vect does not report when a file is non-existent

[johnbaums]

The error thrown by vect when a character string points to a non-existent file is a bit misleading. It should probably alert the user that the file does not exist, as we see with rast:

terra::vect('this-file-does-not-exist')
# Error: [vect] Cannot open this file as a SpatVector

terra::rast('this-file-does-not-exist')
# Error: [rast] file does not exist: this-file-does-not-exist
# In addition: Warning message:
# this-file-does-not-exist: No such file or directory (GDAL error 4)

> sessioninfo::session_info('terra')
─ Session info ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
 setting  value
 version  R version 4.2.1 (2022-06-23)
 os       macOS Big Sur 11.6.2
 system   x86_64, darwin17.0
 ui       RStudio
 language (EN)
 collate  en_AU.UTF-8
 ctype    en_AU.UTF-8
 tz       Australia/Melbourne
 date     2022-08-31
 rstudio  2022.07.1+554 Spotted Wakerobin (desktop)
 pandoc   2.18 @ /Applications/RStudio.app/Contents/MacOS/quarto/bin/tools/ (via rmarkdown)

─ Packages ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
 package * version date (UTC) lib source
 Rcpp      1.0.9   2022-07-08 [1] CRAN (R 4.2.0)
 terra     1.6-7   2022-08-07 [1] CRAN (R 4.2.1)

 [1] /Library/Frameworks/R.framework/Versions/4.2/Resources/library

[rhijmans]

Thanks, I now get:

terra::vect('this-file-does-not-exist')
#Error: [vect] file does not exist: this-file-does-not-exist