python · ericvsmith · Sep 4, 2017 · Aug 26, 2017
diff --git a/Lib/fileinput.py b/Lib/fileinput.py
@@ -330,7 +330,7 @@ def _readline(self):
        else:
            if self._inplace:
                self._backupfilename = (
-                    self._filename + (self._backup or ".bak"))
+                    os.fspath(self._filename) + (self._backup or ".bak"))
                try:
                    os.unlink(self._backupfilename)
                except OSError:

diff --git a/Lib/test/test_fileinput.py b/Lib/test/test_fileinput.py
@@ -544,6 +544,19 @@ def test_pathlib_file(self):
        finally:
            remove_tempfiles(t1)

+    def test_pathlib_file_inplace(self):
+        t1 = None
+        try:
+            t1 = Path(writeTmp(1, ['Pathlib file.']))
+            with FileInput(t1, inplace=True) as fi:
+                line = fi.readline()
+                self.assertEqual(line, 'Pathlib file.')
+                print('Modified %s' % line)
+            with open(t1) as f:
+                self.assertEqual(f.read(), 'Modified Pathlib file.\n')
+        finally:
+            remove_tempfiles(t1)
+

 class MockFileInput:
    """A class that mocks out fileinput.FileInput for use during unit tests"""

diff --git a/Misc/NEWS.d/next/Library/2017-08-29-07-14-14.bpo-31281.DcFyNs.rst b/Misc/NEWS.d/next/Library/2017-08-29-07-14-14.bpo-31281.DcFyNs.rst
@@ -0,0 +1,2 @@
+Fix ``fileinput.FileInput(files, inplace=True)`` when ``files`` contain
+``pathlib.Path`` objects.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Fix ``fileinput.FileInput(files, inplace=True)`` when ``files`` contain
		``pathlib.Path`` objects.