From 8e859503f621ae003ecd4883807007570932c9e4 Mon Sep 17 00:00:00 2001
From: allegroai <>
Date: Tue, 29 Sep 2020 19:10:00 +0300
Subject: [PATCH] Don't raise error for batch requests with no items

---
 trains/backend_api/session/callresult.py | 26 ++++++++++++++++++++----
 trains/backend_api/session/response.py   |  2 +-
 trains/backend_api/session/session.py    | 16 +++++++--------
 trains/version.py                        |  2 +-
 4 files changed, 32 insertions(+), 14 deletions(-)

diff --git a/trains/backend_api/session/callresult.py b/trains/backend_api/session/callresult.py
index 834f166e..e4d6977e 100644
--- a/trains/backend_api/session/callresult.py
+++ b/trains/backend_api/session/callresult.py
@@ -51,17 +51,35 @@ class CallResult(object):
         else:
             self.__response_data = None
 
+    @classmethod
+    def _make_raw_response(cls, request_cls=None, service=None, action=None, status_code=200, text=None):
+        service = service or (request_cls._service if request_cls else 'unknown')
+        action = action or (request_cls._action if request_cls else 'unknown')
+        return cls(request_cls=request_cls, meta=ResponseMeta.from_raw_data(
+            status_code=status_code, text=text, endpoint='%(service)s.%(action)s' % locals()))
+
     @classmethod
     def from_result(cls, res, request_cls=None, logger=None, service=None, action=None, session=None):
         """ From requests result """
         response_cls = get_response_cls(request_cls)
+
+        if res is None:
+            return cls._make_raw_response(
+                request_cls=request_cls,
+                service=service,
+                action=action
+            )
+
         try:
             data = res.json()
         except ValueError:
-            service = service or (request_cls._service if request_cls else 'unknown')
-            action = action or (request_cls._action if request_cls else 'unknown')
-            return cls(request_cls=request_cls, meta=ResponseMeta.from_raw_data(
-                status_code=res.status_code, text=res.text, endpoint='%(service)s.%(action)s' % locals()))
+            return cls._make_raw_response(
+                request_cls=request_cls,
+                service=service,
+                action=action,
+                status_code=res.status_code,
+                text=res.text
+            )
         if 'meta' not in data:
             raise ValueError('Missing meta section in response payload')
         try:
diff --git a/trains/backend_api/session/response.py b/trains/backend_api/session/response.py
index 9025354a..b4b7d513 100644
--- a/trains/backend_api/session/response.py
+++ b/trains/backend_api/session/response.py
@@ -30,7 +30,7 @@ class ResponseMeta(jsonmodels.models.Base):
         return self._is_valid
 
     @classmethod
-    def from_raw_data(cls, status_code, text, endpoint=None):
+    def from_raw_data(cls, status_code, text="", endpoint=None):
         return cls(is_valid=False, result_code=status_code, result_subcode=0, result_msg=text,
                    endpoint=_ResponseEndpoint(name=(endpoint or 'unknown')))
 
diff --git a/trains/backend_api/session/session.py b/trains/backend_api/session/session.py
index 3167372b..0317c2c6 100644
--- a/trains/backend_api/session/session.py
+++ b/trains/backend_api/session/session.py
@@ -341,9 +341,8 @@ class Session(TokenManager):
             raise ValueError("Expecting list, tuple or generator in 'data' or 'json'")
 
         if not data and not json:
-            raise ValueError(
-                "Missing data (data or json), batch requests are meaningless without it."
-            )
+            # Missing data (data or json), batch requests are meaningless without it.
+            return None
 
         headers = headers.copy() if headers else {}
         headers["Content-Type"] = "application/json-lines"
@@ -439,11 +438,12 @@ class Session(TokenManager):
                 headers=headers,
             )
             # TODO: handle multiple results in this case
-            try:
-                res = next(r for r in res if r.status_code != 200)
-            except StopIteration:
-                # all are 200
-                res = res[0]
+            if res is not None:
+                try:
+                    res = next(r for r in res if r.status_code != 200)
+                except StopIteration:
+                    # all are 200
+                    res = res[0]
         else:
             res = self.send_request(
                 service=req_obj._service,
diff --git a/trains/version.py b/trains/version.py
index 8a637f75..87439a97 100644
--- a/trains/version.py
+++ b/trains/version.py
@@ -1 +1 @@
-__version__ = '0.16.2rc1'
+__version__ = '0.16.2rc2'