Issues with shift

[SamHames]

Example 1

I found a weird bug (or bugs) with shifting - I think I can replicate this first one with croaring alone though so I will raise an issue there to confirm. The failures happen with both the current croaring and the latest release (v2.1.0).

import pyroaring
x = pyroaring.BitMap(range(0, 9000, 2)).shift(64000)
y = pyroaring.BitMap.deserialize(x.serialize())
print(y)
print(set(y))

The output should be (64000, 64002, 64004, ...), but you don't even get a set:

BitMap([    0,
            0,
            0,
            0,
            0,
        ...
        87381,
        87381,
        87381,
        87381,
        87381])
{0, 65536, 87381}

Example 2

Another case that fails with a segfault, but only when copy_on_write is enabled (transcribed from the test case - hypothesis doesn't deal well with a segfault). The segfault happens in the final comparison.

from pyroaring import BitMap

cls = BitMap  # Also fails with FrozenBitMap
values = range(67335, 68618, 8) 
offset = 33554432 
cow = True  # Doesn't fail when this is off

bm_before = cls(values, copy_on_write=cow)
bm_copy = cls(bm_before)
bm_after = bm_before.shift(offset)
assert(bm_before == bm_copy)
expected = cls([val+offset for val in values if val+offset in range(0, 2**32)], copy_on_write=cow)
assert(bm_after == expected)

[lemire]

I recommend updating to 2.1.1:
https://github.com/RoaringBitmap/CRoaring/releases/tag/v2.1.1

It should fix the issue.

[lemire]

Fixed the second bug in the next release

https://github.com/RoaringBitmap/CRoaring/releases/tag/v2.1.2