Check store keys length before accessing them

[amaury1093]

Summary of Bug

Before accessing a store key (e.g. a := key[n:m]), we should make that sure key is at least of length m+1.

ref: #8363 (comment)

Version

v0.41.0

Proposal

func assertKeyAtLeastLength(bz []byte, length int) {
  if len(bz) < length {
    panic(fmt.Sprintf("expected key of length at least %d, got %d", length, len(bz)))
  }
}

// in module's keys.go
assertKeyAtLeastLength(key, 2)
addrLen := key[1]
// repeat assert-access steps everywhere

Pros

• Better error message

Cons

• Slightly longer code.

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• Not duplicate issue
• Appropriate labels applied
• Appropriate contributors tagged
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