[pdal] Point cloud viewer in QGIS

[Martin Dobias]

On Mon, Jul 6, 2020 at 11:31 PM Howard Butler <howard at hobu.co> wrote:
>
> Do you foresee users swapping in PDAL versions underneath you? Bas has been tracking our ABI stability with Debian's toolchain. That could be one place to see the history of how we have been changing.

I don't expect users would be intentionally swapping PDAL versions,
rather their packaging system may decide to upgrade pdal package - and
potentially break reverse dependencies if there were ABI changes. I am
no expert in packaging and don't know how e.g. Debian community tracks
ABI stability, if there are some automated tools for that...


> As a C++ library user, it is your responsibility to encapsulate your usage of PDAL. If the C++ API never gets to change, nothing is going to improve. That said, we haven't changed it very much recently, as I've said, and as time goes on it is going to be harder to do so because of all of the PDAL Stages (and external plugins) that have implemented the API.

Sure, I am mainly asking about what should be our expectations. For
example, if we base QGIS implementation on PDAL 2.1.0 ... is it
guaranteed there will be stable API/ABI in other 2.1.x releases? Or
just a stable API but not a stable ABI? Or could the API change as
well during the 2.1.x cycle? And how about further releases like 2.2.x
or 2.3.x, are there any guarantees? I guess this will be important for
QGIS packagers for different platforms so they know whether they can
upgrade the PDAL version at any time and/or whether they need to
rebuild QGIS for that particular version.

Regards
Martin