floating point bounds not as expected

[danschan]

What version of CUE are you using (cue version)?

$ cue version 0.4.0 windows/amd64

Does this issue reproduce with the latest release?

yes

What did you do?

evaluated

foo: {
	"value": >=2.1 & <=1.0
}

What did you expect to see?

foo.value: incompatible bounds >=2.1 and <=1.0

What did you see instead?

foo: {
    value: >=2.1 & <=1.0
}

[verdverm]

Are you trying to say it must be outside of (1.0,2.1)?

What you have wrote is that it must be both >=2.1 and <=1.0 at the same time.

You may be looking for value: >=2.1 | <= 1.0 (a disjunction, of which only one should be valid)

[danschan]

This is only an example for the issue.

If I evaluate ">=2.1 & <=1.1" or ">=2 & <=1" at the same time, cue correctly reports an error. For ">=2.1 & <=1.0" not.

Originally my values were derrived from multiple schemes, but this example reproduces the behaviour in the most simple way.

[verdverm]

Ah, this same unreported error happens for >=number & <= int (>=2.1 & <=1)

I have a hunch this has to do with mixed type comparison (number vs int) and that 1.0 is probably converted to 1 as an int rather than a decimal

[verdverm]

Also, just as an FYI, cue uses an arbitrary precision decimal and not floating point.

https://pkg.go.dev/cuelang.org/[email protected]/internal/core/adt#Num

(the comment there looks to confirm 1.0 is really seen as 1 the int)

[mpvl]

Interesting. Should be easy to fix.

[antong]

I think the bug is around:

cue/internal/core/adt/simplify.go

Line 130 in 3b0a537

switch diff, err := d.Int64(); {

Decimal d.Int64() returns an error if d is not an integer, and SimplifyBounds returns nil. So if the difference between the high and low bound is not integral, then simplification is not done for floats.

>=22.1 & <2.0 // >=22.1 & <2.0
>=22.1 & <2.1 // _|_ incompatible bounds >=22.1 and <2.1
>=22   & <2.0 // _|_ incompatible bounds >=22 and <2.0

[mpvl]

@antong: the bug was indeed in that switch statement.