ST_Simplify 3rd parameter is ignored

[Algunenano]

No matter what you pass as the 3rd parameter to ST_Simplify, it's always assumed as true:

# WITH params2 AS
(
    Select ST_Simplify(the_geom_webmercator, 1000000000) as g from public.benchmark_4c7214d90a79aa6760367a084a4d4a2f61fbe1c6cc4f7f9e76020
),
params3False AS
(
    Select ST_Simplify(the_geom_webmercator, 1000000000, false) as g from public.benchmark_4c7214d90a79aa6760367a084a4d4a2f61fbe1c6cc4f7f9e76020
),
params3True AS
(
    Select ST_Simplify(the_geom_webmercator, 1000000000, true) as g from public.benchmark_4c7214d90a79aa6760367a084a4d4a2f61fbe1c6cc4f7f9e76020
)
Select '2p', count(*) from params2 where g IS NOT NULL
UNION ALL
Select '3p_false', count(*) from params3False where g IS NOT NULL
UNION ALL
Select '3p_true', count(*) from params3True where g IS NOT NULL;
 ?column? | count 
----------+-------
 2p       |     0
 3p_false |    13
 3p_true  |    13
(3 rows)

Passing false as the 3rd parameter is being considered as a request to preserve the collapsed geometries, which is either a bug or highly counterintuitive.

[Algunenano]

Fix in ​https://github.com/postgis/postgis/pull/469

[algunenano]

In 17782:

Fix ST_Simplify ignoring the value of the 3rd parameter

References #4492
Closes ​https://github.com/postgis/postgis/pull/469

[algunenano]

In 17783:

Fix ST_Simplify ignoring the value of the 3rd parameter

References #4492

[algunenano]

In 17784:

Fix ST_Simplify ignoring the value of the 3rd parameter

References #4492

[algunenano]

In 17785:

Fix ST_Simplify ignoring the value of the 3rd parameter

Closes #4492