Please describe the feature you’d like to see added.
Add a “Bech32 string too short” case to Bech32.cpp LocateErrors to reduce ambiguity and collisions with “Invalid separator position” case.
Is your feature related to a problem, if so please describe it.
Error representation when calling LocateErrors within src/test/bech32_tests.cpp is ambiguous and incorrect in some cases because of a missing bech32 string to short case. Not having a too short case causes a fall though into the conditions of "Invalid separator position" || "Missing separator"
Describe the solution you’d like
Simply add a check for a minimum Bech32 string size after or during the check for the maximum size which is already implemented.
Cascading effects of this would be seen in DecodeDestination if https://github.com/bitcoin/bitcoin/blob/32c15237b656209b932c5d6d2e20736c0e3d5a34/src/key_io.cpp#L85-L86 was patched to not consider bech32 invalid then attempt to Base58Decode it becuase of the incorrect HRP for the current chain.
Referenced in #26290
PR #27260
Describe any alternatives you’ve considered
You could case this into other logic on a case by case basis in code. Example make a speical case inside DecodeDestination to display the correct error message to the user by if LocateErrors returns ‘Invalid "separator position" || "Missing separator" then you check to see if the string is to short.
Please leave any additional context
As an aside there is already a check for string length greater than 90 (MAX LEN)
in src/test/bech32_tests.cpp both [“10a06t8”,“1qzzfhee”] produce {"Invalid separator position", {0}} The former is non conformant to BIP173 due not even having enough chars to represent a BASE32 string and the second genuinely has a wrong separator position.
