This PR was squashed before being merged into the 7.2 branch.Discussion----------[Serializer] Introduce named serializers| Q             | A| ------------- | ---| Branch?       | 7.2| Bug fix?      | no| New feature?  | yes| Deprecations? | no| Issues        | -| License       | MITThe idea behind this PR is to allow configuring multiple serializer instances with different default contexts, name converters, and sets of normalizers and encoders. This is useful when your application is communicating with multiple APIs, each with different rules. Similar ideas have been mentioned [before](#35374 (comment)).```yamlserializer:  named_serializers:    api1:      name_converter: 'serializer.name_converter.camel_case_to_snake_case'      default_context:        enable_max_depth: true    api2:      default_context:        enable_max_depth: false```The different serializers can be injected using named aliases:```php#[AsController]class HomeController{    #[Route('/', name: 'app_home')]    public function index(        SerializerInterface $serializer,     // Default serializer        SerializerInterface $api1Serializer, // api1 serializer        #[Target('api2.serializer')]         // api2 serializer        SerializerInterface $someName,    ) {        // ...    }}```Multiple normalizer/encoder instances with different arguments are created as child services of the default ones. ~~I also ensured that the same normalizer/encoder instances are reused between different serializers that have the same default context and name converter to minimize the number of child services created.~~Custom normalizers/encoders can target specific serializers using the `serializer` tag attribute:```yamlget_set_method_normalizer:    class: Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer    autoconfigure: false # This is needed so that it's not included in the default serializer    tags:        # single serializer        - serializer.normalizer: { serializer: 'api1' }        # or multiple ones        - serializer.normalizer: { serializer: [ 'api1', 'api2' ] }        # use * to include the service in all serializers including the default one        - serializer.normalizer: { serializer: '*' }```For BC reasons, not setting the `serializer` tag attribute is the same as setting it to the default one:```yaml    tags:        - serializer.normalizer        # same as        - serializer.normalizer: { serializer: 'default' }```The profiler has been updated to support multiple serializer instances:![image](https://github.com/symfony/symfony/assets/2445045/0468ccf3-8d5a-4c60-a639-09cfe918b163)All normalizers/encoders are tagged with additional named serializer specific tags to help with debugging. To get the priority of normalizers/encoders for a certain serializer, use the `serializer.normalizer.<name>` or `serializer.encoder.<name>` tags:```shell$ bin/console debug:container --tag serializer.normalizer.defaultSymfony Container Services Tagged with "serializer.normalizer.default" Tag========================================================================== ------------------------------------------------- ---------- -------------------------------------------------------------------------------------------  Service ID                                        priority   Class name ------------------------------------------------- ---------- -------------------------------------------------------------------------------------------  serializer.denormalizer.unwrapping                1000       Symfony\Component\Serializer\Normalizer\UnwrappingDenormalizer  serializer.normalizer.flatten_exception           -880       Symfony\Component\Messenger\Transport\Serialization\Normalizer\FlattenExceptionNormalizer  ...  serializer.denormalizer.array                     -990       Symfony\Component\Serializer\Normalizer\ArrayDenormalizer  serializer.normalizer.object                      -1000      Symfony\Component\Serializer\Normalizer\ObjectNormalizer ------------------------------------------------- ---------- -------------------------------------------------------------------------------------------$ bin/console debug:container --tag serializer.normalizer.api1Symfony Container Services Tagged with "serializer.normalizer.api1" Tag======================================================================= ------------------------------------------------- ---------- -------------------------------------------------------------------------------------------  Service ID                                        priority   Class name ------------------------------------------------- ---------- -------------------------------------------------------------------------------------------  serializer.denormalizer.unwrapping                1000       Symfony\Component\Serializer\Normalizer\UnwrappingDenormalizer  get_set_method_normalizer                                    Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer  serializer.normalizer.flatten_exception           -880       Symfony\Component\Messenger\Transport\Serialization\Normalizer\FlattenExceptionNormalizer  ...  serializer.denormalizer.array                     -990       Symfony\Component\Serializer\Normalizer\ArrayDenormalizer  serializer.normalizer.object                      -1000      Symfony\Component\Serializer\Normalizer\ObjectNormalizer ------------------------------------------------- ---------- -------------------------------------------------------------------------------------------$ bin/console debug:container --tag serializer.normalizerSymfony Container Services Tagged with "serializer.normalizer" Tag================================================================== ------------------------------------------------- ---------- ---------- ----------------- -------------------------------------------------------------------------------------------  Service ID                                        standard   priority   serializer        Class name ------------------------------------------------- ---------- ---------- ----------------- -------------------------------------------------------------------------------------------  serializer.denormalizer.unwrapping                1          1000                         Symfony\Component\Serializer\Normalizer\UnwrappingDenormalizer  get_set_method_normalizer                                               ["api1","api2"]   Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer  serializer.normalizer.flatten_exception           1          -880                         Symfony\Component\Messenger\Transport\Serialization\Normalizer\FlattenExceptionNormalizer  ...  serializer.denormalizer.array                     1          -990                         Symfony\Component\Serializer\Normalizer\ArrayDenormalizer  serializer.normalizer.object                      1          -1000                        Symfony\Component\Serializer\Normalizer\ObjectNormalizer ------------------------------------------------- ---------- ---------- ----------------- -------------------------------------------------------------------------------------------```Since Symfony comes with some pre-registered normalizers and encoders, I added options to exclude those in case someone wants to use only custom ones:```yamlserializer:  named_serializers:    api1:      include_built_in_normalizers: false      include_built_in_encoders: true      name_converter: 'serializer.name_converter.camel_case_to_snake_case'      default_context:        enable_max_depth: true```TBH, I have doubts about the usefulness of this, please let me know your thoughts.I've split the PR into two commits to ease reviewing:- the first commit only rearranges the `SerializerPass` without adding any features- the second commit implements the featureCommits-------29bd8ce [Serializer] Introduce named serializers

This PR was squashed before being merged into the 7.2 branch.Discussion----------[Serializer] Introduce named serializers| Q             | A| ------------- | ---| Branch?       | 7.2| Bug fix?      | no| New feature?  | yes| Deprecations? | no| Issues        | -| License       | MITThe idea behind this PR is to allow configuring multiple serializer instances with different default contexts, name converters, and sets of normalizers and encoders. This is useful when your application is communicating with multiple APIs, each with different rules. Similar ideas have been mentioned [before](symfony/symfony#35374 (comment)).```yamlserializer:  named_serializers:    api1:      name_converter: 'serializer.name_converter.camel_case_to_snake_case'      default_context:        enable_max_depth: true    api2:      default_context:        enable_max_depth: false```The different serializers can be injected using named aliases:```php#[AsController]class HomeController{    #[Route('/', name: 'app_home')]    public function index(        SerializerInterface $serializer,     // Default serializer        SerializerInterface $api1Serializer, // api1 serializer        #[Target('api2.serializer')]         // api2 serializer        SerializerInterface $someName,    ) {        // ...    }}```Multiple normalizer/encoder instances with different arguments are created as child services of the default ones. ~~I also ensured that the same normalizer/encoder instances are reused between different serializers that have the same default context and name converter to minimize the number of child services created.~~Custom normalizers/encoders can target specific serializers using the `serializer` tag attribute:```yamlget_set_method_normalizer:    class: Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer    autoconfigure: false # This is needed so that it's not included in the default serializer    tags:        # single serializer        - serializer.normalizer: { serializer: 'api1' }        # or multiple ones        - serializer.normalizer: { serializer: [ 'api1', 'api2' ] }        # use * to include the service in all serializers including the default one        - serializer.normalizer: { serializer: '*' }```For BC reasons, not setting the `serializer` tag attribute is the same as setting it to the default one:```yaml    tags:        - serializer.normalizer        # same as        - serializer.normalizer: { serializer: 'default' }```The profiler has been updated to support multiple serializer instances:![image](https://github.com/symfony/symfony/assets/2445045/0468ccf3-8d5a-4c60-a639-09cfe918b163)All normalizers/encoders are tagged with additional named serializer specific tags to help with debugging. To get the priority of normalizers/encoders for a certain serializer, use the `serializer.normalizer.<name>` or `serializer.encoder.<name>` tags:```shell$ bin/console debug:container --tag serializer.normalizer.defaultSymfony Container Services Tagged with "serializer.normalizer.default" Tag========================================================================== ------------------------------------------------- ---------- -------------------------------------------------------------------------------------------  Service ID                                        priority   Class name ------------------------------------------------- ---------- -------------------------------------------------------------------------------------------  serializer.denormalizer.unwrapping                1000       Symfony\Component\Serializer\Normalizer\UnwrappingDenormalizer  serializer.normalizer.flatten_exception           -880       Symfony\Component\Messenger\Transport\Serialization\Normalizer\FlattenExceptionNormalizer  ...  serializer.denormalizer.array                     -990       Symfony\Component\Serializer\Normalizer\ArrayDenormalizer  serializer.normalizer.object                      -1000      Symfony\Component\Serializer\Normalizer\ObjectNormalizer ------------------------------------------------- ---------- -------------------------------------------------------------------------------------------$ bin/console debug:container --tag serializer.normalizer.api1Symfony Container Services Tagged with "serializer.normalizer.api1" Tag======================================================================= ------------------------------------------------- ---------- -------------------------------------------------------------------------------------------  Service ID                                        priority   Class name ------------------------------------------------- ---------- -------------------------------------------------------------------------------------------  serializer.denormalizer.unwrapping                1000       Symfony\Component\Serializer\Normalizer\UnwrappingDenormalizer  get_set_method_normalizer                                    Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer  serializer.normalizer.flatten_exception           -880       Symfony\Component\Messenger\Transport\Serialization\Normalizer\FlattenExceptionNormalizer  ...  serializer.denormalizer.array                     -990       Symfony\Component\Serializer\Normalizer\ArrayDenormalizer  serializer.normalizer.object                      -1000      Symfony\Component\Serializer\Normalizer\ObjectNormalizer ------------------------------------------------- ---------- -------------------------------------------------------------------------------------------$ bin/console debug:container --tag serializer.normalizerSymfony Container Services Tagged with "serializer.normalizer" Tag================================================================== ------------------------------------------------- ---------- ---------- ----------------- -------------------------------------------------------------------------------------------  Service ID                                        standard   priority   serializer        Class name ------------------------------------------------- ---------- ---------- ----------------- -------------------------------------------------------------------------------------------  serializer.denormalizer.unwrapping                1          1000                         Symfony\Component\Serializer\Normalizer\UnwrappingDenormalizer  get_set_method_normalizer                                               ["api1","api2"]   Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer  serializer.normalizer.flatten_exception           1          -880                         Symfony\Component\Messenger\Transport\Serialization\Normalizer\FlattenExceptionNormalizer  ...  serializer.denormalizer.array                     1          -990                         Symfony\Component\Serializer\Normalizer\ArrayDenormalizer  serializer.normalizer.object                      1          -1000                        Symfony\Component\Serializer\Normalizer\ObjectNormalizer ------------------------------------------------- ---------- ---------- ----------------- -------------------------------------------------------------------------------------------```Since Symfony comes with some pre-registered normalizers and encoders, I added options to exclude those in case someone wants to use only custom ones:```yamlserializer:  named_serializers:    api1:      include_built_in_normalizers: false      include_built_in_encoders: true      name_converter: 'serializer.name_converter.camel_case_to_snake_case'      default_context:        enable_max_depth: true```TBH, I have doubts about the usefulness of this, please let me know your thoughts.I've split the PR into two commits to ease reviewing:- the first commit only rearranges the `SerializerPass` without adding any features- the second commit implements the featureCommits-------29bd8ce6c2 [Serializer] Introduce named serializers