[Rd] Wrong move of NEWS item

[Suharto Anggono Suharto Anggono]

 Then, please announce the change in NEWS. For example:
The result of arithmetic and comparison operations of non-overlapping "ts" objects where either is a matrix is now a matrix.

It seems that the statement "diff(<ts-matrix>) remains matrix, even when it has length zero" was meant for the change to 'Ops.ts'. But the wording is about diff(<ts-matrix>), which is included in the previous statement.

But I've just realized this.
Suppose that
x <- ts(0)
With the change, x - lag(x, -1) and x == lag(x, -1) are NULL.
In R 4.5.2, x - lag(x, -1) is integer(0) and x == lag(x, -1) is logical(0).

________
On Tuesday, 3 March 2026 at 04:02:14 pm GMT+7, Martin Maechler <maechler using stat.math.ethz.ch> wrote:


>>>>> Peter Dalgaard
>>>>>    on Mon, 2 Mar 2026 14:37:22 +0100 writes:

    > I do hope Martin sees this. Code freeze for 4.5.3 is
    > Wednesday @0:02 ...  - Peter


Yes, I did see and think about it, but decided that it was "too
late" now, *and* not a "problem" I think:
`-` now exhibits the correct behaviour  but the diff()
    methods do not yet (but do in R-devel etc).

Martin

    >> On 28 Feb 2026, at 12.57, Suharto Anggono Suharto Anggono
    >> via R-devel <r-devel using r-project.org> wrote:
    >>
    >> Now that the NEWS item is gone from "CHANGES IN R 4.5.2
    >> patched", please also revert the change to 'Ops.ts' in
    >> R-4-5-branch, as I have mentioned. In R-4-5-branch, the
    >> change makes diff(m) inconsistent with m - lag(m, -1) for
    >> 1-row ts matrix m. Previously, neither of them was a
    >> matrix.
    >>
    >> _______ On Monday, 23 February 2026 at 07:16:36 pm GMT+7,
    >> Martin Maechler <maechler using stat.math.ethz.ch> wrote:
    >>
    >>
    >>>>>>> Suharto Anggono Suharto Anggono via R-devel on Sun,
    >>>>>>> 22 Feb 2026 03:58:13 +0000 (UTC) writes:
    >>
    >> > diff(m, lag, dif) for matrix m now still returns >
    >> matrices, also when lag * dif > nrow(m) (PR#18972, thanks
    >> to > Mikael Jagan and Suharto Anggono).  >
    >> diff(<ts-matrix>) remains matrix, even when it has length
    >> zero.
    >>
    >> > The above NEWS item has been moved to "CHANGES IN R
    >> 4.5.2 patched".
    >>
    >> > In fact, in R-4-5-branch, diff(m, lag, dif) for matrix
    >> m is still not a matrix when lag * dif > nrow(m) (see
    >> https://svn.r-project.org/R/branches/R-4-5-branch/src/library/base/R/diff.R
    >> for 'diff.default';
    >> https://svn.r-project.org/R/branches/R-4-5-branch/src/library/base/R/datetime.R
    >> for 'diff.POSIXt';
    >> https://svn.r-project.org/R/branches/R-4-5-branch/src/library/base/R/dates.R
    >> for 'diff.Date';
    >> https://svn.r-project.org/R/branches/R-4-5-branch/src/library/stats/R/ts.R
    >> for 'diff.ts').
    >>
    >> > And I suggest keeping it so. Because it has been like
    >> that simce the beginning, I think changing it in a patch
    >> release is not appropriate.
    >>
    >> We have ported bug fixes of "forever bugs" to the "R
    >> patched branch", before, quite on purpose.  Typically
    >> they have been really rare use cases and for that reason
    >> probably were not detected and reported earlier... and we
    >> (R core) still thought these bugs should disappear as
    >> quickly as possible.
    >>
    >> For the above reason(s), I *had* actually planned to port
    >> this bug fix also to R "4.5.2 patched" ...  But then it
    >> has become somewhat late to do the port only now, and R
    >> 4.5.3 will only be a "wrap up" release anyway..
    >>
    >> Hence, I agree with your opinion and will now move the
    >> NEWS entry instead of porting the bug fix which was the
    >> original plan.
    >>
    >> Martin
    >>
    >>
    >> > What have been ported to R-4-5-branch are just-
    >> replacing 'tsLag' with 'lag' in 'diff.ts'- 'Ops.ts' to
    >> return matrix when e1 or e2 is matrix but e1 and e2 are
    >> not overlapping > I suggest reverting the port. A
    >> justification of diff(m) for 1-row ts matrix m not being
    >> a matrix was that m - lag(m, -1) was not a matrix.  >
    >> Replacing 'tsLag' with 'lag' in 'diff.ts' is actually OK,
    >> but not necessary.
    >>
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    >>
    >> ______________________________________________
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    >> https://stat.ethz.ch/mailman/listinfo/r-devel


    > --
    > Peter Dalgaard, Professor, Center for Statistics,
    > Copenhagen Business School Solbjerg Plads 3, 2000
    > Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23
    > Email: pd.mes using cbs.dk Priv: PDalgd using gmail.com  
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