[PostGIS] #5881: CI failing on raster reprojection loader test

[PostGIS]

#5881: CI failing on raster reprojection loader test
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  Reporter:  pramsey  |      Owner:  pramsey
      Type:  defect   |     Status:  new
  Priority:  blocker  |  Milestone:  PostGIS 3.5.3
 Component:  postgis  |    Version:  master
Resolution:           |   Keywords:
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Comment (by pramsey):

 The problem is introduced in this change to GDAL:

 https://github.com/OSGeo/gdal/commit/757df93e6f42f021e801d818970e9f19215df35f

 In particular, this block
 {{{
 if (psOptions->padfDstNoDataReal == nullptr)
              {
                  CPLError(CE_Failure, CPLE_AppDefined,
                           "BAND_INIT was set to NO_DATA, but a NoData
 value was "
                           "not defined.");
                  return CE_Failure;
              }
 }}}

 The `rt_raster_gdal_warp()` function does a bunch of tap dancing around
 checking if there are nodata values in the source raster, but then feeds
 GDALWarp with `BAND_INIT=NO_DATA` as an option, so in the case of rasters
 like the input to this test, that do not have NODATA set, GDAL fails.
 Since the warp is frequently going to result in a new raster that has
 empty corners and spaces, it makes sense to have a NODATA for the result.
 And in fact `rt_raster_gdal_warp()` has a bunch of code to fill in a
 NODATA place holder when there is not one, but that band-level machinery
 only goes into action if at least one band has tripped a raster-level
 `hasnodata` flag. The solution is to remove the check on `hasnodata`, as
 it is just stopping what should be the correct answer, to infill a default
 NODATA value whenever the input lacks one.
-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/5881#comment:1>
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