The behaviour of the HEX_UNSAFE_REGISTRY boolean seems backwards

[mcoms]

Setting HEX_UNSAFE_REGISTRY=1 causes hex to require a signed registry. Setting HEX_UNSAFE_REGISTRY=0 disables the signature check verification.

This is the opposite of what the warning message returned by hex when accessing an unsigned registry says.

The code here may need to be negated: https://github.com/hexpm/hex/blob/master/lib/hex/state.ex#L45

Hex: 0.13.0, Elixir: 1.3.2, OTP: 19.0.2

[ericmj]

Thanks for the report, this is indeed incorrect. Would you mind sending a PR that adds the same Kernel.not as the line above and flips the default value?

[lexmag]

Closed in #287.