fail to join by .EACHI when `x` has list in .SD and `i` has more elements in join column

[jangorecki]

So if i data.table has more elements than x in a factor column used in join AND x data.table has a list column in .SD it will result an error. When factor in i does not have more elements OR x does not have a list column, issue will not occur:

library(data.table)
dt = data.table(a=factor(1:5, levels=1:10), b=as.list(letters[1:5]))
dt2 = data.table(a=as.factor(1:10))
dt[dt2, .SD, by=.EACHI, on="a", .SDcols="b"]
#Error in `[.data.table`(dt, dt2, .SD, by = .EACHI, on = "a", .SDcols = "b") : 
#  Logical error. Type of column should have been checked by now

dt2 = data.table(a=as.factor(1:5))
dt[dt2, .SD, by=.EACHI, on="a", .SDcols="b"]
# OK
dt = data.table(a=factor(1:5, levels=1:10), b=letters[1:5])
dt2 = data.table(a=as.factor(1:10))
dt[dt2, .SD, by=.EACHI, on="a", .SDcols="b"]
# OK

R version 3.4.1 (2017-06-30)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 16.04.3 LTS

Matrix products: default
BLAS: /usr/lib/libblas/libblas.so.3.6.0
LAPACK: /usr/lib/lapack/liblapack.so.3.6.0

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

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

other attached packages:
[1] data.table_1.10.5

loaded via a namespace (and not attached):
[1] compiler_3.4.1

[franknarf1]

It's not such a special case, I guess, since a similar problem happens with other join cols besides factors:

library(data.table)
data.table(a = 1:2, b = list("yo", NULL))[.(1:3), on=.(a), x.b, by = .EACHI]
# Error in `[.data.table`(data.table(a = 1:2, b = list("yo", NULL)), .(1:3),  : 
#   Logical error. Type of column should have been checked by now

(Testing on 1.10.4. Sorry if this doesn't hold any more; I can't upgrade to dev here.)