Bug Report: vttablet panic on shutdown

[deepthi]

Overview of the Issue

vttablet panics on shutdown.

Reproduction Steps

Edit examples/local/401_teardown.sh and comment out line 69 that deletes $VTDATAROOT.

$ ./101_initial_cluster.sh
...
$ ./401_teardown.sh

Observe the panic in any of the vttablet log files under $VTDATAROOT/tmp

Binary Version

v18

Operating System and Environment details

Any

Log Fragments

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x30 pc=0x1057df668]

goroutine 983 [running]:
vitess.io/vitess/go/vt/topo.(*Server).GetCellInfo(0x14000b14ac0, {0x1073ddde0, 0x140006f7500}, {0x16b0e3216, 0x9}, 0x0)
	vitess.io/vitess/go/vt/topo/cell_info.go:71 +0xd8
vitess.io/vitess/go/vt/topo.(*Server).ConnForCell(0x14000b14ac0, {0x1073ddde0?, 0x140006f7500?}, {0x16b0e3216, 0x9})
	vitess.io/vitess/go/vt/topo/server.go:269 +0x108
vitess.io/vitess/go/vt/topo.(*Server).GetTablet(0x140009afd40?, {0x1073ddde0, 0x140006f7500}, 0x14000b14000)
	vitess.io/vitess/go/vt/topo/tablet.go:228 +0x4c
vitess.io/vitess/go/vt/topo.(*Server).UpdateTabletFields(0x1073ddc78?, {0x1073ddde0?, 0x140006f7500?}, 0x14000b14000, 0x14000ae4f40)
	vitess.io/vitess/go/vt/topo/tablet.go:393 +0x168
vitess.io/vitess/go/vt/vttablet/tabletmanager.(*TabletManager).Close(0x140004d01a0)
	vitess.io/vitess/go/vt/vttablet/tabletmanager/tm_init.go:437 +0x98
vitess.io/vitess/go/cmd/vttablet/cli.run.func1()
	vitess.io/vitess/go/cmd/vttablet/cli/cli.go:162 +0x2c
vitess.io/vitess/go/event.(*Hooks).Fire.func1(0x140010e4000?)
	vitess.io/vitess/go/event/hooks.go:49 +0x2c
created by vitess.io/vitess/go/event.(*Hooks).Fire in goroutine 1
	vitess.io/vitess/go/event/hooks.go:48 +0xe8