topogeom test failing on GEOS 3.9

[robe]

Looks like the topogeom tests have been failing on debbie at least for the past 5 days or so. Looks like a geos issue might just be order of output is different.

18:23:50  ./topology/test/regress/totopogeom .. failed (diff expected obtained: /var/lib/jenkins/workspace/postgis/tmp/3_1_pg12w64/test_191_diff)
18:23:51 -----------------------------------------------------------------------------
18:23:51 --- ./topology/test/regress/totopogeom_expected	2020-03-03 15:25:18.578620504 +0000
18:23:51 +++ /var/lib/jenkins/workspace/postgis/tmp/3_1_pg12w64/test_191_out	2020-11-30 23:23:51.537992477 +0000
18:23:51 @@ -24,7 +24,7 @@
18:23:51  MULTIPOINT(0 -10,5 -10)|t
18:23:51  MULTILINESTRING((-1 10,-10 10),(-10 8,-2 9))|t
18:23:51  MULTIPOLYGON(((100 20,110 20,105 30,100 20),(102 22,108 22,105 28,102 22)),((80 20,90 20,90 60,80 20)))|t
18:23:51 -GEOMETRYCOLLECTION(POINT(-100 -100),LINESTRING(-100 -90,-90 -90),POLYGON((-100 -80,-90 -80,-95 -70,-100 -80),(-98 -78,-92 -78,-95 -72,-98 -78)),MULTIPOINT(-100 -110,-95 -110),LINESTRING EMPTY,MULTILINESTRING((-101 -90,-110 -90),(-110 -92,-102 -91)),MULTIPOLYGON(((0 -80,10 -80,5 -70,0 -80),(2 -78,8 -78,5 -72,2 -78)),((-20 -80,-10 -80,-10 -40,-20 -80))))|GEOMETRYCOLLECTION(MULTIPOLYGON(((-100 -80,-95 -70,-90 -80,-100 -80),(-98 -78,-92 -78,-95 -72,-98 -78)),((0 -80,5 -70,10 -80,0 -80),(2 -78,8 -78,5 -72,2 -78)),((-20 -80,-10 -40,-10 -80,-20 -80))),MULTILINESTRING((-110 -92,-102 -91),(-101 -90,-110 -90),(-100 -90,-90 -90)),MULTIPOINT(-100 -110,-100 -100,-95 -110))
18:23:51 +GEOMETRYCOLLECTION(POINT(-100 -100),LINESTRING(-100 -90,-90 -90),POLYGON((-100 -80,-90 -80,-95 -70,-100 -80),(-98 -78,-92 -78,-95 -72,-98 -78)),MULTIPOINT(-100 -110,-95 -110),LINESTRING EMPTY,MULTILINESTRING((-101 -90,-110 -90),(-110 -92,-102 -91)),MULTIPOLYGON(((0 -80,10 -80,5 -70,0 -80),(2 -78,8 -78,5 -72,2 -78)),((-20 -80,-10 -80,-10 -40,-20 -80))))|GEOMETRYCOLLECTION(MULTIPOLYGON(((-95 -70,-90 -80,-100 -80,-95 -70),(-92 -78,-95 -72,-98 -78,-92 -78)),((-10 -80,-20 -80,-10 -40,-10 -80)),((10 -80,0 -80,5 -70,10 -80),(5 -72,2 -78,8 -78,5 -72))),MULTILINESTRING((-110 -92,-102 -91),(-101 -90,-110 -90),(-100 -90,-90 -90)),MULTIPOINT(-100 -110,-100 -100,-95 -110))
18:23:51  MULTIPOINT EMPTY
18:23:51  MULTIPOINT EMPTY
18:23:51  MULTILINESTRING EMPTY

[robe]

winnie has same issue and according to winnie started happening 11/28 this is the first commit that triggers the error

Summary

    Add ST_ReducePrecision for GEOS 3.9+. (details)

Commit d8fb00c553417d04860256ca5e2be2390248f7e2 by pramsey

Add ST_ReducePrecision for GEOS 3.9+.
Uses GEOS setPrecision CAPI routine to round coordinates
to grid while retaining a fully valid output.

The file was modified	liblwgeom/lwgeom_geos.c
The file was modified	postgis/postgis.sql.in
The file was modified	regress/core/geos39.sql
The file was modified	liblwgeom/lwkmeans.c
The file was modified	regress/core/geos39_expected
The file was modified	NEWS
The file was modified	liblwgeom/liblwgeom.h.in
The file was modified	postgis/lwgeom_geos.c
The file was modified	doc/reference_processing.xml

[Regina Obe <lr@…>]

In b2ad18b/git:

Fix for GEOS 3.9 regression topogeom - references #4809 for PostGIS 3.0

[Regina Obe <lr@…>]

In 76427f6b/git:

Fix for GEOS 3.9 regression topogeom - closes #4809 for PostGIS 3.1

[robe]

oops looks like I accidentally committed the regenerated bison files.