Fix ConstraintViolation#getMessageTemplate() to always return string

Ocramius · Ocramius · commit cb47a358b9e4 · 2021-03-08T16:43:01.000+01:00
`ConstraintViolation#getMessageTemplate()`'s inherited signature states that `string` is to be returned by it at all times, yet the implementation returns `null` when no message template had been provided at instantiation. This patch obviates it, returning an empty string when the message template is `null`. Ref: #40415 (comment)
diff --git a/src/Symfony/Component/Validator/ConstraintViolation.php b/src/Symfony/Component/Validator/ConstraintViolation.php
@@ -100,7 +100,7 @@ public function __toString()
      */
     public function getMessageTemplate()
     {
-        return $this->messageTemplate;
+        return (string) $this->messageTemplate;
     }
 
     /**
diff --git a/src/Symfony/Component/Validator/Tests/ConstraintViolationTest.php b/src/Symfony/Component/Validator/Tests/ConstraintViolationTest.php
@@ -156,4 +156,19 @@ public function testMessageObjectMustBeStringable()
             null
         );
     }
+
+    public function testRetrievedMessageTemplateIsAStringEvenIfNotSet()
+    {
+        self::assertSame(
+            '',
+            (new ConstraintViolation(
+                'irrelevant',
+                null,
+                [],
+                'irrelevant',
+                'irrelevant',
+                null
+            ))->getMessageTemplate()
+        );
+    }
 }

Original file line number	Diff line number	Diff line change
`@@ -100,7 +100,7 @@ public function __toString()`
`100`	`100`	`*/`
`101`	`101`	`public function getMessageTemplate()`
`102`	`102`	`{`
`103`		`- return $this->messageTemplate;`
	`103`	`+ return (string) $this->messageTemplate;`
`104`	`104`	`}`
`105`	`105`
`106`	`106`	`/**`