mosaic causes R crash if SpatRasterCollection elements have multiple layers

[johnbaums]

R crashes when using mosaic on a SpatRasterCollection with elements having multiple layers. Reprex provided for one of the working cases, below.

library(terra)
set.seed(1)
e <- ext(113, 154, -44, -10)
r <- replicate(2, {
  x <- round(sort(runif(2, e[1], e[2])), 2)
  y <- round(sort(runif(2, e[3], e[4])), 2)
  init(rast(ext(c(x, y)), res = 0.05, crs = "EPSG:4326", nlyrs = 2), runif)
}) |> sprc()
terra::mosaic(r)
## Floating point exception (core dumped)

Interestingly, the mosaic operation completes successfully if we use merge first:

library(terra)
#> terra 1.7.71
set.seed(1)
e <- ext(113, 154, -44, -10)
r <- replicate(2, {
  x <- round(sort(runif(2, e[1], e[2])), 2)
  y <- round(sort(runif(2, e[3], e[4])), 2)
  init(rast(ext(c(x, y)), res = 0.05, crs = "EPSG:4326", nlyrs = 2), runif)
}) |> sprc()
terra::merge(r)
#> class       : SpatRaster 
#> dimensions  : 260, 451, 2  (nrow, ncol, nlyr)
#> resolution  : 0.05, 0.05  (x, y)
#> extent      : 123.89, 146.44, -24.52, -11.52  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (EPSG:4326) 
#> source(s)   : memory
#> names       :        lyr.1,        lyr.2 
#> min values  : 0.0001064336, 8.431729e-06 
#> max values  : 0.9999305937, 9.999035e-01
terra::mosaic(r)
#> class       : SpatRaster 
#> dimensions  : 260, 451, 2  (nrow, ncol, nlyr)
#> resolution  : 0.05, 0.05  (x, y)
#> extent      : 123.89, 146.44, -24.52, -11.52  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (EPSG:4326) 
#> source(s)   : memory
#> names       :        lyr.1,        lyr.2 
#> min values  : 0.0001064336, 8.431729e-06 
#> max values  : 0.9999305937, 9.999035e-01

^{Created on 2024-05-30 with reprex v2.1.0}

Session info

sessioninfo::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
#>  setting  value
#>  version  R version 4.3.2 (2023-10-31)
#>  os       Ubuntu 20.04.6 LTS
#>  system   x86_64, linux-gnu
#>  ui       X11
#>  language (EN)
#>  collate  en_AU.UTF-8
#>  ctype    en_AU.UTF-8
#>  tz       Australia/Melbourne
#>  date     2024-05-30
#>  pandoc   2.5 @ /usr/bin/ (via rmarkdown)
#> 
#> ─ Packages ───────────────────────────────────────────────────────────────────
#>  ! package     * version date (UTC) lib source
#>  P cli           3.6.2   2023-12-11 [?] RSPM (R 4.3.0)
#>  P codetools     0.2-19  2023-02-01 [?] CRAN (R 4.2.2)
#>  P digest        0.6.34  2024-01-11 [?] RSPM (R 4.3.0)
#>  P evaluate      0.23    2023-11-01 [?] RSPM (R 4.3.0)
#>  P fastmap       1.1.1   2023-02-24 [?] RSPM (R 4.3.0)
#>    fs            1.6.3   2023-07-20 [1] RSPM (R 4.3.2)
#>  P glue          1.7.0   2024-01-09 [?] RSPM (R 4.3.0)
#>  P htmltools     0.5.8.1 2024-04-04 [?] CRAN (R 4.3.2)
#>  P knitr         1.45    2023-10-30 [?] RSPM (R 4.3.0)
#>  P lifecycle     1.0.4   2023-11-07 [?] RSPM (R 4.3.0)
#>  P magrittr      2.0.3   2022-03-30 [?] RSPM (R 4.3.0)
#>  P purrr         1.0.2   2023-08-10 [?] RSPM (R 4.3.0)
#>    R.cache       0.16.0  2022-07-21 [1] RSPM (R 4.3.2)
#>    R.methodsS3   1.8.2   2022-06-13 [1] RSPM (R 4.3.2)
#>    R.oo          1.26.0  2024-01-24 [1] RSPM (R 4.3.2)
#>    R.utils       2.12.3  2023-11-18 [1] RSPM (R 4.3.2)
#>  P Rcpp          1.0.12  2024-01-09 [?] CRAN (R 4.3.2)
#>    renv          1.0.3   2023-09-19 [1] CRAN (R 4.3.2)
#>  P reprex        2.1.0   2024-01-11 [?] CRAN (R 4.3.2)
#>  P rlang         1.1.3   2024-01-10 [?] RSPM (R 4.3.0)
#>  P rmarkdown     2.27    2024-05-17 [?] CRAN (R 4.3.2)
#>  P sessioninfo   1.2.2   2021-12-06 [?] CRAN (R 4.3.2)
#>    styler        1.10.2  2023-08-29 [1] RSPM (R 4.3.2)
#>  P terra       * 1.7-71  2024-01-31 [?] RSPM (R 4.3.0)
#>  P vctrs         0.6.5   2023-12-01 [?] RSPM (R 4.3.0)
#>  P withr         3.0.0   2024-01-16 [?] RSPM (R 4.3.0)
#>  P xfun          0.41    2023-11-01 [?] RSPM (R 4.3.0)
#>  P yaml          2.3.8   2023-12-11 [?] RSPM (R 4.3.0)
#> 
#>  [1] /home/unimelb.edu.au/jbau/23a-v2/renv/library/R-4.3/x86_64-pc-linux-gnu
#>  [2] /home/unimelb.edu.au/jbau/.cache/R/renv/sandbox/R-4.3/x86_64-pc-linux-gnu/9a444a72
#> 
#>  P ── Loaded and on-disk path mismatch.
#> 
#> ──────────────────────────────────────────────────────────────────────────────

Similarly, the mosaic works fine if the elements of the collection have a single layer:

library(terra)
set.seed(1)
e <- ext(113, 154, -44, -10)
r <- replicate(2, {
  x <- round(sort(runif(2, e[1], e[2])), 2)
  y <- round(sort(runif(2, e[3], e[4])), 2)
  init(rast(ext(c(x, y)), res = 0.05, crs = "EPSG:4326", nlyrs = 1), runif)
}) |> sprc()

terra::mosaic(r)
## class       : SpatRaster 
## dimensions  : 403, 444, 1  (nrow, ncol, nlyr)
## resolution  : 0.05, 0.05  (x, y)
## extent      : 123.89, 146.09, -33.26, -13.11  (xmin, xmax, ymin, ymax)
## coord. ref. : lon/lat WGS 84 (EPSG:4326) 
## source(s)   : memory
## name        :     lyr.1 
## min value   : 0.0000000 
## max value   : 0.9994188