fix: add max_length support to Gzip/Brotli decoders for urllib3 2.6+ (#495)

## Summary
Fixes#491. Supersedes #492 (stale).
`urllib3 >= 2.6.0` now passes `max_length` to `decoder.decompress()` and
accesses `decoder.has_unconsumed_tail`. Our custom `_GzipDecoder` and
`_BrotliDecoder` wrappers didn't accept these, causing `TypeError` at
runtime.
This PR:
- Updates `_GzipDecoder.decompress` and `_BrotliDecoder.decompress` to
accept and forward `max_length`, with a `TypeError` fallback for older
urllib3
- Adds `has_unconsumed_tail` property to `_BrotliDecoder` (the proxy
class that needs it explicitly)
- Applies the same fix to the async `_GzipDecoder` in
`google/_async_resumable_media/`
- Adds test coverage for the new `max_length` forwarding, the fallback
path, and `has_unconsumed_tail`
## Feedback from #492 addressed
- **`max_length=-1` default** (chandra-siri) — uses `-1` to match
[urllib3's
default](https://github.com/urllib3/urllib3/blob/bfe8e198a13800e3ee8ef8124a8928acb170c843/src/urllib3/response.py#L55),
not `None`
- **`has_unconsumed_tail` only on `_BrotliDecoder`** (chandra-siri) —
`_GzipDecoder` inherits this from the parent
`urllib3.response.GzipDecoder`, so no override is needed
- **Lint failure** (BrennaEpp) — no trailing whitespace
- **Missing test coverage for fallback paths** (BrennaEpp) — added tests
for `max_length` forwarding, `TypeError` fallback, and
`has_unconsumed_tail` (with `AttributeError` fallback for older urllib3)
## Test plan
- [x] `pytest tests/unit/requests/test_download.py` — all pass
- [x] `pytest tests_async/unit/requests/test_download.py` — all pass
- [x] Full unit suite (514 tests) — all pass
- [x] No lint issues (flake8 clean)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Chalmer Lowe <chalmerlowe@google.com>

Author: CalNightingale

packages/google-resumable-media/google/_async_resumable_media/requests/download.py

@@ -452,14 +452,19 @@ def __init__(self, checksum):
 super(_GzipDecoder, self).__init__()
 self._checksum=checksum
 
-defdecompress(self, data):
+defdecompress(self, data, max_length=-1):
 """Decompress the bytes.
 
  Args:
  data (bytes): The compressed bytes to be decompressed.
+ max_length (int): Maximum number of bytes to return. -1 for no
+ limit. Forwarded to the underlying decoder when supported.
 
  Returns:
  bytes: The decompressed bytes from ``data``.
  """
 self._checksum.update(data)
-returnsuper(_GzipDecoder, self).decompress(data)
+try:
+returnsuper(_GzipDecoder, self).decompress(data, max_length=max_length)
+exceptTypeError:
+returnsuper(_GzipDecoder, self).decompress(data)

packages/google-resumable-media/google/resumable_media/requests/download.py

@@ -667,17 +667,22 @@ def __init__(self, checksum):
 super().__init__()
 self._checksum=checksum
 
-defdecompress(self, data):
+defdecompress(self, data, max_length=-1):
 """Decompress the bytes.
 
  Args:
  data (bytes): The compressed bytes to be decompressed.
+ max_length (int): Maximum number of bytes to return. -1 for no
+ limit. Forwarded to the underlying decoder when supported.
 
  Returns:
  bytes: The decompressed bytes from ``data``.
  """
 self._checksum.update(data)
-returnsuper().decompress(data)
+try:
+returnsuper().decompress(data, max_length=max_length)
+exceptTypeError:
+returnsuper().decompress(data)
 
 
 # urllib3.response.BrotliDecoder might not exist depending on whether brotli is
@@ -703,17 +708,29 @@ def __init__(self, checksum):
 self._decoder=urllib3.response.BrotliDecoder()
 self._checksum=checksum
 
-defdecompress(self, data):
+defdecompress(self, data, max_length=-1):
 """Decompress the bytes.
 
  Args:
  data (bytes): The compressed bytes to be decompressed.
+ max_length (int): Maximum number of bytes to return. -1 for no
+ limit. Forwarded to the underlying decoder when supported.
 
  Returns:
  bytes: The decompressed bytes from ``data``.
  """
 self._checksum.update(data)
-returnself._decoder.decompress(data)
+try:
+returnself._decoder.decompress(data, max_length=max_length)
+exceptTypeError:
+returnself._decoder.decompress(data)
+
+@property
+defhas_unconsumed_tail(self):
+try:
+returnself._decoder.has_unconsumed_tail
+exceptAttributeError:
+returnFalse
 
 defflush(self):
 returnself._decoder.flush()

packages/google-resumable-media/tests/unit/requests/test_download.py

@@ -1274,6 +1274,37 @@ def test_decompress(self):
 assertresult==b""
 md5_hash.update.assert_called_once_with(data)
 
+deftest_decompress_with_max_length(self):
+md5_hash=mock.Mock(spec=["update"])
+decoder=download_mod._GzipDecoder(md5_hash)
+
+withmock.patch.object(
+type(decoder).__bases__[0], "decompress"
+ ) asmock_super_decompress:
+mock_super_decompress.return_value=b"decompressed"
+data=b"\x1f\x8b\x08\x08"
+result=decoder.decompress(data, max_length=10)
+
+assertresult==b"decompressed"
+md5_hash.update.assert_called_once_with(data)
+mock_super_decompress.assert_called_once_with(data, max_length=10)
+
+deftest_decompress_with_max_length_fallback(self):
+md5_hash=mock.Mock(spec=["update"])
+decoder=download_mod._GzipDecoder(md5_hash)
+
+withmock.patch.object(
+type(decoder).__bases__[0],
+"decompress",
+side_effect=[TypeError, b"decompressed"],
+ ) asmock_super_decompress:
+data=b"\x1f\x8b\x08\x08"
+result=decoder.decompress(data, max_length=10)
+
+assertresult==b"decompressed"
+md5_hash.update.assert_called_once_with(data)
+assertmock_super_decompress.call_count==2
+
 
 classTest_BrotliDecoder(object):
 deftest_constructor(self):
@@ -1290,6 +1321,45 @@ def test_decompress(self):
 assertresult==b""
 md5_hash.update.assert_called_once_with(data)
 
+deftest_decompress_with_max_length(self):
+md5_hash=mock.Mock(spec=["update"])
+decoder=download_mod._BrotliDecoder(md5_hash)
+
+decoder._decoder=mock.Mock(spec=["decompress"])
+decoder._decoder.decompress.return_value=b"decompressed"
+
+data=b"compressed"
+result=decoder.decompress(data, max_length=10)
+
+assertresult==b"decompressed"
+md5_hash.update.assert_called_once_with(data)
+decoder._decoder.decompress.assert_called_once_with(data, max_length=10)
+
+deftest_decompress_with_max_length_fallback(self):
+md5_hash=mock.Mock(spec=["update"])
+decoder=download_mod._BrotliDecoder(md5_hash)
+
+decoder._decoder=mock.Mock(spec=["decompress"])
+decoder._decoder.decompress.side_effect= [TypeError, b"decompressed"]
+
+data=b"compressed"
+result=decoder.decompress(data, max_length=10)
+
+assertresult==b"decompressed"
+md5_hash.update.assert_called_once_with(data)
+assertdecoder._decoder.decompress.call_count==2
+
+deftest_has_unconsumed_tail(self):
+decoder=download_mod._BrotliDecoder(mock.sentinel.md5_hash)
+decoder._decoder=mock.Mock(spec=["has_unconsumed_tail"])
+decoder._decoder.has_unconsumed_tail=True
+assertdecoder.has_unconsumed_tailisTrue
+
+deftest_has_unconsumed_tail_fallback(self):
+decoder=download_mod._BrotliDecoder(mock.sentinel.md5_hash)
+decoder._decoder=mock.Mock(spec=[])
+assertdecoder.has_unconsumed_tailisFalse
+
 
 def_mock_response(status_code=http.client.OK, chunks=(), headers=None):
 ifheadersisNone:

packages/google-resumable-media/tests_async/unit/requests/test_download.py

@@ -761,6 +761,21 @@ def test_decompress(self):
 assertresult==b""
 md5_hash.update.assert_called_once_with(data)
 
+deftest_decompress_with_max_length(self):
+md5_hash=mock.Mock(spec=["update"])
+decoder=download_mod._GzipDecoder(md5_hash)
+
+withmock.patch.object(
+type(decoder).__bases__[0], "decompress"
+ ) asmock_super_decompress:
+mock_super_decompress.return_value=b"decompressed"
+data=b"\x1f\x8b\x08\x08"
+result=decoder.decompress(data, max_length=10)
+
+assertresult==b"decompressed"
+md5_hash.update.assert_called_once_with(data)
+mock_super_decompress.assert_called_once_with(data, max_length=10)
+
 
 classAsyncIter:
 def__init__(self, items):