Revert "eth: Lower bound 4 on number of peers to broadcast new blocks"

This reverts commit 0c33200e13.

eth/handler.go

@@ -49,9 +49,6 @@ const (
 	// txChanSize is the size of channel listening to NewTxsEvent.
 	// The number is referenced from the size of tx pool.
 	txChanSize = 4096
-
-	// minimim number of peers to broadcast new blocks to
-	minBroadcastPeers = 4
 )
 
 var (
@@ -708,14 +705,7 @@ func (pm *ProtocolManager) BroadcastBlock(block *types.Block, propagate bool) {
 			return
 		}
 		// Send the block to a subset of our peers
-		transferLen := int(math.Sqrt(float64(len(peers))))
+		transfer := peers[:int(math.Sqrt(float64(len(peers))))]
-		if transferLen < minBroadcastPeers {
-			transferLen = minBroadcastPeers
-		}
-		if transferLen > len(peers) {
-			transferLen = len(peers)
-		}
-		transfer := peers[:transferLen]
 		for _, peer := range transfer {
 			peer.AsyncSendNewBlock(block, td)
 		}

eth/handler_test.go

@@ -17,7 +17,6 @@
 package eth
 
 import (
-    "fmt"
 	"math"
 	"math/big"
 	"math/rand"
@@ -473,11 +472,8 @@ func testDAOChallenge(t *testing.T, localForked, remoteForked bool, timeout bool
 		config        = &params.ChainConfig{DAOForkBlock: big.NewInt(1), DAOForkSupport: localForked}
 		gspec         = &core.Genesis{Config: config}
 		genesis       = gspec.MustCommit(db)
+		blockchain, _ = core.NewBlockChain(db, nil, config, pow, vm.Config{})
 	)
-	blockchain, err := core.NewBlockChain(db, nil, config, pow, vm.Config{})
-	if err != nil {
-		t.Fatalf("failed to create new blockchain: %v", err)
-	}
 	pm, err := NewProtocolManager(config, downloader.FullSync, DefaultConfig.NetworkId, evmux, new(testTxPool), pow, blockchain, db)
 	if err != nil {
 		t.Fatalf("failed to start test protocol manager: %v", err)
@@ -524,89 +520,3 @@ func testDAOChallenge(t *testing.T, localForked, remoteForked bool, timeout bool
 		}
 	}
 }
-
-func TestBroadcastBlock(t *testing.T) {
-	var tests = []struct {
-		totalPeers int
-		broadcastExpected int
-	}{
-		{1, 1},
-		{2, 2},
-		{3, 3},
-		{4, 4},
-		{5, 4},
-		{9, 4},
-		{12, 4},
-		{16, 4},
-		{26, 5},
-		{100, 10},
-	}
-	for _, test := range tests {
-		testBroadcastBlock(t, test.totalPeers, test.broadcastExpected)
-	}
-}
-
-func testBroadcastBlock(t *testing.T, totalPeers, broadcastExpected int) {
-	var (
-		evmux         = new(event.TypeMux)
-		pow           = ethash.NewFaker()
-		db            = ethdb.NewMemDatabase()
-		config        = &params.ChainConfig{}
-		gspec         = &core.Genesis{Config: config}
-		genesis       = gspec.MustCommit(db)
-	)
-	blockchain, err := core.NewBlockChain(db, nil, config, pow, vm.Config{})
-	if err != nil {
-		t.Fatalf("failed to create new blockchain: %v", err)
-	}
-	pm, err := NewProtocolManager(config, downloader.FullSync, DefaultConfig.NetworkId, evmux, new(testTxPool), pow, blockchain, db)
-	if err != nil {
-		t.Fatalf("failed to start test protocol manager: %v", err)
-	}
-	pm.Start(1000)
-	defer pm.Stop()
-	var peers []*testPeer
-	for i := 0; i < totalPeers; i++ {
-		peer, _ := newTestPeer(fmt.Sprintf("peer %d", i), eth63, pm, true)
-		defer peer.close()
-		peers = append(peers, peer)
-	}
-	chain, _ := core.GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 1, func(i int, gen *core.BlockGen) {})
-	pm.BroadcastBlock(chain[0], true /*propagate*/)
-
-	errCh := make(chan error, totalPeers)
-	doneCh := make(chan struct{}, totalPeers)
-	for _, peer := range peers {
-		go func(p *testPeer) {
-			if err := p2p.ExpectMsg(p.app, NewBlockMsg, &newBlockData{Block: chain[0], TD: big.NewInt(131136)}); err != nil {
-				errCh <- err
-			} else {
-				doneCh <- struct{}{}
-			}
-		}(peer)
-	}
-	timeoutCh := time.NewTimer(time.Millisecond*100).C
-	var receivedCount int
-	outer: for {
-		select {
-		case err =<- errCh:
-			break outer
-		case <- doneCh:
-			receivedCount++
-			if receivedCount == totalPeers {
-				break outer
-			}
-		case <- timeoutCh:
-			break outer
-		}
-	}
-	for _, peer := range peers {
-		peer.app.Close()
-	}
-	if err != nil {
-		t.Errorf("error matching block by peer: %v", err)
-	}
-	if receivedCount != broadcastExpected {
-		t.Errorf("block broadcast to %d peers, expected %d", receivedCount, broadcastExpected)
-	}
-}