topology failures in trunk

[robe]

This seems to be happening on all bots

 regress/topogeo_addlinestring .. failed (diff expected obtained: /var/lib/jenkins/workspace/postgis/tmp/2_5_pg9.6w64/test_29_diff)
-----------------------------------------------------------------------------
--- regress/topogeo_addlinestring_expected	2017-10-06 21:25:46.075418731 +0000
+++ /var/lib/jenkins/workspace/postgis/tmp/2_5_pg9.6w64/test_29_out	2017-10-06 21:26:12.335413798 +0000
@@ -186,8 +186,7 @@
 t3280.end|Topology 'bug3280' dropped
 t3380.start|t
 t3380.L1|1
-t3380.L2|3
-t3380.L2|4
+ERROR:  Invalid edge (no two distinct vertices exist)
 t3380.L3|5
 t3380.end|Topology 'bug3380' dropped
 t3402.start|t
-----------------------------------------------------------------------------

I'tm guessing this isn't caused by topology directly but because of pramsey vaccuming and dusting in #3877.

Issue started happening at r15925

[strk]

in_place removing too many points ?

[strk]

Paul please fix this ASAP as it blocks the ability to test new code

[strk]

could it be the line was already invalid before calling remove_repeated_point ? as reading the code chances are the old code would return a 2-equal-points line in that case, while current code fails the (maxpoints > 1) and thus returns it untouched (limits of "in-place")

[strk]

The failing test is for issue #3380 where you can find some data

[strk]

This is the test, self-contained, which can be tried with and without r15925:

SELECT 't3380.start', CreateTopology( 'bug3380', 0, 0.01) > 0;
SELECT 't3380.L1', TopoGeo_AddLinestring('bug3380', '
LINESTRING(
1612829.90652844007126987 4841274.48807844985276461,
1612830.1566380700096488 4841287.23833953030407429,
1612883.15799825009889901 4841277.73794914968311787)
', 0);
SELECT 't3380.L2', TopoGeo_AddLinestring('bug3380', '
LINESTRING(
1612790.88055733009241521 4841286.88526585046201944,
1612830.15823523001745343 4841287.12674008030444384,
1612829.98813172010704875 4841274.56198261026293039)
', 0);