Handle _R_CHECK_DEPENDS_ONLY_ correctly for other.Rraw to work in -occasional CI

[MichaelChirico]

** NB: currently targeting #7837 **

This should resolve the main issue with other.Rraw failing broadly.

This GHA-only fix was diagnosed and fixed by Gemini (to be precise: any change written by Gemini is kept pristine and annotated in the commit message). That diagnosis (lightly edited) follows:

---

Setting _R_CHECK_DEPENDS_ONLY_: false in .github/workflows/R-CMD-check-occasional.yaml overrides a default behavior of --as-cran in R CMD check that hides optional packages from the test suite:

1. Default Behavior of --as-cran in R CMD check

Under --as-cran, R automatically enables _R_CHECK_DEPENDS_ONLY_=true:

data.table/.github/workflows/R-CMD-check-occasional.yaml

Line 117 in fae95de

check_args = c("--no-manual", "--as-cran")

When active, R creates a restricted, temporary library (.libPaths()) during the check containing only the packages explicitly listed in DESCRIPTION (Depends, Imports, Suggests, and Enhances), plus base/recommended R packages. Any other packages installed on the system are hidden from the search path during test execution.

2. Why This Broke other.Rraw in CI

In step 82 of R-CMD-check-occasional.yaml, the workflow installs "fully optional packages" (other_pkgs such as caret, dplyr, ggplot2, sf, vctrs, etc.) so they can be tested for interoperability in inst/tests/other.Rraw. These optional packages are intentionally not listed in data.table's DESCRIPTION file.

Because they are omitted from DESCRIPTION, --as-cran stripped them from .libPaths() during check execution. Even though the step successfully installed all 19 optional packages and set TEST_DATA_TABLE_WITH_OTHER_PACKAGES=TRUE, inside R CMD check, other.Rraw could not find them and aborted across all CI runners with:

test.data.table('other.Rraw') failed to attach required package(s): caret, DBI, dplyr, gdata, ggplot2, hexbin, knitr, nanotime, nlme, plyr, RSQLite, sf, vctrs.

3. Effect of the Change

By explicitly setting _R_CHECK_DEPENDS_ONLY_: false, we prevent R CMD check from isolating the check library strictly to DESCRIPTION dependencies. This allows other.Rraw to see and attach the optional packages installed in the runner library during the check.

[github-actions]

• HEAD=occasional-fix much faster for as.data.table.array improved in #7019
• HEAD=occasional-fix much faster for transform improved in #5493
  

Generated via commit d04e4a2

Download link for the artifact containing the test results: ↓ atime-results.zip

Task	Duration
R setup and installing dependencies	2 minutes and 53 seconds
Installing different package versions	1 minutes and 10 seconds
Running and plotting the test cases	7 minutes and 34 seconds

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.01%. Comparing base (f93fce1) to head (ab2efd5).

Additional details and impacted files

@@                 Coverage Diff                 @@
##           test-err-show-diff    #7832   +/-   ##
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  Coverage               99.01%   99.01%           
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  Files                      88       88           
  Lines                   17234    17234           
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  Hits                    17065    17065           
  Misses                    169      169           

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