Move dataframe trim to within jsondatahandler

freqtrade/data/datahandlers/idatahandler.py

@@ -55,11 +55,7 @@ class IDataHandler(ABC):
                 f'No history data for pair: "{pair}", timeframe: {timeframe}. '
                 'Use `freqtrade download-data` to download the data'
             )
-            return pairdf
-        else:
-            if timerange_startup:
-                self._validate_pairdata(pair, pairdf, timerange_startup)
-            return pairdf
+        return pairdf
 
     def _validate_pairdata(self, pair, pairdata: DataFrame, timerange: TimeRange):
         """

freqtrade/data/datahandlers/jsondatahandler.py

@@ -78,13 +78,18 @@ class JsonDataHandler(IDataHandler):
                                        utc=True,
                                        infer_datetime_format=True)
 
+        enddate = pairdata.iloc[-1]['date']
+
         if timerange:
+            self._validate_pairdata(pair, pairdata, timerange)
             pairdata = trim_dataframe(pairdata, timerange)
 
+        # incomplete candles should only be dropped if we didn't trim the end beforehand.
         return clean_ohlcv_dataframe(pairdata, timeframe,
                                      pair=pair,
                                      fill_missing=fill_missing,
-                                     drop_incomplete=drop_incomplete)
+                                     drop_incomplete=(drop_incomplete and
+                                                      enddate == pairdata.iloc[-1]['date']))
 
     def ohlcv_append(self, pair: str, timeframe: str, data: DataFrame) -> None:
         """
@@ -140,6 +145,18 @@ class JsonDataHandler(IDataHandler):
 
         return tradesdata
 
+    def trades_purge(self, pair: str) -> bool:
+        """
+        Remove data for this pair
+        :param pair: Delete data for this pair.
+        :return: True when deleted, false if file did not exist.
+        """
+        filename = self._pair_trades_filename(self._datadir, pair)
+        if filename.is_file():
+            filename.unlink()
+            return True
+        return False
+
     @classmethod
     def _pair_data_filename(cls, datadir: Path, pair: str, timeframe: str) -> Path:
         pair_s = pair.replace("/", "_")

freqtrade/data/history.py

@@ -369,11 +369,9 @@ def refresh_backtest_trades_data(exchange: Exchange, pairs: List[str], datadir:
             logger.info(f"Skipping pair {pair}...")
             continue
 
-        dl_file = pair_trades_filename(datadir, pair)
-        if erase and dl_file.exists():
-            logger.info(
-                f'Deleting existing data for pair {pair}.')
-            dl_file.unlink()
+        if erase:
+            if data_handler.trades_purge(pair):
+                logger.info(f'Deleting existing data for pair {pair}.')
 
         logger.info(f'Downloading trades for pair {pair}.')
         _download_trades_history(datadir=datadir, exchange=exchange,