GateIO: Update API fields due to widespread upgrade (thrasher-corp#2158)

* fix: update Gate.io websocket handling for size and amount conversions

- Added "X-Gate-Size-Decimal" header in the websocket connection for spot trading.
- Updated futures and options processing to convert sizes and amounts to float64 where necessary.
- Ensured consistency in handling size and amount across various functions in the Gate.io exchange wrapper.

* rm verbosity

* docs: Update type usage guidelines for API number handling due to benchmarks below

`types.Number` vs `float64` with `,string` — benchmark findings

Benchmarked at count=100 on AMD Ryzen 7 5800X (Windows, amd64):

| Field type | Avg ns/op | B/op | allocs/op |
|---|---|---|---|
| `float64` (bare number) | ~414 | 216 | 4 |
| `types.Number` (quoted string) | ~403 | 216 | 4 |
| `float64` + `,string` tag (quoted string) | ~506 | 264 | **7** |

`types.Number` is identical in cost to a bare `float64` — the custom `UnmarshalJSON` allocates nothing of its own (the compiler eliminates the `string(data)` conversion in `strconv.ParseFloat`). By contrast, `float64` with `,string` is ~25% slower and produces 3 extra allocations and 48 extra bytes per decode due to the stdlib reflection path it takes.

+**Calling `.Float64()` on a `types.Number` field is optional** — `types.Number` is defined as `type Number float64`, so a direct conversion `float64(n)` or storing it as `types.Number` and passing it where a `float64` is needed are both zero-cost. `.Float64()` is a convenience accessor and may be omitted when the call site already works with `types.Number` directly.

* glorious: don't send header down the spot connection, mv it to the futures connection

* crank/glorious: nits

* thrasher-:nits

* glorious: nits in your head

* Update exchanges/gateio/gateio_test.go

Co-authored-by: Adrian Gallagher <adrian.gallagher@thrasher.io>

* Update exchanges/gateio/gateio_test.go

Co-authored-by: Adrian Gallagher <adrian.gallagher@thrasher.io>

* Update exchanges/gateio/gateio_test.go

Co-authored-by: Adrian Gallagher <adrian.gallagher@thrasher.io>

* gate f usage

---------

Co-authored-by: Ryan O'Hara-Reid <ryan.oharareid@thrasher.io>
Co-authored-by: Adrian Gallagher <adrian.gallagher@thrasher.io>

Author: 3 people

docs/CODING_GUIDELINES.md

@@ -22,11 +22,9 @@ Refer to the [ADD_NEW_EXCHANGE.md](/docs/ADD_NEW_EXCHANGE.md) document for compr
 ### Type Usage
 
 - Use the most appropriate native Go types for struct fields:
-  - If the API returns numbers as strings, use float64 with the `json:",string"` tag.
-  - For timestamps, use `time.Time` if Go's JSON unmarshalling supports the format directly.
-- If native Go types are not supported directly, use the following built-in types:
-  - `types.Time` for Unix timestamps that require custom unmarshalling.
-  - `types.Number` for numerical float values where an exchange API may return either a `string` or `float64` value.
+  - If the API always returns a number as a bare JSON number, use `float64`.
+  - If the API returns a number as a quoted JSON string, or may return either a string or a bare number, use `types.Number` — **do not** use `float64` with the `json:",string"` tag.
+  - For timestamps, use `time.Time` if Go's JSON unmarshalling supports the format directly; otherwise use `types.Time` for Unix timestamps that require custom unmarshalling.
 - Always use full and descriptive field names for clarity and consistency. Avoid short API-provided aliases unless compatibility requires it.
 - Default to `uint64` for exchange API parameters and structs for integers where appropriate.
   - Avoid `int` (size varies by architecture) or `int64` (allows negatives where they don't make sense).
@@ -112,13 +110,27 @@ Use `require` and `assert` appropriately:
 
 - Use when test flow depends on the result.
 - Messages must contain **"must"** (e.g., "response must not be nil").
-- Use the *f* variants when using format specifiers (e.g., `require.Equalf`).
 
 #### assert
 
 - Use when the test can proceed regardless of the check.
 - Messages must contain **"should"** (e.g., "status code should be 200").
-- Use `assert.Equalf`, etc., when applicable.
+
+#### `f` variants (`assert.ErrorIsf`, `require.NoErrorf`, etc.)
+
+- Only use `f` variants when the message contains **format verbs** (e.g., `%s`, `%d`, `%v`).
+- If the message is a plain string with no format verbs, use the non-`f` variant.
+
+```go
+    // Correct — format verb %s requires the f variant:
+    assert.NoErrorf(t, err, "UpdateAccountInfo should not error for asset %s", a)
+
+    // Correct — plain message, no format verbs:
+    assert.ErrorIs(t, err, errInvalidOrderSize, "validate should return expected error")
+
+    // Wrong — f variant used without format verbs:
+    assert.ErrorIsf(t, err, errInvalidOrderSize, "validate should return expected error")
+```
 
 ### Test Coverage
 

exchanges/gateio/gateio.go

@@ -933,6 +933,7 @@ func (e *Exchange) SendAuthenticatedHTTPRequest(ctx context.Context, ep exchange
 		headers["TIMESTAMP"] = strconv.FormatInt(timestamp.Unix(), 10)
 		headers["Accept"] = "application/json"
 		headers["SIGN"] = sig
+		headers["X-Gate-Size-Decimal"] = "1"
 		urlPath = ePoint + urlPath
 		if param != nil {
 			urlPath = common.EncodeURLValues(urlPath, param)
@@ -993,6 +994,7 @@ func (e *Exchange) SendHTTPRequest(ctx context.Context, ep exchange.URL, epl req
 		HTTPDebugging:          e.HTTPDebugging,
 		HTTPRecording:          e.HTTPRecording,
 		HTTPMockDataSliceLimit: e.HTTPMockDataSliceLimit,
+		Headers:                map[string]string{"X-Gate-Size-Decimal": "1"},
 	}
 	return e.SendPayload(ctx, epl, func() (*request.Item, error) {
 		return item, nil
@@ -1220,12 +1222,12 @@ func (e *Exchange) GetWithdrawalStatus(ctx context.Context, ccy currency.Code) (
 }
 
 // GetSubAccountBalances retrieve sub account balances
-func (e *Exchange) GetSubAccountBalances(ctx context.Context, subAccountUserID string) ([]FuturesSubAccountBalance, error) {
+func (e *Exchange) GetSubAccountBalances(ctx context.Context, subAccountUserID string) ([]SubAccountBalance, error) {
 	params := url.Values{}
 	if subAccountUserID != "" {
 		params.Set("sub_uid", subAccountUserID)
 	}
-	var response []FuturesSubAccountBalance
+	var response []SubAccountBalance
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, walletSubAccountBalancesEPL, http.MethodGet, walletSubAccountBalance, params, nil, &response)
 }
 
@@ -2236,17 +2238,17 @@ func (e *Exchange) UpdatePositionLeverageInDualMode(ctx context.Context, settle
 // Set reduce_only to true can keep the position from changing side when reducing position size
 // In single position mode, to close a position, you need to set size to 0 and close to true
 // In dual position mode, to close one side position, you need to set auto_size side, reduce_only to true and size to 0
-func (e *Exchange) PlaceFuturesOrder(ctx context.Context, arg *ContractOrderCreateParams) (*Order, error) {
+func (e *Exchange) PlaceFuturesOrder(ctx context.Context, arg *FuturesOrderCreateParams) (*FuturesOrder, error) {
 	if err := arg.validate(true); err != nil {
 		return nil, err
 	}
-	var response *Order
+	var response *FuturesOrder
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, perpetualSubmitOrderEPL, http.MethodPost, futuresPath+arg.Settle.Item.Lower+ordersPath, nil, &arg, &response)
 }
 
 // GetFuturesOrders retrieves list of futures orders
 // Zero-filled order cannot be retrieved 10 minutes after order cancellation
-func (e *Exchange) GetFuturesOrders(ctx context.Context, contract currency.Pair, status, lastID string, settle currency.Code, limit, offset uint64, countTotal bool) ([]Order, error) {
+func (e *Exchange) GetFuturesOrders(ctx context.Context, contract currency.Pair, status, lastID string, settle currency.Code, limit, offset uint64, countTotal bool) ([]FuturesOrder, error) {
 	if settle.IsEmpty() {
 		return nil, errEmptyOrInvalidSettlementCurrency
 	}
@@ -2270,13 +2272,13 @@ func (e *Exchange) GetFuturesOrders(ctx context.Context, contract currency.Pair,
 	if countTotal && status != statusOpen {
 		params.Set("count_total", "1")
 	}
-	var response []Order
+	var response []FuturesOrder
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, perpetualGetOrdersEPL, http.MethodGet, futuresPath+settle.Item.Lower+ordersPath, params, nil, &response)
 }
 
 // CancelMultipleFuturesOpenOrders ancel all open orders
 // Zero-filled order cannot be retrieved 10 minutes after order cancellation
-func (e *Exchange) CancelMultipleFuturesOpenOrders(ctx context.Context, contract currency.Pair, side string, settle currency.Code) ([]Order, error) {
+func (e *Exchange) CancelMultipleFuturesOpenOrders(ctx context.Context, contract currency.Pair, side string, settle currency.Code) ([]FuturesOrder, error) {
 	if settle.IsEmpty() {
 		return nil, errEmptyOrInvalidSettlementCurrency
 	}
@@ -2288,7 +2290,7 @@ func (e *Exchange) CancelMultipleFuturesOpenOrders(ctx context.Context, contract
 		params.Set("side", side)
 	}
 	params.Set("contract", contract.String())
-	var response []Order
+	var response []FuturesOrder
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, perpetualGetOrdersEPL, http.MethodDelete, futuresPath+settle.Item.Lower+ordersPath, params, nil, &response)
 }
 
@@ -2300,7 +2302,7 @@ func (e *Exchange) CancelMultipleFuturesOpenOrders(ctx context.Context, contract
 // In the returned result, the succeeded field of type bool indicates whether the execution was successful or not
 // If the execution is successful, the normal order content is included; if the execution fails, the label field is included to indicate the cause of the error
 // In the rate limiting, each order is counted individually
-func (e *Exchange) PlaceBatchFuturesOrders(ctx context.Context, settle currency.Code, args []ContractOrderCreateParams) ([]Order, error) {
+func (e *Exchange) PlaceBatchFuturesOrders(ctx context.Context, settle currency.Code, args []FuturesOrderCreateParams) ([]FuturesOrder, error) {
 	if settle.IsEmpty() {
 		return nil, errEmptyOrInvalidSettlementCurrency
 	}
@@ -2315,36 +2317,36 @@ func (e *Exchange) PlaceBatchFuturesOrders(ctx context.Context, settle currency.
 			return nil, fmt.Errorf("%w: %q expected %q", errEmptyOrInvalidSettlementCurrency, args[x].Settle, settle)
 		}
 	}
-	var response []Order
+	var response []FuturesOrder
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, perpetualSubmitBatchOrdersEPL, http.MethodPost, futuresPath+settle.Item.Lower+"/batch_orders", nil, &args, &response)
 }
 
 // GetSingleFuturesOrder retrieves a single order by its identifier
-func (e *Exchange) GetSingleFuturesOrder(ctx context.Context, settle currency.Code, orderID string) (*Order, error) {
+func (e *Exchange) GetSingleFuturesOrder(ctx context.Context, settle currency.Code, orderID string) (*FuturesOrder, error) {
 	if settle.IsEmpty() {
 		return nil, errEmptyOrInvalidSettlementCurrency
 	}
 	if orderID == "" {
 		return nil, fmt.Errorf("%w, 'order_id' cannot be empty", errInvalidOrderID)
 	}
-	var response *Order
+	var response *FuturesOrder
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, perpetualFetchOrderEPL, http.MethodGet, futuresPath+settle.Item.Lower+"/orders/"+orderID, nil, nil, &response)
 }
 
 // CancelSingleFuturesOrder cancel a single order
-func (e *Exchange) CancelSingleFuturesOrder(ctx context.Context, settle currency.Code, orderID string) (*Order, error) {
+func (e *Exchange) CancelSingleFuturesOrder(ctx context.Context, settle currency.Code, orderID string) (*FuturesOrder, error) {
 	if settle.IsEmpty() {
 		return nil, errEmptyOrInvalidSettlementCurrency
 	}
 	if orderID == "" {
 		return nil, fmt.Errorf("%w, 'order_id' cannot be empty", errInvalidOrderID)
 	}
-	var response *Order
+	var response *FuturesOrder
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, perpetualCancelOrderEPL, http.MethodDelete, futuresPath+settle.Item.Lower+"/orders/"+orderID, nil, nil, &response)
 }
 
 // AmendFuturesOrder amends an existing futures order
-func (e *Exchange) AmendFuturesOrder(ctx context.Context, settle currency.Code, orderID string, arg AmendFuturesOrderParam) (*Order, error) {
+func (e *Exchange) AmendFuturesOrder(ctx context.Context, settle currency.Code, orderID string, arg AmendFuturesOrderParam) (*FuturesOrder, error) {
 	if settle.IsEmpty() {
 		return nil, errEmptyOrInvalidSettlementCurrency
 	}
@@ -2354,7 +2356,7 @@ func (e *Exchange) AmendFuturesOrder(ctx context.Context, settle currency.Code,
 	if arg.Size <= 0 && arg.Price <= 0 {
 		return nil, errors.New("missing update 'size' or 'price', please specify 'size' or 'price' or both information")
 	}
-	var response *Order
+	var response *FuturesOrder
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, perpetualAmendOrderEPL, http.MethodPut, futuresPath+settle.Item.Lower+"/orders/"+orderID, nil, &arg, &response)
 }
 
@@ -2756,17 +2758,17 @@ func (e *Exchange) UpdateDeliveryPositionLeverage(ctx context.Context, settle cu
 
 // PlaceDeliveryOrder create a futures order
 // Zero-filled order cannot be retrieved 10 minutes after order cancellation
-func (e *Exchange) PlaceDeliveryOrder(ctx context.Context, arg *ContractOrderCreateParams) (*Order, error) {
+func (e *Exchange) PlaceDeliveryOrder(ctx context.Context, arg *DeliveryOrderCreateParams) (*FuturesOrder, error) {
 	if err := arg.validate(true); err != nil {
 		return nil, err
 	}
-	var response *Order
+	var response *FuturesOrder
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, deliverySubmitOrderEPL, http.MethodPost, deliveryPath+arg.Settle.Item.Lower+ordersPath, nil, &arg, &response)
 }
 
 // GetDeliveryOrders list futures orders
 // Zero-filled order cannot be retrieved 10 minutes after order cancellation
-func (e *Exchange) GetDeliveryOrders(ctx context.Context, contract currency.Pair, status string, settle currency.Code, lastID string, limit, offset uint64, countTotal bool) ([]Order, error) {
+func (e *Exchange) GetDeliveryOrders(ctx context.Context, contract currency.Pair, status string, settle currency.Code, lastID string, limit, offset uint64, countTotal bool) ([]FuturesOrder, error) {
 	if settle.IsEmpty() {
 		return nil, errEmptyOrInvalidSettlementCurrency
 	}
@@ -2790,13 +2792,13 @@ func (e *Exchange) GetDeliveryOrders(ctx context.Context, contract currency.Pair
 	if countTotal && status != statusOpen {
 		params.Set("count_total", "1")
 	}
-	var response []Order
+	var response []FuturesOrder
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, deliveryGetOrdersEPL, http.MethodGet, deliveryPath+settle.Item.Lower+ordersPath, params, nil, &response)
 }
 
 // CancelMultipleDeliveryOrders cancel all open orders matched
 // Zero-filled order cannot be retrieved 10 minutes after order cancellation
-func (e *Exchange) CancelMultipleDeliveryOrders(ctx context.Context, contract currency.Pair, side string, settle currency.Code) ([]Order, error) {
+func (e *Exchange) CancelMultipleDeliveryOrders(ctx context.Context, contract currency.Pair, side string, settle currency.Code) ([]FuturesOrder, error) {
 	if settle.IsEmpty() {
 		return nil, errEmptyOrInvalidSettlementCurrency
 	}
@@ -2808,32 +2810,32 @@ func (e *Exchange) CancelMultipleDeliveryOrders(ctx context.Context, contract cu
 		params.Set("side", side)
 	}
 	params.Set("contract", contract.String())
-	var response []Order
+	var response []FuturesOrder
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, deliveryCancelOrdersEPL, http.MethodDelete, deliveryPath+settle.Item.Lower+ordersPath, params, nil, &response)
 }
 
 // GetSingleDeliveryOrder Get a single order
 // Zero-filled order cannot be retrieved 10 minutes after order cancellation
-func (e *Exchange) GetSingleDeliveryOrder(ctx context.Context, settle currency.Code, orderID string) (*Order, error) {
+func (e *Exchange) GetSingleDeliveryOrder(ctx context.Context, settle currency.Code, orderID string) (*FuturesOrder, error) {
 	if settle.IsEmpty() {
 		return nil, errEmptyOrInvalidSettlementCurrency
 	}
 	if orderID == "" {
 		return nil, fmt.Errorf("%w, 'order_id' cannot be empty", errInvalidOrderID)
 	}
-	var response *Order
+	var response *FuturesOrder
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, deliveryGetOrderEPL, http.MethodGet, deliveryPath+settle.Item.Lower+"/orders/"+orderID, nil, nil, &response)
 }
 
 // CancelSingleDeliveryOrder cancel a single order
-func (e *Exchange) CancelSingleDeliveryOrder(ctx context.Context, settle currency.Code, orderID string) (*Order, error) {
+func (e *Exchange) CancelSingleDeliveryOrder(ctx context.Context, settle currency.Code, orderID string) (*FuturesOrder, error) {
 	if settle.IsEmpty() {
 		return nil, errEmptyOrInvalidSettlementCurrency
 	}
 	if orderID == "" {
 		return nil, fmt.Errorf("%w, 'order_id' cannot be empty", errInvalidOrderID)
 	}
-	var response *Order
+	var response *FuturesOrder
 	return response, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, deliveryCancelOrderEPL, http.MethodDelete, deliveryPath+settle.Item.Lower+"/orders/"+orderID, nil, nil, &response)
 }
 
@@ -3571,40 +3573,53 @@ func (e *Exchange) GetUserTransactionRateLimitInfo(ctx context.Context) ([]UserT
 	return resp, e.SendAuthenticatedHTTPRequest(ctx, exchange.RestSpot, spotAccountsEPL, http.MethodGet, "account/rate_limit", nil, nil, &resp)
 }
 
-// validate validates the ContractOrderCreateParams
-func (c *ContractOrderCreateParams) validate(isRest bool) error {
+// validate validates the FuturesOrderCreateParams
+func (c *FuturesOrderCreateParams) validate(isRest bool) error {
 	if err := common.NilGuard(c); err != nil {
 		return err
 	}
-	if c.Contract.IsEmpty() {
+	return validateOrderCreateParams(c.Contract, c.Size, c.Price, c.AutoSize, c.TimeInForce, c.Text, c.Settle, isRest)
+}
+
+// validate validates the DeliveryOrderCreateParams
+func (c *DeliveryOrderCreateParams) validate(isRest bool) error {
+	if err := common.NilGuard(c); err != nil {
+		return err
+	}
+	return validateOrderCreateParams(c.Contract, c.Size, c.Price, c.AutoSize, c.TimeInForce, c.Text, c.Settle, isRest)
+}
+
+// validateOrderCreateParams validates common order creation parameters shared by futures and delivery orders.
+func validateOrderCreateParams(contract currency.Pair, size, price float64, autoSize, timeInForce, text string, settle currency.Code, isRest bool) error {
+	if contract.IsEmpty() {
 		return currency.ErrCurrencyPairEmpty
 	}
-	if c.Size == 0 && c.AutoSize == "" {
+	if size == 0 && autoSize == "" {
 		return errInvalidOrderSize
 	}
-	if c.TimeInForce != "" {
-		if _, err := timeInForceFromString(c.TimeInForce); err != nil {
+	if timeInForce != "" {
+		if _, err := timeInForceFromString(timeInForce); err != nil {
 			return err
 		}
 	}
-	if c.Price == 0 && c.TimeInForce != iocTIF && c.TimeInForce != fokTIF {
-		return fmt.Errorf("%w: %q; only 'ioc' and 'fok' allowed for market order", order.ErrUnsupportedTimeInForce, c.TimeInForce)
+	if price == 0 && timeInForce != iocTIF && timeInForce != fokTIF {
+		return fmt.Errorf("%w: %q; only 'ioc' and 'fok' allowed for market order", order.ErrUnsupportedTimeInForce, timeInForce)
 	}
-	if c.Text != "" && !strings.HasPrefix(c.Text, "t-") {
+	if text != "" && !strings.HasPrefix(text, "t-") {
 		return errInvalidTextPrefix
 	}
-	if c.AutoSize != "" {
-		if c.AutoSize != "close_long" && c.AutoSize != "close_short" {
-			return fmt.Errorf("%w: %q", errInvalidAutoSize, c.AutoSize)
+	if autoSize != "" {
+		if autoSize != "close_long" && autoSize != "close_short" {
+			return fmt.Errorf("%w: %q", errInvalidAutoSize, autoSize)
 		}
-		if c.Size != 0 {
+		if size != 0 {
 			return fmt.Errorf("%w: size needs to be zero when auto size is set", errInvalidOrderSize)
 		}
 	}
 	// REST requests require a settlement currency, but it can be anything
 	// Websocket requests may have an empty settlement currency, or it must be BTC or USDT
-	if (isRest && c.Settle.IsEmpty()) ||
-		(!isRest && !c.Settle.IsEmpty() && !c.Settle.Equal(currency.BTC) && !c.Settle.Equal(currency.USDT)) {
+	if (isRest && settle.IsEmpty()) ||
+		(!isRest && !settle.IsEmpty() && !settle.Equal(currency.BTC) && !settle.Equal(currency.USDT)) {
 		return errEmptyOrInvalidSettlementCurrency
 	}
 	return nil