les/api.go: bad loop var capture #24755
Description
Describe the bug
we use tool scopelint to scan this repo, and find some warnings.
In les/api.go: 258-310 line:
loop var is used in some anonymous functions, and these anonymous functions will be executed after the whole loop iteration.
but they always only use the last element in the loop instead of all of them.
benchmarks := make([]requestBenchmark, len(setups))
for i, setup := range setups {
if t, ok := setup["type"].(string); ok {
getInt := func(field string, def int) int {
if value, ok := setup[field].(float64); ok {
return int(value)
}
return def
}
getBool := func(field string, def bool) bool {
if value, ok := setup[field].(bool); ok {
return value
}
return def
}
switch t {
case "header":
benchmarks[i] = &benchmarkBlockHeaders{
amount: getInt("amount", 1),
skip: getInt("skip", 1),
byHash: getBool("byHash", false),
reverse: getBool("reverse", false),
}
case "body":
benchmarks[i] = &benchmarkBodiesOrReceipts{receipts: false}
case "receipts":
benchmarks[i] = &benchmarkBodiesOrReceipts{receipts: true}
case "proof":
benchmarks[i] = &benchmarkProofsOrCode{code: false}
case "code":
benchmarks[i] = &benchmarkProofsOrCode{code: true}
case "cht":
benchmarks[i] = &benchmarkHelperTrie{
bloom: false,
reqCount: getInt("amount", 1),
}
case "bloom":
benchmarks[i] = &benchmarkHelperTrie{
bloom: true,
reqCount: getInt("amount", 1),
}
case "txSend":
benchmarks[i] = &benchmarkTxSend{}
case "txStatus":
benchmarks[i] = &benchmarkTxStatus{}
default:
return nil, errUnknownBenchmarkType
}
} else {
return nil, errUnknownBenchmarkType
}
}
rs := api.server.handler.runBenchmark(benchmarks, passCount, time.Millisecond*time.Duration(length))
Expected behavior
value of loop var is different value from each iteration when getInt/getBool is called instead of a single value.
how to fix it
benchmarks := make([]requestBenchmark, len(setups))
for i, setup := range setups {
setup := setup // add this line
if t, ok := setup["type"].(string); ok {
getInt := func(field string, def int) int {
if value, ok := setup[field].(float64); ok {
return int(value)
}
return def
}
getBool := func(field string, def bool) bool {
if value, ok := setup[field].(bool); ok {
return value
}
return def
}
switch t {
case "header":
benchmarks[i] = &benchmarkBlockHeaders{
amount: getInt("amount", 1),
skip: getInt("skip", 1),
byHash: getBool("byHash", false),
reverse: getBool("reverse", false),
}
case "body":
benchmarks[i] = &benchmarkBodiesOrReceipts{receipts: false}
case "receipts":
benchmarks[i] = &benchmarkBodiesOrReceipts{receipts: true}
case "proof":
benchmarks[i] = &benchmarkProofsOrCode{code: false}
case "code":
benchmarks[i] = &benchmarkProofsOrCode{code: true}
case "cht":
benchmarks[i] = &benchmarkHelperTrie{
bloom: false,
reqCount: getInt("amount", 1),
}
case "bloom":
benchmarks[i] = &benchmarkHelperTrie{
bloom: true,
reqCount: getInt("amount", 1),
}
case "txSend":
benchmarks[i] = &benchmarkTxSend{}
case "txStatus":
benchmarks[i] = &benchmarkTxStatus{}
default:
return nil, errUnknownBenchmarkType
}
} else {
return nil, errUnknownBenchmarkType
}
}
rs := api.server.handler.runBenchmark(benchmarks, passCount, time.Millisecond*time.Duration(length))