Fix integer underflow in assertion in SparseFixedBitSet#16347
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For values close to Integer.MAX_VALUE, the blockCount calculation in SparseFixedBitSet can result in an assertion tripping. The method checks that the calculated block count will cover the full length of the bitset; if the block count covers the whole integer range, the check will underflow to a negative value, which compares as smaller than the passed-in length. This is fixed by a simple cast to long. Note that the error is only in the assertion; the actual calculated block count is correct and there is no production bug.
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Elasticsearch CI uncovered this - it's very rare, the randomised test in question has been running for a year and only just found the bug. |
dweiss
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For values close to Integer.MAX_VALUE, the blockCount calculation in SparseFixedBitSet can result in an assertion tripping. The method checks that the calculated block count will cover the full length of the bitset; if the block count covers the whole integer range, the check will underflow to a negative value, which compares as smaller than the passed-in length. This is fixed by a simple cast to long. Note that the error is only in the assertion; the actual calculated block count is correct and there is no production bug.
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For values close to Integer.MAX_VALUE, the blockCount calculation in SparseFixedBitSet can result in an assertion tripping. The method checks that the calculated block count will cover the full length of the bitset; if the block count covers the whole integer range, the check will underflow to a negative value, which compares as smaller than the passed-in length. This is fixed by a simple cast to long.
Note that the error is only in the assertion; the actual calculated block count is correct and there is no production bug.