Kind of a PSA.
I switched to Pro 3.1.3 and was testing some tools I wrote in Pro 2.9.
One works with an input feature layer, which then has an update cursor applied.
It kept failing because it couldn't acquire a lock.
Turns out, that "lock" is created by having the attribute table open.
Things that are definitely not contributing:
- The feature class is not being edited, am in fact using manual edit sessions and I'm not in one.
- In the tool, the update cursor is wrapped in an editor object.
It is literally just having the attribute table open.
I can't believe this is intended behavior (it's never worked like this before), so I have to assume it's a bug.
Hopefully this saves someone else a huge headache in the future.
Edit to add: This seems to be only a problem when using tools. Python window is fine.