chore: fix potential nil pointer errors (#3454)

core/iox/bufferpool.go

@@ -32,6 +32,10 @@ func (bp *BufferPool) Get() *bytes.Buffer {
 
 // Put returns buf into bp.
 func (bp *BufferPool) Put(buf *bytes.Buffer) {
+	if buf == nil {
+		return
+	}
+
 	if buf.Cap() < bp.capability {
 		bp.pool.Put(buf)
 	}

core/iox/bufferpool_test.go

@@ -13,3 +13,26 @@ func TestBufferPool(t *testing.T) {
 	pool.Put(bytes.NewBuffer(make([]byte, 0, 2*capacity)))
 	assert.True(t, pool.Get().Cap() <= capacity)
 }
+
+func TestBufferPool_Put(t *testing.T) {
+	t.Run("with nil buf", func(t *testing.T) {
+		pool := NewBufferPool(1024)
+		pool.Put(nil)
+		val := pool.Get()
+		assert.IsType(t, new(bytes.Buffer), val)
+	})
+
+	t.Run("with less-cap buf", func(t *testing.T) {
+		pool := NewBufferPool(1024)
+		pool.Put(bytes.NewBuffer(make([]byte, 0, 512)))
+		val := pool.Get()
+		assert.IsType(t, new(bytes.Buffer), val)
+	})
+
+	t.Run("with more-cap buf", func(t *testing.T) {
+		pool := NewBufferPool(1024)
+		pool.Put(bytes.NewBuffer(make([]byte, 0, 1024<<1)))
+		val := pool.Get()
+		assert.IsType(t, new(bytes.Buffer), val)
+	})
+}

core/mapping/unmarshaler.go

@@ -878,7 +878,7 @@ func (u *Unmarshaler) processNamedFieldWithoutValue(fieldType reflect.Type, valu
 
 func (u *Unmarshaler) unmarshalWithFullName(m valuerWithParent, v any, fullName string) error {
 	rv := reflect.ValueOf(v)
-	if err := ValidatePtr(&rv); err != nil {
+	if err := ValidatePtr(rv); err != nil {
 		return err
 	}
 

core/mapping/utils.go

@@ -79,7 +79,7 @@ func SetMapIndexValue(tp reflect.Type, value, key, target reflect.Value) {
 }
 
 // ValidatePtr validates v if it's a valid pointer.
-func ValidatePtr(v *reflect.Value) error {
+func ValidatePtr(v reflect.Value) error {
 	// sequence is very important, IsNil must be called after checking Kind() with reflect.Ptr,
 	// panic otherwise
 	if !v.IsValid() || v.Kind() != reflect.Ptr || v.IsNil() {

core/mapping/utils_test.go

@@ -218,25 +218,25 @@ func TestParseSegments(t *testing.T) {
 func TestValidatePtrWithNonPtr(t *testing.T) {
 	var foo string
 	rve := reflect.ValueOf(foo)
-	assert.NotNil(t, ValidatePtr(&rve))
+	assert.NotNil(t, ValidatePtr(rve))
 }
 
 func TestValidatePtrWithPtr(t *testing.T) {
 	var foo string
 	rve := reflect.ValueOf(&foo)
-	assert.Nil(t, ValidatePtr(&rve))
+	assert.Nil(t, ValidatePtr(rve))
 }
 
 func TestValidatePtrWithNilPtr(t *testing.T) {
 	var foo *string
 	rve := reflect.ValueOf(foo)
-	assert.NotNil(t, ValidatePtr(&rve))
+	assert.NotNil(t, ValidatePtr(rve))
 }
 
 func TestValidatePtrWithZeroValue(t *testing.T) {
 	var s string
 	e := reflect.Zero(reflect.TypeOf(s))
-	assert.NotNil(t, ValidatePtr(&e))
+	assert.NotNil(t, ValidatePtr(e))
 }
 
 func TestSetValueNotSettable(t *testing.T) {

core/stores/sqlx/orm.go

@@ -146,7 +146,7 @@ func unmarshalRow(v any, scanner rowsScanner, strict bool) error {
 	}
 
 	rv := reflect.ValueOf(v)
-	if err := mapping.ValidatePtr(&rv); err != nil {
+	if err := mapping.ValidatePtr(rv); err != nil {
 		return err
 	}
 
@@ -182,7 +182,7 @@ func unmarshalRow(v any, scanner rowsScanner, strict bool) error {
 
 func unmarshalRows(v any, scanner rowsScanner, strict bool) error {
 	rv := reflect.ValueOf(v)
-	if err := mapping.ValidatePtr(&rv); err != nil {
+	if err := mapping.ValidatePtr(rv); err != nil {
 		return err
 	}
 

core/trace/agent.go

@@ -26,6 +26,7 @@ const (
 	kindOtlpGrpc = "otlpgrpc"
 	kindOtlpHttp = "otlphttp"
 	kindFile     = "file"
+	protocolUdp  = "udp"
 )
 
 var (
@@ -65,9 +66,10 @@ func createExporter(c Config) (sdktrace.SpanExporter, error) {
 	// Just support jaeger and zipkin now, more for later
 	switch c.Batcher {
 	case kindJaeger:
-		u, _ := url.Parse(c.Endpoint)
+		u, err := url.Parse(c.Endpoint)
-		if u.Scheme == "udp" {
+		if err == nil && u.Scheme == protocolUdp {
-			return jaeger.New(jaeger.WithAgentEndpoint(jaeger.WithAgentHost(u.Hostname()), jaeger.WithAgentPort(u.Port())))
+			return jaeger.New(jaeger.WithAgentEndpoint(jaeger.WithAgentHost(u.Hostname()),
+				jaeger.WithAgentPort(u.Port())))
 		}
 		return jaeger.New(jaeger.WithCollectorEndpoint(jaeger.WithEndpoint(c.Endpoint)))
 	case kindZipkin: