Fix situation where a traceback entry "path" returns a str object

Fix #1133

CHANGELOG

@@ -7,6 +7,10 @@
 - fix #331: don't collect tests if their failure cannot be reported correctly
   e.g. they are a callable instance of a class.
 
+- fix #1133: fixed internal error when filtering tracebacks where one entry
+  belongs to a file which is no longer available.
+  Thanks Bruno Oliveira for the PR.
+
 2.8.2
 -----
 
@@ -50,9 +54,9 @@
   "pytest-xdist" plugin, with test reports being assigned to the wrong tests.
   Thanks Daniel Grunwald for the report and Bruno Oliveira for the PR.
 
-- (experimental) adapt more SEMVER style versioning and change meaning of 
-  master branch in git repo: "master" branch now keeps the bugfixes, changes 
-  aimed for micro releases.  "features" branch will only be be released 
+- (experimental) adapt more SEMVER style versioning and change meaning of
+  master branch in git repo: "master" branch now keeps the bugfixes, changes
+  aimed for micro releases.  "features" branch will only be be released
   with minor or major pytest releases.
 
 - Fix issue #766 by removing documentation references to distutils.
@@ -77,7 +81,7 @@
 -----------------------------
 
 - new ``--lf`` and ``-ff`` options to run only the last failing tests or
-  "failing tests first" from the last run.  This functionality is provided 
+  "failing tests first" from the last run.  This functionality is provided
   through porting the formerly external pytest-cache plugin into pytest core.
   BACKWARD INCOMPAT: if you used pytest-cache's functionality to persist
   data between test runs be aware that we don't serialize sets anymore.
@@ -183,9 +187,9 @@
 
 - fix issue735: assertion failures on debug versions of Python 3.4+
 
-- new option ``--import-mode`` to allow to change test module importing 
-  behaviour to append to sys.path instead of prepending.  This better allows 
-  to run test modules against installated versions of a package even if the 
+- new option ``--import-mode`` to allow to change test module importing
+  behaviour to append to sys.path instead of prepending.  This better allows
+  to run test modules against installated versions of a package even if the
   package under test has the same import root.  In this example::
 
         testing/__init__.py
@@ -193,7 +197,7 @@
         pkg_under_test/
 
   the tests will run against the installed version
-  of pkg_under_test when ``--import-mode=append`` is used whereas 
+  of pkg_under_test when ``--import-mode=append`` is used whereas
   by default they would always pick up the local version.  Thanks Holger Krekel.
 
 - pytester: add method ``TmpTestdir.delete_loaded_modules()``, and call it

_pytest/python.py

@@ -58,14 +58,17 @@ def _has_positional_arg(func):
 
 
 def filter_traceback(entry):
-    # entry.path might sometimes return a str() object when the entry
+    # entry.path might sometimes return a str object when the entry
     # points to dynamically generated code
     # see https://bitbucket.org/pytest-dev/py/issues/71
     raw_filename = entry.frame.code.raw.co_filename
     is_generated = '<' in raw_filename and '>' in raw_filename
     if is_generated:
         return False
-    return entry.path != cutdir1 and not entry.path.relto(cutdir2)
+    # entry.path might point to an inexisting file, in which case it will
+    # alsso return a str object. see #1133
+    p = py.path.local(entry.path)
+    return p != cutdir1 and not p.relto(cutdir2)
 
 
 def get_real_func(obj):

testing/python/collect.py

@@ -771,10 +771,12 @@ class TestTracebackCutting:
             "* 1 error in *",
         ])
 
-    def test_filter_traceback_accepts_non_paths(self):
-        """test that filter_traceback() works around py.code.Code bug
-        where sometimes its "path" attribute is not a py.path.local object:
-            https://bitbucket.org/pytest-dev/py/issues/71
+    def test_filter_traceback_generated_code(self):
+        """test that filter_traceback() works with the fact that
+        py.code.Code.path attribute might return an str object.
+        In this case, one of the entries on the traceback was produced by
+        dynamically generated code.
+        See: https://bitbucket.org/pytest-dev/py/issues/71
         This fixes #995.
         """
         from _pytest.python import filter_traceback
@@ -783,13 +785,35 @@ class TestTracebackCutting:
             exec('def foo(): raise ValueError', ns)
             ns['foo']()
         except ValueError:
-            import sys
             _, _, tb = sys.exc_info()
 
         tb = py.code.Traceback(tb)
-        assert isinstance(tb[-1].path, str)  # symptom of the py.code bug
+        assert isinstance(tb[-1].path, str)
         assert not filter_traceback(tb[-1])
 
+    def test_filter_traceback_path_no_longer_valid(self, testdir):
+        """test that filter_traceback() works with the fact that
+        py.code.Code.path attribute might return an str object.
+        In this case, one of the files in the traceback no longer exists.
+        This fixes #1133.
+        """
+        from _pytest.python import filter_traceback
+        testdir.syspathinsert()
+        testdir.makepyfile(filter_traceback_entry_as_str='''
+            def foo():
+                raise ValueError
+        ''')
+        try:
+            import filter_traceback_entry_as_str
+            filter_traceback_entry_as_str.foo()
+        except ValueError:
+            _, _, tb = sys.exc_info()
+
+        testdir.tmpdir.join('filter_traceback_entry_as_str.py').remove()
+        tb = py.code.Traceback(tb)
+        assert isinstance(tb[-1].path, str)
+        assert filter_traceback(tb[-1])
+
 
 class TestReportInfo:
     def test_itemreport_reportinfo(self, testdir, linecomp):