ST_Intersection returns invalid Linestring with Polygon and Linestring

[nbvfgh]

Take the intersection of the polygon and line string shown in the following figure：

SELECT ST_AsText(ST_Intersection(geom.b, geom.a))AS intersection 
    FROM (SELECT ST_GeomFromText('POLYGON ((2 0, 0 2, 2 2, 2 0))') As a,
    ST_GeomFromText('LINESTRING(0 0, 0.4 1.6, 1 0)') As b) As geom;

-- expected : {Point(0.4, 1.6)}
-- actual   : {LINESTRING(0.4 1.6,0.4 1.6)}

And the returned Linestring is invalid:

SELECT ST_IsValid('LINESTRING(0.4 1.6,0.4 1.6)');

-- result : {f}

Version Info:
GEOS="3.13.0-CAPI-1.19.0"

[dr-jts]

This is essentially the same issue as #1136.

[nbvfgh]

I wonder if this is a bug or if it's pre-defined. Thank you.

This is essentially the same issue as #1136.

[dr-jts]

I wonder if this is a bug or if it's pre-defined.

It's more of a design choice than a bug. And it seems that it's an unpopular one :)