minor #47412 [Form] Add generics to DataTransformerInterface (VincentLanglet)

This PR was squashed before being merged into the 6.2 branch.

Discussion
----------

[Form] Add generics to DataTransformerInterface

| Q             | A
| ------------- | ---
| Branch?       | 6.2
| Bug fix?      | no
| New feature?  | not really
| Deprecations? | no
| Tickets       | Fix #... <!-- prefix each issue number with "Fix #", no need to create an issue if none exist, explain below instead -->
| License       | MIT
| Doc PR        | symfony/symfony-docs#... <!-- required for new features -->

Now that some generics are added to the Symfony codebase, I think we could add more.
For people using phpstan/psalm this will be helpful:
- It avoid duplicating the generics in both psalm-plugin/phpstan-plugin
- It avoid duplicating code between symfony and plugins
- When phpstan/psalm report an error it's less confusing to look for the generic in the symfony file rather the plugin one.

You can look at the current generic definition
for psalm https://github.com/psalm/psalm-plugin-symfony/blob/master/src/Stubs/common/Component/Form/DataTransformerInterface.stubphp
for phpstan https://github.com/phpstan/phpstan-symfony/blob/1.2.x/stubs/Symfony/Component/Form/DataTransformerInterface.stub

Commits
-------

dff26d39bf [Form] Add generics to DataTransformerInterface

Author: fabpot

DataTransformerInterface.php

@@ -17,6 +17,9 @@
  * Transforms a value between different representations.
  *
  * @author Bernhard Schussek <[email protected]>
+ *
+ * @template TValue
+ * @template TTransformedValue
  */
 interface DataTransformerInterface
 {
@@ -53,9 +56,9 @@ interface DataTransformerInterface
      * of the first data transformer outputs NULL, the second must be able to
      * process that value.
      *
-     * @param mixed $value The value in the original representation
+     * @param TValue|null $value The value in the original representation
      *
-     * @return mixed
+     * @return TTransformedValue|null
      *
      * @throws TransformationFailedException when the transformation fails
      */
@@ -82,9 +85,9 @@ public function transform(mixed $value);
      * By convention, reverseTransform() should return NULL if an empty string
      * is passed.
      *
-     * @param mixed $value The value in the transformed representation
+     * @param TTransformedValue|null $value The value in the transformed representation
      *
-     * @return mixed
+     * @return TValue|null
      *
      * @throws TransformationFailedException when the transformation fails
      */

Extension/Core/DataTransformer/ArrayToPartsTransformer.php

@@ -16,6 +16,8 @@
 
 /**
  * @author Bernhard Schussek <[email protected]>
+ *
+ * @implements DataTransformerInterface<array, array>
  */
 class ArrayToPartsTransformer implements DataTransformerInterface
 {

Extension/Core/DataTransformer/BaseDateTimeTransformer.php

@@ -14,6 +14,10 @@
 use Symfony\Component\Form\DataTransformerInterface;
 use Symfony\Component\Form\Exception\InvalidArgumentException;
 
+/**
+ * @template TTransformedValue
+ * @implements DataTransformerInterface<\DateTimeInterface, TTransformedValue>
+ */
 abstract class BaseDateTimeTransformer implements DataTransformerInterface
 {
     protected static $formats = [

Extension/Core/DataTransformer/BooleanToStringTransformer.php

@@ -20,6 +20,8 @@
  *
  * @author Bernhard Schussek <[email protected]>
  * @author Florian Eckerstorfer <[email protected]>
+ *
+ * @implements DataTransformerInterface<bool, string>
  */
 class BooleanToStringTransformer implements DataTransformerInterface
 {

Extension/Core/DataTransformer/ChoiceToValueTransformer.php

@@ -17,6 +17,8 @@
 
 /**
  * @author Bernhard Schussek <[email protected]>
+ *
+ * @implements DataTransformerInterface<string, string>
  */
 class ChoiceToValueTransformer implements DataTransformerInterface
 {

Extension/Core/DataTransformer/ChoicesToValuesTransformer.php

@@ -17,6 +17,8 @@
 
 /**
  * @author Bernhard Schussek <[email protected]>
+ *
+ * @implements DataTransformerInterface<array, array>
  */
 class ChoicesToValuesTransformer implements DataTransformerInterface
 {

Extension/Core/DataTransformer/DateIntervalToArrayTransformer.php

@@ -19,6 +19,8 @@
  * Transforms between a normalized date interval and an interval string/array.
  *
  * @author Steffen Roßkamp <[email protected]>
+ *
+ * @implements DataTransformerInterface<\DateInterval, array>
  */
 class DateIntervalToArrayTransformer implements DataTransformerInterface
 {

Extension/Core/DataTransformer/DateIntervalToStringTransformer.php

@@ -19,6 +19,8 @@
  * Transforms between a date string and a DateInterval object.
  *
  * @author Steffen Roßkamp <[email protected]>
+ *
+ * @implements DataTransformerInterface<\DateInterval, string>
  */
 class DateIntervalToStringTransformer implements DataTransformerInterface
 {

Extension/Core/DataTransformer/DateTimeImmutableToDateTimeTransformer.php

@@ -18,6 +18,8 @@
  * Transforms between a DateTimeImmutable object and a DateTime object.
  *
  * @author Valentin Udaltsov <[email protected]>
+ *
+ * @implements DataTransformerInterface<\DateTimeImmutable, \DateTime>
  */
 final class DateTimeImmutableToDateTimeTransformer implements DataTransformerInterface
 {

Extension/Core/DataTransformer/DateTimeToArrayTransformer.php

@@ -18,6 +18,8 @@
  *
  * @author Bernhard Schussek <[email protected]>
  * @author Florian Eckerstorfer <[email protected]>
+ *
+ * @extends BaseDateTimeTransformer<array>
  */
 class DateTimeToArrayTransformer extends BaseDateTimeTransformer
 {