[postgis-devel] GEOSLineMergeDirected

[Regina Obe]

It won’t cause any problems if you overload it rather than add a default arg.

 

The default arg is cleaner, since we won’t have an additional function to contend with.

The main danger with adding a default arg is anybody who is using ST_LineMerge in views will have some upgrade issues.  Since adding a default arg requires dropping the old version.

 

Though Sandro made some adjustments to partly resolve that. https://trac.osgeo.org/postgis/ticket/5033

It renames the old function (assuming you put in the right availability comments) and then if there are views dependent on the old (because views references the oid of the function, and not the function name),  then the upgrade will be in an incomplete upgrade state (will just have those dangling old names)

 

https://trac.osgeo.org/postgis/changeset/3d947448b9c939b321bc22b85c719845722ecc3d/git

 

 

 

 

From: postgis-devel [mailto:postgis-devel-bounces at lists.osgeo.org] On Behalf Of Martin Davis
Sent: Tuesday, May 24, 2022 1:57 PM
To: PostGIS Development Discussion <postgis-devel at lists.osgeo.org>
Subject: [postgis-devel] GEOSLineMergeDirected

 

This is now merged in GEOS (for the upcoming 3.11).

 

How should it be exposed in PostGIS?  Nicest might be an optional "directed=false" flag on ST_LineMerge.  But will that cause upgrade problems?

 

Less nice IMO would be a new function ST_LineMergeDirected.

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