test/ci: lock cross-platform shareData behavior and add scheduled C-safety checks #95

Problem

The test suite already covers most cross-platform behavior:

• inst/tinytest/test-share.R:22-26 checks the POSIX read-once vs Windows repeat-read difference.
• inst/tinytest/test-nthread.R checks that nThread = 1 and nThread = 2 give identical results for the five OpenMP functions.
• inst/tinytest/test-enc.R checks checkEnc = TRUE vs FALSE.
• inst/tinytest/test-psort.R checks c.locale = TRUE against sort(method = "radix").

Two gaps remain:

1. The docs will say a leading / in map_name is optional. Add a test for that on both POSIX and Windows.
2. CI only runs normal execution. The package has manual memory management, hash tables, OpenMP, and long-vector paths. Add scheduled gctorture and valgrind jobs.

What to change

Test

Add to inst/tinytest/test-share.R:

# map_name without a leading slash must work on every platform
noslash <- paste0("kit55-noslash-", Sys.getpid())
h <- tryCatch(shareData(mtcars, noslash), error = function(err) NULL)
if (!is.null(h)) {
  expect_identical(getData(noslash), mtcars,
                   info = "share-0055.015 no leading slash")
  expect_true(clearData(h), info = "share-0055.016 no leading slash cleanup")
}

CI

Add a scheduled job (weekly or manual) that runs:

• R CMD check --use-gct --no-manual --no-build-vignettes
• R CMD check --use-valgrind --no-manual --no-build-vignettes

Keep these off pull requests; they are slow.

  c-safety:
    if: github.event_name == 'schedule' || github.event_name == 'workflow_dispatch'
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: r-lib/actions/setup-r@v2
      - uses: r-lib/actions/setup-r-dependencies@v2
        with:
          extra-packages: any::tinytest
      - name: gctorture
        run: R CMD check --use-gct --no-manual --no-build-vignettes .
      - name: valgrind
        run: |
          sudo apt-get update
          sudo apt-get install -y valgrind
          rm -rf kit.Rcheck
          R CMD check --use-valgrind --no-manual --no-build-vignettes .

R floor

DESCRIPTION says R (>= 3.5.0), but CI's oldest job is oldrel-4. Either:

• add a rocker/r-ver:3.5.3 job that runs the tests, or
• bump the floor to a version CI actually tests and remove the old-R shims in src/kit.h.

Acceptance

• The no-slash shareData test passes on Linux, macOS, and Windows.
• Scheduled gctorture and valgrind jobs exist and pass.
• The declared R floor is tested, or the floor is raised.

Notes

--use-gct failed locally on macOS with cannot open file 'startup.Rs': Permission denied. That is a local sandbox issue, not a package failure. Run it on Linux CI.

Related: #63 (closed) covered earlier test gaps; #57 (closed) covered the CI matrix.