Panics when opening a corrupted Badger DB

Issues Badger
1

What version of Go are you using (go version)?

$ go version
go version go1.16.2 windows/amd64

What operating system are you using?

Windows 10 1903 (OS build 18362.1082)

What version of Badger are you using?

github.com/dgraph-io/badger/v3 v3.2011.1

Does this issue reproduce with the latest master?

Yes

Steps to Reproduce the issue

Simply open the DB with

badger.Open(badger.DefaultOptions(dbPath).WithVerifyValueChecksum(true))

The corrupted DB can be found in my gdrive (2.6MB):

What Badger options were set?

badger.DefaultOptions(dbPath)
WithVerifyValueChecksum(true)

What did you do?

Calling badger.Open()

What did you expect to see?

Return an error showing the DB is corrupted

What did you see instead?

Panic in another goroutine, which I cannot recover.

panic: runtime error: index out of range [3] with length 0 [recovered]
	panic: 
== Recovering from initIndex crash ==
File Info: [ID: 38, Size: 408, Zeros: 408]
isEnrypted: false checksumLen: 0 checksum:  indexLen: 0 index: [] 
== Recovered ==


goroutine 80 [running]:
github.com/dgraph-io/badger/v3/table.(*Table).initBiggestAndSmallest.func1.1(0xc0001c1aa0)
	C:/gocode/pkg/mod/github.com/dgraph-io/badger/v3@v3.2011.1/table/table.go:351 +0x165
github.com/dgraph-io/badger/v3/table.(*Table).initBiggestAndSmallest.func1(0xc0001d6180)
	C:/gocode/pkg/mod/github.com/dgraph-io/badger/v3@v3.2011.1/table/table.go:397 +0x6e
panic(0x1d77ca0, 0xc0003bcd68)
	C:/go/src/runtime/panic.go:971 +0x49a
github.com/google/flatbuffers/go.GetInt32(...)
	C:/gocode/pkg/mod/github.com/google/flatbuffers@v1.12.0/go/encode.go:85
github.com/google/flatbuffers/go.GetUOffsetT(...)
	C:/gocode/pkg/mod/github.com/google/flatbuffers@v1.12.0/go/encode.go:121
github.com/dgraph-io/badger/v3/fb.GetRootAsTableIndex(...)
	C:/gocode/pkg/mod/github.com/dgraph-io/badger/v3@v3.2011.1/fb/TableIndex.go:14
github.com/dgraph-io/badger/v3/table.(*Table).readTableIndex(0xc0001d6180, 0x0, 0x8, 0xc0001c1a40)
	C:/gocode/pkg/mod/github.com/dgraph-io/badger/v3@v3.2011.1/table/table.go:704 +0x491
github.com/dgraph-io/badger/v3/table.(*Table).initIndex(0xc0001d6180, 0x0, 0x0, 0xc0002a3260)
	C:/gocode/pkg/mod/github.com/dgraph-io/badger/v3@v3.2011.1/table/table.go:462 +0x545
github.com/dgraph-io/badger/v3/table.(*Table).initBiggestAndSmallest(0xc0001d6180, 0x0, 0x0)
	C:/gocode/pkg/mod/github.com/dgraph-io/badger/v3@v3.2011.1/table/table.go:401 +0xab
github.com/dgraph-io/badger/v3/table.OpenTable(0xc000434280, 0x0, 0x200000, 0x0, 0x0, 0x3f847ae147ae147b, 0x1000, 0x0, 0x1, 0xc00053a080, ...)
	C:/gocode/pkg/mod/github.com/dgraph-io/badger/v3@v3.2011.1/table/table.go:308 +0x36e
github.com/dgraph-io/badger/v3.newLevelsController.func1(0xc00043e180, 0xc0002b57b0, 0xc000589000, 0xc0002b5798, 0xc000178d10, 0x7, 0x7, 0xc00050a780, 0x21, 0x6, ...)
	C:/gocode/pkg/mod/github.com/dgraph-io/badger/v3@v3.2011.1/levels.go:150 +0x2d8
created by github.com/dgraph-io/badger/v3.newLevelsController
	C:/gocode/pkg/mod/github.com/dgraph-io/badger/v3@v3.2011.1/levels.go:129 +0xc2b