Aborting update can leave lock file

[mgsloan]

I'm having a hard time reproducing the issue, but see this stack issue: commercialhaskell/stack#3055

Seems like it's possible to leave the lock file if an async exception is thrown in the middle of updating (in this case via ctrl-C

[ezyang]

I commented on the downstream for more clarification.

[ezyang]

Based on discussion in downstream, there is nothing we can do; this situation can occur if you C-c a process twice.

[chris-martin]

Can't we show a better error message, though, including remediation instructions? Am I supposed to manually delete ~/.stack/indices/Hackage/hackage-security-lock now?