message change

Author: venom1204

R/data.table.R

@@ -1243,7 +1243,7 @@ replace_dot_alias = function(e) {
             } else if (.is_simple_extraction(name)) {
               .assign_in_parent(
                 name, x, parent.frame(),
-                err_msg_len = "Cannot assign to an under-allocated recursively indexed list -- L[[i]][,:=] syntax is only valid when i is length 1, but its length is %d",
+                err_msg_len = "The index for recursive assignment must be length 1, but its length is %d.",
                 err_msg_na  = NULL # Triggers internal_error for this case
               )
             } # TO DO: else if env$<- or list$<-

inst/tests/tests.Rraw

@@ -15880,7 +15880,7 @@ test(2074.03, data.table(grade=c(50L, 91L, 95L, 51L, 89L))[ , .N, by=evaluate(gr
 ## error: use recursive character list indexing to assign when also doing alloc.col()
 opt = options(datatable.alloccol=1L)
 l = list(foo = list(bar = data.table(a = 1:3, b = 4:6)))
-test(2074.04, l[[c('foo', 'bar')]][ , (letters) := 16:18], error = 'under-allocated recursively indexed list')
+test(2074.04, l[[c('foo', 'bar')]][ , (letters) := 16:18], error = 'The index for recursive assignment must be length 1')
 options(opt)
 ## alloc.col when using 0-truelength j assigning to a subset
 DT = data.table(a=1)
@@ -21167,3 +21167,9 @@ test(2317.6, DT1[DF1, on='a', .(d = x.a + i.d)]$d, 5)
 test(2317.7, DT1[DF2, on='a', e := i.e]$e, 5)
 test(2317.8, DT1[DF2, on='a', e2 := x.a + i.e]$e2, 6)
 test(2317.9, DT1[DF2, on='a', .(e = x.a + i.e)]$e, 6)
+
+# Test for issue #6702: ensure setDT gives a user-friendly error on multi-element recursive indexes
+test(2318.1, {
+  data_store = list(nested = list(df_to_fix = data.frame(id = 1:3, val = letters[1:3])))
+  setDT(data_store[[c("nested", "df_to_fix")]])
+}, error = "index for recursive assignment must be length 1")