strange concurrency bug

[twillouer]

Hi,

I have a very strange concurrency bug.

When I use @JsonTypeInfo, in a wrapper class, sometimes, the property disapear !
If I doesn't use the wrapped class, all is fine.

If I put only one thread (Executors.newFixedThreadPool(1);), all is fine.

If I use ObjectWritter (like line who is commented), all is fine.

But in this configuration, there a concurrency issue and the "type" information is lost :-/

I make a huge usage of "jongo" and this concurrency problem appears a lot in my unit test.

Can you help me ?

[twillouer]

And if I uncomment the line 92 (and keep line 102 commented), all is fine again.

[cowtowncoder]

That certainly sounds unusual, and not something I have seen before. Last concurrency bugs fixed were somewhere in 1.8 or so...

[twillouer]

Hi,

I cherry-pick my commit and backport to jackson-databind2.2, 2.3, 2.4 and all is fine.

in 2.5.0, the bug occurred.

[cowtowncoder]

Thank you for the test; I hope to have a look at this soon. Concurrency bugs are certainly not acceptable. I wonder if it could be related to caching changes.

[cowtowncoder]

As per my notes on #738, I suspect this is related to #735, and caused by improper caching.
Initial fix is included in jackson-databind (micro)path 2.4.5.1, as well as in 2.5 branch (2.5.2-SNAPSHOT). I am not confident this is yet the full fix however.

[cowtowncoder]

Looking at the test, couple of thoughts:

1. May not be directly related to @JsonDeserialize on Map with contentUsing custom deserializer overwrites default behavior #735 or @JsonTypeInfo non-deterministically ignored in 2.5.1 #738, since this is for serialization, not deserialization
2. Use of ObjectWriter may work around the issue because it will (by default) eagerly fetch JsonSerializer to use, and avoid either concurrency issue, or ordering issue, whichever triggers the problem
3. This may still be due to caching.

I will use the test, just need to figure out proper way to backport as I want to use the test for 2.5 branch at least.

[cowtowncoder]

Ok. Having worked on #738, I suspect these two are the same. Since this is a PR, #738 issue, I'll close this as dup, leave other open until fix which should occur soon.

[twillouer]

works now, thanks !

[cowtowncoder]

@twillouer thank you for verifying this!