feature #19672 [VarDumper] Allow dumping subparts of cloned Data stru…

…ctures (nicolas-grekas)

This PR was merged into the 3.2-dev branch.

Discussion
----------

[VarDumper] Allow dumping subparts of cloned Data structures

| Q             | A
| ------------- | ---
| Branch?       | master
| New feature?  | yes
| Tests pass?   | yes
| License       | MIT
| Doc PR     | symfony/symfony-docs#6891

ping @wouterj: with this, we'll be able to dump only the trace for deprecations in #19614 instead of being forced to dump the full exception right now. See test case.
We'd do `{{ profiler_dump(log.context.seek('trace')) }}` in `logger.html.twig`.

Commits
-------

8f2f440 [VarDumper] Allow dumping subparts of cloned Data structures

src/Symfony/Component/VarDumper/Cloner/Data.php

@@ -11,12 +11,16 @@
 
 namespace Symfony\Component\VarDumper\Cloner;
 
+use Symfony\Component\VarDumper\Caster\Caster;
+
 /**
  * @author Nicolas Grekas <p@tchwork.com>
  */
 class Data
 {
     private $data;
+    private $position = 0;
+    private $key = 0;
     private $maxDepth = 20;
     private $maxItemsPerDepth = -1;
     private $useRefHandles = -1;
@@ -82,13 +86,57 @@ public function withRefHandles($useRefHandles)
         return $data;
     }
 
+    /**
+     * Seeks to a specific key in nested data structures.
+     *
+     * @param string|int $key The key to seek to
+     *
+     * @return self|null A clone of $this of null if the key is not set
+     */
+    public function seek($key)
+    {
+        $item = $this->data[$this->position][$this->key];
+
+        if (!$item instanceof Stub || !$item->position) {
+            return;
+        }
+        $keys = array($key);
+
+        switch ($item->type) {
+            case Stub::TYPE_OBJECT:
+                $keys[] = Caster::PREFIX_DYNAMIC.$key;
+                $keys[] = Caster::PREFIX_PROTECTED.$key;
+                $keys[] = Caster::PREFIX_VIRTUAL.$key;
+                $keys[] = "\0$item->class\0$key";
+            case Stub::TYPE_ARRAY:
+            case Stub::TYPE_RESOURCE:
+                break;
+            default:
+                return;
+        }
+
+        $data = null;
+        $children = $this->data[$item->position];
+
+        foreach ($keys as $key) {
+            if (isset($children[$key]) || array_key_exists($key, $children)) {
+                $data = clone $this;
+                $data->key = $key;
+                $data->position = $item->position;
+                break;
+            }
+        }
+
+        return $data;
+    }
+
     /**
      * Dumps data with a DumperInterface dumper.
      */
     public function dump(DumperInterface $dumper)
     {
         $refs = array(0);
-        $this->dumpItem($dumper, new Cursor(), $refs, $this->data[0][0]);
+        $this->dumpItem($dumper, new Cursor(), $refs, $this->data[$this->position][$this->key]);
     }
 
     /**

src/Symfony/Component/VarDumper/Test/VarDumperTestTrait.php

@@ -29,7 +29,7 @@ public function assertDumpMatchesFormat($dump, $data, $message = '')
         $this->assertStringMatchesFormat(rtrim($dump), $this->getDump($data), $message);
     }
 
-    protected function getDump($data)
+    protected function getDump($data, $key = null)
     {
         $flags = getenv('DUMP_LIGHT_ARRAY') ? CliDumper::DUMP_LIGHT_ARRAY : 0;
         $flags |= getenv('DUMP_STRING_LENGTH') ? CliDumper::DUMP_STRING_LENGTH : 0;
@@ -39,7 +39,11 @@ protected function getDump($data)
         $cloner->setMaxItems(-1);
         $dumper = new CliDumper($h, null, $flags);
         $dumper->setColors(false);
-        $dumper->dump($cloner->cloneVar($data)->withRefHandles(false));
+        $data = $cloner->cloneVar($data)->withRefHandles(false);
+        if (null !== $key && null === $data = $data->seek($key)) {
+            return;
+        }
+        $dumper->dump($data);
         $data = stream_get_contents($h, -1, 0);
         fclose($h);
 

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

@@ -59,6 +59,31 @@ public function testDefaultSettings()
         $this->assertDumpMatchesFormat($expectedDump, $e);
     }
 
+    public function testSeek()
+    {
+        $e = $this->getTestException(2);
+
+        $expectedDump = <<<'EODUMP'
+{
+  %d. %sExceptionCasterTest.php:23: {
+    22: {
+    23:     return new \Exception('foo');
+    24: }
+  }
+  %d. %sExceptionCasterTest.php:%d: {
+    %d: {
+    %d:     $e = $this->getTestException(2);
+    %d: 
+    args: {
+      2
+    }
+  }
+%A
+EODUMP;
+
+        $this->assertStringMatchesFormat($expectedDump, $this->getDump($e, 'trace'));
+    }
+
     public function testNoArgs()
     {
         $e = $this->getTestException(1);

src/Symfony/Component/VarDumper/Tests/VarClonerTest.php

@@ -52,6 +52,8 @@ public function testMaxIntBoundary()
 
         )
 
+    [position:Symfony\Component\VarDumper\Cloner\Data:private] => 0
+    [key:Symfony\Component\VarDumper\Cloner\Data:private] => 0
     [maxDepth:Symfony\Component\VarDumper\Cloner\Data:private] => 20
     [maxItemsPerDepth:Symfony\Component\VarDumper\Cloner\Data:private] => -1
     [useRefHandles:Symfony\Component\VarDumper\Cloner\Data:private] => -1
@@ -126,6 +128,8 @@ public function testClone()
 
         )
 
+    [position:Symfony\Component\VarDumper\Cloner\Data:private] => 0
+    [key:Symfony\Component\VarDumper\Cloner\Data:private] => 0
     [maxDepth:Symfony\Component\VarDumper\Cloner\Data:private] => 20
     [maxItemsPerDepth:Symfony\Component\VarDumper\Cloner\Data:private] => -1
     [useRefHandles:Symfony\Component\VarDumper\Cloner\Data:private] => -1
@@ -143,7 +147,7 @@ public function testJsonCast()
         $clone = $cloner->cloneVar($data);
 
         $expected = <<<'EOTXT'
-object(Symfony\Component\VarDumper\Cloner\Data)#%i (4) {
+object(Symfony\Component\VarDumper\Cloner\Data)#%i (6) {
   ["data":"Symfony\Component\VarDumper\Cloner\Data":private]=>
   array(2) {
     [0]=>
@@ -187,6 +191,10 @@ public function testJsonCast()
       }
     }
   }
+  ["position":"Symfony\Component\VarDumper\Cloner\Data":private]=>
+  int(0)
+  ["key":"Symfony\Component\VarDumper\Cloner\Data":private]=>
+  int(0)
   ["maxDepth":"Symfony\Component\VarDumper\Cloner\Data":private]=>
   int(20)
   ["maxItemsPerDepth":"Symfony\Component\VarDumper\Cloner\Data":private]=>
@@ -242,6 +250,8 @@ public function testCaster()
 
         )
 
+    [position:Symfony\Component\VarDumper\Cloner\Data:private] => 0
+    [key:Symfony\Component\VarDumper\Cloner\Data:private] => 0
     [maxDepth:Symfony\Component\VarDumper\Cloner\Data:private] => 20
     [maxItemsPerDepth:Symfony\Component\VarDumper\Cloner\Data:private] => -1
     [useRefHandles:Symfony\Component\VarDumper\Cloner\Data:private] => -1