ipip-445: HTTP 400 on raw root cid

Ref.
#445 (comment)

Author: lidel

src/http-gateways/trustless-gateway.md

@@ -196,14 +196,8 @@ It accepts two values:
 
 When not specified a gateway implementation MUST assume `n`.
 
-:::note Notes for implementers
-
-A `skip-raw-blocks=y` request for a content path with `raw` root CID does not
-make sense and SHOULD NOT be sent by clients.
-
-A Gateway SHOULD return HTTP error 400 Bad Request
-
-:::
+A Gateway MUST return HTTP error 400 Bad Request when `skip-raw-blocks=y` is
+sent for a content path with a root CID with the `raw` multicodec.
 
 # HTTP Response
 

src/ipips/ipip-0445.md

@@ -152,6 +152,7 @@ This IPIP does not impact security model of trustless gateway.
 TODO: update below section with CIDs or CARs from conformance tests
 
 Scenarios we should check:
+- [ ] request for `/ipfs/cid` where CID has `raw` codec MUST return HTTP 400 (Bad Request)
 - [ ] reuse existing UnixFS DAG that has raw-leaves, request it with
   `skip-raw-blocks=n`, confirm the response includes expected raw leaves' CIDs
 - [ ] create a new CAR fixture that only have non-raw blocks. Request it with