Bring back filename parameter to compression_wrapper (piskvorky#497)

* bring back filename to compression_wrapper

* fix docstring

* move fallback inside try-catch

* fix flake8 failures (unrelated to PR)

* Update smart_open/compression.py

Co-authored-by: Michael Penkov <m@penkov.dev>

Co-authored-by: Michael Penkov <m@penkov.dev>

Author: piskvorky

smart_open/compression.py

@@ -62,20 +62,22 @@ def _handle_gzip(file_obj, mode):
     return gzip.GzipFile(fileobj=file_obj, mode=mode)
 
 
-def compression_wrapper(file_obj, mode):
+def compression_wrapper(file_obj, mode, filename=None):
     """
     This function will wrap the file_obj with an appropriate
     [de]compression mechanism based on the extension of the filename.
 
     file_obj must either be a filehandle object, or a class which behaves
-        like one.  It must have a .name attribute.
+    like one. It must have a .name attribute unless ``filename`` is given.
 
     If the filename extension isn't recognized, will simply return the original
     file_obj.
-    """
 
+    """
     try:
-        _, ext = os.path.splitext(file_obj.name)
+        if filename is None:
+            filename = file_obj.name
+        _, ext = os.path.splitext(filename)
     except (AttributeError, TypeError):
         logger.warning(
             'unable to transparently decompress %r because it '

smart_open/doctools.py

@@ -163,7 +163,7 @@ def extract_examples_from_readme_rst(indent='    '):
         start = lines.index('.. _doctools_before_examples:\n')
         end = lines.index(".. _doctools_after_examples:\n")
         lines = lines[start+4:end-2]
-        return ''.join([indent + re.sub('^  ', '', l) for l in lines])
+        return ''.join([indent + re.sub('^  ', '', line) for line in lines])
     except Exception:
         return indent + 'See README.rst'
 

smart_open/tests/test_smart_open.py

@@ -721,7 +721,7 @@ def test_readline_iter(self):
 
         reader = smart_open.smart_open("s3://mybucket/mykey", "rb")
 
-        actual_lines = [l.decode("utf-8") for l in reader]
+        actual_lines = [line.decode("utf-8") for line in reader]
         self.assertEqual(2, len(actual_lines))
         self.assertEqual(lines[0], actual_lines[0])
         self.assertEqual(lines[1], actual_lines[1])
@@ -1273,9 +1273,7 @@ def write_callback(request):
 
 
 class CompressionFormatTest(unittest.TestCase):
-    """
-    Test that compression
-    """
+    """Test transparent (de)compression."""
 
     def write_read_assertion(self, suffix):
         test_file = make_buffer(name='file' + suffix)

smart_open/tests/test_smart_open_old.py

@@ -218,7 +218,7 @@ def test_readline_iter(self):
 
         reader = smart_open.smart_open("s3://mybucket/mykey", "rb")
 
-        actual_lines = [l.decode("utf-8") for l in reader]
+        actual_lines = [line.decode("utf-8") for line in reader]
         self.assertEqual(2, len(actual_lines))
         self.assertEqual(lines[0], actual_lines[0])
         self.assertEqual(lines[1], actual_lines[1])