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manifest: delay import of `typing.ByteString` for py 3.14 support (issue6940)...
manifest: delay import of `typing.ByteString` for py 3.14 support (issue6940) Since Python 2.7 and 3.5, `typing.ByteString` was defined as an alias for `bytes | bytearray | memoryview`, and `bytes` was also accepted as a shorthand for this, so we have `bytes` sprinkled all over the codebase. But then PEP-688 reversed all of that by deprecating `typing.ByteString` and its successor `collections.abc.ByteString` in Python 3.12 (as well as the `bytes` shorthand)[1], and removing it completely in Python 3.14. That leaves us with a couple of problems, namely defining something useful that spans py3.8-py3.13 and keeps pytype happy, and finding all of the instances where `bytes` doesn't really mean `bytes`. The current successor to all of this is `collections.abc.Buffer` in Python 3.12 (or `typing_extensions.Buffer` in previous versions). However, the current CI does type checking using Python 3.11 (so the former is not avaiable), and pytype has issues with importing `typing_extensions.Buffer`[2]. The good news is we don't need to deal with this mess immediately, since the type annotation evaluation is delayed to the type checking phase, and we're making no effort at supporting it in all supported versions of Python. So by delaying the import of this particular symbol, we can still use it for type checking purposes, but can start assessing Python 3.14 problems without doing a lot of extra work. Putting this on stable will allow people interested in 3.14 to work on it 4-5 extra months earlier (and apparently there's some interest). [1] https://peps.python.org/pep-0688/#no-special-meaning-for-bytes [2] https://github.com/google/pytype/issues/1772

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test_data_structures.py
255 lines | 8.9 KiB | text/x-python | PythonLexer
import sys
import unittest
import zstandard as zstd
from .common import (
make_cffi,
TestCase,
)
@make_cffi
class TestCompressionParameters(TestCase):
def test_bounds(self):
zstd.ZstdCompressionParameters(
window_log=zstd.WINDOWLOG_MIN,
chain_log=zstd.CHAINLOG_MIN,
hash_log=zstd.HASHLOG_MIN,
search_log=zstd.SEARCHLOG_MIN,
min_match=zstd.MINMATCH_MIN + 1,
target_length=zstd.TARGETLENGTH_MIN,
strategy=zstd.STRATEGY_FAST,
)
zstd.ZstdCompressionParameters(
window_log=zstd.WINDOWLOG_MAX,
chain_log=zstd.CHAINLOG_MAX,
hash_log=zstd.HASHLOG_MAX,
search_log=zstd.SEARCHLOG_MAX,
min_match=zstd.MINMATCH_MAX - 1,
target_length=zstd.TARGETLENGTH_MAX,
strategy=zstd.STRATEGY_BTULTRA2,
)
def test_from_level(self):
p = zstd.ZstdCompressionParameters.from_level(1)
self.assertIsInstance(p, zstd.CompressionParameters)
self.assertEqual(p.window_log, 19)
p = zstd.ZstdCompressionParameters.from_level(-4)
self.assertEqual(p.window_log, 19)
def test_members(self):
p = zstd.ZstdCompressionParameters(
window_log=10,
chain_log=6,
hash_log=7,
search_log=4,
min_match=5,
target_length=8,
strategy=1,
)
self.assertEqual(p.window_log, 10)
self.assertEqual(p.chain_log, 6)
self.assertEqual(p.hash_log, 7)
self.assertEqual(p.search_log, 4)
self.assertEqual(p.min_match, 5)
self.assertEqual(p.target_length, 8)
self.assertEqual(p.compression_strategy, 1)
p = zstd.ZstdCompressionParameters(compression_level=2)
self.assertEqual(p.compression_level, 2)
p = zstd.ZstdCompressionParameters(threads=4)
self.assertEqual(p.threads, 4)
p = zstd.ZstdCompressionParameters(
threads=2, job_size=1048576, overlap_log=6
)
self.assertEqual(p.threads, 2)
self.assertEqual(p.job_size, 1048576)
self.assertEqual(p.overlap_log, 6)
self.assertEqual(p.overlap_size_log, 6)
p = zstd.ZstdCompressionParameters(compression_level=-1)
self.assertEqual(p.compression_level, -1)
p = zstd.ZstdCompressionParameters(compression_level=-2)
self.assertEqual(p.compression_level, -2)
p = zstd.ZstdCompressionParameters(force_max_window=True)
self.assertEqual(p.force_max_window, 1)
p = zstd.ZstdCompressionParameters(enable_ldm=True)
self.assertEqual(p.enable_ldm, 1)
p = zstd.ZstdCompressionParameters(ldm_hash_log=7)
self.assertEqual(p.ldm_hash_log, 7)
p = zstd.ZstdCompressionParameters(ldm_min_match=6)
self.assertEqual(p.ldm_min_match, 6)
p = zstd.ZstdCompressionParameters(ldm_bucket_size_log=7)
self.assertEqual(p.ldm_bucket_size_log, 7)
p = zstd.ZstdCompressionParameters(ldm_hash_rate_log=8)
self.assertEqual(p.ldm_hash_every_log, 8)
self.assertEqual(p.ldm_hash_rate_log, 8)
def test_estimated_compression_context_size(self):
p = zstd.ZstdCompressionParameters(
window_log=20,
chain_log=16,
hash_log=17,
search_log=1,
min_match=5,
target_length=16,
strategy=zstd.STRATEGY_DFAST,
)
# 32-bit has slightly different values from 64-bit.
self.assertAlmostEqual(
p.estimated_compression_context_size(), 1294464, delta=400
)
def test_strategy(self):
with self.assertRaisesRegex(
ValueError, "cannot specify both compression_strategy"
):
zstd.ZstdCompressionParameters(strategy=0, compression_strategy=0)
p = zstd.ZstdCompressionParameters(strategy=2)
self.assertEqual(p.compression_strategy, 2)
p = zstd.ZstdCompressionParameters(strategy=3)
self.assertEqual(p.compression_strategy, 3)
def test_ldm_hash_rate_log(self):
with self.assertRaisesRegex(
ValueError, "cannot specify both ldm_hash_rate_log"
):
zstd.ZstdCompressionParameters(
ldm_hash_rate_log=8, ldm_hash_every_log=4
)
p = zstd.ZstdCompressionParameters(ldm_hash_rate_log=8)
self.assertEqual(p.ldm_hash_every_log, 8)
p = zstd.ZstdCompressionParameters(ldm_hash_every_log=16)
self.assertEqual(p.ldm_hash_every_log, 16)
def test_overlap_log(self):
with self.assertRaisesRegex(
ValueError, "cannot specify both overlap_log"
):
zstd.ZstdCompressionParameters(overlap_log=1, overlap_size_log=9)
p = zstd.ZstdCompressionParameters(overlap_log=2)
self.assertEqual(p.overlap_log, 2)
self.assertEqual(p.overlap_size_log, 2)
p = zstd.ZstdCompressionParameters(overlap_size_log=4)
self.assertEqual(p.overlap_log, 4)
self.assertEqual(p.overlap_size_log, 4)
@make_cffi
class TestFrameParameters(TestCase):
def test_invalid_type(self):
with self.assertRaises(TypeError):
zstd.get_frame_parameters(None)
# Python 3 doesn't appear to convert unicode to Py_buffer.
if sys.version_info[0] >= 3:
with self.assertRaises(TypeError):
zstd.get_frame_parameters(u"foobarbaz")
else:
# CPython will convert unicode to Py_buffer. But CFFI won't.
if zstd.backend == "cffi":
with self.assertRaises(TypeError):
zstd.get_frame_parameters(u"foobarbaz")
else:
with self.assertRaises(zstd.ZstdError):
zstd.get_frame_parameters(u"foobarbaz")
def test_invalid_input_sizes(self):
with self.assertRaisesRegex(
zstd.ZstdError, "not enough data for frame"
):
zstd.get_frame_parameters(b"")
with self.assertRaisesRegex(
zstd.ZstdError, "not enough data for frame"
):
zstd.get_frame_parameters(zstd.FRAME_HEADER)
def test_invalid_frame(self):
with self.assertRaisesRegex(zstd.ZstdError, "Unknown frame descriptor"):
zstd.get_frame_parameters(b"foobarbaz")
def test_attributes(self):
params = zstd.get_frame_parameters(zstd.FRAME_HEADER + b"\x00\x00")
self.assertEqual(params.content_size, zstd.CONTENTSIZE_UNKNOWN)
self.assertEqual(params.window_size, 1024)
self.assertEqual(params.dict_id, 0)
self.assertFalse(params.has_checksum)
# Lowest 2 bits indicate a dictionary and length. Here, the dict id is 1 byte.
params = zstd.get_frame_parameters(zstd.FRAME_HEADER + b"\x01\x00\xff")
self.assertEqual(params.content_size, zstd.CONTENTSIZE_UNKNOWN)
self.assertEqual(params.window_size, 1024)
self.assertEqual(params.dict_id, 255)
self.assertFalse(params.has_checksum)
# Lowest 3rd bit indicates if checksum is present.
params = zstd.get_frame_parameters(zstd.FRAME_HEADER + b"\x04\x00")
self.assertEqual(params.content_size, zstd.CONTENTSIZE_UNKNOWN)
self.assertEqual(params.window_size, 1024)
self.assertEqual(params.dict_id, 0)
self.assertTrue(params.has_checksum)
# Upper 2 bits indicate content size.
params = zstd.get_frame_parameters(
zstd.FRAME_HEADER + b"\x40\x00\xff\x00"
)
self.assertEqual(params.content_size, 511)
self.assertEqual(params.window_size, 1024)
self.assertEqual(params.dict_id, 0)
self.assertFalse(params.has_checksum)
# Window descriptor is 2nd byte after frame header.
params = zstd.get_frame_parameters(zstd.FRAME_HEADER + b"\x00\x40")
self.assertEqual(params.content_size, zstd.CONTENTSIZE_UNKNOWN)
self.assertEqual(params.window_size, 262144)
self.assertEqual(params.dict_id, 0)
self.assertFalse(params.has_checksum)
# Set multiple things.
params = zstd.get_frame_parameters(
zstd.FRAME_HEADER + b"\x45\x40\x0f\x10\x00"
)
self.assertEqual(params.content_size, 272)
self.assertEqual(params.window_size, 262144)
self.assertEqual(params.dict_id, 15)
self.assertTrue(params.has_checksum)
def test_input_types(self):
v = zstd.FRAME_HEADER + b"\x00\x00"
mutable_array = bytearray(len(v))
mutable_array[:] = v
sources = [
memoryview(v),
bytearray(v),
mutable_array,
]
for source in sources:
params = zstd.get_frame_parameters(source)
self.assertEqual(params.content_size, zstd.CONTENTSIZE_UNKNOWN)
self.assertEqual(params.window_size, 1024)
self.assertEqual(params.dict_id, 0)
self.assertFalse(params.has_checksum)