From mick.jordan at oracle.com  Sat Mar 12 17:43:07 2016
From: mick.jordan at oracle.com (Mick Jordan)
Date: Sat, 12 Mar 2016 08:43:07 -0800
Subject: [Rd] Regression in strptime
In-Reply-To: <7CB65C37-52E1-48E4-9AF9-83FE0BAEFCC8@gmail.com>
References: <56E34F4E.30006@oracle.com>
	<7CB65C37-52E1-48E4-9AF9-83FE0BAEFCC8@gmail.com>
Message-ID: <56E4471B.6020001@oracle.com>

On 3/12/16 12:33 AM, peter dalgaard wrote:
>> On 12 Mar 2016, at 00:05 , Mick Jordan <mick.jordan at oracle.com> wrote:
>>
>> This is definitely obscure but we had a unit test that called .Internal(strptime, "1942/01/01", %Y/%m/%d") with timezone (TZ) set to CET.
> Umm, that doesn't even parse. And fixing the typo, it doesn't run:
>
>> .Internal(strptime, "1942/01/01", %Y/%m/%d")
> Error: unexpected SPECIAL in ".Internal(strptime, "1942/01/01", %Y/%"
>> .Internal(strptime, "1942/01/01", "%Y/%m/%d")
> Error in .Internal(strptime, "1942/01/01", "%Y/%m/%d") :
>    3 arguments passed to '.Internal' which requires 1
>
>
>
>> In R-3.1.3 that returned "1942-01-01 CEST" which, paradoxically, is correct as they evidently did strange things in Germany during the war period. Java also returns the same. However, R-3.2.4 returns "1942-01-01 CET".
> Did you mean:
>
> pd$ r-release-branch/BUILD-dist/bin/R
>
> R version 3.2.4 Patched (2016-03-10 r70319) -- "Very Secure Dishes"
> Copyright (C) 2016 The R Foundation for Statistical Computing
> Platform: x86_64-apple-darwin13.4.0/x86_64 (64-bit)
> [...]
>> strptime("1942/01/01", "%Y/%m/%d", tz="CET")
> [1] "1942-01-01 CEST"
>
> But then as you see, it does have DST on New Years Day.
>
> All in all, there is something you are not telling us.
>
> Notice that all DST information is OS dependent as it depends on which version of the "Olson database" is installed.
>
>
You are correct that I was sloppy with syntax for the example. We are, 
for better or worse, calling the .Internal, but actually with a large 
vector of arguments, of which the 1942 entry is element 82. I can 
confirm that for the vector of length 1 example that I didn't test but 
just assumed would also fail, the answer is correct. However, it is not 
for the full vector:

 > .Internal(strptime(argv[[1]], argv[[2]], "CET"))
   [1] "1937-01-01 CET" "1916-01-01 CET" "1913-01-01 CET" "1927-01-01 CET"
   [5] "1947-01-01 CET" "1913-01-01 CET" "1917-01-01 CET" "1923-01-01 CET"
   [9] "1921-01-01 CET" "1926-01-01 CET" "1920-01-01 CET" "1915-01-01 CET"
  [13] "1914-01-01 CET" "1914-01-01 CET" "1914-01-01 CET" "1919-01-01 CET"
  [17] "1948-01-01 CET" "1911-01-01 CET" "1909-01-01 CET" "1913-01-01 CET"
  [21] "1925-01-01 CET" "1926-01-01 CET" "1910-01-01 CET" "1917-01-01 CET"
  [25] "1936-01-01 CET" "1938-01-01 CET" "1960-01-01 CET" "1915-01-01 CET"
  [29] "1919-01-01 CET" "1924-01-01 CET" "1914-01-01 CET" "1905-01-01 CET"
  [33] "1921-01-01 CET" "1929-01-01 CET" "1926-01-01 CET" "1921-01-01 CET"
  [37] "1908-01-01 CET" "1928-01-01 CET" "1919-01-01 CET" "1921-01-01 CET"
  [41] "1925-01-01 CET" "1934-01-01 CET" "1927-01-01 CET" "1928-01-01 CET"
  [45] "1934-01-01 CET" "1922-01-01 CET" "1923-01-01 CET" "1915-01-01 CET"
  [49] "1934-01-01 CET" "1925-01-01 CET" "1922-01-01 CET" "1930-01-01 CET"
  [53] "1924-01-01 CET" "1923-01-01 CET" "1919-01-01 CET" "1932-01-01 CET"
  [57] "1930-01-01 CET" "1923-01-01 CET" "1930-01-01 CET" "1922-01-01 CET"
  [61] "1919-01-01 CET" "1932-01-01 CET" "1939-01-01 CET" "1923-01-01 CET"
  [65] "1920-01-01 CET" "1919-01-01 CET" "1952-01-01 CET" "1927-01-01 CET"
  [69] "1924-01-01 CET" "1919-01-01 CET" "1925-01-01 CET" "1945-01-01 CET"
  [73] "1916-01-01 CET" "1943-01-01 CET" "1920-01-01 CET" "1920-01-01 CET"
  [77] "1931-01-01 CET" "1924-01-01 CET" "1919-01-01 CET" "1926-01-01 CET"
  [81] "1920-01-01 CET" "1942-01-01 CET" "1919-01-01 CET" "1930-01-01 CET"
  [85] "1925-01-01 CET" "1924-01-01 CET" "1926-01-01 CET" "1918-01-01 CET"
  [89] "1922-01-01 CET" "1921-01-01 CET" "1925-01-01 CET" "1928-01-01 CET"
  [93] "1925-01-01 CET" "1929-01-01 CET" "1933-01-01 CET" "1947-01-01 CET"
  [97] "1950-01-01 CET" "1945-01-01 CET" "1924-01-01 CET" "1939-01-01 CET"
[101] "1924-01-01 CET" "1933-01-01 CET" "1928-01-01 CET"
 > .Internal( strptime("1942/01/01", "%Y/%m/%d", ''))
[1] "1942-01-01 CEST"
 > > argv[[1]][[82]]
[1] "1942/01/01"

We actually pass "" as the timezone, having set TZ=CET in the shell.

I am attaching a file that defines the large vector for sourcing.

Mick

-------------- next part --------------
argv <- list(c('1937/01/01', '1916/01/01', '1913/01/01', '1927/01/01', '1947/01/01', '1913/01/01', '1917/01/01', '1923/01/01',
               '1921/01/01', '1926/01/01', '1920/01/01', '1915/01/01', '1914/01/01', '1914/01/01', '1914/01/01', '1919/01/01',
               '1948/01/01', '1911/01/01', '1909/01/01', '1913/01/01', '1925/01/01', '1926/01/01', '1910/01/01', '1917/01/01',
               '1936/01/01', '1938/01/01', '1960/01/01', '1915/01/01', '1919/01/01', '1924/01/01', '1914/01/01', '1905/01/01',
               '1921/01/01', '1929/01/01', '1926/01/01', '1921/01/01', '1908/01/01', '1928/01/01', '1919/01/01', '1921/01/01',
               '1925/01/01', '1934/01/01', '1927/01/01', '1928/01/01', '1934/01/01', '1922/01/01', '1923/01/01', '1915/01/01',
               '1934/01/01', '1925/01/01', '1922/01/01', '1930/01/01', '1924/01/01', '1923/01/01', '1919/01/01', '1932/01/01',
               '1930/01/01', '1923/01/01', '1930/01/01', '1922/01/01', '1919/01/01', '1932/01/01', '1939/01/01', '1923/01/01',
               '1920/01/01', '1919/01/01', '1952/01/01', '1927/01/01', '1924/01/01', '1919/01/01', '1925/01/01', '1945/01/01',
               '1916/01/01', '1943/01/01', '1920/01/01', '1920/01/01', '1931/01/01', '1924/01/01', '1919/01/01', '1926/01/01',
               '1920/01/01', '1942/01/01', '1919/01/01', '1930/01/01', '1925/01/01', '1924/01/01', '1926/01/01', '1918/01/01',
               '1922/01/01', '1921/01/01', '1925/01/01', '1928/01/01', '1925/01/01', '1929/01/01', '1933/01/01', '1947/01/01',
               '1950/01/01', '1945/01/01', '1924/01/01', '1939/01/01', '1924/01/01', '1933/01/01', '1928/01/01'), '%Y/%m/%d', '');


[Rd] Regression in strptime
Mick Jordan