[Rd] survival changes

Sun Jun 2 16:10:24 CEST 2019

Terry

Let me call this things to think about, rather than advice. I went 
through a similar process twice, once about 30 years ago and once about 
20 years ago. I had fewer dependent packages of course, but still enough 
to cause headaches. I don't recommend doing it often.

- I think you need to consider where you would like to end up before 
deciding how to get there. If you end up having to maintain a lot of 
legacy stuff I don't think you will be very happy. So then the problem 
becomes how to help people get off the part you want to abandon, rather 
then how to help them stay on it.

- I know you are very experienced, but I will be really impressed if you 
get the new approach perfect on the first shot. That argues for having a 
new package with hardly any users so you can fiddle with the API more 
easily, and not deprecating the old one until you are really happy with 
the new one.

- There may be a part which is common to both old and new and/or there 
may be a part which is what most dependent packages use. If you can 
separate that out as something like survivalBase it would make your life 
easier. That will be especial true if that part is more stable, so don't 
put in anything you are experimenting with.

Good luck,
Paul Gilbert

On 6/1/19 8:02 PM, Therneau, Terry M., Ph.D. via R-devel wrote:
> 
> 
> On 6/1/19 1:32 PM, Marc Schwartz wrote:
>>
>>> On Jun 1, 2019, at 12:59 PM, Peter Langfelder 
>>> <peter.langfelder using gmail.com> wrote:
>>>
>>> On Sat, Jun 1, 2019 at 3:22 AM Therneau, Terry M., Ph.D. via R-devel
>>> <r-devel using r-project.org> wrote:
>>>> In the next version of the survival package I intend to make a 
>>>> non-upwardly compatable
>>>> change to the survfit object.  With over 600 dependent packages this 
>>>> is not something to
>>>> take lightly, and I am currently undecided about the best way to go 
>>>> about it.  I'm looking
>>>> for advice.
>>>>
>>>> The change: 20+ years ago I had decided not to include the initial 
>>>> x=0,y=1 data point in
>>>> the survfit object itself.  It was not formally an estimand and the 
>>>> plot/points/lines etc
>>>> routines could add this on themselves.  That turns out to have been 
>>>> a mistake, and has led
>>>> to a steady proliferation of extra bits as I realized that the time 
>>>> axis doesn't always
>>>> start at 0, and later (with multi state) that y does not always 
>>>> start at 1 (though the
>>>> states sum to 1), and later the the error doesn't always start at 0, 
>>>> and another
>>>> realization with cumulative hazard, and ...
>>>> The new survfit method for multi-state coxph models was going to add 
>>>> yet another special
>>>> case.  Basically every component is turning into a duplicate of "row 
>>>> 1" vs "all the
>>>> others".  (And inconsistently named.)
>>>>
>>>> Three possible solutions
>>>> 1. Current working draft of survival_3.0.3:  Add a 'version' element 
>>>> to the survfit object
>>>> and a 'survfit2.3' function that converts old to new.  All my 
>>>> downstream functions (print,
>>>> plot,...) start with an "if (old) update to new" line.  This has 
>>>> allowed me to stage
>>>> updates to the functions that create survfit objects -- I expect it 
>>>> to happen slowly.
>>>> There will also be a survfit3.2 function to go backwards. Both the 
>>>> forward and backwards
>>>> functions leave objects alone if they are currently in the desired 
>>>> format.
>>>>
>>>> 2. Make a new class "survfit3" and the necessary 'as' functions. The 
>>>> package would contain
>>>> plot.survfit and plot.survfit3 methods, the former a two line 
>>>> "convert and call the
>>>> second" function.
>>>>
>>>> 3. Something I haven't thought of.
>>> A more "clean break" solution would be to start a whole new package
>>> (call it survival2) that would make these changes, and deprecate the
>>> current survival. You could add warnings about deprecation and urging
>>> users to switch in existing survival functions. You could continue
>>> bugfixes for survival but only add new features to survival2. The new
>>> survival2 and the current survival could live side by side on CRAN for
>>> quite some time, giving maintainers of dependent packages (and just
>>> plain users) enough time to switch. This could allow you to
>>> change/clean up other parts of the package that you could perhaps also
>>> use a rethink/rewrite, without too much concern for backward
>>> compatibility.
>>>
>>> Peter
>>
>> Hi,
>>
>> I would be cautious in going in that direction, bearing in mind that 
>> survival is a Recommended package, therefore included in the default R 
>> distribution from the R Foundation and other parties. To have two 
>> versions can/will result in substantial confusion, and I would argue 
>> against that approach.
>>
>> There is language in the CRAN submission policy that covers API 
>> changes, which strictly speaking, may or may not be the case here, 
>> depending upon which direction Terry elects to go:
>>
>> "If an update will change the package’s API and hence affect packages 
>> depending on it, it is expected that you will contact the maintainers 
>> of affected packages and suggest changes, and give them time (at least 
>> 2 weeks, ideally more) to prepare updates before submitting your 
>> updated package. Do mention in the submission email which packages are 
>> affected and that their maintainers have been informed. In order to 
>> derive the reverse dependencies of a package including the addresses 
>> of maintainers who have to be notified upon changes, the function 
>> reverse_dependencies_with_maintainers is available from the developer 
>> website."
>>
>>
>> Given the potential extent and impact of the changes being considered, 
>> it would seem reasonable to:
>>
>> 1. Post a note to R-Devel (possibly R-Help to cover a larger useR 
>> base) regarding whatever changes are finalized and formally announce 
>> them. The changes are likely to affect end useRs as well as package 
>> maintainers.
>>
>> 2. Send communications directly via e-mail to the relevant package 
>> maintainers that have dependencies on survival.
>>
>> 3. Consider a longer deprecation time frame for relevant functions, to 
>> raise awareness and allow for changes to be made by package 
>> maintainers and useRs as may be apropos. Perhaps post reminders to 
>> R-Help at relevant time points in advance as you approach the formal 
>> deprecation and release of the updated package.
>>
>>
>> Terry, if you have not used it yet and/or are not aware of it, take a 
>> look at ?Deprecated in base:
>>
>>    
>> https://stat.ethz.ch/R-manual/R-devel/library/base/html/Deprecated.html
>>
>> which is helpful in setting up a deprecation process. If you Google 
>> "deprecating functions in R", there are numerous examples/flows of use 
>> and the associated processes, since the help page does not contain any 
>> examples at present.
>>
>> Regards,
>>
>> Marc Schwartz
>>
> 
> Thanks for the comments thus far.
> I think that a new package is out of the question, survival is just too 
> deeply embedded.
> 
> Note that my standard policy is to run R CMD check on ALL of the 
> packages in CRAN that depend, import, or suggest survival, before any 
> update to CRAN.  Well, almost all: I skip the bioconductor ones, and 
> there are a handful that want a GIS or some other addition not on my 
> test box.  It usually takes a week or more to chase down everything.  
> Then the CRAN folks do the same, and often find one or two that I 
> missed.  I plan to make the github version available well before pushing 
> to CRAN.  Any change to the package will be painful to me as well.
> 
> Terry T.
> 
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