[Rd] base::order breaking change in R-devel

[Jan Gorecki]

Hi R developers,
There seems to be breaking change in base::order on Windows in
R-devel. Code below yields different results on R 4.0.0 and R-devel
(2020-05-22 r78545). I haven't found any info about that change in
NEWS. Was the change intentional?

Sys.setlocale("LC_CTYPE","C")
Sys.setlocale("LC_COLLATE","C")
x1 = "fa\xE7ile"
Encoding(x1) = "latin1"
x2 = iconv(x1, "latin1", "UTF-8")
base::order(c(x2,x1,x1,x2))
Encoding(x2) = "unknown"
base::order(c(x2,x1,x1,x2))

# R 4.0.0
base::order(c(x2,x1,x1,x2))
#[1] 1 4 2 3
Encoding(x2) = "unknown"
base::order(c(x2,x1,x1,x2))
#[1] 2 3 1 4

# R-devel
base::order(c(x2,x1,x1,x2))
#[1] 1 2 3 4
Encoding(x2) = "unknown"
base::order(c(x2,x1,x1,x2))
#[1] 1 4 2 3

Best Regards,
Jan Gorecki