[Rd] Patch proposal for bug 17770 - xtabs does not act as documented for na.action = na.pass

[SOEIRO Thomas]

Dear all,

(This issue was previously reported on Bugzilla (https://bugs.r-project.org/bugzilla/show_bug.cgi?id=17770) and discussed on Stack Overflow (https://stackoverflow.com/q/61240049).)

The documentation of xtabs says:

"na.action: When it is na.pass and formula has a left hand side (with counts), sum(*, na.rm = TRUE) is used instead of sum(*) for the counts."

However, this is not the case:
 
DF <- data.frame(group = c("a", "a", "b", "b"),
                 count = c(NA, TRUE, FALSE, TRUE))

xtabs(formula = count ~ group,
      data = DF,
      na.action = na.pass)

# group
# a b
# 1

In the code, na.rm is TRUE if and only if na.action = na.omit:

na.rm <- 
  identical(naAct, quote(na.omit)) || identical(naAct, na.omit) ||
  identical(naAct, "na.omit")

xtabs(formula = count ~ group,
      data = DF,
      na.action = na.omit)

# group
# a b
# 1 1

The example works as documented if we change the code to:

na.rm <- 
  identical(naAct, quote(na.pass)) || identical(naAct, na.pass) ||
  identical(naAct, "na.pass")

However, there may be something I am missing, and na.omit may be necessary for something else...

Best regards,

Thomas