[gdal-dev] [gdal 3.12beta] Normal chain of explicit destruction does not work with ComputedDataset

[Even Rouault]

Hi,

you should not destroy the dataset of a GDALComputedRasterBand. The 
GDALComputedRasterBand destructor does that automatically.

Even

Le 24/10/2025 à 12:40, Momtchil Momtchev via gdal-dev a écrit :
>
> I have modified one of the algebra examples as follows:
>
> #include<gdal_priv.h>
> intmain() {
> GDALAllRegister();
> autopoDS=std::unique_ptr<GDALDataset>(GDALDataset::Open("test/data/a39se10.jpg"));
> auto&R=*(poDS->GetRasterBand(1));
> auto&G=*(poDS->GetRasterBand(2));
> auto&B=*(poDS->GetRasterBand(3));
> GDALRasterBand*graylevel=newGDALComputedRasterBand((0.299*R+0.587*G+0.114*B).AsType(GDT_Byte));
> autopoGTiffDrv=GetGDALDriverManager()->GetDriverByName("GTiff");
> std::unique_ptr<GDALDataset>(
> poGTiffDrv->CreateCopy("graylevel.tif", graylevel->GetDataset(), 
> false, nullptr, nullptr, nullptr))
> .reset();
> GDALDataset*dh=graylevel->GetDataset();
> deletegraylevel;
> dh->Close();
> return0;
> }
>
> I allocate graylevel on the heap, I obtain a pointer to the 
> GDALComputedDataset and I attempt to destroy first the 
> GDALComputedRasterBand then the GDALComputedDataset. This fails with a 
> crash in Close. Is this a bug or am I not supposed to do this? I am 
> doing it, because this is the usual chain of destruction events for 
> objects returned to JS. RasterBands hold a reference to their Dataset 
> in order to prevent the object from being GCed.
>
> -- 
> Momtchil Momtchev<momtchil at momtchev.com>
>
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/gdal-dev

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