[QGIS-Developer] PSA: do NOT build QGIS with libspatialindex >= 2.0

[Nyall Dawson]

On Tue, 16 Sept 2025 at 10:37, Nyall Dawson <nyall.dawson at gmail.com> wrote:

> Hi list,
>
> While tracking down the failures from
> https://github.com/qgis/QGIS/pull/63180, it's revealed that using QGIS
> with libspatialindex >= 2.0 gives completely misleading results for nearest
> neighbour geometry searches.
>
> The root cause is an optimisation from the upstream library (
> https://github.com/libspatialindex/libspatialindex/commit/6fe9ff769243579ed74f7f27409dd1dda6591634)
> that breaks how downstream clients could previously implement custom
> nearest neighbour comparators. From my research I don't think this is
> fixable in QGIS, and will need an upstream fix.
>

Sorry -- to clarify, that should have been >= 2.1 . 2.0 did not include the
offending commit.

Nyall
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20250916/e5a98d3a/attachment.htm>