Tests self reference of a data.table

Description

In rare situations, as presented in examples below, a data.table object may lose its internal attribute that holds a self-reference. This function tests just that.

It is not expected that many end users will have need for this highly technical function about data.table internals.

Usage

  .selfref.ok(x)

Arguments

Value

TRUE if self reference attribute is properly set, FALSE otherwise.

Examples

d1 = list(V1=1L)
class(d1) = c("data.table", "data.frame")
.selfref.ok(d1)
setDT(d1)
.selfref.ok(d1)

saveRDS(d1, f<-tempfile())
d2 = readRDS(f)
.selfref.ok(d2)
invisible(file.remove(f))
setDT(d2)
.selfref.ok(d2)

d3 = unserialize(serialize(d2, NULL))
.selfref.ok(d3)
setDT(d3)
.selfref.ok(d3)