v3.3.0 breaks

[mattdowle]

covr is always so reliable and awesome! Today hit a very rare problem.
Seems to have started to fail on Travis for data.table with the recent update. Is it data.table-only or affecting more packages? Haven't debugged it yet. Thought I'd see if you were aware first.
I can reproduce it locally :

> library(covr)
> packageVersion("covr")
[1] ‘3.2.1’
> package_coverage()    # ok with v3.2.1
data.table Coverage: 98.47%
... snip ...
R/xts.R: 100.00%

> library(covr)
> packageVersion("covr")
[1] ‘3.3.0’
> package_coverage()  # not ok
files differ in number of lines:
31,33d30
<    a
< 1: 1
< 2: 4

files differ in number of lines:
36,42d35
< ```
< ##    x y  z
< ## 1: 1 4 10
< ## 2: 2 5 11
< ## 3: 3 6 12
< ```
< 

[jimhester]

I can reproduce the error, 3.3.0 had a regression that caused the visibly of returned arguments to change, e.g. f(1) would normally be invisible, because having an assignment as the last expression makes the value implicitly invisible.

f <- function(x) {
  x <- 1
}

However covr 3.3.0 it would convert that call to essentially

f <- function(x) {
  ({ x <- 1 })
}

Which would then print, as () makes its value visible. 89029d4 fixes this by using identity() rather than ().

f <- function(x) {
  identity({ x <- 1 })
}

Which preserves the original visibility.

data.table has tests to verify that DT = data.table(x=1:3, y=4:6) does not print, as it is an assignment, and this was failing due to the above issue.

I will submit a new release of covr to CRAN early next week with this fix. In the meantime you can use the development version on travis etc, by putting Remotes: r-lib/covr in your DESCRIPTION file.

[mattdowle]

Wow - thank's for the awesome reply, quick fix, and workaround too!

[mattdowle]

I tried adding Remotes: r-lib/covr in DESCRIPTION. Travis passed but it still used the 3.3.0 version of covr, so the coverage part still failed. My guess is that was because covr was named in the r_packages section of our travis.yml. My guess is that since it already had covr from CRAN before it got to the Remotes: part, it already had the dependency satisfied and didn't upgrade to the GitHub version.

Anyway, what did work was using r_github_packages: r-lib/covr. See this commit. Coverage working and updating again. Yay! Doing it this way also avoids the --as-cran note about the Remotes: field too. The workaround being in travis.yml only is nice and means a comment works there too (TIL that comments don't work in DESCRIPTION file!)