Fix cloning entities when using lazy-ghost proxies

[nicolas-grekas]

Fixes #10817
Replaces #10818
Replaces symfony/symfony#50899

[stof]

this looks like array<class-string, ProxyDefinition>

[nicolas-grekas]

I borrowed from the parent class ;)

[nicolas-grekas]

All green 🍏

[greg0ire]

Thanks @nicolas-grekas !

[mpdude]

Can you guys provide an example when/how it is useful to clone entities and what the semantics of this operation are?

Does the new (cloned) entity let go of its ID? Should the EntityManager know about it? Is it in MANAGED or DETACHED state etc.?

[stof]

@mpdude the cloned object will not be managed by the entity manager

[mpdude]

When the entity that is cloned is an uninitialized proxy at that point in time, what happens when I call a method on the clone that triggers loading?

[mpdude]

Coming from #3037 and #10785 where one source of "weird" problems is corruption of internal UoW state-tracking fields. This may be caused when using proxies directly created by the ProxyFactory.

My concern is that cloning a proxy object might be no different:

Suddenly there are two objects claiming to proxy the same entity. But, "there can be only one", only the proxy object the UoW knows about should be initialized and is the sole object representing that entity.

[GrimReaper1908]

When the entity that is cloned is an uninitialized proxy at that point in time, what happens when I call a method on the clone that triggers loading?

I stumbled upon this while investigating an issue that seems to be related to this fix, and your suspicion seems to be confirmed.

Since doctrine/orm 2.15.4 I encounter the following problem:

• I have a lazy-loaded entity original
• I clone original into clone
• I read some data from original, causing it to load the remaining data
• I modify some data on original

Up until now, everything is as expected. However, once I read some data from clone , it reads the missing data back from the database and populates it into clone and original, causing the modifications on original to be lost.

[nicolas-grekas]

Please open a dedicated issue with a reproducer. Commenting on closed issues/PRs isn't tracked.