Stop Eloquent model setAttribute() modifying date cast string values

This affects model attribute casts 'date', 'datetime', 'immutable_date',
and 'immutable_datetime' with a custom date format being used.

e.g., $casts = ['month' => 'datetime:Y-m']

Last week a fix was introduced for attributes being set with Carbon
objects that were mistakenly flagged as "dirty" in the model even though
dates were the same. However that fix broke behavior of date _strings_
such as $request->validated() being filled into a model.

For:

$model->fill(['month' => '2021-09'])->save();

Instead of the SQL query binding being "2021-09", it's "2021-09-01 00:00:00"
because the date string is reformatted through fromDateTime(), using
getDateFormat() and not the custom cast date.

Keep the v8.60.0 behavior that sets the raw date string in the
attributes payload which is eventually bound in the database query.
Avoid going through fromDateTime() that reformats that string.

Also remove the added redundant conditional in originalIsEquivalent()
as method isDateAttribute() already includes isDateCastable().

src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php

@@ -761,7 +761,9 @@ public function setAttribute($key, $value)
         // If an attribute is listed as a "date", we'll convert it from a DateTime
         // instance into a form proper for storage on the database tables using
         // the connection grammar's date format. We will auto set the values.
-        elseif ($value && $this->isDateAttribute($key)) {
+        elseif ($value && $this->isDateAttribute($key) && !(
+            $this->hasCast($key, ['custom_datetime', 'immutable_custom_datetime']) && is_string($value)
+        )) {
             $value = $this->fromDateTime($value);
         }
 
@@ -1643,7 +1645,7 @@ public function originalIsEquivalent($key)
             return true;
         } elseif (is_null($attribute)) {
             return false;
-        } elseif ($this->isDateAttribute($key) || $this->isDateCastable($key)) {
+        } elseif ($this->isDateAttribute($key)) {
             return $this->fromDateTime($attribute) ===
                 $this->fromDateTime($original);
         } elseif ($this->hasCast($key, ['object', 'collection'])) {

tests/Integration/Database/EloquentModelDateCastingTest.php

@@ -40,7 +40,46 @@ public function testDatesAreCustomCastable()
         $this->assertInstanceOf(Carbon::class, $user->datetime_field);
     }
 
-    public function testCustomDateCastsAreComparedAsDates()
+    public function testDatesFormattedAttributeBindings()
+    {
+        $bindings = [];
+
+        $this->app->make('db')->listen(static function ($query) use (&$bindings) {
+            $bindings = $query->bindings;
+        });
+
+        $user = TestModel1::create([
+            'date_field' => '2019-10',
+            'datetime_field' => new CarbonImmutable('2019-10-01 10:15:20'),
+            'immutable_date_field' => new CarbonImmutable('2019-10-01'),
+            'immutable_datetime_field' => '2019-10-01 10:15',
+        ]);
+
+        $this->assertSame(['2019-10', '2019-10-01 10:15:20', '2019-10-01 00:00:00', '2019-10-01 10:15'], $bindings);
+    }
+
+    public function testCustomDateCastsAreComparedAsDatesForStringValues()
+    {
+        /** @var TestModel1 */
+        $user = TestModel1::create([
+            'date_field' => '2019-10-01',
+            'datetime_field' => '2019-10-01 10:15:20',
+            'immutable_date_field' => '2019-10-01',
+            'immutable_datetime_field' => '2019-10-01 10:15:20',
+        ]);
+
+        $user->date_field = '2019-10-01';
+        $user->datetime_field = '2019-10-01 10:15:20';
+        $user->immutable_date_field = '2019-10-01';
+        $user->immutable_datetime_field = '2019-10-01 10:15:20';
+
+        $this->assertArrayNotHasKey('date_field', $user->getDirty());
+        $this->assertArrayNotHasKey('datetime_field', $user->getDirty());
+        $this->assertArrayNotHasKey('immutable_date_field', $user->getDirty());
+        $this->assertArrayNotHasKey('immutable_datetime_field', $user->getDirty());
+    }
+
+    public function testCustomDateCastsAreComparedAsDatesForCarbonValues()
     {
         /** @var TestModel1 */
         $user = TestModel1::create([