Fail to summarize by using variable

[mmoisse]

With upgrading data.table to the latest version 1.16.0 I noticed that the code below no longer works and throws the error Error in is.call(bysub) && !(bysub[[1L]] %chin% c("list", "as.list", "{", : 'length = 3' in coercion to 'logical(1)'

which is this piece of code

data.table/R/data.table.R

Line 789 in 8cc2dd1

} else if (is.call(bysub) && !(bysub[[1L]] %chin% c("list", "as.list", "{", ".", ":"))) {

In older version of data.table e.g. 1.14.8 it all works find. Also, when I replace base::mget by mget it also seems to work. Could it be caused by specifying the package?

---

Minimal example

dat <- data.table::as.data.table(datasets::iris)
cat_vars <- c("Species")
dat[, .(V1 = .N), by = base::mget(cat_vars)]
# Error in is.call(bysub) && !(bysub[[1L]] %chin% c("list", "as.list", "{",  : 
#  'length = 3' in coercion to 'logical(1)'

---

Session info

R version 4.4.1 (2024-06-14)
Platform: x86_64-pc-linux-gnu
Running under: Ubuntu LTS

Matrix products: default
BLAS:   /usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3 
LAPACK: /usr/lib/x86_64-linux-gnu/openblas-pthread/liblapack.so.3;  LAPACK version 3.9.0

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=en_IE.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=en_IE.UTF-8    LC_MESSAGES=en_US.UTF-8   
 [7] LC_PAPER=en_IE.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_IE.UTF-8 LC_IDENTIFICATION=C       

tzcode source: system (glibc)

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] data.table_1.16.99

loaded via a namespace (and not attached):
[1] compiler_4.4.1 cli_3.6.3      tools_4.4.1    jsonlite_1.8.8 rlang_1.1.4   

[MichaelChirico]

you can use by=cat_vars

[MichaelChirico]

Another workaround for now: just use mget(), not base::mget(). Fix is in #6499.