We are missing 4 bytes in the LZ4 compression buffer.

[fulmicoton]

Closes #831

[codecov-commenter]

Codecov Report

Merging #1226 (1aecb4e) into main (f378d9a) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1226      +/-   ##
==========================================
+ Coverage   94.10%   94.12%   +0.02%     
==========================================
  Files         205      205              
  Lines       34453    34452       -1     
==========================================
+ Hits        32421    32428       +7     
+ Misses       2032     2024       -8     

Impacted Files	Coverage Δ
src/store/compression_lz4_block.rs	89.47% <100.00%> (-0.27%)	⬇️
src/tokenizer/stemmer.rs	63.63% <0.00%> (-1.82%)	⬇️
src/directory/watch_event_router.rs	96.15% <0.00%> (-0.77%)	⬇️
src/query/union.rs	99.39% <0.00%> (+0.60%)	⬆️
src/indexer/segment_updater.rs	95.34% <0.00%> (+1.03%)	⬆️

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[PSeitz]

The 4 bytes are already included in get_maximum_output_size, but let's not rely on that

[fulmicoton]

The 4 bytes are already included in get_maximum_output_size, but let's not rely on that

The previous code was creating a slice with unallocated memory. (in addition to being uninitialized)

[PSeitz]

The previous code was creating a slice with unallocated memory. (in addition to being uninitialized)

With the reserve call, it should be allocated?
Uninitialized data is being handled in lz4_flex via MaybeUninit.

[fulmicoton]

@PSeitz Now it is allocated. Before this PR, the last 4 bytes were not necessarily allocated.
If you know how to deal with the MaybeUninitialized thing that would be awesome to remove the allow clippy thing.