Crash on reload with diffable data source

[belousovgm]

exception message:

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (7) must be equal to the number of rows contained in that section before the update (1), plus or minus the number of rows inserted or deleted from that section (0 inserted, 0 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).

how to reproduce:

• load table view with one set of units
• begin update table view with another set of units using diffable data source
• interrupt update animation, for example navigate to another screen
• try to update table view with second set of units

Looks like table view have not updated with old units set, but it use to obtain diff with new units set.

Maybe need add extra check to ensure that old units set is actual before update