lint: errcheck (tendermint#5091)

## Description

add more error checks to tests


gonna do a third PR that tackles the non test cases

CHANGELOG_PENDING.md

@@ -55,7 +55,7 @@ Friendly reminder, we have a [bug bounty program](https://hackerone.com/tendermi
   - [crypto] [\#4721](https://github.com/tendermint/tendermint/pull/4721) Remove `SimpleHashFromMap()` and `SimpleProofsFromMap()` (@erikgrinaker)
   - [crypto] \#4940 All keys have become `[]byte` instead of `[<size>]byte`. The byte method no longer returns the marshaled value but just the `[]byte` form of the data.
   - [crypto] \4988 Removal of key type multisig
-    - The key has been moved to the Cosmos-SDK (https://github.com/cosmos/cosmos-sdk/blob/master/crypto/types/multisig/multisignature.go)
+    - The key has been moved to the [Cosmos-SDK](https://github.com/cosmos/cosmos-sdk/blob/master/crypto/types/multisig/multisignature.go)
   - [crypto] \#4989 Remove `Simple` prefixes from `SimpleProof`, `SimpleValueOp` & `SimpleProofNode`.
     - `merkle.Proof` has been renamed to `ProofOps`.
     - Protobuf messages `Proof` & `ProofOp` has been moved to `proto/crypto/merkle`

abci/client/socket_client.go

@@ -295,80 +295,119 @@ func (cli *socketClient) FlushSync() error {
 
 func (cli *socketClient) EchoSync(msg string) (*types.ResponseEcho, error) {
 	reqres := cli.queueRequest(types.ToRequestEcho(msg))
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetEcho(), cli.Error()
 }
 
 func (cli *socketClient) InfoSync(req types.RequestInfo) (*types.ResponseInfo, error) {
 	reqres := cli.queueRequest(types.ToRequestInfo(req))
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetInfo(), cli.Error()
 }
 
 func (cli *socketClient) SetOptionSync(req types.RequestSetOption) (*types.ResponseSetOption, error) {
 	reqres := cli.queueRequest(types.ToRequestSetOption(req))
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetSetOption(), cli.Error()
 }
 
 func (cli *socketClient) DeliverTxSync(req types.RequestDeliverTx) (*types.ResponseDeliverTx, error) {
 	reqres := cli.queueRequest(types.ToRequestDeliverTx(req))
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetDeliverTx(), cli.Error()
 }
 
 func (cli *socketClient) CheckTxSync(req types.RequestCheckTx) (*types.ResponseCheckTx, error) {
 	reqres := cli.queueRequest(types.ToRequestCheckTx(req))
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetCheckTx(), cli.Error()
 }
 
 func (cli *socketClient) QuerySync(req types.RequestQuery) (*types.ResponseQuery, error) {
 	reqres := cli.queueRequest(types.ToRequestQuery(req))
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetQuery(), cli.Error()
 }
 
 func (cli *socketClient) CommitSync() (*types.ResponseCommit, error) {
 	reqres := cli.queueRequest(types.ToRequestCommit())
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetCommit(), cli.Error()
 }
 
 func (cli *socketClient) InitChainSync(req types.RequestInitChain) (*types.ResponseInitChain, error) {
 	reqres := cli.queueRequest(types.ToRequestInitChain(req))
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetInitChain(), cli.Error()
 }
 
 func (cli *socketClient) BeginBlockSync(req types.RequestBeginBlock) (*types.ResponseBeginBlock, error) {
 	reqres := cli.queueRequest(types.ToRequestBeginBlock(req))
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetBeginBlock(), cli.Error()
 }
 
 func (cli *socketClient) EndBlockSync(req types.RequestEndBlock) (*types.ResponseEndBlock, error) {
 	reqres := cli.queueRequest(types.ToRequestEndBlock(req))
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetEndBlock(), cli.Error()
 }
 
 func (cli *socketClient) ListSnapshotsSync(req types.RequestListSnapshots) (*types.ResponseListSnapshots, error) {
 	reqres := cli.queueRequest(types.ToRequestListSnapshots(req))
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetListSnapshots(), cli.Error()
 }
 
 func (cli *socketClient) OfferSnapshotSync(req types.RequestOfferSnapshot) (*types.ResponseOfferSnapshot, error) {
 	reqres := cli.queueRequest(types.ToRequestOfferSnapshot(req))
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetOfferSnapshot(), cli.Error()
 }
 
 func (cli *socketClient) LoadSnapshotChunkSync(
 	req types.RequestLoadSnapshotChunk) (*types.ResponseLoadSnapshotChunk, error) {
 	reqres := cli.queueRequest(types.ToRequestLoadSnapshotChunk(req))
-	cli.FlushSync()
+	if err := cli.FlushSync(); err != nil {
+		return nil, err
+	}
+
 	return reqres.Response.GetLoadSnapshotChunk(), cli.Error()
 }
 

abci/client/socket_client_test.go

@@ -43,14 +43,23 @@ func TestProperSyncCalls(t *testing.T) {
 	app := slowApp{}
 
 	s, c := setupClientServer(t, app)
-	defer s.Stop()
-	defer c.Stop()
+	t.Cleanup(func() {
+		if err := s.Stop(); err != nil {
+			t.Error(err)
+		}
+	})
+	t.Cleanup(func() {
+		if err := c.Stop(); err != nil {
+			t.Error(err)
+		}
+	})
 
 	resp := make(chan error, 1)
 	go func() {
 		// This is BeginBlockSync unrolled....
 		reqres := c.BeginBlockAsync(types.RequestBeginBlock{})
-		c.FlushSync()
+		err := c.FlushSync()
+		require.NoError(t, err)
 		res := reqres.Response.GetBeginBlock()
 		require.NotNil(t, res)
 		resp <- c.Error()
@@ -69,8 +78,16 @@ func TestHangingSyncCalls(t *testing.T) {
 	app := slowApp{}
 
 	s, c := setupClientServer(t, app)
-	defer s.Stop()
-	defer c.Stop()
+	t.Cleanup(func() {
+		if err := s.Stop(); err != nil {
+			t.Log(err)
+		}
+	})
+	t.Cleanup(func() {
+		if err := c.Stop(); err != nil {
+			t.Log(err)
+		}
+	})
 
 	resp := make(chan error, 1)
 	go func() {
@@ -81,7 +98,8 @@ func TestHangingSyncCalls(t *testing.T) {
 		// no response yet from server
 		time.Sleep(20 * time.Millisecond)
 		// kill the server, so the connections break
-		s.Stop()
+		err := s.Stop()
+		require.NoError(t, err)
 
 		// wait for the response from BeginBlock
 		reqres.Wait()

abci/cmd/abci-cli/abci-cli.go

@@ -642,7 +642,9 @@ func cmdCounter(cmd *cobra.Command, args []string) error {
 	// Stop upon receiving SIGTERM or CTRL-C.
 	tmos.TrapSignal(logger, func() {
 		// Cleanup
-		srv.Stop()
+		if err := srv.Stop(); err != nil {
+			logger.Error("Error while stopping server", "err", err)
+		}
 	})
 
 	// Run forever.
@@ -674,7 +676,9 @@ func cmdKVStore(cmd *cobra.Command, args []string) error {
 	// Stop upon receiving SIGTERM or CTRL-C.
 	tmos.TrapSignal(logger, func() {
 		// Cleanup
-		srv.Stop()
+		if err := srv.Stop(); err != nil {
+			logger.Error("Error while stopping server", "err", err)
+		}
 	})
 
 	// Run forever.

abci/example/example_test.go

@@ -56,15 +56,23 @@ func testStream(t *testing.T, app types.Application) {
 	if err := server.Start(); err != nil {
 		require.NoError(t, err, "Error starting socket server")
 	}
-	defer server.Stop() //nolint:errcheck // ignore for tests
+	t.Cleanup(func() {
+		if err := server.Stop(); err != nil {
+			t.Error(err)
+		}
+	})
 
 	// Connect to the socket
 	client := abcicli.NewSocketClient(socket, false)
 	client.SetLogger(log.TestingLogger().With("module", "abci-client"))
 	if err := client.Start(); err != nil {
 		t.Fatalf("Error starting socket client: %v", err.Error())
 	}
-	defer client.Stop() //nolint:errcheck // ignore for tests
+	t.Cleanup(func() {
+		if err := client.Stop(); err != nil {
+			t.Error(err)
+		}
+	})
 
 	done := make(chan struct{})
 	counter := 0
@@ -132,14 +140,24 @@ func testGRPCSync(t *testing.T, app types.ABCIApplicationServer) {
 	if err := server.Start(); err != nil {
 		t.Fatalf("Error starting GRPC server: %v", err.Error())
 	}
-	defer server.Stop() //nolint:errcheck // ignore for tests
+
+	t.Cleanup(func() {
+		if err := server.Stop(); err != nil {
+			t.Error(err)
+		}
+	})
 
 	// Connect to the socket
 	conn, err := grpc.Dial(socket, grpc.WithInsecure(), grpc.WithContextDialer(dialerFunc))
 	if err != nil {
 		t.Fatalf("Error dialing GRPC server: %v", err.Error())
 	}
-	defer conn.Close()
+
+	t.Cleanup(func() {
+		if err := conn.Close(); err != nil {
+			t.Error(err)
+		}
+	})
 
 	client := types.NewABCIApplicationClient(conn)
 

abci/example/kvstore/kvstore_test.go

@@ -278,17 +278,34 @@ func TestClientServer(t *testing.T) {
 	kvstore := NewApplication()
 	client, server, err := makeSocketClientServer(kvstore, "kvstore-socket")
 	require.NoError(t, err)
-	defer server.Stop() //nolint:errcheck // ignore for tests
-	defer client.Stop() //nolint:errcheck // ignore for tests
+	t.Cleanup(func() {
+		if err := server.Stop(); err != nil {
+			t.Error(err)
+		}
+	})
+	t.Cleanup(func() {
+		if err := client.Stop(); err != nil {
+			t.Error(err)
+		}
+	})
 
 	runClientTests(t, client)
 
 	// set up grpc app
 	kvstore = NewApplication()
 	gclient, gserver, err := makeGRPCClientServer(kvstore, "kvstore-grpc")
 	require.NoError(t, err)
-	defer gserver.Stop() //nolint:errcheck // ignore for tests
-	defer gclient.Stop() //nolint:errcheck // ignore for tests
+
+	t.Cleanup(func() {
+		if err := gserver.Stop(); err != nil {
+			t.Error(err)
+		}
+	})
+	t.Cleanup(func() {
+		if err := gclient.Stop(); err != nil {
+			t.Error(err)
+		}
+	})
 
 	runClientTests(t, gclient)
 }

blockchain/v0/pool_test.go

@@ -90,7 +90,11 @@ func TestBlockPoolBasic(t *testing.T) {
 		t.Error(err)
 	}
 
-	defer pool.Stop()
+	t.Cleanup(func() {
+		if err := pool.Stop(); err != nil {
+			t.Error(err)
+		}
+	})
 
 	peers.start()
 	defer peers.stop()
@@ -144,7 +148,11 @@ func TestBlockPoolTimeout(t *testing.T) {
 	if err != nil {
 		t.Error(err)
 	}
-	defer pool.Stop()
+	t.Cleanup(func() {
+		if err := pool.Stop(); err != nil {
+			t.Error(err)
+		}
+	})
 
 	for _, peer := range peers {
 		t.Logf("Peer %v", peer.id)
@@ -206,7 +214,11 @@ func TestBlockPoolRemovePeer(t *testing.T) {
 	pool.SetLogger(log.TestingLogger())
 	err := pool.Start()
 	require.NoError(t, err)
-	defer pool.Stop()
+	t.Cleanup(func() {
+		if err := pool.Stop(); err != nil {
+			t.Error(err)
+		}
+	})
 
 	// add peers
 	for peerID, peer := range peers {

blockchain/v2/reactor_test.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	dbm "github.com/tendermint/tm-db"
 
 	abci "github.com/tendermint/tendermint/abci/types"
@@ -387,7 +388,8 @@ func TestReactorHelperMode(t *testing.T) {
 			reactor := newTestReactor(params)
 			mockSwitch := &mockSwitchIo{switchedToConsensus: false}
 			reactor.io = mockSwitch
-			reactor.Start()
+			err := reactor.Start()
+			require.NoError(t, err)
 
 			for i := 0; i < len(tt.msgs); i++ {
 				step := tt.msgs[i]
@@ -415,7 +417,8 @@ func TestReactorHelperMode(t *testing.T) {
 					}
 				}
 			}
-			reactor.Stop()
+			err = reactor.Stop()
+			require.NoError(t, err)
 		})
 	}
 }