Preventing Terra from writing auxiliary files when writing to disc

Question

Background:
When writing .png rasters to disc using the terra R package, not only the intended raster is written, but also auxiliary files (.png.aux.xml and .png.aux.json files, depending on version of the package) with geographic information (since the PNG file standard does not support that).

Problem
Those files causes me a bit of a pain, since I'm writing many thousand small rasters and have no interest in the auxiliary information. Currently I am relying on code removing the newly written aux.xml and aux.json, but I believe this is a terribly inefficient solution (that, in the end, consumes quite a bit of time given the large amount of files). Further, the aux-files take up multiple times the disk space that my rasters do, so leaving the problem unaddressed is not really a good option.

Question
I cannot seem to find any option turning this feature off. Is there an option that I am missing? or any other ways to solve this?

Minimal reproducible example:

library(terra)
# Make raster:
test_raster <- rast(nrows=5, ncols=5, vals=1:25)

# Create a temporary folder and path to write to:
folder_path <- paste0(tempdir(),"\\rasters")
dir.create(folder_path, showWarnings = F)
  
# Write raster
writeRaster(test_raster, file.path(folder_path, "raster.png"), overwrite=TRUE)

# List files: (will show both .png and .png.aux.xml)
list.files(folder_path)

(The example works on my Windows machine, but I have not checked if the files paths are suitable for other systems.)

Answer 1

There's a function in rgdal that can set the GDAL option to disable this - the option gets respected by terra's writeRaster apart from a little warning:

Nothing in the box:

> list.files()
character(0)

Set the option:

> rgdal::setCPLConfigOption("GDAL_PAM_ENABLED", "FALSE")
[1] "FALSE"

Write the raster:

> writeRaster(test_raster,"raster.png", overwrite=TRUE)
Warning message:
[rast] unknown extent

What's in the box?

> list.files()
[1] "raster.png"

Shazam, no auxiliary XML files.

I don't see a way to set this with anything in the terra package though, or to pass this option into writeRaster. The gdal= option only passes driver options, not GDAL CPL options as far as I can tell.

Answer 2

With terra version >= 1.5-27 you can use setGDALconfig.

library(terra)
#terra 1.5.27

test_raster <- rast(nrows=5, ncols=5, vals=1:25)
folder_path <- paste0(tempdir(),"\\rasters")
dir.create(folder_path, showWarnings = F)

setGDALconfig("GDAL_PAM_ENABLED", "FALSE")
  
writeRaster(test_raster, file.path(folder_path, "raster.png"), overwrite=TRUE)
#Warning message:
#[rast] unknown extent
 
list.files(folder_path)
#[1] "raster.png"