fix: remove HistoryFilterParams from fetchOHLCV to fix Python SDK oneOf deserialization error

Author: realfishsam

changelog.md

@@ -2,6 +2,12 @@
 
 All notable changes to this project will be documented in this file.
 
+## [2.17.8] - 2026-02-25
+
+### Fixed
+
+- **Python SDK `fetch_ohlcv` deserialization error**: Calling `fetch_ohlcv()` raised `ValueError: Multiple matches found when deserializing... with oneOf schemas: HistoryFilterParams, OHLCVParams` because the OpenAPI spec emitted `oneOf: [OHLCVParams, HistoryFilterParams]` for the `params` argument. Since both schemas are structurally identical in JSON (same four fields, differing only in `resolution` being optional vs. required), pydantic matched both branches and raised an exception. Fixed by removing the deprecated `HistoryFilterParams` union from `fetchOHLCV` in `BaseExchange.ts` and all exchange implementations, then regenerating the OpenAPI spec. The spec now emits only `OHLCVParams` for this parameter. `fetchTrades` is unaffected as its `HistoryFilterParams | TradesParams` union has no structural ambiguity.
+
 ## [2.17.7] - 2026-02-25
 
 ### Fixed

core/src/BaseExchange.ts

@@ -607,7 +607,7 @@ export abstract class PredictionMarketExchange {
      * @notes Polymarket: outcomeId is the CLOB Token ID. Kalshi: outcomeId is the Market Ticker.
      * @notes Resolution options: '1m' | '5m' | '15m' | '1h' | '6h' | '1d'
      */
-    async fetchOHLCV(id: string, params: OHLCVParams | HistoryFilterParams): Promise<PriceCandle[]> {
+    async fetchOHLCV(id: string, params: OHLCVParams): Promise<PriceCandle[]> {
         throw new Error("Method fetchOHLCV not implemented.");
     }
 

core/src/exchanges/kalshi/fetchOHLCV.ts

@@ -1,12 +1,12 @@
-import { HistoryFilterParams, OHLCVParams } from "../../BaseExchange";
+import { OHLCVParams } from "../../BaseExchange";
 import { PriceCandle } from "../../types";
 import { mapIntervalToKalshi } from "./utils";
 import { validateIdFormat } from "../../utils/validation";
 import { kalshiErrorMapper } from "./errors";
 
 export async function fetchOHLCV(
   id: string,
-  params: OHLCVParams | HistoryFilterParams,
+  params: OHLCVParams,
   callApi: (operationId: string, params?: Record<string, any>) => Promise<any>,
 ): Promise<PriceCandle[]> {
   validateIdFormat(id, "OHLCV");

core/src/exchanges/kalshi/index.ts

@@ -158,7 +158,7 @@ export class KalshiExchange extends PredictionMarketExchange {
 
   async fetchOHLCV(
     id: string,
-    params: OHLCVParams | HistoryFilterParams,
+    params: OHLCVParams,
   ): Promise<PriceCandle[]> {
     return fetchOHLCV(id, params, this.callApi.bind(this));
   }

core/src/exchanges/limitless/fetchOHLCV.ts

@@ -1,4 +1,4 @@
-import { HistoryFilterParams, OHLCVParams } from '../../BaseExchange';
+import { OHLCVParams } from '../../BaseExchange';
 import { PriceCandle } from '../../types';
 import { mapIntervalToFidelity } from './utils';
 import { validateIdFormat } from '../../utils/validation';
@@ -8,7 +8,7 @@ import { limitlessErrorMapper } from './errors';
  * Fetch historical price data (candles) for a specific market.
  * @param id - The market slug
  */
-export async function fetchOHLCV(id: string, params: OHLCVParams | HistoryFilterParams, callApi: (operationId: string, params?: Record<string, any>) => Promise<any>): Promise<PriceCandle[]> {
+export async function fetchOHLCV(id: string, params: OHLCVParams, callApi: (operationId: string, params?: Record<string, any>) => Promise<any>): Promise<PriceCandle[]> {
     validateIdFormat(id, 'OHLCV');
 
     // Validate resolution is provided

core/src/exchanges/limitless/index.ts

@@ -139,7 +139,7 @@ export class LimitlessExchange extends PredictionMarketExchange {
         return fetchEvents(params, this.callApi.bind(this), this.http);
     }
 
-    async fetchOHLCV(id: string, params: OHLCVParams | HistoryFilterParams): Promise<PriceCandle[]> {
+    async fetchOHLCV(id: string, params: OHLCVParams): Promise<PriceCandle[]> {
         return fetchOHLCV(id, params, this.callApi.bind(this));
     }
 

core/src/exchanges/myriad/fetchOHLCV.ts

@@ -1,4 +1,4 @@
-import { OHLCVParams, HistoryFilterParams } from '../../BaseExchange';
+import { OHLCVParams } from '../../BaseExchange';
 import { PriceCandle, CandleInterval } from '../../types';
 import { myriadErrorMapper } from './errors';
 
@@ -26,7 +26,7 @@ function selectTimeframe(interval: CandleInterval): string {
 
 export async function fetchOHLCV(
     id: string,
-    params: OHLCVParams | HistoryFilterParams,
+    params: OHLCVParams,
     callApi: (operationId: string, params?: Record<string, any>) => Promise<any>
 ): Promise<PriceCandle[]> {
     if (!params.resolution) {

core/src/exchanges/myriad/index.ts

@@ -87,7 +87,7 @@ export class MyriadExchange extends PredictionMarketExchange {
         return fetchEvents(params, this.getHeaders(), this.http);
     }
 
-    async fetchOHLCV(id: string, params: OHLCVParams | HistoryFilterParams): Promise<PriceCandle[]> {
+    async fetchOHLCV(id: string, params: OHLCVParams): Promise<PriceCandle[]> {
         return fetchOHLCV(id, params, this.callApi.bind(this));
     }
 

core/src/exchanges/polymarket/fetchOHLCV.ts

@@ -1,4 +1,4 @@
-import { HistoryFilterParams, OHLCVParams } from '../../BaseExchange';
+import { OHLCVParams } from '../../BaseExchange';
 import { PriceCandle } from '../../types';
 import { mapIntervalToFidelity } from './utils';
 import { validateIdFormat, validateOutcomeId } from '../../utils/validation';
@@ -8,7 +8,7 @@ import { polymarketErrorMapper } from './errors';
  * Fetch historical price data (OHLCV candles) for a specific token.
  * @param id - The CLOB token ID (e.g., outcome token ID)
  */
-export async function fetchOHLCV(id: string, params: OHLCVParams | HistoryFilterParams, callApi: (operationId: string, params?: Record<string, any>) => Promise<any>): Promise<PriceCandle[]> {
+export async function fetchOHLCV(id: string, params: OHLCVParams, callApi: (operationId: string, params?: Record<string, any>) => Promise<any>): Promise<PriceCandle[]> {
     validateIdFormat(id, 'OHLCV');
     validateOutcomeId(id, 'OHLCV');
 

core/src/exchanges/polymarket/index.ts

@@ -203,7 +203,7 @@ export class PolymarketExchange extends PredictionMarketExchange {
         return fetchEvents(params, this.http);
     }
 
-    async fetchOHLCV(id: string, params: OHLCVParams | HistoryFilterParams): Promise<PriceCandle[]> {
+    async fetchOHLCV(id: string, params: OHLCVParams): Promise<PriceCandle[]> {
         return fetchOHLCV(id, params, this.callApi.bind(this));
     }