fix issue498: if a fixture finalizer fails, make sure that the fixture

is still invalidated.

--HG--
branch : issue498

CHANGELOG

@@ -1,6 +1,9 @@
 NEXT (2.6)
 -----------------------------------
 
+- fix issue498: if a fixture finalizer fails, make sure that 
+  the fixture is still invalidated.
+
 - fix issue453: the result of the pytest_assertrepr_compare hook now gets
   it's newlines escaped so that format_exception does not blow up.
 

_pytest/python.py

@@ -1778,13 +1778,15 @@ class FixtureDef:
         self._finalizer.append(finalizer)
 
     def finish(self):
-        while self._finalizer:
-            func = self._finalizer.pop()
-            func()
         try:
-            del self.cached_result
-        except AttributeError:
-            pass
+            while self._finalizer:
+                func = self._finalizer.pop()
+                func()
+        finally:
+            # even if finalization fails, we invalidate
+            # the cached fixture value
+            if hasattr(self, "cached_result"):
+                del self.cached_result
 
     def execute(self, request):
         # get required arguments and register our own finish()

testing/python/fixture.py

@@ -2087,6 +2087,35 @@ class TestErrors:
             "*1 error*",
         ])
 
+    def test_issue498_fixture_finalizer_failing(self, testdir):
+        testdir.makepyfile("""
+            import pytest
+            @pytest.fixture
+            def fix1(request):
+                def f():
+                    raise KeyError
+                request.addfinalizer(f) 
+                return object()
+
+            l = []
+            def test_1(fix1):
+                l.append(fix1)
+            def test_2(fix1):
+                l.append(fix1)
+            def test_3():
+                assert l[0] != l[1]
+        """)
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines("""
+            *ERROR*teardown*test_1*
+            *KeyError*
+            *ERROR*teardown*test_2*
+            *KeyError*
+            *3 pass*2 error*
+        """)
+        
+
+
     def test_setupfunc_missing_funcarg(self, testdir):
         testdir.makepyfile("""
             import pytest