Merge pull request #2849 from ApaDoctor/disable-repeated-fixture

provide error fixture applied to the same func

_pytest/fixtures.py

@@ -851,6 +851,11 @@ class FixtureFunctionMarker(object):
         if isclass(function):
             raise ValueError(
                 "class fixtures not supported (may be in the future)")
+
+        if getattr(function, "_pytestfixturefunction", False):
+            raise ValueError(
+                    "fixture is being applied more than once to the same function")
+
         function._pytestfixturefunction = self
         return function
 

changelog/2334.feature

@@ -0,0 +1 @@
+Now when ``@pytest.fixture`` is applied more than once to the same function a ``ValueError`` is raised. This buggy behavior would cause surprising problems and if was working for a test suite it was mostly by accident.

testing/python/fixture.py

@@ -2992,6 +2992,14 @@ class TestShowFixtures(object):
                 Hi from test module
         ''')
 
+    def test_fixture_disallow_twice(self):
+        """Test that applying @pytest.fixture twice generates an error (#2334)."""
+        with pytest.raises(ValueError):
+            @pytest.fixture
+            @pytest.fixture
+            def foo():
+                pass
+
 
 @pytest.mark.parametrize('flavor', ['fixture', 'yield_fixture'])
 class TestContextManagerFixtureFuncs(object):