bug symfony#21542 [VarDumper] Fixed dumping of terminated generator (lyrixx)

This PR was merged into the 2.8 branch.

Discussion
----------

[VarDumper] Fixed dumping of terminated generator

| Q             | A
| ------------- | ---
| Branch?       | 2.8
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Commits
-------

c5094a0 [VarDumper] Fixed dumping of terminated generator

Author: nicolas-grekas

src/Symfony/Component/VarDumper/Caster/ReflectionCaster.php

@@ -76,7 +76,20 @@ public static function castClosure(\Closure $c, array $a, Stub $stub, $isNested)
 
     public static function castGenerator(\Generator $c, array $a, Stub $stub, $isNested)
     {
-        return class_exists('ReflectionGenerator', false) ? self::castReflectionGenerator(new \ReflectionGenerator($c), $a, $stub, $isNested) : $a;
+        if (!class_exists('ReflectionGenerator', false)) {
+            return $a;
+        }
+
+        // Cannot create ReflectionGenerator based on a terminated Generator
+        try {
+            $reflectionGenerator = new \ReflectionGenerator($c);
+        } catch (\Exception $e) {
+            $a[Caster::PREFIX_VIRTUAL.'closed'] = true;
+
+            return $a;
+        }
+
+        return self::castReflectionGenerator($reflectionGenerator, $a, $stub, $isNested);
     }
 
     public static function castType(\ReflectionType $c, array $a, Stub $stub, $isNested)
@@ -99,31 +112,33 @@ public static function castReflectionGenerator(\ReflectionGenerator $c, array $a
         if ($c->getThis()) {
             $a[$prefix.'this'] = new CutStub($c->getThis());
         }
-        $x = $c->getFunction();
+        $function = $c->getFunction();
         $frame = array(
-            'class' => isset($x->class) ? $x->class : null,
-            'type' => isset($x->class) ? ($x->isStatic() ? '::' : '->') : null,
-            'function' => $x->name,
+            'class' => isset($function->class) ? $function->class : null,
+            'type' => isset($function->class) ? ($function->isStatic() ? '::' : '->') : null,
+            'function' => $function->name,
             'file' => $c->getExecutingFile(),
             'line' => $c->getExecutingLine(),
         );
         if ($trace = $c->getTrace(DEBUG_BACKTRACE_IGNORE_ARGS)) {
-            $x = new \ReflectionGenerator($c->getExecutingGenerator());
+            $function = new \ReflectionGenerator($c->getExecutingGenerator());
             array_unshift($trace, array(
                 'function' => 'yield',
-                'file' => $x->getExecutingFile(),
-                'line' => $x->getExecutingLine() - 1,
+                'file' => $function->getExecutingFile(),
+                'line' => $function->getExecutingLine() - 1,
             ));
             $trace[] = $frame;
             $a[$prefix.'trace'] = new TraceStub($trace, false, 0, -1, -1);
         } else {
-            $x = new FrameStub($frame, false, true);
-            $x = ExceptionCaster::castFrameStub($x, array(), $x, true);
+            $function = new FrameStub($frame, false, true);
+            $function = ExceptionCaster::castFrameStub($function, array(), $function, true);
             $a[$prefix.'executing'] = new EnumStub(array(
-                $frame['class'].$frame['type'].$frame['function'].'()' => $x[$prefix.'src'],
+                $frame['class'].$frame['type'].$frame['function'].'()' => $function[$prefix.'src'],
             ));
         }
 
+        $a[Caster::PREFIX_VIRTUAL.'closed'] = false;
+
         return $a;
     }
 

src/Symfony/Component/VarDumper/Tests/Caster/ReflectionCasterTest.php

@@ -149,11 +149,10 @@ public function testGenerator()
             $this->markTestSkipped('xdebug is active');
         }
 
-        $g = new GeneratorDemo();
-        $g = $g->baz();
-        $r = new \ReflectionGenerator($g);
+        $generator = new GeneratorDemo();
+        $generator = $generator->baz();
 
-        $xDump = <<<'EODUMP'
+        $expectedDump = <<<'EODUMP'
 Generator {
   this: Symfony\Component\VarDumper\Tests\Fixtures\GeneratorDemo { …}
   executing: {
@@ -165,16 +164,17 @@ public function testGenerator()
         """
     }
   }
+  closed: false
 }
 EODUMP;
 
-        $this->assertDumpMatchesFormat($xDump, $g);
+        $this->assertDumpMatchesFormat($expectedDump, $generator);
 
-        foreach ($g as $v) {
+        foreach ($generator as $v) {
             break;
         }
 
-        $xDump = <<<'EODUMP'
+        $expectedDump = <<<'EODUMP'
 array:2 [
   0 => ReflectionGenerator {
     this: Symfony\Component\VarDumper\Tests\Fixtures\GeneratorDemo { …}
@@ -207,6 +207,7 @@ public function testGenerator()
         }
       }
     }
+    closed: false
   }
   1 => Generator {
     executing: {
@@ -218,11 +219,23 @@ public function testGenerator()
           """
       }
     }
+    closed: false
   }
 ]
 EODUMP;
 
-        $this->assertDumpMatchesFormat($xDump, array($r, $r->getExecutingGenerator()));
+        $r = new \ReflectionGenerator($generator);
+        $this->assertDumpMatchesFormat($expectedDump, array($r, $r->getExecutingGenerator()));
+
+        foreach ($generator as $v) {
+        }
+
+        $expectedDump = <<<'EODUMP'
+Generator {
+  closed: true
+}
+EODUMP;
+        $this->assertDumpMatchesFormat($expectedDump, $generator);
     }
 }