gh-101961 fileinput.hookcompressed should not set the encoding value for the binary mode

Lib/fileinput.py

@@ -399,7 +399,7 @@ def isstdin(self):
 
 
 def hook_compressed(filename, mode, *, encoding=None, errors=None):
- if encoding is None: # EncodingWarning is emitted in FileInput() already.
+ if encoding is None and "b" not in mode: # EncodingWarning is emitted in FileInput() already.
  encoding = "locale"
  ext = os.path.splitext(filename)[1]
  if ext == '.gz':

Lib/test/test_fileinput.py

@@ -855,29 +855,29 @@ def setUp(self):
  self.fake_open = InvocationRecorder()
 
  def test_empty_string(self):
- self.do_test_use_builtin_open("", 1)
+ self.do_test_use_builtin_open_text("", "r")
 
  def test_no_ext(self):
- self.do_test_use_builtin_open("abcd", 2)
+ self.do_test_use_builtin_open_text("abcd", "r")
 
  @unittest.skipUnless(gzip, "Requires gzip and zlib")
  def test_gz_ext_fake(self):
  original_open = gzip.open
  gzip.open = self.fake_open
  try:
- result = fileinput.hook_compressed("test.gz", "3")
+ result = fileinput.hook_compressed("test.gz", "r")
  finally:
  gzip.open = original_open
 
  self.assertEqual(self.fake_open.invocation_count, 1)
- self.assertEqual(self.fake_open.last_invocation, (("test.gz", "3"), {}))
+ self.assertEqual(self.fake_open.last_invocation, (("test.gz", "r"), {}))
 
  @unittest.skipUnless(gzip, "Requires gzip and zlib")
  def test_gz_with_encoding_fake(self):
  original_open = gzip.open
  gzip.open = lambda filename, mode: io.BytesIO(b'Ex-binary string')
  try:
- result = fileinput.hook_compressed("test.gz", "3", encoding="utf-8")
+ result = fileinput.hook_compressed("test.gz", "r", encoding="utf-8")
  finally:
  gzip.open = original_open
  self.assertEqual(list(result), ['Ex-binary string'])
@@ -887,23 +887,40 @@ def test_bz2_ext_fake(self):
  original_open = bz2.BZ2File
  bz2.BZ2File = self.fake_open
  try:
- result = fileinput.hook_compressed("test.bz2", "4")
+ result = fileinput.hook_compressed("test.bz2", "r")
  finally:
  bz2.BZ2File = original_open
 
  self.assertEqual(self.fake_open.invocation_count, 1)
- self.assertEqual(self.fake_open.last_invocation, (("test.bz2", "4"), {}))
+ self.assertEqual(self.fake_open.last_invocation, (("test.bz2", "r"), {}))
 
  def test_blah_ext(self):
- self.do_test_use_builtin_open("abcd.blah", "5")
+ self.do_test_use_builtin_open_binary("abcd.blah", "rb")
 
  def test_gz_ext_builtin(self):
- self.do_test_use_builtin_open("abcd.Gz", "6")
+ self.do_test_use_builtin_open_binary("abcd.Gz", "rb")
 
  def test_bz2_ext_builtin(self):
- self.do_test_use_builtin_open("abcd.Bz2", "7")
+ self.do_test_use_builtin_open_binary("abcd.Bz2", "rb")
 
- def do_test_use_builtin_open(self, filename, mode):
+ def test_binary_mode_encoding(self):
+ self.do_test_use_builtin_open_binary("abcd", "rb")
+
+ def test_text_mode_encoding(self):
+ self.do_test_use_builtin_open_text("abcd", "r")
+
+ def do_test_use_builtin_open_binary(self, filename, mode):
+ original_open = self.replace_builtin_open(self.fake_open)
+ try:
+ result = fileinput.hook_compressed(filename, mode)
+ finally:
+ self.replace_builtin_open(original_open)
+
+ self.assertEqual(self.fake_open.invocation_count, 1)
+ self.assertEqual(self.fake_open.last_invocation,
+ ((filename, mode), {'encoding': None, 'errors': None}))
+
+ def do_test_use_builtin_open_text(self, filename, mode):
  original_open = self.replace_builtin_open(self.fake_open)
  try:
  result = fileinput.hook_compressed(filename, mode)

Misc/ACKS

@@ -927,6 +927,7 @@ Tyler Kieft
 Mads Kiilerich
 Jason Killen
 Derek D. Kim
+Gihwan Kim
 Jan Kim
 Taek Joo Kim
 Sam Kimbrel

Misc/NEWS.d/next/Library/2023-02-21-10-05-33.gh-issue-101961.7e56jh.rst

@@ -0,0 +1,2 @@
+For the binary mode, :func:`file input.hookcompressed` doesn't set the ``encoding`` value
+even if the value is ``None``. Patch by Gihwan Kim.