I've been trying to build R 3.3.1 inside of a Nix environment on a
Ubuntu 16.04 machine. It builds, but then it fails a regression test
related to time zones, and I hope that someone could help me debug the
problem.
The failing test is in tests/reg-tests-rc.R
(https://github.com/wch/r-source/blob/c3fe9cd4/tests/reg-tests-1c.R#L1577-L1587):
## format.POSIXlt() of Jan.1 if 1941 or '42 is involved:
tJan1 <- function(n1, n2)
strptime(paste0(n1:n2,"/01/01"), "%Y/%m/%d",
tz="CET")
wDSTJan1 <- function(n1, n2)
which("CEST" == sub(".* ", '',
format(tJan1(n1,n2), usetz=TRUE)))
(w8 <- wDSTJan1(1801, 2300))
(w9 <- wDSTJan1(1901, 2300))
stopifnot(identical(w8, 141:142),# exactly 1941:1942 had CEST on Jan.1
identical(w9, 41: 42))
## for R-devel Jan.2016 to Mar.14 -- *AND* for R 3.2.4 -- the above gave
## integer(0) and c(41:42, 99:100, ..., 389:390) respectively
The resulting output is:> (w8 <- wDSTJan1(1801, 2300))
integer(0)> (w9 <- wDSTJan1(1901, 2300))
integer(0)> stopifnot(identical(w8, 141:142),# exactly 1941:1942 had CEST on Jan.1
+ identical(w9, 41: 42))
Error: identical(w8, 141:142) is not TRUE
Execution halted
In this build of R, I get the following:> strptime(paste0(1940:1945,"/01/01"), "%Y/%m/%d",
tz="CET")
[1] "1940-01-01 CET" "1941-01-01 CET" "1942-01-01
CET" "1943-01-01 CET"
[5] "1944-01-01 CET" "1945-01-01 CET"
However, when I run the same code in R 3.3.1 installed via the .deb
packages on cran.r-project.org, I get a different result: years 1941
and 1942 have the CEST time zone. This is what the tests above were
expecting.> strptime(paste0(1940:1945,"/01/01"), "%Y/%m/%d",
tz="CET")
[1] "1940-01-01 CET" "1941-01-01 CEST" "1942-01-01
CEST" "1943-01-01 CET"
[5] "1944-01-01 CET" "1945-01-01 CET"
I'm not sure where to start looking to fix this problem, and I'd
appreciate any pointers.
For reference, the test was introduced in:
https://github.com/wch/r-source/commit/55cdf88dv
And that commit's message says that it fixed a bug introduced by:
https://github.com/wch/r-source/commit/2e36b365
-Winston
