Use unicode_filename more, and account for missing filesystemencoding

2 files changed, 4 insertions, 7 deletions

diff --git a/coverage/files.py b/coverage/files.py
index 855d8157..44997d12 100644
--- a/coverage/files.py
+++ b/coverage/files.py
@@ -67,8 +67,6 @@ def canonical_filename(filename):
                     filename = f
                     break
         cf = abs_file(filename)
-        if env.PY2 and isinstance(cf, str):
-            cf = cf.decode(sys.getfilesystemencoding())
         CANONICAL_FILENAME_CACHE[filename] = cf
     return CANONICAL_FILENAME_CACHE[filename]
 
@@ -135,7 +133,8 @@ if env.PY2:
     def unicode_filename(filename):
         """Return a Unicode version of `filename`."""
         if isinstance(filename, str):
-            filename = filename.decode(sys.getfilesystemencoding())
+            encoding = sys.getfilesystemencoding() or sys.getdefaultencoding()
+            filename = filename.decode(encoding, "replace")
         return filename
 else:
     @contract(filename='unicode', returns='unicode')
diff --git a/coverage/python.py b/coverage/python.py
index fe32150a..a4247ce6 100644
--- a/coverage/python.py
+++ b/coverage/python.py
@@ -96,8 +96,7 @@ class PythonFileReporter(FileReporter):
         else:
             filename = morf
 
-        if env.PY2 and isinstance(filename, str):
-            filename = filename.decode(sys.getfilesystemencoding())
+        filename = files.unicode_filename(filename)
 
         # .pyc files should always refer to a .py instead.
         if filename.endswith(('.pyc', '.pyo')):
@@ -110,8 +109,7 @@ class PythonFileReporter(FileReporter):
         if hasattr(morf, '__name__'):
             name = morf.__name__
             name = name.replace(".", os.sep) + ".py"
-            if isinstance(name, bytes):
-                name = name.decode(sys.getfilesystemencoding())
+            name = files.unicode_filename(name)
         else:
             name = files.relative_filename(filename)
         self.relname = name