ST_Subdivide loses boxes on some inputs

[komzpa]

There is landmass geometry that ST_Subdivide fails to correctly split. It loses a whole big box, producing a warning:

[local] gis@gis=# select ST_IsValid(geom) from bad_geom;
┌────────────┐
│ st_isvalid │
├────────────┤
│ t          │
└────────────┘
(1 row)

Time: 686,142 ms
[local] gis@gis=# select ST_IsSimple(geom) from bad_geom;
┌─────────────┐
│ st_issimple │
├─────────────┤
│ t           │
└─────────────┘
(1 row)

Time: 37,460 ms
[local] gis@gis=# select ST_Subdivide(geom) from bad_geom limit 1;
NOTICE:  00000: Error performing rectangular clipping: IllegalArgumentException: Invalid number of points in LinearRing found 3 - must be 0 or >= 4
LOCATION:  pg_notice, lwgeom_pg.c:184
┌────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│                                                                                            st_subdivide                                                                                            │
├────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ 0103000020110F00000100000005000000DB916D3B01A260C100000060C3CE5141000000F00C9F60C100000060C3CE5141000000F00C9F60C1E7B8076F2BC85141F6285CC78CA160C148E17A94BFCD5141DB916D3B01A260C100000060C3CE5141 │
└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
(1 row)

Time: 2070,714 ms (00:02,071)

[komzpa]

On ST_Subdivide(geom, 10) it has two such boxes.

[komzpa]

I hope that ​https://github.com/postgis/postgis/pull/154 may be a way to fix.

I don't know how to make a smaller reproducer to put it into regress tests.

[komzpa]

Workaround: ST_Subdivide(ST_FilterSmallRings(geom, 1)) using ST_FilterSmallRings from ​https://github.com/gojuno/lostgis/blob/master/sql/functions/ST_FilterSmallRings.sql

[pramsey]

In 15965:

Fix rare missing boxes in geometry subdivision
References #3886

[pramsey]

In 15966:

Fix rare missing boxes in geometry subdivision
Closes #3886

[robe]

@pramsey minor gripe.

You are supposed to put Darafei Praliaskouski in the commit and NEWS credits

[strk]

I'm so glad you're around Regina

PS: I've instructed other contributors to do this themselves, and it worked nicely. Kompza take note!