Merge branch '1.x' into 2.x

* 1.x:
  Optimize block('foo') ?? 'bar'
  bumped version to 1.42.4-DEV
  prepared the 1.42.3 release
  updated  ChANGELOG

CHANGELOG

@@ -274,10 +274,16 @@
  * improved the performance of the filesystem loader
  * removed features that were deprecated in 1.x
 
-* 1.42.3 (2019-XX-XX)
+* 1.42.4 (2019-XX-XX)
 
+ * n/a
+
+* 1.42.3 (2019-08-24)
+
+ * fixed the "split" filter when the delimiter is "0"
  * fixed the "empty" test on Traversable instances
  * fixed cache when opcache is installed but disabled
+ * fixed PHP 7.4 compatibility
  * bumped the minimal PHP version to 5.5
 
 * 1.42.2 (2019-06-18)

src/Node/Expression/NullCoalesceExpression.php

@@ -22,11 +22,15 @@ class NullCoalesceExpression extends ConditionalExpression
 {
     public function __construct(Node $left, Node $right, int $lineno)
     {
-        $test = new AndBinary(
-            new DefinedTest(clone $left, 'defined', new Node(), $left->getTemplateLine()),
-            new NotUnary(new NullTest($left, 'null', new Node(), $left->getTemplateLine()), $left->getTemplateLine()),
-            $left->getTemplateLine()
-        );
+        $test = new DefinedTest(clone $left, 'defined', new Node(), $left->getTemplateLine());
+        // for "block()", we don't need the null test as the return value is always a string
+        if (!$left instanceof BlockReferenceExpression) {
+            $test = new AndBinary(
+                $test,
+                new NotUnary(new NullTest($left, 'null', new Node(), $left->getTemplateLine()), $left->getTemplateLine()),
+                $left->getTemplateLine()
+            );
+        }
 
         parent::__construct($test, $left, $right, $lineno);
     }

tests/Fixtures/tests/null_coalesce_block.test

@@ -0,0 +1,9 @@
+--TEST--
+Twig supports the ?? operator with blocks
+--TEMPLATE--
+{% block foo %}OK{% endblock %}
+{{ block('foo') ?? 'KO' }}
+--DATA--
+return []
+--EXPECT--
+OKOK