[Rd] [Bug Fix] Default values not applied to ... arguments

[Sahil Kang]

I'm glad I could help, and I look forward to reading your patch so that I can learn more about the R internals. It'd be nice to close this 4 year old bug.

Sahil



-------- Original Message --------
From: Tomas Kalibera <tomas.kalibera at gmail.com>
Sent: July 7, 2017 11:10:05 AM PDT
To: Sahil Kang <sahil.kang at asilaycomputing.com>
Subject: Re: [Rd] [Bug Fix] Default values not applied to ... arguments

As I said the old behavior had been for several years both in AST and BC 
interpreter. I fixed it in AST and I will fix it in BC. I know exactly 
where it is and how to fix it, there is no more help I could use on this 
issue and I don't think there is any need to discuss this further, and 
particularly so on R-devel. Please do not send speculative emails to 
R-devel, in the interest of saving time of people following the list.

Thanks
Tomas

On 07/07/2017 11:42 AM, Sahil Kang wrote:
> Yes, I see what you mean. My patch only disables JIT compilation for 
> closures. If a user manually compiles a closure, however, the bug pops 
> up again.
>

> I think the bug may either lie in how the byte-compiler compiles 
> closures, or how closures with compiled body's are executed by the AST 
> interpreter (without my patch applied):
>
> compiler::enableJIT(0) # turn off JIT compilation
> f <- function(...) { g(...) }
> g <- function(a=4, b=5, c=6) {
>   print(c(missing(a), missing(b), missing(c)))
>   b
> }
>
> f(1,,3) # works fine
> # [1] FALSE TRUE FALSE
> # [1] 5
>
> f(1,,3) # works fine
> # [1] FALSE TRUE FALSE
> # [1] 5
>
> ff_1 <- compiler::compile(f) # compile f
> ff_2 <- compiler::cmpfun(f) # compile body of closure
>
> eval(ff_1)(1,,3) # works fine
> # [1] FALSE TRUE FALSE
> # [1] 5
>
> eval(ff_2)(1,,3) # bug shows up again
> # [1] FALSE TRUE FALSE
> # Error in g(...) : argument is missing, with no default
>
> Thanks,
> Sahil
>
> On 07/06/2017 09:29 AM, Tomas Kalibera wrote:
>>
>> Thanks for the report, I've fixed 15199 in the AST interpreter in 
>> 72664, I will fix it in the byte-code interpreter as well.
>>
>> If you ever needed to disable the JIT, there is API for that, see 
>> ?compiler. Note though that by disabling the JIT you won't disable 
>> the byte-code interpreter, because code also gets compiled when 
>> packages are installed or when the compiler is invoked explicitly.
>>
>> Best,
>> Tomas
>>
>> On 07/06/2017 04:40 PM, Sahil Kang wrote:
>>> Hi Duncan, Martin
>>>
>>> Here's a small patch that fixes bug 15199 reported at:
>>> https://bugs.r-project.org/bugzilla3/show_bug.cgi?id=15199
>>>
>>> I was able to reproduce the bug as Duncan had outlined just fine, 
>>> but I did notice that when we debug(f), the problem went away.
>>> I later realized that f(1,,3) behaved correctly the first time it 
>>> was executed, but misbehaved as documented on subsequent calls.
>>> This narrowed the problem down to the byte-compilation that occurs 
>>> on subsequent function calls.
>>>
>>> This patch prevents byte-compilation on closure objects.
>>> Although it's a less than ideal solution, this patch fixes the bug 
>>> at least until the underlying byte-compilation issue can be found 
>>> (I'm currently scrutinizing the promiseArgs function at eval.c:2771).
>>>
>>> Thanks,
>>> Sahil
>>>
>>>
>>> ______________________________________________
>>> R-devel at r-project.org  mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
>>
>