build-cran-binaries/.superpowers/handoff/task-B1-brief.md

Task B1: Create the patch registry with the RcppParallel entry

Files:

• Create: local/patches/registry.json
• Create: local/patches/README.md

Interfaces:

• Produces: the curated registry consumed by bincraft's patches argument.

• Step 1: Write the registry

[
  {
    "package": "RcppParallel",
    "versions": "*",
    "platforms": ["alpine", "ubuntu-2604"],
    "env": { "RCPP_PARALLEL_USE_TBB": "0" },
    "configure_args": [],
    "makevars": {},
    "patch": null,
    "reason": "bundled Intel TBB fails to build on musl and on newer toolchains (e.g. g++ 15 on ubuntu-2604); disabling TBB falls back to TinyThread"
  }
]

• Step 2: Write the README

local/patches/README.md documents the schema (copy the field table from specs/2026-06-30-package-patching-design.md), how to add an entry, and that source diffs go in local/patches/<pkg>/<file>.patch referenced by the patch field.

• Step 3: Verify it parses

Run: Rscript -e 'x <- jsonlite::fromJSON("local/patches/registry.json", simplifyVector = FALSE); stopifnot(length(x) == 1L, x[[1]]$package == "RcppParallel"); cat("ok\n")' Expected: ok.

• Step 4: Commit

git add local/patches/registry.json local/patches/README.md
git commit -m "feat(patches): add patch registry with RcppParallel TBB workaround"

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