bug(shares/GetSharesByNamespace): missing response type ErrNamespaceNotFound

[distractedm1nd]

In the current implementation, the response from a shrex-nd server for "Hey, my EDS store doesn't have that EDS, so I can't give you the ND" and "Hey, that EDS is in my store, and the data you are looking for doesn't exist in it" are the same. This causes many issues in the stack, leading to a timeout for GetSharesByNamespace calls, even when the correct response has been found. This will clearly require a protocol breaking change.

This must also be fixed in CascadeGetter, which should recognize the difference between ErrNotFound, which moves onto the next getter, and ErrNamespaceNotFound, which should return the data and error.

This means IPLDGetter should also return a share.ErrNamespaceNotFound for the same reason.

[nashqueue]

Is this related : rollkit/rollkit#897 ?

[distractedm1nd]

@nashqueue yes, partially

[jcstein]

I'm getting something similar on a rollup, just every so often though

da  | 2023-05-03T19:44:32.020Z	ERROR	ipld	ipld/namespace_data.go:216	getLeavesWithProofsByNamespace:could not retrieve node	{"nID": "\ufffd\ufffd\ufffdy\ufffdq\u0016\ufffd", "pos": 0, "err": "context canceled"}

[jcstein]

I made an issue for the error above, as I believe the error is different, but related #2174