Fix --debug=sys. #907

3 files changed, 13 insertions, 1 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 262a44ec..40e8d2d2 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -33,8 +33,12 @@ Unreleased
 - A new warning ("dynamic-conflict") is issued if two mechanisms are trying to
   change the dynamic context.  Closes `issue 901`_.
 
+- ``coverage run --debug=sys`` would fail with an AttributeError. This is now
+  fixed (`issue 907`_).
+
 .. _issue 890: https://github.com/nedbat/coveragepy/issues/890
 .. _issue 901: https://github.com/nedbat/coveragepy/issues/901
+.. _issue 907: https://github.com/nedbat/coveragepy/issues/907
 
 
 .. _changes_501:
diff --git a/coverage/control.py b/coverage/control.py
index c40508da..889ef55c 100644
--- a/coverage/control.py
+++ b/coverage/control.py
@@ -1005,7 +1005,7 @@ class Coverage(object):
                 if self.config._config_contents
                 else '-none-'
             ),
-            ('data_file', self._data.filename if self._data else "-none-"),
+            ('data_file', self._data.data_filename() if self._data is not None else "-none-"),
             ('python', sys.version.replace('\n', '')),
             ('platform', platform.platform()),
             ('implementation', platform.python_implementation()),
diff --git a/tests/test_api.py b/tests/test_api.py
index 0a6b71b9..287391cb 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -714,6 +714,14 @@ class ApiTest(CoverageTest):
         cov.start()
         cov.stop()
 
+    def test_run_debug_sys(self):
+        # https://github.com/nedbat/coveragepy/issues/907
+        cov = coverage.Coverage()
+        cov.start()
+        d = dict(cov.sys_info())        # pragma: nested
+        cov.stop()                      # pragma: nested
+        assert d['data_file'].endswith(".coverage")
+
 
 class CurrentInstanceTest(CoverageTest):
     """Tests of Coverage.current()."""