bug symfony#18924 [DoctrineBridge] Don't use object IDs in DoctrineChoiceLoader when passing a value closure (webmozart)

This PR was merged into the 2.7 branch.

Discussion
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[DoctrineBridge] Don't use object IDs in DoctrineChoiceLoader when passing a value closure

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

This PR is porting an optimization done for `loadChoicesForValues()` in 64c80a6 to `loadValuesForChoices()`.

Commits
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f6e5298 [DoctrineBridge] Don't use object IDs in DoctrineChoiceLoader when passing a value closure

Author: fabpot

src/Symfony/Bridge/Doctrine/Form/ChoiceList/DoctrineChoiceLoader.php

@@ -110,9 +110,10 @@ public function loadValuesForChoices(array $choices, $value = null)
 
         // Optimize performance for single-field identifiers. We already
         // know that the IDs are used as values
+        $optimize = null === $value || is_array($value) && $value[0] === $this->idReader;
 
         // Attention: This optimization does not check choices for existence
-        if (!$this->choiceList && $this->idReader->isSingleId()) {
+        if ($optimize && !$this->choiceList && $this->idReader->isSingleId()) {
             $values = array();
 
             // Maintain order and indices of the given objects