intersection return empty

[ljw0701]

Why I do intersection with wagyu return 'MULTIPOLYGON EMPTY',but do intersection with GEOS return a geometry object?
e.g.
select st_astext(st_intersection(ST_GeomFromText('POLYGON((2600140.901 -603782.437400002, 2600545.2722 -603782.437400002, 2600545.2722 -603279.563999999, 2600140.901 -603279.563999999, 2600140.901 -603782.437400002))', 3857), ST_GeomFromText('POLYGON((2600245.2722 -603682.437400002,2600245.2722 -603682.437400002,2600244.66725 -603682.174225002,2600244.0623 -603681.911050001,2600243.45735 -603681.647875001,2600242.8524 -603681.3847,2600242.8524 -603681.3847,2600242.8524 -603681.3847,2600242.8524 -603681.3847,2600242.61455 -603680.929525,2600242.3767 -603680.47435,2600242.13885 -603680.019175,2600241.901 -603679.563999999,2600241.901 -603679.563999999,2600241.901 -603679.563999999,2600241.901 -603679.563999999,2600242.7438 -603680.28235,2600243.5866 -603681.000700001,2600244.4294 -603681.719050001,2600245.2722 -603682.437400002,2600245.2722 -603682.437400002))', 3857)));

[springmeyer]

/cc @flippmoke @ericfischer

[flippmoke]

@ljw0701 could you provide a screen shot of the original geometry, my bet here is that Wagyu simply collapses the resulting geometry into a line then removes it. This happens due to the way that Wagyu uses snap rounding internally in the algorithm.