ban usage of require.Len when testing for length 0

indexer/indexer_test.go

@@ -77,11 +77,11 @@ func TestNewIndexer(t *testing.T) {
 	require.True(idxr.indexingEnabled)
 	require.True(idxr.allowIncompleteIndex)
 	require.NotNil(idxr.blockIndices)
-	require.Len(idxr.blockIndices, 0)
+	require.Empty(idxr.blockIndices)
 	require.NotNil(idxr.txIndices)
-	require.Len(idxr.txIndices, 0)
+	require.Empty(idxr.txIndices)
 	require.NotNil(idxr.vtxIndices)
-	require.Len(idxr.vtxIndices, 0)
+	require.Empty(idxr.vtxIndices)
 	require.NotNil(idxr.blockAcceptorGroup)
 	require.NotNil(idxr.txAcceptorGroup)
 	require.NotNil(idxr.vertexAcceptorGroup)
@@ -178,8 +178,8 @@ func TestIndexer(t *testing.T) {
 	require.Equal("index/chain1", server.bases[0])
 	require.Equal("/block", server.endpoints[0])
 	require.Len(idxr.blockIndices, 1)
-	require.Len(idxr.txIndices, 0)
-	require.Len(idxr.vtxIndices, 0)
+	require.Empty(idxr.txIndices)
+	require.Empty(idxr.vtxIndices)
 
 	// Accept a container
 	blkID, blkBytes := ids.GenerateTestID(), utils.RandomBytes(32)
@@ -236,9 +236,9 @@ func TestIndexer(t *testing.T) {
 	idxr = idxrIntf.(*indexer)
 	now = time.Now()
 	idxr.clock.Set(now)
-	require.Len(idxr.blockIndices, 0)
-	require.Len(idxr.txIndices, 0)
-	require.Len(idxr.vtxIndices, 0)
+	require.Empty(idxr.blockIndices)
+	require.Empty(idxr.txIndices)
+	require.Empty(idxr.vtxIndices)
 	require.True(idxr.hasRunBefore)
 	previouslyIndexed, err = idxr.previouslyIndexed(chain1Ctx.ChainID)
 	require.NoError(err)
@@ -445,7 +445,7 @@ func TestIncompleteIndex(t *testing.T) {
 	isIncomplete, err = idxr.isIncomplete(chain1Ctx.ChainID)
 	require.NoError(err)
 	require.True(isIncomplete)
-	require.Len(idxr.blockIndices, 0)
+	require.Empty(idxr.blockIndices)
 
 	// Close and re-open the indexer, this time with indexing enabled
 	require.NoError(config.DB.(*versiondb.Database).Commit())
@@ -523,5 +523,5 @@ func TestIgnoreNonDefaultChains(t *testing.T) {
 	// RegisterChain should return without adding an index for this chain
 	chainVM := mocks.NewMockChainVM(ctrl)
 	idxr.RegisterChain("chain1", chain1Ctx, chainVM)
-	require.Len(idxr.blockIndices, 0)
+	require.Empty(idxr.blockIndices)
 }

network/throttling/bandwidth_throttler_test.go

@@ -31,7 +31,7 @@ func TestBandwidthThrottler(t *testing.T) {
 	require.NotNil(throttler.limiters)
 	require.Equal(config.RefillRate, throttler.RefillRate)
 	require.Equal(config.MaxBurstSize, throttler.MaxBurstSize)
-	require.Len(throttler.limiters, 0)
+	require.Empty(throttler.limiters)
 
 	// Add a node
 	nodeID1 := ids.GenerateTestNodeID()
@@ -40,7 +40,7 @@ func TestBandwidthThrottler(t *testing.T) {
 
 	// Remove the node
 	throttler.RemoveNode(nodeID1)
-	require.Len(throttler.limiters, 0)
+	require.Empty(throttler.limiters)
 
 	// Add the node back
 	throttler.AddNode(nodeID1)

network/throttling/inbound_msg_buffer_throttler_test.go

@@ -64,7 +64,7 @@ func TestMsgBufferThrottler(t *testing.T) {
 	throttler.release(nodeID1)
 	throttler.release(nodeID1)
 	throttler.release(nodeID1)
-	require.Len(throttler.nodeToNumProcessingMsgs, 0)
+	require.Empty(throttler.nodeToNumProcessingMsgs)
 }
 
 // Test inboundMsgBufferThrottler when an acquire is cancelled

network/throttling/inbound_msg_byte_throttler_test.go

@@ -139,16 +139,16 @@ func TestInboundMsgByteThrottler(t *testing.T) {
 	throttler.Acquire(context.Background(), 1, vdr1ID)
 	require.Equal(config.AtLargeAllocSize-1, throttler.remainingAtLargeBytes)
 	require.Equal(config.VdrAllocSize, throttler.remainingVdrBytes)
-	require.Len(throttler.nodeToVdrBytesUsed, 0)
+	require.Empty(throttler.nodeToVdrBytesUsed)
 	require.Len(throttler.nodeToAtLargeBytesUsed, 1)
 	require.Equal(uint64(1), throttler.nodeToAtLargeBytesUsed[vdr1ID])
 
 	// Release the bytes
 	throttler.release(&msgMetadata{msgSize: 1}, vdr1ID)
 	require.Equal(config.AtLargeAllocSize, throttler.remainingAtLargeBytes)
 	require.Equal(config.VdrAllocSize, throttler.remainingVdrBytes)
-	require.Len(throttler.nodeToVdrBytesUsed, 0)
-	require.Len(throttler.nodeToAtLargeBytesUsed, 0)
+	require.Empty(throttler.nodeToVdrBytesUsed)
+	require.Empty(throttler.nodeToAtLargeBytesUsed)
 
 	// Use all the at-large allocation bytes and 1 of the validator allocation bytes
 	// Should return immediately.
@@ -170,7 +170,7 @@ func TestInboundMsgByteThrottler(t *testing.T) {
 	require.Equal(config.VdrAllocSize/2, throttler.nodeToVdrBytesUsed[vdr2ID])
 	require.Len(throttler.nodeToVdrBytesUsed, 2)
 	require.Len(throttler.nodeToAtLargeBytesUsed, 1)
-	require.Len(throttler.nodeToWaitingMsgID, 0)
+	require.Empty(throttler.nodeToWaitingMsgID)
 	require.Zero(throttler.waitingToAcquire.Len())
 
 	// vdr1 should be able to acquire the rest of the validator allocation
@@ -256,14 +256,14 @@ func TestInboundMsgByteThrottler(t *testing.T) {
 	require.Len(throttler.nodeToVdrBytesUsed, 1)
 	require.Zero(throttler.nodeToVdrBytesUsed[vdr1ID])
 	require.Equal(config.AtLargeAllocSize/2-2, throttler.remainingAtLargeBytes)
-	require.Len(throttler.nodeToWaitingMsgID, 0)
+	require.Empty(throttler.nodeToWaitingMsgID)
 	require.Zero(throttler.waitingToAcquire.Len())
 
 	// Non-validator should be able to take the rest of the at-large bytes
 	throttler.Acquire(context.Background(), config.AtLargeAllocSize/2-2, nonVdrID)
 	require.Zero(throttler.remainingAtLargeBytes)
 	require.Equal(config.AtLargeAllocSize/2-1, throttler.nodeToAtLargeBytesUsed[nonVdrID])
-	require.Len(throttler.nodeToWaitingMsgID, 0)
+	require.Empty(throttler.nodeToWaitingMsgID)
 	require.Zero(throttler.waitingToAcquire.Len())
 
 	// But should block on subsequent Acquires
@@ -292,15 +292,15 @@ func TestInboundMsgByteThrottler(t *testing.T) {
 
 	require.Zero(throttler.nodeToAtLargeBytesUsed[vdr2ID])
 	require.Equal(config.VdrAllocSize, throttler.remainingVdrBytes)
-	require.Len(throttler.nodeToVdrBytesUsed, 0)
+	require.Empty(throttler.nodeToVdrBytesUsed)
 	require.Zero(throttler.remainingAtLargeBytes)
 	require.NotContains(throttler.nodeToWaitingMsgID, nonVdrID)
 	require.Zero(throttler.waitingToAcquire.Len())
 
 	// Release all of vdr1's messages
 	throttler.release(&msgMetadata{msgSize: 1}, vdr1ID)
 	throttler.release(&msgMetadata{msgSize: config.AtLargeAllocSize/2 - 1}, vdr1ID)
-	require.Len(throttler.nodeToVdrBytesUsed, 0)
+	require.Empty(throttler.nodeToVdrBytesUsed)
 	require.Equal(config.VdrAllocSize, throttler.remainingVdrBytes)
 	require.Equal(config.AtLargeAllocSize/2, throttler.remainingAtLargeBytes)
 	require.Zero(throttler.nodeToAtLargeBytesUsed[vdr1ID])
@@ -311,10 +311,10 @@ func TestInboundMsgByteThrottler(t *testing.T) {
 	throttler.release(&msgMetadata{msgSize: 1}, nonVdrID)
 	throttler.release(&msgMetadata{msgSize: 1}, nonVdrID)
 	throttler.release(&msgMetadata{msgSize: config.AtLargeAllocSize/2 - 2}, nonVdrID)
-	require.Len(throttler.nodeToVdrBytesUsed, 0)
+	require.Empty(throttler.nodeToVdrBytesUsed)
 	require.Equal(config.VdrAllocSize, throttler.remainingVdrBytes)
 	require.Equal(config.AtLargeAllocSize, throttler.remainingAtLargeBytes)
-	require.Len(throttler.nodeToAtLargeBytesUsed, 0)
+	require.Empty(throttler.nodeToAtLargeBytesUsed)
 	require.Zero(throttler.nodeToAtLargeBytesUsed[nonVdrID])
 	require.NotContains(throttler.nodeToWaitingMsgID, nonVdrID)
 	require.Zero(throttler.waitingToAcquire.Len())

network/throttling/outbound_msg_throttler_test.go

@@ -57,16 +57,16 @@ func TestSybilOutboundMsgThrottler(t *testing.T) {
 	require.True(acquired)
 	require.Equal(config.AtLargeAllocSize-1, throttler.remainingAtLargeBytes)
 	require.Equal(config.VdrAllocSize, throttler.remainingVdrBytes)
-	require.Len(throttler.nodeToVdrBytesUsed, 0)
+	require.Empty(throttler.nodeToVdrBytesUsed)
 	require.Len(throttler.nodeToAtLargeBytesUsed, 1)
 	require.Equal(uint64(1), throttler.nodeToAtLargeBytesUsed[vdr1ID])
 
 	// Release the bytes
 	throttlerIntf.Release(msg, vdr1ID)
 	require.Equal(config.AtLargeAllocSize, throttler.remainingAtLargeBytes)
 	require.Equal(config.VdrAllocSize, throttler.remainingVdrBytes)
-	require.Len(throttler.nodeToVdrBytesUsed, 0)
-	require.Len(throttler.nodeToAtLargeBytesUsed, 0)
+	require.Empty(throttler.nodeToVdrBytesUsed)
+	require.Empty(throttler.nodeToAtLargeBytesUsed)
 
 	// Use all the at-large allocation bytes and 1 of the validator allocation bytes
 	msg = testMsgWithSize(ctrl, config.AtLargeAllocSize+1)
@@ -142,24 +142,24 @@ func TestSybilOutboundMsgThrottler(t *testing.T) {
 	throttlerIntf.Release(msg, vdr2ID)
 	require.Zero(throttler.nodeToAtLargeBytesUsed[vdr2ID])
 	require.Equal(config.VdrAllocSize, throttler.remainingVdrBytes)
-	require.Len(throttler.nodeToVdrBytesUsed, 0)
+	require.Empty(throttler.nodeToVdrBytesUsed)
 	require.Zero(throttler.remainingAtLargeBytes)
 
 	// Release all of vdr1's messages
 	msg = testMsgWithSize(ctrl, config.VdrAllocSize/2-1)
 	throttlerIntf.Release(msg, vdr1ID)
-	require.Len(throttler.nodeToVdrBytesUsed, 0)
+	require.Empty(throttler.nodeToVdrBytesUsed)
 	require.Equal(config.VdrAllocSize, throttler.remainingVdrBytes)
 	require.Equal(config.AtLargeAllocSize/2-1, throttler.remainingAtLargeBytes)
 	require.Zero(throttler.nodeToAtLargeBytesUsed[vdr1ID])
 
 	// Release nonVdr's messages
 	msg = testMsgWithSize(ctrl, config.AtLargeAllocSize/2+1)
 	throttlerIntf.Release(msg, nonVdrID)
-	require.Len(throttler.nodeToVdrBytesUsed, 0)
+	require.Empty(throttler.nodeToVdrBytesUsed)
 	require.Equal(config.VdrAllocSize, throttler.remainingVdrBytes)
 	require.Equal(config.AtLargeAllocSize, throttler.remainingAtLargeBytes)
-	require.Len(throttler.nodeToAtLargeBytesUsed, 0)
+	require.Empty(throttler.nodeToAtLargeBytesUsed)
 	require.Zero(throttler.nodeToAtLargeBytesUsed[nonVdrID])
 }
 

scripts/lint.sh

@@ -21,7 +21,7 @@ fi
 # by default, "./scripts/lint.sh" runs all lint tests
 # to run only "license_header" test
 # TESTS='license_header' ./scripts/lint.sh
-TESTS=${TESTS:-"golangci_lint license_header require_error_is_no_funcs_as_params single_import interface_compliance_nil require_equal_zero"}
+TESTS=${TESTS:-"golangci_lint license_header require_error_is_no_funcs_as_params single_import interface_compliance_nil require_equal_zero require_len_zero"}
 
 function test_golangci_lint {
   go install -v github.com/golangci/golangci-lint/cmd/golangci-lint@v1.51.2
@@ -75,6 +75,15 @@ function test_require_equal_zero {
   fi
 }
 
+function test_require_len_zero {
+  if grep -R -o -P 'require\.Len\((t, )?.+, 0(,|\))' .; then
+    echo ""
+    echo "Use require.Empty instead of require.Len when testing for 0 length."
+    echo ""
+    return 1
+  fi
+}
+
 # Ref: https://go.dev/doc/effective_go#blank_implements
 function test_interface_compliance_nil {
   if grep -R -o -P '_ .+? = &.+?\{\}' .; then

snow/consensus/snowman/poll/set_test.go

@@ -76,17 +76,17 @@ func TestCreateAndFinishPollOutOfOrder_NewerFinishesFirst(t *testing.T) {
 
 	// vote out of order
 	results = s.Vote(1, vdr1, vtx1)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 	results = s.Vote(2, vdr2, vtx2)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 	results = s.Vote(2, vdr3, vtx2)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 
 	results = s.Vote(2, vdr1, vtx2) // poll 2 finished
-	require.Len(t, results, 0)      // expect 2 to not have finished because 1 is still pending
+	require.Empty(t, results)       // expect 2 to not have finished because 1 is still pending
 
 	results = s.Vote(1, vdr2, vtx1)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 
 	results = s.Vote(1, vdr3, vtx1) // poll 1 finished, poll 2 should be finished as well
 	require.Len(t, results, 2)
@@ -129,14 +129,14 @@ func TestCreateAndFinishPollOutOfOrder_OlderFinishesFirst(t *testing.T) {
 
 	// vote out of order
 	results = s.Vote(1, vdr1, vtx1)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 	results = s.Vote(2, vdr2, vtx2)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 	results = s.Vote(2, vdr3, vtx2)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 
 	results = s.Vote(1, vdr2, vtx1)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 
 	results = s.Vote(1, vdr3, vtx1) // poll 1 finished, poll 2 still remaining
 	require.Len(t, results, 1)      // because 1 is the oldest
@@ -190,25 +190,25 @@ func TestCreateAndFinishPollOutOfOrder_UnfinishedPollsGaps(t *testing.T) {
 	// vote out of order
 	// 2 finishes first to create a gap of finished poll between two unfinished polls 1 and 3
 	results = s.Vote(2, vdr3, vtx2)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 	results = s.Vote(2, vdr2, vtx2)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 	results = s.Vote(2, vdr1, vtx2)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 
 	// 3 finishes now, 2 has already finished but 1 is not finished so we expect to receive no results still
 	results = s.Vote(3, vdr2, vtx3)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 	results = s.Vote(3, vdr3, vtx3)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 	results = s.Vote(3, vdr1, vtx3)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 
 	// 1 finishes now, 2 and 3 have already finished so we expect 3 items in results
 	results = s.Vote(1, vdr1, vtx1)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 	results = s.Vote(1, vdr2, vtx1)
-	require.Len(t, results, 0)
+	require.Empty(t, results)
 	results = s.Vote(1, vdr3, vtx1)
 	require.Len(t, results, 3)
 	require.Equal(t, vtx1, results[0].List()[0])

snow/engine/snowman/block/batched_vm_test.go

@@ -27,7 +27,7 @@ func TestGetAncestorsDatabaseNotFound(t *testing.T) {
 	}
 	containers, err := GetAncestors(context.Background(), vm, someID, 10, 10, 1*time.Second)
 	require.NoError(t, err)
-	require.Len(t, containers, 0)
+	require.Empty(t, containers)
 }
 
 // TestGetAncestorsPropagatesErrors checks errors other than

snow/networking/benchlist/benchlist_test.go

@@ -72,7 +72,7 @@ func TestBenchlistAdd(t *testing.T) {
 	require.False(t, b.isBenched(vdrID2))
 	require.False(t, b.isBenched(vdrID3))
 	require.False(t, b.isBenched(vdrID4))
-	require.Len(t, b.failureStreaks, 0)
+	require.Empty(t, b.failureStreaks)
 	require.Zero(t, b.benchedQueue.Len())
 	require.Zero(t, b.benchlistSet.Len())
 	b.lock.Unlock()
@@ -126,7 +126,7 @@ func TestBenchlistAdd(t *testing.T) {
 	require.Equal(t, vdrID0, next.nodeID)
 	require.True(t, !next.benchedUntil.After(now.Add(duration)))
 	require.True(t, !next.benchedUntil.Before(now.Add(duration/2)))
-	require.Len(t, b.failureStreaks, 0)
+	require.Empty(t, b.failureStreaks)
 	require.True(t, benched)
 	benchable.BenchedF = nil
 	b.lock.Unlock()
@@ -146,15 +146,15 @@ func TestBenchlistAdd(t *testing.T) {
 	require.False(t, b.isBenched(vdrID1))
 	require.Equal(t, b.benchedQueue.Len(), 1)
 	require.Equal(t, b.benchlistSet.Len(), 1)
-	require.Len(t, b.failureStreaks, 0)
+	require.Empty(t, b.failureStreaks)
 	b.lock.Unlock()
 
 	// Register another failure for vdr0, who is benched
 	b.RegisterFailure(vdrID0)
 
 	// A failure for an already benched validator should not count against it
 	b.lock.Lock()
-	require.Len(t, b.failureStreaks, 0)
+	require.Empty(t, b.failureStreaks)
 	b.lock.Unlock()
 }
 
@@ -369,7 +369,7 @@ func TestBenchlistRemove(t *testing.T) {
 	require.True(t, b.isBenched(vdrID2))
 	require.Equal(t, 3, b.benchedQueue.Len())
 	require.Equal(t, 3, b.benchlistSet.Len())
-	require.Len(t, b.failureStreaks, 0)
+	require.Empty(t, b.failureStreaks)
 
 	// Ensure the benched queue root has the min end time
 	minEndTime := b.benchedQueue[0].benchedUntil