What to do with multibase prefixed cid v0 string

[olizilla]

I can get the mutltibase for a block that isn't dag-pb, and then prefix it with the multibase z for base58btc and CID.parse is happy with it, but per the CID spec, but its not CID V0 string as mutlibase prefix is explicitly provided

the multibase of the string representation is always base58btc and implicit (not written)
– https://github.com/multiformats/cid#versions

nor a CID v1 as cid version and and multicodec are not provided

$ ipfs add --cid-version=1 olizilla.png
added bafkreiawm5lgdgchgrhep4kxo2g4tptewtpcnfzusyfcopytpuj2fnzf2m olizilla.png

$ ipfs cid format bafkreiawm5lgdgchgrhep4kxo2g4tptewtpcnfzusyfcopytpuj2fnzf2m -f %m -b z
zQmPr755CxWUwt39C2Yiw4UGKrv16uZhSgeZJmoHUUS9TSJ

$ node
Welcome to Node.js v18.12.1.
Type ".help" for more information.
> const CID = (await import('multiformats/cid')).CID
undefined
> CID.parse('zQmPr755CxWUwt39C2Yiw4UGKrv16uZhSgeZJmoHUUS9TSJ')
CID(zQmPr755CxWUwt39C2Yiw4UGKrv16uZhSgeZJmoHUUS9TSJ)

[olizilla]

zQmTFGZgypZBYozPTF2qqeho5n17MJXSkHRMDhRqmkroAZu is a bad one as it points to a raw block but existing tooling would error when trying to decode it as dag-pb. e.g.

$ ipfs get zQmPr755CxWUwt39C2Yiw4UGKrv16uZhSgeZJmoHUUS9TSJ
Error: protobuf: (PBNode) invalid wireType, expected 2, got 1

If it happened to point to a dag-pb node then ignoring the z might be an option, but it's not knowable from the CID, so CID.parse should probably throw an error for a multibase prefixed CID v0

[lidel]

CID.parse should probably throw an error for a multibase prefixed CID v0

👍 , this library should error on zQms, these are not part fo the spec
@olizilla are you willing to create a PR against https://github.com/multiformats/js-multiformats?
I'm up for reviewing.

ps. I filled ipfs/kubo#9556 to remove some related papercuts from ipfs cid format as well.