Possible missing case in ghc-pkg

I saw this while compiling

utils\ghc-pkg\Main.hs:761:25: Warning:
    Pattern match(es) are non-exhaustive
    In a case alternative: Patterns not matched: GhcPkg.DbOpenReadOnly

I don't know if this is indicative of a bug in the implementation or not?

Trac metadata

Trac field	Value
Version	8.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Package system
Test case
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