Broken when subsetting data table

[sunnyghk]

Recently I have upgraded to data.table 1.9.4, and notice the subsetting is broken when the column name is 'class'. It can be resolve by setting datatable.auto.index to FALSE, but nonetheless is causing a pretty major problem:

test = data.table(class=c('a','b'), x=c(1,2))
test[class=='a']
Error in setattr(attr(x, "index"), paste(cols, collapse = "__"), o) :
attempt to set invalid 'class' attribute
options(datatable.auto.index=FALSE)
test[class=='a']
class x
1: a 1

[mattdowle]

Thanks for the nice report. Fixed and closed by 4aa7c0c