golangci-lint: add copyloopvar linter and auto-fixes (#18829)

Signed-off-by: Tim Vaillancourt <[email protected]>

Author: timvaillancourt

.golangci.yml

@@ -5,6 +5,7 @@ linters:
   default: none
   enable:
     - bodyclose
+    - copyloopvar
     - depguard
     - errcheck
     - govet

go/cmd/zk/internal/zkfs/zkfs_test.go

@@ -75,7 +75,7 @@ func TestFormatACL(t *testing.T) {
 	}
 
 	for _, tc := range testCases {
-		tc := tc
+
 		t.Run(tc.name, func(t *testing.T) {
 			assert.Equal(t, tc.expected, FormatACL(tc.acl))
 		})

go/test/endtoend/vtgate/foreignkey/stress/fk_stress_test.go

@@ -473,7 +473,7 @@ func waitForReplicationCatchup(t *testing.T) {
 	primaryPos := getTabletPosition(t, primary)
 	var wg sync.WaitGroup
 	for _, replica := range []*cluster.Vttablet{replicaNoFK, replicaFK} {
-		replica := replica
+
 		wg.Add(1)
 		go func() {
 			waitForReplicaCatchup(t, ctx, replica, primaryPos)

go/vt/mysqlctl/schema.go

@@ -114,7 +114,6 @@ func (mysqld *Mysqld) GetSchema(ctx context.Context, dbName string, request *tab
 	tableNames := make([]string, 0, len(tds))
 	for _, td := range tds {
 		tableNames = append(tableNames, td.Name)
-		td := td
 
 		eg.Go(func() error {
 			fields, columns, schema, err := mysqld.collectSchema(ctx, dbName, td.Name, td.Type, request.TableSchemaOnly)

go/vt/topo/keyspace.go

@@ -301,7 +301,6 @@ func (ts *Server) FindAllShardsInKeyspace(ctx context.Context, keyspace string,
 	eg.SetLimit(int(opt.Concurrency))
 
 	for _, shard := range shards {
-		shard := shard
 
 		eg.Go(func() error {
 			si, err := ts.GetShard(ctx, keyspace, shard)

go/vt/topo/shard_test.go

@@ -350,7 +350,7 @@ func TestValidateShardName(t *testing.T) {
 	}
 
 	for _, tcase := range cases {
-		tcase := tcase
+
 		t.Run(tcase.name, func(t *testing.T) {
 			t.Parallel()
 

go/vt/topo/topoproto/tablet_test.go

@@ -118,10 +118,6 @@ func TestIsTabletsInList(t *testing.T) {
 	}
 
 	for _, testcase := range testcases {
-		// We create an explicit copy of the range variable for each parallel runner
-		// to be sure that they each run as expected. You can see more information on
-		// this here: https://pkg.go.dev/testing#hdr-Subtests_and_Sub_benchmarks
-		testcase := testcase
 		t.Run(testcase.name, func(t *testing.T) {
 			t.Parallel()
 			out := IsTabletInList(testcase.tablet, testcase.allTablets)

go/vt/vtadmin/cluster/cluster_test.go

@@ -1694,7 +1694,7 @@ func TestGetSchema(t *testing.T) {
 	ctx := context.Background()
 
 	for i, tt := range tests {
-		i := i
+
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 

go/vt/vtadmin/http/api_test.go

@@ -72,7 +72,7 @@ func TestDeprecateQueryParam(t *testing.T) {
 	}
 
 	for _, tcase := range cases {
-		tcase := tcase
+
 		t.Run("", func(t *testing.T) {
 			query := url.Values(tcase.in)
 

go/vt/vtadmin/http/handlers/panic_recovery_test.go

@@ -55,7 +55,7 @@ func TestPanicRecoveryHandler(t *testing.T) {
 	}
 
 	for _, tcase := range cases {
-		tcase := tcase
+
 		t.Run(tcase.route, func(t *testing.T) {
 			rec := httptest.ResponseRecorder{
 				Body: bytes.NewBuffer(nil),