From 58a95f364c4dea6f0865567631b7508574c0a8e6 Mon Sep 17 00:00:00 2001
From: Marcin Rataj <lidel@lidel.org>
Date: Wed, 4 Mar 2020 21:31:22 +0100
Subject: [PATCH] refactor: error on resolve /ipns/{cidv1-dag-pb}

ipfs resolve of /ipns/{cidv1}
where CID has multicodec other than libp2p-key returns a meaningful error
that includes fixed multicodec

See also: https://github.com/ipfs/go-ipfs/pull/6096#discussion_r387184055

License: MIT
Signed-off-by: Marcin Rataj <lidel@lidel.org>
---
 namesys/namesys.go             | 20 +++++++++++++++++++-
 namesys/routing.go             | 18 ------------------
 test/sharness/t0160-resolve.sh |  9 +++++++++
 3 files changed, 28 insertions(+), 19 deletions(-)

diff --git a/namesys/namesys.go b/namesys/namesys.go
index ce84f6a9859..d25e08e84a3 100644
--- a/namesys/namesys.go
+++ b/namesys/namesys.go
@@ -2,10 +2,12 @@ package namesys
 
 import (
 	"context"
+	"fmt"
 	"strings"
 	"time"
 
 	lru "github.com/hashicorp/golang-lru"
+	cid "github.com/ipfs/go-cid"
 	ds "github.com/ipfs/go-datastore"
 	path "github.com/ipfs/go-path"
 	opts "github.com/ipfs/interface-go-ipfs-core/options/namesys"
@@ -116,7 +118,23 @@ func (ns *mpns) resolveOnceAsync(ctx context.Context, name string, options opts.
 	// 3. otherwise resolve through the "proquint" resolver
 
 	var res resolver
-	if _, err := peer.Decode(key); err == nil {
+	_, err := peer.Decode(key)
+
+	// CIDs in IPNS are expected to have libp2p-key multicodec
+	// We ease the transition by returning a more meaningful error with a valid CID
+	if err != nil && err.Error() == "can't convert CID of type protobuf to a peer ID" {
+		ipnsCid, cidErr := cid.Decode(key)
+		if cidErr == nil && ipnsCid.Version() == 1 && ipnsCid.Type() != cid.Libp2pKey {
+			fixedCid := cid.NewCidV1(cid.Libp2pKey, ipnsCid.Hash()).String()
+			codecErr := fmt.Errorf("peer ID represented as CIDv1 require libp2p-key multicodec: retry with %s", fixedCid)
+			log.Debugf("RoutingResolver: could not convert public key hash %s to peer ID: %s\n", key, codecErr)
+			out <- onceResult{err: codecErr}
+			close(out)
+			return out
+		}
+	}
+
+	if err == nil {
 		res = ns.ipnsResolver
 	} else if isd.IsDomain(key) {
 		res = ns.dnsResolver
diff --git a/namesys/routing.go b/namesys/routing.go
index bf94abb4aa6..8eec9df802f 100644
--- a/namesys/routing.go
+++ b/namesys/routing.go
@@ -60,25 +60,7 @@ func (r *IpnsResolver) resolveOnceAsync(ctx context.Context, name string, option
 
 	name = strings.TrimPrefix(name, "/ipns/")
 
-	// Fix PeerID represented as CIDv1 with invalid multicodec
-	if name[:4] == "bafy" { // TODO: is this a safe way of detecting base32-dag-pb?
-		ipnsCid, err := cid.Decode(name)
-		if err == nil && ipnsCid.Type() != cid.Libp2pKey {
-			// CIDs in IPNS are expected to have libp2p-key multicodec.
-			// We ease the transition by fixing multicodec on the fly:
-			// https://github.com/ipfs/go-ipfs/issues/5287#issuecomment-492163929
-			name = cid.NewCidV1(cid.Libp2pKey, ipnsCid.Hash()).String()
-		}
-	}
-
 	pid, err := peer.Decode(name)
-	if err != nil {
-		log.Debugf("RoutingResolver: could not convert public key hash %s to peer ID: %s\n", name, err)
-		out <- onceResult{err: err}
-		close(out)
-		cancel()
-		return out
-	}
 
 	// Name should be the hash of a public key retrievable from ipfs.
 	// We retrieve the public key here to make certain that it's in the peer
diff --git a/test/sharness/t0160-resolve.sh b/test/sharness/t0160-resolve.sh
index 87740685644..03062778116 100755
--- a/test/sharness/t0160-resolve.sh
+++ b/test/sharness/t0160-resolve.sh
@@ -116,6 +116,15 @@ test_resolve_cmd_b32() {
 
   test_resolve_setup_name "self" "/ipfs/$c_hash_b32"
   test_resolve "/ipns/$self_hash" "/ipfs/$c_hash_b32" --cid-base=base32
+
+  # peer ID represented as CIDv1 require libp2p-key multicodec
+  # https://github.com/libp2p/specs/blob/master/RFC/0001-text-peerid-cid.md
+  local self_hash_b32protobuf=$(echo $self_hash | ipfs cid format -v 1 -b b --codec protobuf)
+  local self_hash_b32libp2pkey=$(echo $self_hash | ipfs cid format -v 1 -b b --codec libp2p-key)
+  test_expect_success "resolve of /ipns/{cidv1} with multicodec other than libp2p-key returns a meaningful error" '
+    test_expect_code 1 ipfs resolve /ipns/$self_hash_b32protobuf 2>cidcodec_error &&
+    grep "Error: peer ID represented as CIDv1 require libp2p-key multicodec: retry with $self_hash_b32libp2pkey" cidcodec_error
+  '
 }