Panic at epoch boundary

[joe-bowman]

Summary of Bug

A panic occurs if there is no PR allocation, in the participation rewards hook.

We refer to err.Error in a log, but err is nil at this point.

Stack trace:

Mar 13 17:00:10 test01 quicksilverd[4146983]: 5:00PM ERR recovered (runtime.Error) panic: runtime error: invalid memory address or nil pointer dereference
Mar 13 17:00:10 test01 quicksilverd[4146983]: 5:00PM ERR stack trace: goroutine 839 [running]:
Mar 13 17:00:10 test01 quicksilverd[4146983]: runtime/debug.Stack()
Mar 13 17:00:10 test01 quicksilverd[4146983]:         runtime/debug/stack.go:24 +0x5e
Mar 13 17:00:10 test01 quicksilverd[4146983]: github.com/quicksilver-zone/quicksilver/third-party-chains/osmosis-types/osmoutils.PrintPanicRecoveryError({{0x31e9f08, 0x4758280}, {0x31fd680, 0xc18e08d380}, {{0xb, 0x0}, {0xc00bf91770, 0xd}, 0x615afb, {0x638d4db, ...}, ...}, ...}, ...)
Mar 13 17:00:10 test01 quicksilverd[4146983]:         github.com/quicksilver-zone/quicksilver/third-party-chains/osmosis-types/osmoutils/cache_ctx.go:41 +0x45
Mar 13 17:00:10 test01 quicksilverd[4146983]: github.com/quicksilver-zone/quicksilver/third-party-chains/osmosis-types/osmoutils.ApplyFuncIfNoError.func1()
Mar 13 17:00:10 test01 quicksilverd[4146983]:         github.com/quicksilver-zone/quicksilver/third-party-chains/osmosis-types/osmoutils/cache_ctx.go:20 +0x78
Mar 13 17:00:10 test01 quicksilverd[4146983]: panic({0x2257020?, 0x4602040?})
Mar 13 17:00:10 test01 quicksilverd[4146983]:         runtime/panic.go:914 +0x21f
Mar 13 17:00:10 test01 quicksilverd[4146983]: github.com/quicksilver-zone/quicksilver/x/participationrewards/keeper.(*Keeper).AfterEpochEnd(_, {{0x31e9f08, 0x4758280}, {0x31fd680, 0xc197af3580}, {{0xb, 0x0}, {0xc00bf91770, 0xd}, 0x615afb, ...}, ...}, ...)
Mar 13 17:00:10 test01 quicksilverd[4146983]:         github.com/quicksilver-zone/quicksilver/x/participationrewards/keeper/hooks.go:79 +0x87d
Mar 13 17:00:10 test01 quicksilverd[4146983]: github.com/quicksilver-zone/quicksilver/x/participationrewards/keeper.Hooks.AfterEpochEnd({_}, {{0x31e9f08, 0x4758280}, {0x31fd680, 0xc197af3580}, {{0xb, 0x0}, {0xc00bf91770, 0xd}, 0x615afb, ...}, ...}, ...)

Expected Behaviour

Nil allocation exits quietly and completes the epoch.

Version

v1.5.0