saethlin opened a new pull request, #1906:
URL: https://github.com/apache/arrow-rs/pull/1906
Previously, this code tried to turn a &[u8] into a &[u32] without
checking alignment. This means it could and did create misaligned
references, which is UB. This can be detected by running the tests with
-Zbuild-std --target=x86_64-unknown-linux-gnu (or whatever your host
is). This change adopts the approach from the murmurhash implementation.
The previous implementation also ignored the tail bytes. The loop at the
end treats num_bytes as if it is the full length of the slice, but it
isn't, num_bytes number of bytes after the last 4-byte group. This can
be observed for example by changing "hello" to just "hell" in the tests.
Under the old implementation, the test will still pass. Now, the value
that comes out changes, and "hello" and "hell" hash to different values.
# Which issue does this PR close?
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# Rationale for this change
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