Clarify multiple multiple-error semantics

[rogpeppe]

The error-codes section allows for multiple errors to be returned, but doesn't clarify how the client should interpret such a return. For example, there might be several different error codes. What if they conflict?

Do any registries return multiple error codes in the real world, and if so, under what circumstances?

[sudo-bmitch]

I suspect a lot of clients throw up their hands and return the error back to the user or logs. I'm only using the http status codes for my own client logic.

[sudo-bmitch]

Here's an example response from distribution/distribution when pushing a manifest list without first pushing the manifests:

{"errors":[
  {"code":"MANIFEST_BLOB_UNKNOWN","message":"blob unknown to registry","detail":"sha256:600cac71919fc686481c9c1d652c493c630ceeb13d207f9ae8c0a7bb9fde4a71"},
  {"code":"MANIFEST_BLOB_UNKNOWN","message":"blob unknown to registry","detail":"sha256:cbb9856571c5127304224b528345cb3a5ea5caf13e7cedfa8c1e6bb9f8414156"},
  {"code":"MANIFEST_BLOB_UNKNOWN","message":"blob unknown to registry","detail":"sha256:52a873d6833e53105450c58321a19677433c74740a81d3a55310a99889b9cb9e"},
  {"code":"MANIFEST_BLOB_UNKNOWN","message":"blob unknown to registry","detail":"sha256:01d6fd6646fed9e6781c953ff80652ce8979a79b1c61cb36a07e240167341f32"},
  {"code":"MANIFEST_BLOB_UNKNOWN","message":"blob unknown to registry","detail":"sha256:361e6c3e59da161f15fd59b68df876e3346e7e043277f4ebdb13bfe7f23aeab6"}
]}