Incorrect usage of abs_sub
#120
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`x.abs_sub(y)` is defined ([confusingly](rust-lang/rust#30315)) as `max(x-y, 0)`, not `abs(x-y)`. This wasn't caught in tests since `t_x - t_y` in [src/algorithm/intersects.rs:48](https://github.com/georust/rust-geo/blob/master/src/algorithm/intersects.rs#L48) is positive in all of the given examples.
src/algorithm/intersects.rs
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| @@ -442,6 +442,7 @@ mod test { | |||
| #[test] | |||
| fn point_intersects_line_test() { | |||
| let p0 = Point::new(2., 4.); | |||
| let p1 = Point::new(0., 0.); | |||
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No big deal, but rather than adding another point, it seems like the existing pattern of this test is to have one point, and then a line for every test case with a comment explaining why that particular line is interesting.
As written, it's not clear why that point is an interesting test case outside of the context of this PR.
Maybe this would be a little clearer:
// Line below point
let line4 = Line::new(Point::new(0.,0.), Point::new(5., 0.)
assert!(!line4.intersects(&p0));
// Line above point
let line5 = Line::new(Point::new(0.,5.), Point::new(5., 5.)
assert!(!line5.intersects(&p0));
| assert!(!line6.intersects(&p0)); | ||
| assert!(!p0.intersects(&line6)); | ||
| assert!(!line7.intersects(&p0)); | ||
| assert!(!p0.intersects(&line7)); |
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@michaelkirk: to follow up on your previous comment, the failure occurs when the point is above a line with positive slope or below a line with negative slope. So I included examples above and below lines with positive and negative slopes. On master, lines 465-466 (line4) and lines 471-472 (line7) will fail.
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Wow, good catch! Thanks! 🙇♂️ |
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bors: r+ |
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bors r+ |
120: Incorrect usage of `abs_sub` r=frewsxcv `x.abs_sub(y)` is defined ([confusingly](rust-lang/rust#30315)) as `max(x-y, 0)`, not `abs(x-y)`. This wasn't caught in tests since `t_x - t_y` in [src/algorithm/intersects.rs:48](https://github.com/georust/rust-geo/blob/master/src/algorithm/intersects.rs#L48) happens to be positive in all of the given examples so I've added a new example where `t_x - t_y` is negative.
Build succeeded |
x.abs_sub(y)is defined (confusingly) asmax(x-y, 0), notabs(x-y). This wasn't caught in tests sincet_x - t_yin src/algorithm/intersects.rs:48 happens to be positive in all of the given examples so I've added a new example wheret_x - t_yis negative.