Make TestCounterAddLarge more robust #567
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The previous `float64(math.MaxUint64 + 1)` is too close to `float64(math.MaxUint64)` to actually overflow as indended. The counter code is actually converting forward and backward and compare the original and twice-converted value. On most platform, this will create a deviation and thus trigger the expected behavior. By sheer "luck", one might end up with the same value and thus still use the uint64 representation. Which is OK within the precision we can expect. But it breaks the test. With this change, the next representable floating point value greater than the floating point value used to represent math.MaxUint64 is used. Signed-off-by: Bjoern Rabenstein <bjoern@rabenste.in>
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Thanks @brian-brazil . This change makes things saner in any case. @xnox please follow up on this (or #530) if your tests are still failing. |
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With this patch applied, build passed on arm64 ppc64el s390x. Cherrypicked into Ubuntu and uploaded. |
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The previous
float64(math.MaxUint64 + 1)is too close tofloat64(math.MaxUint64)to actually overflow as indended.The counter code is actually converting forward and backward and
compare the original and twice-converted value. On most platform, this
will create a deviation and thus trigger the expected behavior. By
sheer "luck", one might end up with the same value and thus still use
the uint64 representation. Which is OK within the precision we can
expect. But it breaks the test. With this change, the next
representable floating point value greater than the floating point
value used to represent math.MaxUint64 is used.
@xnox this should fix #530. Could you verify?
@TheTincho you might have seen this issue, too, for the Debian builds on the affected platforms.