can't restrict files, NullPointerException in populateDatasetUpdateFailureMessage(DatasetPage.java:2247)

[pdurbin]

A regression was introduced recently in the 4.2.1 branch wherein it is impossible to restrict files. This has been reproduced independently by me and @sekmiller on out laptops. The stack trace below is from my laptop running 3ae2013 as originally reported at #2648 (comment)

stack.txt

@sekmiller said he'd take a look.

[bencomp]

Optimistic locking is a strategy for handling concurrency. As the message says, it appears that an object is changed or deleted by one process while at the same time another process tries to save a modification of the object.

I see a connection with #2460 in that concurrency is not implemented correctly.

[landreev]

@sekmiller - Steve, I should probably take this, because this has defintiely been caused by my changes from yesterday. (I know for the fact that we were able to restrict files yesterday; a few of us were able to that is).

[landreev]

This should be working now.
However, the evil wrong file bug (which I believe is unrelated to this) may strike back without a warning.
If you are observing it, comment out the versions tab, and try again (as described in my email earlier).
I'm not suggesting disabling the versions tab as a reliable workaround. Just so that you may be able to test other issues.
I'm hoping for some insight from Steve and Gustavo - as to what could be happening in that tab to cause this.

[kcondon]

This is now working. Will separately test wrong file bug and open ticket as needed.