empty data.table + list column + keyby

[jangorecki]

some gap, simple case below:

library(data.table)
d1 <- data.table(a = character(), b = list())
d1[, b,, a]
# Error in `[.data.table`(d1, , b, , a) : 
#   Logical error. Type of column should have been checked by now
sessionInfo()
# R version 3.2.1 (2015-06-18)
# Platform: x86_64-pc-linux-gnu (64-bit)
# Running under: Ubuntu 14.04.2 LTS
# 
# locale:
#  [1] LC_CTYPE=en_GB.UTF-8       LC_NUMERIC=C               LC_TIME=en_GB.UTF-8        LC_COLLATE=en_GB.UTF-8     LC_MONETARY=en_GB.UTF-8    LC_MESSAGES=en_GB.UTF-8   
#  [7] LC_PAPER=en_GB.UTF-8       LC_NAME=C                  LC_ADDRESS=C               LC_TELEPHONE=C             LC_MEASUREMENT=en_GB.UTF-8 LC_IDENTIFICATION=C       
# 
# attached base packages:
# [1] stats     graphics  grDevices utils     datasets  methods   base     
# 
# other attached packages:
# [1] anchormodeling_0.3.9 testthat_0.10.0      devtools_1.8.0       R6_2.0.1             data.table_1.9.5    
# 
# loaded via a namespace (and not attached):
#  [1] Rcpp_0.11.6          xml2_0.1.1           magrittr_1.5         roxygen2_4.1.0.9001  MASS_7.3-40          munsell_0.4.2        colorspace_1.2-6     stringr_1.0.0       
#  [9] plyr_1.8.3           tools_3.2.1          grid_3.2.1           gtable_0.1.2         git2r_0.10.1         rversions_1.0.1      digest_0.6.8         crayon_1.3.0        
# [17] reshape2_1.4.1       ggplot2_1.0.1        microbenchmark_1.4-2 curl_0.8             memoise_0.2.1        stringi_0.5-2        scales_0.2.5         chron_2.3-47        
# [25] proto_0.3-10