Matej Cepl
93092331ad
(gh#MagicStack/immutables#69) so we have removed skip_32bit_tests.patch and added new solution which actually fixes the issue: test_none_collisions-32-bit.patch. OBS-URL: https://build.opensuse.org/package/show/devel:languages:python/python-immutables?expand=0&rev=15
72 lines
2.2 KiB
Diff
72 lines
2.2 KiB
Diff
From a52107d45023a29fe24b97efe849915429e9bb96 Mon Sep 17 00:00:00 2001
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From: Elvis Pranskevichus <elvis@edgedb.com>
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Date: Tue, 3 Aug 2021 18:04:22 -0700
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Subject: [PATCH] Fix test_none_collisions on 32-bit systems
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There are two issues at play here:
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1. Python version of `map_hash` unnecessarily performs hash truncation
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even if the hash is already 32-bit wide, which potentially converts
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it from signed int to unsigned long.
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2. The `test_none_collisions` test generates a collision node with
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hash greater than 2^32.
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Both of these are problematic on 32-bit systems, where `sizeof(Py_hash_t)`
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is 4, and so anything that doesn't fit into `Py_hash_t` gets bit-mangled,
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breaking the `hash(x) != x` invariance that the test relies upon.
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Fixes: #53
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Fixes: #50
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---
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immutables/map.py | 5 ++++-
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tests/test_none_keys.py | 14 +++++++++-----
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2 files changed, 13 insertions(+), 6 deletions(-)
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--- a/immutables/map.py
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+++ b/immutables/map.py
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@@ -19,7 +19,10 @@ _mut_id = itertools.count(1).__next__
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def map_hash(o):
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x = hash(o)
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- return (x & 0xffffffff) ^ ((x >> 32) & 0xffffffff)
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+ if sys.hash_info.width > 32:
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+ return (x & 0xffffffff) ^ ((x >> 32) & 0xffffffff)
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+ else:
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+ return x
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def map_mask(hash, shift):
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--- a/tests/test_none_keys.py
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+++ b/tests/test_none_keys.py
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@@ -1,3 +1,4 @@
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+import ctypes
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import unittest
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from immutables.map import map_hash, map_mask, Map as PyMap
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@@ -6,16 +7,19 @@ from immutables._testutils import HashKe
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none_hash = map_hash(None)
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assert(none_hash != 1)
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-assert((none_hash >> 32) == 0)
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+assert(none_hash.bit_length() <= 32)
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-not_collision = 0xffffffff & (~none_hash)
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+none_hash_u = ctypes.c_size_t(none_hash).value
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+not_collision = 0xffffffff & (~none_hash_u)
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mask = 0x7ffffffff
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-none_collisions = [none_hash & (mask >> shift)
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+none_collisions = [none_hash_u & (mask >> shift)
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for shift in reversed(range(0, 32, 5))]
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assert(len(none_collisions) == 7)
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-none_collisions = [h | (not_collision & (mask << shift))
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- for shift, h in zip(range(5, 37, 5), none_collisions)]
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+none_collisions = [
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+ ctypes.c_ssize_t(h | (not_collision & (mask << shift))).value
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+ for shift, h in zip(range(5, 37, 5), none_collisions)
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+]
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class NoneCollision(HashKey):
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