ensure sending of wantlist to friendly peers

bitswap.go

@@ -262,6 +262,7 @@ func (bs *bitswap) ReceiveMessage(ctx context.Context, p peer.Peer, incoming bsm
 		}
 	}
 
+	first := true
 	for _, key := range incoming.Wantlist() {
 		// TODO: might be better to check if we have the block before checking
 		//			if we should send it to someone
@@ -272,10 +273,12 @@ func (bs *bitswap) ReceiveMessage(ctx context.Context, p peer.Peer, incoming bsm
 				// Create a separate message to send this block in
 				blkmsg := bsmsg.New()
 
-				// TODO: only send this the first time
+				if first {
 					for _, k := range bs.wantlist.Keys() {
 						blkmsg.AddWanted(k)
 					}
+					first = false
+				}
 
 				blkmsg.AddBlock(block)
 				bs.strategy.MessageSent(p, blkmsg)
@@ -284,6 +287,16 @@ func (bs *bitswap) ReceiveMessage(ctx context.Context, p peer.Peer, incoming bsm
 		}
 	}
 
+	// If they send us a block, we should guarantee that we send
+	// them our updated want list one way or another
+	if len(incoming.Blocks()) > 0 && first {
+		message := bsmsg.New()
+		for _, k := range bs.wantlist.Keys() {
+			message.AddWanted(k)
+		}
+		return p, message
+	}
+
 	return nil, nil
 }
 

bitswap_test.go

-package bitswap
+package bitswap_test
 
 import (
 	"bytes"
@@ -7,6 +7,7 @@ import (
 	"time"
 
 	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
+	. "github.com/jbenet/go-ipfs/exchange/bitswap"
 
 	ds "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore"
 	ds_sync "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore/sync"