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Use correct flags variable for c-i #50

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Use correct flags variable for c-i #50

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@theuni theuni commented Sep 28, 2021

CFLAGS is unused, so the tests have likely been running without these flags set.

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Use correct flags variable for c-i
9eeab47 
CFLAGS is unused, so the tests have likely been running without these flags
set.
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theuni commented Sep 28, 2021

This uncovered some potential UB in a test:

$ ./test-verify

Running libminisketch tests in verify mode with complexity=4
src/test.cpp:118:45: runtime error: shift exponent 64 is too large for 64-bit type 'long unsigned int'
#0 0x562072e2453c in (anonymous namespace)::TestExhaustive(unsigned int, unsigned long) (/home/cory/dev/minisketch/test-verify+0x6a153c)
#1 0x562072e26df9 in main (/home/cory/dev/minisketch/test-verify+0x6a3df9)
#2 0x7f5a8c7070b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
#3 0x562072e235ad in _start (/home/cory/dev/minisketch/test-verify+0x6a05ad)

@sipa sipa mentioned this pull request Sep 29, 2021
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sipa commented Sep 29, 2021

See #51.

sipa added a commit that referenced this pull request Oct 1, 2021
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Merge #51: Fix exhaustive test check
c1a4488 
294b6c5 Use correct flags variable for c-i (Cory Fields)
8d52856 Fix exhaustive test check (Pieter Wuille)

Pull request description:

  There were 3 issues:

  1. The comparison between `counts[...]` and `Combination()` wasn't running at all (`(i >> bits)` is always 0 for i==0, so the loop would instantly exit).
  2. The `counts` values were wrong (because it was counting a sum across all implementation), so if they would be compared to something, the test would incorrectly fail.
  3. `(i >> bits)` is undefined when bits==64.

  (1) would be fixed by changing `i >> bits` to `(i >> bits) == 0`, but that leaves issue (3), so introduce a `mask` and use a different way of writing the same, that keeps working for bits==64. (2) is fixed by only incrementing counts[...] for impl==0.

  This was discovered through #50.

ACKs for top commit:
  naumenkogs:
    ACK 294b6c5

Tree-SHA512: 770af770898fb82abf390b7cd21f6ac8657d16dbf391c1d5825c62a3c17c8d50a36481f91254020bd00bfdda493507406df2110292fe8edc396db28181ca94b5
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sipa commented Oct 1, 2021

Merged as part of #51.

@sipa sipa closed this Oct 1, 2021
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