[postgis-tickets] [PostGIS] #3989: Add single-sided buffer functionality from geos

[PostGIS]

#3989: Add single-sided buffer functionality from geos
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 Reporter:  stev00   |      Owner:  pramsey
     Type:  patch    |     Status:  new
 Priority:  medium   |  Milestone:  PostGIS 2.4.3
Component:  postgis  |    Version:  2.4.x
 Keywords:           |
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 I noticed that the ST_Buffer function does not implement the single-sided
 option available in geos (since CAPIv1 I think looking at git blame).

 I have added a patch to address this. It is not yet comprehensive as,
 being a new contributor, I would like some feedback on what the function
 signature should be etc.

 At the moment, it is implemented as a text string in
 buffer_style_parameters as this seemed like an appropriate option, but
 very happy to be corrected on this. It is a slightly messy implementation,
 as the parameter to the geos function is an integer, so I have kept it as
 that, although it could easily be a text 't' or 'f' or 'true' or 'false'.
 I also noted that the other parameters didn't raise any exceptions if
 input wasn't as expected, so have retained this behaviour.

 I have done some limited testing, and run regression tests with no
 failures. I have not yet written additional tests and documentation, but
 will do that if and when the broad approach gets some sort of thumbs-up.

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Ticket URL: <https://trac.osgeo.org/postgis/ticket/3989>
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