Subplots should always be included in responses

freqtrade/rpc/api_server/api_schemas.py

@@ -268,7 +268,7 @@ class DeleteTrade(BaseModel):
 
 class PlotConfig_(BaseModel):
     main_plot: Dict[str, Any]
-    subplots: Optional[Dict[str, Any]]
+    subplots: Dict[str, Any]
 
 
 class PlotConfig(BaseModel):

freqtrade/rpc/rpc.py

@@ -845,5 +845,7 @@ class RPC:
                                               df_analyzed, arrow.Arrow.utcnow().datetime)
 
     def _rpc_plot_config(self) -> Dict[str, Any]:
-
+        if (self._freqtrade.strategy.plot_config and
+                'subplots' not in self._freqtrade.strategy.plot_config):
+            self._freqtrade.strategy.plot_config['subplots'] = {}
         return self._freqtrade.strategy.plot_config

tests/rpc/test_rpc_apiserver.py

@@ -1142,6 +1142,14 @@ def test_api_plot_config(botclient):
     assert_response(rc)
     assert rc.json() == ftbot.strategy.plot_config
     assert isinstance(rc.json()['main_plot'], dict)
+    assert isinstance(rc.json()['subplots'], dict)
+
+    ftbot.strategy.plot_config = {'main_plot': {'sma': {}}}
+    rc = client_get(client, f"{BASE_URI}/plot_config")
+    assert_response(rc)
+
+    assert isinstance(rc.json()['main_plot'], dict)
+    assert isinstance(rc.json()['subplots'], dict)
 
 
 def test_api_strategies(botclient):