPERCASE2');
+INSERT INTO `product_attribute` (id, product_sku, value) VALUES (3, 'ARTi01', 'EXACT');

tests/data/sqlite.sql

@@ -30,6 +30,8 @@ DROP TABLE IF EXISTS "T_constraints_2";
 DROP TABLE IF EXISTS "T_constraints_1";
 DROP TABLE IF EXISTS "T_upsert";
 DROP TABLE IF EXISTS "T_upsert_1";
+DROP TABLE IF EXISTS "product";
+DROP TABLE IF EXISTS "product_attribute";
 
 CREATE TABLE "profile" (
   id INTEGER NOT NULL,
@@ -360,3 +362,20 @@ CREATE TABLE "T_upsert_1"
 (
     "a" INTEGER NOT NULL PRIMARY KEY
 );
+
+CREATE TABLE "product" (
+       sku varchar(45) NOT NULL,
+       title varchar(128) NOT NULL,
+       PRIMARY KEY (sku)
+);
+
+CREATE TABLE "product_attribute" (
+       id INTEGER NOT NULL PRIMARY KEY,
+       product_sku varchar(45),
+       value varchar(128)
+);
+INSERT INTO "product" (sku, title) VALUES ('ARTi01', 'Yii1');
+INSERT INTO "product" (sku, title) VALUES ('ARTI02', 'Yii2');
+INSERT INTO "product_attribute" (id, product_sku, value) VALUES (1, 'ARTI01', 'UPPERCASE');
+INSERT INTO "product_attribute" (id, product_sku, value) VALUES (2, 'ARTI01', 'UPPERCASE2');
+INSERT INTO "product_attribute" (id, product_sku, value) VALUES (3, 'ARTi01', 'EXACT');

tests/framework/db/ActiveRecordTest.php

@@ -31,6 +31,8 @@
 use yiiunit\data\ar\OrderItemWithNullFK;
 use yiiunit\data\ar\OrderWithConstructor;
 use yiiunit\data\ar\OrderWithNullFK;
+use yiiunit\data\ar\Product;
+use yiiunit\data\ar\ProductAttribute;
 use yiiunit\data\ar\Profile;
 use yiiunit\data\ar\ProfileWithConstructor;
 use yiiunit\data\ar\Type;
@@ -200,6 +202,39 @@ public function testFindLazyViaTable()
         $this->assertInternalType('array', $order);
     }
 
+    /**
+     * related to https://github.com/yiisoft/active-record/issues/22#issuecomment-443460996
+     */
+    public function testCaseInsensitiveKeysPopulation()
+    {
+        if (!in_array($this->driverName, ['mysql'])) {
+            $this->markTestSkipped('This test only for databases that make case insensitive search by key like MySQL or postgres with citext');
+        }
+
+        $productAttributes = ProductAttribute::find()->where(['product_sku' => 'ARTi01'])->all();
+        $this->assertCount(3, $productAttributes); // there are here ARTi01 and ARTI01 records
+
+        // explicitly change to caseSensitive collation utf8_bin
+        $this->getConnection()->createCommand("ALTER TABLE " . Product::tableName() . " CONVERT TO CHARACTER SET utf8 COLLATE utf8_bin")
+            ->execute();
+        $this->getConnection()->createCommand("ALTER TABLE " . ProductAttribute::tableName() . " CONVERT TO CHARACTER SET utf8 COLLATE utf8_bin")
+            ->execute();
+
+        $product = Product::find()->where(['sku' => 'ARTi01'])->with('productAttributes')->one(); // join for ARTi01
+        $this->assertNotNull($product);
+        $this->assertNotCount(3, $product->productAttributes); // joined one record of 3
+
+        // revert to caseInsensitive collation utf8_general_ci
+        $this->getConnection()->createCommand("ALTER TABLE " . Product::tableName() . " CHARACTER SET utf8 COLLATE utf8_general_ci")
+            ->execute();
+        $this->getConnection()->createCommand("ALTER TABLE " . ProductAttribute::tableName() . " CHARACTER SET utf8 COLLATE utf8_general_ci")
+            ->execute();
+
+        $product = Product::find()->where(['sku' => 'ARTi01'])->with('productAttributes')->one(); // join for ARTi01
+        $this->assertCount(3, $product->productAttributes);
+
+    }
+
     public function testFindEagerViaTable()
     {
         $orders = Order::find()->with('books')->orderBy('id')->all();