R devel - Sep 2017 - Bug: dput/deparse with named character vector inside list

Hi,
I noticed some R-devel failures on CRAN on a package I maintain:
https://cloud.r-project.org/web/checks/check_results_httptest.html

It appears that 'dput'/'deparse' is returning an invalid object
when
there is a named character vector inside a list. Here is a minimal
example that reproduces the issue:
> z <- list(a=c(b="foo"))
> str(z)
List of 1
 $ a: Named chr "foo"
  ..- attr(*, "names")= chr "b"
> dput(z)
list(a = b = "foo")
> parse(text=deparse(z))
Error in parse(text = deparse(z)) : <text>:1:12: unexpected '='
1: list(a = b                ^

But it works fine if you just provide a named character vector:

> dput(z$a)
structure("foo", .Names = "b")


I know that there were some recent improvements to 'deparse' (c73120,
73144). Among the failures on my package on R-devel on CRAN, a test
run on version as old as r73150 does manifest this bug
(https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-fedora-gcc/httptest-00check.html),
so the timing does suggest that those changes could be related.

Neal

> sessionInfo()
R Under development (unstable) (2017-09-07 r73219)
Platform: x86_64-apple-darwin15.6.0 (64-bit)
Running under: macOS Sierra 10.12.6

Matrix products: default
BLAS:
/Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRblas.0.dylib
LAPACK:
/Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRlapack.dylib

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

loaded via a namespace (and not attached):
[1] compiler_3.5.0

>>>>> Neal Richardson <neal.p.richardson at gmail.com>
>>>>>     on Fri, 8 Sep 2017 10:52:32 -0700 writes:
    > Hi,
    > I noticed some R-devel failures on CRAN on a package I maintain:
    > https://cloud.r-project.org/web/checks/check_results_httptest.html

    > It appears that 'dput'/'deparse' is returning an
invalid object when
    > there is a named character vector inside a list. Here is a minimal
    > example that reproduces the issue:

    >> z <- list(a=c(b="foo"))
    >> str(z)
    > List of 1
    > $ a: Named chr "foo"
    > ..- attr(*, "names")= chr "b"

    >> dput(z)
    > list(a = b = "foo")
    >> parse(text=deparse(z))
    > Error in parse(text = deparse(z)) : <text>:1:12: unexpected
'='
    > 1: list(a = b     > ^

    > But it works fine if you just provide a named character vector:


    >> dput(z$a)
    > structure("foo", .Names = "b")

("of course", because that had been tested quite extensively).

Thank you for reporting.  It is clearly a bug.
We're happy if your report it formally (https://bugs.r-project.org),
but as it is only in "R-devel", the development version of R, to
report here is indeed perfect.

    > I know that there were some recent improvements to 'deparse'
(c73120,
    > 73144). Among the failures on my package on R-devel on CRAN, a test
    > run on version as old as r73150 does manifest this bug
    >
(https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-fedora-gcc/httptest-00check.html),
    > so the timing does suggest that those changes could be related.

I'm sure they are (and it is mea culpa).
I will address this ASAP.

Martin

    > Neal


    >> sessionInfo()
    > R Under development (unstable) (2017-09-07 r73219)
    > Platform: x86_64-apple-darwin15.6.0 (64-bit)
    > Running under: macOS Sierra 10.12.6

    > Matrix products: default
    > BLAS:
/Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRblas.0.dylib
    > LAPACK:
/Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRlapack.dylib

    > locale:
    > [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

    > attached base packages:
    > [1] stats     graphics  grDevices utils     datasets  methods   base

    > loaded via a namespace (and not attached):
    > [1] compiler_3.5.0