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

[Sahil Kang]

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
>
>


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