gh-117722: Fix Stream.readuntil with non-bytes buffer objects (#117723)

gh-16429 introduced support for an iterable of separators in
Stream.readuntil. Since bytes-like types are themselves iterable, this
can introduce ambiguities in deciding whether the argument is an
iterator of separators or a singleton separator. In gh-16429, only 'bytes'
was considered a singleton, but this will break code that passes other
buffer object types.

Fix it by only supporting tuples rather than arbitrary iterables.

Closes gh-117722.

1 files changed, 14 insertions, 7 deletions

diff --git a/Lib/test/test_asyncio/test_streams.py b/Lib/test/test_asyncio/test_streams.py
index 792e887..ae943f3 100644
--- a/Lib/test/test_asyncio/test_streams.py
+++ b/Lib/test/test_asyncio/test_streams.py
@@ -384,9 +384,9 @@ class StreamTests(test_utils.TestCase):
         with self.assertRaisesRegex(ValueError, 'Separator should be'):
             self.loop.run_until_complete(stream.readuntil(separator=b''))
         with self.assertRaisesRegex(ValueError, 'Separator should be'):
-            self.loop.run_until_complete(stream.readuntil(separator=[b'']))
+            self.loop.run_until_complete(stream.readuntil(separator=(b'',)))
         with self.assertRaisesRegex(ValueError, 'Separator should contain'):
-            self.loop.run_until_complete(stream.readuntil(separator=[]))
+            self.loop.run_until_complete(stream.readuntil(separator=()))
 
     def test_readuntil_multi_chunks(self):
         stream = asyncio.StreamReader(loop=self.loop)
@@ -475,15 +475,15 @@ class StreamTests(test_utils.TestCase):
 
         # Simple case
         stream.feed_data(b'line 1\nline 2\r')
-        data = self.loop.run_until_complete(stream.readuntil([b'\r', b'\n']))
+        data = self.loop.run_until_complete(stream.readuntil((b'\r', b'\n')))
         self.assertEqual(b'line 1\n', data)
-        data = self.loop.run_until_complete(stream.readuntil([b'\r', b'\n']))
+        data = self.loop.run_until_complete(stream.readuntil((b'\r', b'\n')))
         self.assertEqual(b'line 2\r', data)
         self.assertEqual(b'', stream._buffer)
 
         # First end position matches, even if that's a longer match
         stream.feed_data(b'ABCDEFG')
-        data = self.loop.run_until_complete(stream.readuntil([b'DEF', b'BCDE']))
+        data = self.loop.run_until_complete(stream.readuntil((b'DEF', b'BCDE')))
         self.assertEqual(b'ABCDE', data)
         self.assertEqual(b'FG', stream._buffer)
 
@@ -493,7 +493,7 @@ class StreamTests(test_utils.TestCase):
 
         with self.assertRaisesRegex(asyncio.LimitOverrunError,
                                     'is found') as cm:
-            self.loop.run_until_complete(stream.readuntil([b'A', b'ome dataA']))
+            self.loop.run_until_complete(stream.readuntil((b'A', b'ome dataA')))
 
         self.assertEqual(b'some dataA', stream._buffer)
 
@@ -504,7 +504,7 @@ class StreamTests(test_utils.TestCase):
         stream = asyncio.StreamReader(loop=self.loop)
         stream.feed_data(b'data')
 
-        readuntil_task = self.loop.create_task(stream.readuntil([b'A', b'long sep']))
+        readuntil_task = self.loop.create_task(stream.readuntil((b'A', b'long sep')))
         self.loop.call_soon(stream.feed_data, b'Z')
         self.loop.call_soon(stream.feed_data, b'Aaaa')
 
@@ -512,6 +512,13 @@ class StreamTests(test_utils.TestCase):
         self.assertEqual(b'dataZA', data)
         self.assertEqual(b'aaa', stream._buffer)
 
+    def test_readuntil_bytearray(self):
+        stream = asyncio.StreamReader(loop=self.loop)
+        stream.feed_data(b'some data\r\n')
+        data = self.loop.run_until_complete(stream.readuntil(bytearray(b'\r\n')))
+        self.assertEqual(b'some data\r\n', data)
+        self.assertEqual(b'', stream._buffer)
+
     def test_readexactly_zero_or_less(self):
         # Read exact number of bytes (zero or less).
         stream = asyncio.StreamReader(loop=self.loop)