dfd605fc1b
This PR was squashed before being merged into the master branch (closes #7890).
Discussion
----------
ProxyManager Bridge
As of @beberlei's suggestion, I re-implemented #7527 as a new bridge to avoid possible hidden dependencies.
Everything is like #7527 except that the new namespace (and possibly package/subtree split) `Symfony\Bridge\ProxyManager` is introduced
| Q | A
| ------------- | ---
| Bug fix? | no
| New feature? | yes
| BC breaks? | no
| Deprecations? | no
| Tests pass? | yes
| Fixed tickets | #6140 (supersedes) #5012 #6102 (maybe) #7527 (supersedes)
| License | MIT (attached code) - BSD-3-Clause (transitive dependency)
| Doc PR | Please pester me to death so I do it
This PR introduces lazy services along the lines of zendframework/zf2#4146
It introduces an **OPTIONAL** dependency to [ProxyManager](https://github.com/Ocramius/ProxyManager) and transitively to [`"zendframework/zend-code": "2.*"`](https://github.com/zendframework/zf2/tree/master/library/Zend/Code).
## Lazy services: why? A comprehensive example
For those who don't know what this is about, here's an example.
Assuming you have a service class like following:
```php
class MySuperSlowClass
{
public function __construct()
{
// inject large object graph or do heavy computation
sleep(10);
}
public function doFoo()
{
echo 'Foo!';
}
}
```
The DIC will hang for 10 seconds when calling:
```php
$container->get('my_super_slow_class');
```
With this PR, this can be avoided, and the following call will return a proxy immediately.
```php
$container->getDefinitions('my_super_slow_class')->setLazy(true);
$service = $container->get('my_super_slow_class');
```
The 10 seconds wait time will be delayed until the object is actually used:
```php
$service->doFoo(); // wait 10 seconds, then 'Foo!'
```
A more extensive description of the functionality can be found [here](https://github.com/Ocramius/ProxyManager/blob/master/docs/lazy-loading-value-holder.md).
## When do we need it?
Lazy services can be used to optimize the dependency graph in cases like:
* Webservice endpoints
* Db connections
* Objects that cause I/O in general
* Large dependency graphs that are not always used
This could also help in reducing excessive service location usage as I've explained [here](http://ocramius.github.com/blog/zf2-and-symfony-service-proxies-with-doctrine-proxies/).
## Implementation quirks of this PR
There's a couple of quirks in the implementation:
* `Symfony\Component\DependencyInjection\CompilerBuilder#createService` is now public because of the limitations of PHP 5.3
* `Symfony\Component\DependencyInjection\Dumper\PhpDumper` now with extra mess!
* The proxies are dumped at the end of compiled containers, therefore the container class is not PSR compliant anymore
Commits
-------
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||
|---|---|---|
| .. | ||
| Compiler | ||
| Dumper | ||
| Extension | ||
| Fixtures | ||
| LazyProxy | ||
| Loader | ||
| ParameterBag | ||
| ContainerBuilderTest.php | ||
| ContainerTest.php | ||
| CrossCheckTest.php | ||
| DefinitionDecoratorTest.php | ||
| DefinitionTest.php | ||
| ParameterTest.php | ||
| ReferenceTest.php | ||