Fix to query_update(None) (#792)

* Handled case where update_query() is handed None as an argument. Added corresponding test file as well.

* Added Changes file

* Rename 790.bugfix.rst to 792.bugfix.rst

Co-authored-by: Andrew Svetlov <[email protected]>

Author: dereckt

CHANGES/792.bugfix.rst

@@ -0,0 +1 @@
+Fixed an issue with update_query() not getting rid of the query when argument is None.

tests/test_update_query.py

@@ -40,6 +40,12 @@ def test_update_query_with_multiple_args():
         url.update_query("a", "b")
 
 
+def test_update_query_with_none_arg():
+    url = URL("http://example.com/?foo=bar&baz=foo")
+    expected_url = URL("http://example.com/")
+    assert url.update_query(None) == expected_url
+
+
 def test_with_query_list_of_pairs():
     url = URL("http://example.com")
     assert str(url.with_query([("a", "1")])) == "http://example.com/?a=1"

yarl/_url.py

@@ -985,9 +985,11 @@ def with_query(self, *args, **kwargs):
     def update_query(self, *args, **kwargs):
         """Return a new URL with query part updated."""
         s = self._get_str_query(*args, **kwargs)
-        new_query = MultiDict(parse_qsl(s, keep_blank_values=True))
-        query = MultiDict(self.query)
-        query.update(new_query)
+        query = None
+        if s:
+            new_query = MultiDict(parse_qsl(s, keep_blank_values=True))
+            query = MultiDict(self.query)
+            query.update(new_query)
 
         return URL(self._val._replace(query=self._get_str_query(query)), encoded=True)