feat(edge): gate per-minor routing on published minors and add a staging zone (#175)

## Motivation

`UNION_SLOTS` is empty, so per-minor routing has never been exercised end to end. Before it can be enabled and advertised, two things were missing: a way to test it without pointing production at it, and evidence that the published indexes actually support it.

Verifying the data first turned up a defect that would have broken users the moment the flag was flipped.

## The defect

`contribPath()` redirects to `contrib/<minor>/` whenever the User-Agent carries any R minor, with no existence check and no fallback:

```ts
const rMinor = extractRMinor(userAgent);
return rMinor ? `/${slot}/latest/src/contrib/${rMinor}/${rest}` : flat;
```

Only `4.4`, `4.5` and `4.6` are published. `4.3` and `4.2` return 404 on all 16 slots. With `UNION_SLOTS` set, an R 4.3 client would be redirected to a non-existent index and see **zero** packages: a silent, total failure rather than a degraded one. R 4.3 is still advertised as supported on the website and in `docs/configuration.mdoc`, though `build-env-images` now pins only 4.6.0/4.5.3/4.4.3.

## Changes

- **Gate routing on `KNOWN_MINORS`** (default `4.4,4.5,4.6`), falling back to the flat index for anything else. Unknown minor now behaves exactly as today.
- **Honour `EXTRA_PUBLIC_HOSTS`.** `publicCdnOrigin()` falls back to the hardcoded `PUBLIC_CDN_ORIGIN` for any hostname not in `PUBLIC_CDN_HOSTS`, so a staging zone on a `b-cdn.net` hostname would redirect into *production* and silently measure the wrong system. This lets the identical script run on staging and redirect within itself.
- **Add the `cran-rpkgs-test` pull zone** with `UNION_SLOTS` pre-enabled for all 16 slots, same B2 origin, served on the bunny default hostname so it needs no DNS record and is never advertised.
- **Add `scripts/verify-r-minor-routing.sh`**, covering every `<arch>/<os>` slot: index reachability per minor, the union property against flat, `Path:` target resolution, coverage parity across minors, and with `--live` the real User-Agent routing, the non-R User-Agent case, and that tarballs are never rewritten.
- **Cover the fallback in the edge test suite** for both an unpublished minor (4.3) and a future one (4.7).

## Findings from the full run

112 passed, 16 failed across the 16 slots. Every failure is the same: no R 4.3 index.

All 16 slots carry union indexes that are supersets of flat, every sampled `Path:` target resolves, and all indexes were republished within minutes of each other, so the build side is healthy.

Coverage is **not** yet even, which is why "full coverage for ABI-sensitive packages" is not a claim to make yet:

| slot | flat | 4.4 | 4.5 | 4.6 |
|---|---|---|---|---|
| amd64/resolute | 24305 | 24402 | 24748 | 24395 |
| amd64/alpine324 | 24397 | 24457 | 24744 | 24448 |
| amd64/noble | 24780 | 24805 | 24805 | 24805 |

On the R 4.5-built distros (`resolute`, `alpine324`, and their arm64 twins) a 4.4 or 4.6 client sees ~300 fewer packages than a 4.5 client. On `noble`/`jammy`/`rhel9`/`alpine323` the spread is under 5. The new parity check encodes this with a configurable `PARITY_TOLERANCE`.

## Verification

- `just edge-test`: 18 steps pass. The two new steps were confirmed to fail with the `KNOWN_MINORS` gate removed and pass with it.
- `tofu validate`: passes. **Not applied** - no bunny.net or state credentials were available, so the staging zone still needs a `tofu apply`.
- `scripts/verify-r-minor-routing.sh`: full 16-slot run, results above.
- `shellcheck`: clean.

## Not done here

Applying the staging zone, then running `BASE=https://cran-rpkgs-test.b-cdn.net scripts/verify-r-minor-routing.sh --live` against it. Production `UNION_SLOTS` is deliberately left empty.

Reviewed-on: #175

.crow/auto-apply-patches.yaml

@@ -58,7 +58,7 @@ steps:
       - git clone -q https://pat-s:$$REPO_RO_TOKEN@git.devxy.io/devxy/build-cran-binaries.git .
       - mkdir -p /mnt/cache/R-pkgs
       - rm -rf /mnt/cache/R-pkgs/00LOCK-*
-      - UVR_R_BIN=/opt/R/$R_VERSION/bin/R local/uvr-install.sh httr2 jsonlite
+      - UVR_R_BIN=/opt/R/$R_VERSION/bin/R local/uvr-install.sh RPostgres httr2 jsonlite
       - /opt/R/$R_VERSION/bin/Rscript local/propose-patches.R --open-pr --limit $PATCH_LIMIT
     backend_options:
       kubernetes:

.crow/process-updates.yaml

@@ -3,15 +3,15 @@
 # Routing is preserved 1:1:
 #   - cron:   each existing `process-cran-updates-<os>-<arch>` cron fires only
 #             its matching matrix row (via the per-row `cron:` name filter).
-#   - manual: pick a target from the `process_cran_updates` dropdown
-#             ("all" = every os/arch).
+#   - manual: pick a target from the `process_cran_updates` dropdown;
+#             "all" fans out every os/arch as parallel matrix workflows.
 # Arch placement is handled by the group label (rpkgs-amd64, rpkgs-arm64).
 variables:
   # Gates this pipeline. A manual pipeline creation instantiates every file in
   # .crow/, and a declared default is applied even when the run never passed
   # this variable, so the default must be a value that matches no matrix row.
   process_cran_updates:
-    description: "Manual run target: a specific <os>-<arch>, 'all' for every os/arch, or 'none' to run nothing."
+    description: "Manual run target: a specific <os>-<arch>, 'all' to run every os/arch in parallel, or 'none' to run nothing."
     options:
       - none
       - all
@@ -203,6 +203,7 @@ steps:
       - rm -rf /mnt/cache/R-pkgs/00LOCK-* /mnt/cache/R-pkgs/bincraft
       - mkdir -p /mnt/cache/uvr/cache /mnt/cache/uvr/packages /mnt/cache/R-pkgs /mnt/cache/ccache /mnt/cache/packages
       - /opt/R/$R_VERSION/bin/Rscript local/install-bincraft.R
+      - UVR_R_BIN=/opt/R/$R_VERSION/bin/R local/uvr-install.sh RPostgres
       - /opt/R/$R_VERSION/bin/R -q -e 'packageVersion("bincraft")'
       # rhel-10 ships xwfb-run (Xwayland) instead of xvfb-run; prefer it and start weston, else fall back to xvfb-run
       - XVFB=$(command -v xwfb-run 2>/dev/null || command -v xvfb-run); XVFB_ARGS=""; if command -v xwfb-run >/dev/null 2>&1; then dnf install -y -q weston 2>/dev/null; XVFB_ARGS="-c weston"; fi
@@ -218,6 +219,7 @@ steps:
           LIB="/mnt/cache/R-pkgs-$RMINOR"
           mkdir -p "$LIB"
           R_LIBS_USER="$LIB" "$(dirname "$RBIN")/Rscript" local/install-bincraft.R || true
+          R_LIBS_USER="$LIB" UVR_R_BIN="$RBIN" local/uvr-install.sh RPostgres || true
           R_LIBS_USER="$LIB" $XVFB $XVFB_ARGS -- "$(dirname "$RBIN")/R" -q -e "options(crayon.enabled = TRUE, Ncpus = 4, future.globals.onReference = NULL); bincraft::process_cran_updates(interval = $INTERVAL, platform = '${OS}', process_updated = TRUE, process_new = FALSE, process_removed = FALSE, patches = 'local/patches', r_minor_detection = 'classifier',r_minor_sensitive_only = TRUE, s3_endpoint = 'https://s3.eu-central-003.backblazeb2.com', s3_region = 'eu-central-003', s3_bucket = 'devxy-rpkgs-binaries', s3_access_key_id = Sys.getenv('B2_S3_ACCESS_KEY'), s3_secret_access_key = Sys.getenv('B2_S3_SECRET_KEY'), metadata_db_host = 'r-binaries.devxy.io', metadata_db_name = 'build_metadata', metadata_db_table = 'single_builds', metadata_db_user = 'rpkgs', metadata_db_password = Sys.getenv('PGPASS'), metadata_db_sslmode = 'require', metadata_db_port = 15432, archive = TRUE, upload = TRUE, store_build_metadata = TRUE)" || true
         done
       - /opt/R/$R_VERSION/bin/R -q -e 'library(bincraft); upload_package_index(codename = "${OS_ID}", s3_endpoint = "https://s3.eu-central-003.backblazeb2.com", s3_region = "eu-central-003", s3_bucket = "devxy-rpkgs-binaries", s3_access_key_id = Sys.getenv("B2_S3_ACCESS_KEY"), s3_secret_access_key = Sys.getenv("B2_S3_SECRET_KEY"))'

.crow/weekly-audit-missing.yaml

@@ -3,15 +3,15 @@
 # Routing is preserved 1:1:
 #   - cron:   each existing `weekly-audit-missing-<os>-<arch>` cron fires only
 #             its matching matrix row (via the per-row `cron:` name filter).
-#   - manual: pick a target from the `weekly_audit_missing` dropdown
-#             ("all" = every os/arch).
+#   - manual: pick a target from the `weekly_audit_missing` dropdown;
+#             "all" fans out every os/arch as parallel matrix workflows.
 # Arch placement is via the group label (rpkgs-amd64, rpkgs-arm64).
 variables:
   # Gates this pipeline. A manual pipeline creation instantiates every file in
   # .crow/, and a declared default is applied even when the run never passed
   # this variable, so the default must be a value that matches no matrix row.
   weekly_audit_missing:
-    description: "Manual run target: a specific <os>-<arch>, 'all' for every os/arch, or 'none' to run nothing."
+    description: "Manual run target: a specific <os>-<arch>, 'all' to run every os/arch in parallel, or 'none' to run nothing."
     options:
       - none
       - all
@@ -147,7 +147,7 @@ steps:
       - mkdir -p /mnt/cache/packages /mnt/cache/R-pkgs
       - rm -rf /mnt/cache/R-pkgs/00LOCK-*
       - /opt/R/$R_VERSION/bin/Rscript local/install-bincraft.R
-      - UVR_R_BIN=/opt/R/$R_VERSION/bin/R local/uvr-install.sh httr2 jsonlite
+      - UVR_R_BIN=/opt/R/$R_VERSION/bin/R local/uvr-install.sh RPostgres httr2 jsonlite
       - /opt/R/$R_VERSION/bin/R -q -e 'source("local/weekly-missing-binaries-audit.R")'
     backend_options:
       docker:

.crow/weekly-patch-proposals.yaml

@@ -53,7 +53,7 @@ steps:
       - git clone -q https://pat-s:$$REPO_RO_TOKEN@git.devxy.io/devxy/build-cran-binaries.git .
       - mkdir -p /mnt/cache/R-pkgs
       - rm -rf /mnt/cache/R-pkgs/00LOCK-*
-      - UVR_R_BIN=/opt/R/$R_VERSION/bin/R local/uvr-install.sh httr2 jsonlite
+      - UVR_R_BIN=/opt/R/$R_VERSION/bin/R local/uvr-install.sh RPostgres httr2 jsonlite
       - /opt/R/$R_VERSION/bin/Rscript local/propose-patches.R --open-issue
       - /opt/R/$R_VERSION/bin/Rscript local/proposal-tracking.R --open-issue
     backend_options:

.crow/weekly-rebuild-missing.yaml

@@ -1,18 +1,27 @@
 # Consolidated weekly-rebuild-missing pipeline (all platforms, both arches).
-# One matrix row per OS/arch replaces the former per-platform files.
+# Three matrix rows per OS/arch, one per shard of that slot's rebuild list.
 # Routing is preserved 1:1:
 #   - cron:   each existing `weekly-rebuild-missing-<os>-<arch>` cron fires only
-#             its matching matrix row (via the per-row `cron:` name filter).
-#   - manual: `weekly_rebuild_missing` dropdown, default "all" (matches the
-#             previous bare manual trigger that ran every os/arch); pick a
-#             single <os>-<arch> to run just one.
+#             its matching matrix rows (via the per-row `cron:` name filter),
+#             which is now all three shards of that slot.
+#   - manual: pick a target from the `weekly_rebuild_missing` dropdown;
+#             "all" fans out every os/arch and shard as parallel matrix
+#             workflows, while a single <os>-<arch> runs its three shards.
 # Arch placement is handled by the group label (rpkgs-amd64, rpkgs-arm64).
+#
+# The shard picks up its own slice and re-derives what is still outstanding
+# from the bucket, so a restart resumes rather than replaying; see
+# local/rebuild-missing.R.
+#
+# Re-indexing and the CDN purge deliberately do NOT live here. Three shards
+# writing one slot's PACKAGES concurrently would race, so they moved to
+# .crow/weekly-rebuild-reindex.yaml, which depends on this pipeline.
 variables:
   # Gates this pipeline. A manual pipeline creation instantiates every file in
   # .crow/, and a declared default is applied even when the run never passed
   # this variable, so the default must be a value that matches no matrix row.
   weekly_rebuild_missing:
-    description: "Manual run target: a specific <os>-<arch>, 'all' for every os/arch, or 'none' to run nothing."
+    description: "Manual run target: a specific <os>-<arch>, 'all' to run every os/arch in parallel, or 'none' to run nothing."
     options:
       - none
       - all
@@ -53,74 +62,326 @@ matrix:
       ARCH: amd64
       R_VERSION: 4.5.3
       IMG: alpine:3.22
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: alpine-322
+      ARCH: amd64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.22
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: alpine-322
+      ARCH: amd64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.22
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: alpine-322
       ARCH: arm64
       R_VERSION: 4.5.3
       IMG: alpine:3.22
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: alpine-322
+      ARCH: arm64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.22
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: alpine-322
+      ARCH: arm64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.22
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: alpine-323
       ARCH: amd64
       R_VERSION: 4.5.3
       IMG: alpine:3.23
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: alpine-323
+      ARCH: amd64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.23
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: alpine-323
+      ARCH: amd64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.23
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: alpine-323
       ARCH: arm64
       R_VERSION: 4.5.3
       IMG: alpine:3.23
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: alpine-323
+      ARCH: arm64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.23
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: alpine-323
+      ARCH: arm64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.23
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: alpine-324
       ARCH: amd64
       R_VERSION: 4.5.3
       IMG: alpine:3.24
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: alpine-324
+      ARCH: amd64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.24
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: alpine-324
+      ARCH: amd64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.24
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: alpine-324
       ARCH: arm64
       R_VERSION: 4.5.3
       IMG: alpine:3.24
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: alpine-324
+      ARCH: arm64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.24
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: alpine-324
+      ARCH: arm64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.24
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: redhat-8
       ARCH: amd64
       R_VERSION: 4.4.3
       IMG: redhat:8
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: redhat-8
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: redhat:8
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: redhat-8
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: redhat:8
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: redhat-8
       ARCH: arm64
       R_VERSION: 4.4.3
       IMG: redhat:8
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: redhat-8
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: redhat:8
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: redhat-8
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: redhat:8
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: redhat-9
       ARCH: amd64
       R_VERSION: 4.4.3
       IMG: redhat:9
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: redhat-9
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: redhat:9
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: redhat-9
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: redhat:9
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: redhat-9
       ARCH: arm64
       R_VERSION: 4.4.3
       IMG: redhat:9
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: redhat-9
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: redhat:9
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: redhat-9
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: redhat:9
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: redhat-10
       ARCH: amd64
       R_VERSION: 4.5.3
       IMG: redhat:10
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: redhat-10
+      ARCH: amd64
+      R_VERSION: 4.5.3
+      IMG: redhat:10
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: redhat-10
+      ARCH: amd64
+      R_VERSION: 4.5.3
+      IMG: redhat:10
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: redhat-10
       ARCH: arm64
       R_VERSION: 4.5.3
       IMG: redhat:10
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: redhat-10
+      ARCH: arm64
+      R_VERSION: 4.5.3
+      IMG: redhat:10
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: redhat-10
+      ARCH: arm64
+      R_VERSION: 4.5.3
+      IMG: redhat:10
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: ubuntu-2204
       ARCH: amd64
       R_VERSION: 4.4.3
       IMG: ubuntu:jammy
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: ubuntu-2204
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:jammy
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: ubuntu-2204
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:jammy
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: ubuntu-2204
       ARCH: arm64
       R_VERSION: 4.4.3
       IMG: ubuntu:jammy
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: ubuntu-2204
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:jammy
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: ubuntu-2204
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:jammy
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: ubuntu-2404
       ARCH: amd64
       R_VERSION: 4.4.3
       IMG: ubuntu:noble
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: ubuntu-2404
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:noble
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: ubuntu-2404
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:noble
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: ubuntu-2404
       ARCH: arm64
       R_VERSION: 4.4.3
       IMG: ubuntu:noble
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: ubuntu-2404
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:noble
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: ubuntu-2404
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:noble
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: ubuntu-2604
       ARCH: amd64
       R_VERSION: 4.4.3
       IMG: ubuntu:resolute
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: ubuntu-2604
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:resolute
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: ubuntu-2604
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:resolute
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
     - OS: ubuntu-2604
       ARCH: arm64
       R_VERSION: 4.4.3
       IMG: ubuntu:resolute
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 1
+    - OS: ubuntu-2604
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:resolute
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 2
+    - OS: ubuntu-2604
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:resolute
+      SPLIT_INTO: 3
+      SPLIT_INDEX: 3
 
 steps:
   - name: 'Rebuild missing binaries'
@@ -153,6 +414,12 @@ steps:
       PLATFORM: ${OS}
       ARCH: ${ARCH}
       NCPUS: 2
+      SPLIT_INTO: ${SPLIT_INTO}
+      SPLIT_INDEX: ${SPLIT_INDEX}
+      # Wall clock after which the shard stops cleanly instead of having to be
+      # killed. A kill matches neither `success` nor `failure`, so it would skip
+      # the dependent re-index and leave rebuilt binaries behind a stale edge.
+      REBUILD_BUDGET_HOURS: 20
     commands:
       - git clone -q https://pat-s:$$REPO_RO_TOKEN@git.devxy.io/devxy/build-cran-binaries.git .
       - mkdir -p /mnt/cache/uvr/cache /mnt/cache/uvr/packages /mnt/cache/R-pkgs /mnt/cache/ccache /mnt/cache/packages
@@ -162,18 +429,7 @@ steps:
       - XVFB=$(command -v xwfb-run 2>/dev/null || command -v xvfb-run); XVFB_ARGS=""; if command -v xwfb-run >/dev/null 2>&1; then dnf install -y -q weston 2>/dev/null; XVFB_ARGS="-c weston"; fi
       - UVR_R_BIN=/opt/R/$R_VERSION/bin/R local/uvr-install.sh httr2
       - /opt/R/$R_VERSION/bin/R -q -e 'source("local/fetch-rebuild-packages-from-issue.R")'
-      - $XVFB $XVFB_ARGS -- /opt/R/$R_VERSION/bin/R -q -e "sink(stdout(), type = 'message'); options(crayon.enabled = TRUE, Ncpus = $NCPUS, future.globals.onReference = NULL); pkgs <- readLines('/tmp/rebuild_pkgs.txt'); if (length(pkgs) == 0) { cat('Nothing to rebuild\n'); q('no') }; excluded <- jsonlite::fromJSON('local/excluded-packages.json')[['package']]; pkgs <- setdiff(pkgs, excluded); cat(sprintf('Rebuilding %d packages\n', length(pkgs))); n <- length(pkgs); for (i in seq_along(pkgs)) { x <- pkgs[i]; cat(sprintf('[%d/%d] %s\n', i, n, x)); tryCatch(bincraft::build_binary_package(x, tag_limit = 1L, patches = 'local/patches', s3_endpoint = 'https://s3.eu-central-003.backblazeb2.com', s3_region = 'eu-central-003', s3_bucket = 'devxy-rpkgs-binaries', s3_access_key_id = Sys.getenv('B2_S3_ACCESS_KEY'), s3_secret_access_key = Sys.getenv('B2_S3_SECRET_KEY'), metadata_db_host = 'r-binaries.devxy.io', metadata_db_name = 'build_metadata', metadata_db_table = 'single_builds', metadata_db_user = 'rpkgs', metadata_db_password = Sys.getenv('PGPASS'), metadata_db_sslmode = 'require', metadata_db_port = 15432, archive = TRUE, upload = TRUE, store_build_metadata = TRUE), error = function(e) cat(sprintf('ERROR building %s - %s\n', x, conditionMessage(e)))) }" 2>&1
-      # A rebuild replaces objects in place, so the slot's index still advertises
-      # the old MD5 and, for anything that had been served from source, no Built
-      # stamp. Re-index here rather than waiting for the next process-updates
-      # run, or the rebuilt binaries stay invisible to clients until then.
-      # The codename is detected from the image's /etc/os-release.
-      - /opt/R/$R_VERSION/bin/R -q -e 'library(bincraft); upload_package_index(s3_endpoint = "https://s3.eu-central-003.backblazeb2.com", s3_region = "eu-central-003", s3_bucket = "devxy-rpkgs-binaries", s3_access_key_id = Sys.getenv("B2_S3_ACCESS_KEY"), s3_secret_access_key = Sys.getenv("B2_S3_SECRET_KEY"))'
-      - |
-        for RBIN in /opt/R/[0-9]*/bin/R; do
-          RMINOR=$(basename "$(dirname "$(dirname "$RBIN")")" | cut -d. -f1-2)
-          /opt/R/$R_VERSION/bin/R -q -e "library(bincraft); upload_package_index(r_minor = '$RMINOR', s3_endpoint = 'https://s3.eu-central-003.backblazeb2.com', s3_region = 'eu-central-003', s3_bucket = 'devxy-rpkgs-binaries', s3_access_key_id = Sys.getenv('B2_S3_ACCESS_KEY'), s3_secret_access_key = Sys.getenv('B2_S3_SECRET_KEY'))" || true
-        done
+      - $XVFB $XVFB_ARGS -n $SPLIT_INDEX -- /opt/R/$R_VERSION/bin/Rscript local/rebuild-missing.R $SPLIT_INTO $SPLIT_INDEX $REBUILD_BUDGET_HOURS 2>&1
     backend_options:
       docker:
         resources:
@@ -183,25 +439,3 @@ steps:
           limits:
             memory: 18Gi
             cpu: 3000m
-
-  - name: Purge CDN cache
-    image: reg.devxy.io/docker.io/library/alpine:3.24
-    environment:
-      OTEL_R_TRACES_EXPORTER: none
-      OTEL_R_LOGS_EXPORTER: none
-      OTEL_R_METRICS_EXPORTER: none
-      BUNNYNET_API_KEY:
-        from_secret: BUNNYNET_API_KEY
-      REPO_RO_TOKEN:
-        from_secret: REPO_RO_TOKEN
-      # All hostnames on the zone share this id, so one purge covers
-      # cran.devxy.io, cran.allianceswisspass.devxy.io and cran.rpkgs.com.
-      BUNNY_PULLZONE: '3857050'
-    commands:
-      - apk add --no-cache -q bash curl git
-      - git clone -q https://pat-s:$$REPO_RO_TOKEN@git.devxy.io/devxy/build-cran-binaries.git .
-      - bash scripts/purge_cdn_zone.sh "$BUNNYNET_API_KEY" "$BUNNY_PULLZONE"
-    # A rebuild that died part-way still replaced objects, and those are exactly
-    # the ones a stale edge would keep hiding, so purge either way.
-    when:
-      - status: [success, failure]

.crow/weekly-rebuild-reindex.yaml

@@ -0,0 +1,191 @@
+# Re-index and purge after weekly-rebuild-missing.
+#
+# weekly-rebuild-missing runs three shards per slot. Each of them replaces
+# objects in place, so the slot's index still advertises the old MD5 and, for
+# anything that had been served from source, no Built stamp. Re-indexing from
+# inside a shard would mean three concurrent `upload_package_index()` calls on
+# one prefix: `cranlike::update_PACKAGES()` lists the live bucket, so an early
+# lister that uploads last publishes an index missing its siblings' work.
+#
+# So it happens exactly once per slot, here, after every shard has finished.
+# `runs_on: [success, failure]` keeps that true when a shard fails; only an
+# explicit cancel skips it, and this pipeline can then be triggered on its own.
+
+variables:
+  # Mirrors the gate on weekly-rebuild-missing so a manual run re-indexes
+  # exactly the slots it rebuilt. A manual pipeline creation instantiates every
+  # file in .crow/, so the default must match no matrix row.
+  weekly_rebuild_missing:
+    description: "Manual run target: a specific <os>-<arch>, 'all' to run every os/arch in parallel, or 'none' to run nothing."
+    options:
+      - none
+      - all
+      - alpine-322-amd64
+      - alpine-322-arm64
+      - alpine-323-amd64
+      - alpine-323-arm64
+      - alpine-324-amd64
+      - alpine-324-arm64
+      - redhat-8-amd64
+      - redhat-8-arm64
+      - redhat-9-amd64
+      - redhat-9-arm64
+      - redhat-10-amd64
+      - redhat-10-arm64
+      - ubuntu-2204-amd64
+      - ubuntu-2204-arm64
+      - ubuntu-2404-amd64
+      - ubuntu-2404-arm64
+      - ubuntu-2604-amd64
+      - ubuntu-2604-arm64
+    default: none
+
+when:
+  - event: cron
+    cron: weekly-rebuild-missing-${OS}-${ARCH}
+  - event: manual
+    evaluate: 'weekly_rebuild_missing == "all" || weekly_rebuild_missing == "${OS}-${ARCH}"'
+
+depends_on:
+  - weekly-rebuild-missing
+
+runs_on: [success, failure]
+
+skip_clone: true
+
+labels:
+  group: rpkgs-${ARCH}
+
+matrix:
+  include:
+    - OS: alpine-322
+      ARCH: amd64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.22
+    - OS: alpine-322
+      ARCH: arm64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.22
+    - OS: alpine-323
+      ARCH: amd64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.23
+    - OS: alpine-323
+      ARCH: arm64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.23
+    - OS: alpine-324
+      ARCH: amd64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.24
+    - OS: alpine-324
+      ARCH: arm64
+      R_VERSION: 4.5.3
+      IMG: alpine:3.24
+    - OS: redhat-8
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: redhat:8
+    - OS: redhat-8
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: redhat:8
+    - OS: redhat-9
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: redhat:9
+    - OS: redhat-9
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: redhat:9
+    - OS: redhat-10
+      ARCH: amd64
+      R_VERSION: 4.5.3
+      IMG: redhat:10
+    - OS: redhat-10
+      ARCH: arm64
+      R_VERSION: 4.5.3
+      IMG: redhat:10
+    - OS: ubuntu-2204
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:jammy
+    - OS: ubuntu-2204
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:jammy
+    - OS: ubuntu-2404
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:noble
+    - OS: ubuntu-2404
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:noble
+    - OS: ubuntu-2604
+      ARCH: amd64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:resolute
+    - OS: ubuntu-2604
+      ARCH: arm64
+      R_VERSION: 4.4.3
+      IMG: ubuntu:resolute
+
+steps:
+  - name: 'Re-index the slot'
+    image: reg.devxy.io/rpkgs/build-env-${IMG}
+    pull: true
+    environment:
+      OTEL_R_TRACES_EXPORTER: none
+      OTEL_R_LOGS_EXPORTER: none
+      OTEL_R_METRICS_EXPORTER: none
+      RED_HAT_DEV_PW:
+        from_secret: RED_HAT_DEV_PW
+      B2_S3_ACCESS_KEY:
+        from_secret: B2_S3_ACCESS_KEY
+      B2_S3_SECRET_KEY:
+        from_secret: B2_S3_SECRET_KEY
+      REPO_RO_TOKEN:
+        from_secret: REPO_RO_TOKEN
+      GIT_USER: pat-s
+      R_LIBS_USER: /mnt/cache/R-pkgs
+      R_VERSION: ${R_VERSION}
+      PLATFORM: ${OS}
+      ARCH: ${ARCH}
+    commands:
+      - git clone -q https://pat-s:$$REPO_RO_TOKEN@git.devxy.io/devxy/build-cran-binaries.git .
+      - mkdir -p /mnt/cache/R-pkgs
+      - rm -rf /mnt/cache/R-pkgs/00LOCK-*
+      - /opt/R/$R_VERSION/bin/Rscript local/install-bincraft.R
+      # The codename is detected from the image's /etc/os-release.
+      - /opt/R/$R_VERSION/bin/R -q -e 'library(bincraft); upload_package_index(s3_endpoint = "https://s3.eu-central-003.backblazeb2.com", s3_region = "eu-central-003", s3_bucket = "devxy-rpkgs-binaries", s3_access_key_id = Sys.getenv("B2_S3_ACCESS_KEY"), s3_secret_access_key = Sys.getenv("B2_S3_SECRET_KEY"))'
+      - |
+        for RBIN in /opt/R/[0-9]*/bin/R; do
+          RMINOR=$(basename "$(dirname "$(dirname "$RBIN")")" | cut -d. -f1-2)
+          /opt/R/$R_VERSION/bin/R -q -e "library(bincraft); upload_package_index(r_minor = '$RMINOR', s3_endpoint = 'https://s3.eu-central-003.backblazeb2.com', s3_region = 'eu-central-003', s3_bucket = 'devxy-rpkgs-binaries', s3_access_key_id = Sys.getenv('B2_S3_ACCESS_KEY'), s3_secret_access_key = Sys.getenv('B2_S3_SECRET_KEY'))" || true
+        done
+
+  - name: Purge CDN cache
+    image: reg.devxy.io/docker.io/library/alpine:3.24
+    environment:
+      OTEL_R_TRACES_EXPORTER: none
+      OTEL_R_LOGS_EXPORTER: none
+      OTEL_R_METRICS_EXPORTER: none
+      BUNNYNET_API_KEY:
+        from_secret: BUNNYNET_API_KEY
+      # cran.rpkgs.com and cran.allianceswisspass.devxy.io are on separate
+      # Bunny pull zones, so both must be purged after the shared origin changes.
+      BUNNY_PULLZONES: '3857050 cran.allianceswisspass.devxy.io'
+    commands:
+      - apk add --no-cache -q bash curl jq
+      # Crow carries the checkout from the re-index step into this step.
+      - bash scripts/purge_cdn_zone.sh "$BUNNYNET_API_KEY" $BUNNY_PULLZONES
+    # Runs on every row rather than on one designated slot: a cron fires only
+    # its own slot's row, so gating on a named slot would leave every other
+    # slot unpurged. A manual "all" run therefore purges the zone 18 times,
+    # which is a cheap API call and rare.
+    #
+    # Run it even when the re-index above failed: the objects were still
+    # replaced, and a stale edge is exactly what keeps them hidden.
+    when:
+      - status: [success, failure]

.pre-commit-config.yaml

@@ -36,7 +36,7 @@ repos:
     hooks:
       - id: air-format
   - repo: https://github.com/editorconfig-checker/editorconfig-checker
-    rev: v3.11.1
+    rev: v3.11.2
     hooks:
       - id: editorconfig-checker
         exclude: ^local/patches/.*\.patch$

.terraform.lock.hcl

@@ -2,79 +2,79 @@
 # Manual edits may be lost in future updates.
 
 provider "registry.opentofu.org/hashicorp/http" {
-  version = "3.6.0"
+  version = "3.6.1"
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 }
 
 provider "registry.terraform.io/bunnyway/bunnynet" {
-  version     = "0.17.0"
-  constraints = "~> 0.17"
+  version     = "0.18.2"
+  constraints = "~> 0.18"
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-    "zh:606919a930f0299948504adbdcd0f239a8af5c418f85741c48f8add370a3d038",
-    "zh:66963d5b445639511939fc508513fd31da3ee1d4ee1a565ee396c9532897a349",
-    "zh:6c981ec0c8545556395c43e2511861ab65ee9ecf2a960480e7889c3af0d23af3",
-    "zh:7334a1bdb726ce1f1bf0a3155f30f84f65206980c229c832ff5f0b0718c44e0b",
-    "zh:75f6c86bf74511e605423332d113711c76c8028361a32282fb3359d6c7ecae9e",
-    "zh:7aebb1a01cfe8be54903853202ae06eba14ad99c37d230ed93ce7d6633e05e9b",
+    "h1:3rZl+Co3WMpwj8SciPaCNXoGA31aSoqp6iweLarr5m4=",
+    "h1:6d9cKLhz8QOZ4R5yVX1G0TsWL+K1Abtfbm3xngndxto=",
+    "h1:EBjjkfp5Gx7nXP1DVO+tLhsow6fEUvaIjsCEFRT2fY8=",
+    "h1:Nu2DoHGOv2YN7ag4kFGpfnPeRDh6bzWqY5anW+ETGpM=",
+    "h1:OnvZxg28m4/UJeEhHVLU4kM2MZ704sxRzYfLWlLxnhA=",
+    "h1:PiCse2/UcB7nkPxosveHsJN/jKdBC8AH6tKTxcHSYKw=",
+    "h1:QAahdtlDBUon7eMwNN0D2V6CxgasOXIi+9/UExik6Sg=",
+    "h1:Su5z0A7/UaSm/E7FJnFjpDVQaa1Ju5+fZ8Mirf8E+k8=",
+    "h1:UA3a78FJAPAGqCCvlIg9ekPltpVsrmEhwFLalWCFnew=",
+    "h1:XAlCTNHRtgUkNjdUItkiak6ajjT7wFJzJN8frXKD5Ms=",
+    "h1:ZgLBOPebYxH059z1cGHmjYO8CTf+tbWPb3VbO97S2YM=",
+    "h1:anR91C2F6NDJoQQQIy6KHChodnTaSKnApSWSGM4jSX0=",
+    "h1:gVmaNmIu4gEiITM+CAb66e+zncAqzNBYkniTZfvxZ5Y=",
+    "h1:pODlGrkPqHV4yhXiO7LLLu11HtcuxOAB2zUx3B8w1vI=",
+    "h1:qEYeHEKVRcc78q5xiRGJSY8DGQpLj40KafEXUxFfaQc=",
+    "h1:qdVz+O0lLHhyf5YX3ujmoVvAGlKqvi+YOPUzVTqpKzY=",
+    "h1:yTrPkdc9eQkxfPLBYydFf0fpcjarP5w0sdLPzekD9RQ=",
+    "zh:0fe3987c927d81196c97504470ce4d26c3ad0014f8ee3d0c1be422d08cfcf49c",
+    "zh:15c36dc69e058876921ac887213e1716217d159b7ee7f0f233e21fb35be85178",
+    "zh:29d58d7b76dcb142a06d4edd15b8500fe6c1afb7f7c056ada17e2d42bb999fbd",
+    "zh:33d313836c0e985186b3456c0946e062b27cacfcb08611d0a394f36db9ee1aef",
+    "zh:47e085e52e9b24ad85fa2988dbb8604256a970a6f53f7fa6aab04d8ae756a738",
+    "zh:4ba4f87571ca72fbc6c24ab71f2f7b5a086938262e2d8e5c0b39701ed52f8bbc",
+    "zh:4c6bae97b543c5b328e1ecbcf7c976351b4b381654e9d3e569270dcab3ba816c",
     "zh:890df766e9b839623b1f0437355032a3c006226a6c200cd911e15ee1a9014e9f",
-    "zh:9041d0e20c9ceea532de6eebf5cb3a27dad0bb49d3f5b5154be2a08d68fbbf1f",
-    "zh:a6bbf65431a02be4df0ebb1cbe01185ad357ff6e33c01bd0558f59bed90c8f36",
-    "zh:c6d075a31096f080c388dfe46036f451c0cc114c3311a4f46ab8dbe1938a202f",
-    "zh:dd8703f7b55b8bc8e10f8718bea889781100b18e932b04898995b63178c3d36e",
-    "zh:dd92a5cd4e133a4000e7e5bc8cce876ae0ed803543cedd2f3d590661ba244d04",
-    "zh:e024fdf121bebc48c1e6debea344c6d4f174117f3ae605fca6e13b9705d92d22",
-    "zh:ee0e80c31b438e35fa1608f6a2f5824d2806db1e5e8b9f7a90986585c7bcb895",
-    "zh:fc2d4b705411b48f8c045981f9368a3ea2f74969dd6302008c31ff0bedd51f0a",
+    "zh:9ba7ab56537963db2449d217528a751469c9dc4e413dec3e3d63fd7daf3db4ef",
+    "zh:a3c48eda7e11b03b831f2a639797524bb335f155f0dff0e999cf3496994da8b3",
+    "zh:aab8f4814d55ef8c6c285d2496ae412437017d0fd1be70106f7b3a4a6e764feb",
+    "zh:b92b9beacf71ae894717c2036ceb68db52c9c43af4a01b8209eceae9f91a2c8e",
+    "zh:da389285938e22e1249e6a00cebf12a9f67334743f0b3f66399e6881028bda11",
+    "zh:dadcc33d06e6f64a17d1965478af5e8bbdc971e92ec9b14e384c5d43861d63f7",
+    "zh:e090c916e6da685125194af4f0a1fd772494a0c63f3f16ab3741782e17f4a8f9",
+    "zh:e5881e00fa970c08e66e8079b47d69b76def6e7ff3bdc35b68d7811e5ece55d1",
+    "zh:eeebb25a066a6287d545c91c0fc264acee5b28174d0979faeebdac3bd14f0fff",
+    "zh:f368195116c9ce0181aa7527c51ae5e7ab23d42fb966acf4eddca344621ae339",
   ]
 }

cdn.tf

@@ -32,7 +32,7 @@
 #   cache_stale           = ["offline", "updating"]
 #   use_background_update = true
 
-  # block_ips = var.cdn_block_ips
+# block_ips = var.cdn_block_ips
 
 #   # 50 TB
 #   limit_bandwidth = 50000000000000
@@ -52,6 +52,26 @@
 
 ### cran.rpkgs.com
 
+locals {
+  rpkgs_slots = [
+    for pair in setproduct(
+      ["amd64", "arm64"],
+      ["resolute", "noble", "jammy", "rhel8", "rhel9", "rhel10", "alpine323", "alpine324"]
+    ) : "${pair[0]}/${pair[1]}"
+  ]
+
+  # The supported R minors: the current one plus the two previous, which is
+  # exactly what build-env-images installs as R_VERSION_LATEST / PREV1 / PREV2.
+  # These must stay in step. A minor listed here without a published index
+  # sends those clients to a 404; a published minor missing from this list
+  # sends them to CRAN for sources instead of serving the binaries we built.
+  rpkgs_supported_minors = ["4.4", "4.5", "4.6"]
+
+  # bunny.net serves every pull zone on <name>.b-cdn.net, so staging needs no
+  # DNS record and is never advertised.
+  rpkgs_test_hostname = "cran-rpkgs-test.b-cdn.net"
+}
+
 # The edge middleware that resolves the bare cran.rpkgs.com form to an
 # <arch>/<os> slot and routes PACKAGES* to the per-R-minor slot. The source of
 # truth is edge/rpkgs-router.ts; `tofu apply` publishes a new release.
@@ -75,6 +95,13 @@ resource "bunnynet_compute_script_variable" "rpkgs_router_union_slots" {
   required      = false
 }
 
+resource "bunnynet_compute_script_variable" "rpkgs_router_known_minors" {
+  script        = bunnynet_compute_script.rpkgs_router.id
+  name          = "KNOWN_MINORS"
+  default_value = join(",", local.rpkgs_supported_minors)
+  required      = false
+}
+
 resource "bunnynet_pullzone" "cran_rpkgs_com" {
   name = "cran-rpkgs"
 
@@ -82,7 +109,7 @@ resource "bunnynet_pullzone" "cran_rpkgs_com" {
 
   cache_expiration_time = 31919000
   websockets_enabled    = false
-  errorpage_whitelabel = true
+  errorpage_whitelabel  = true
 
   origin {
     type              = "OriginUrl"
@@ -147,6 +174,151 @@ resource "bunnynet_pullzone_hostname" "cran_rpkgs_com" {
   tls_enabled = true
 }
 
+### Staging zone for edge-router changes
+
+# Every published <arch>/<os> slot. The staging zone enables per-minor routing
+# for all of them at once; production adopts the same list only after
+# `scripts/verify-r-minor-routing.sh --live` passes against staging.
+
+# A second copy of the same router, bound to the same B2 origin, so UNION_SLOTS
+# can be exercised end to end before production is touched.
+resource "bunnynet_compute_script" "rpkgs_router_test" {
+  type    = "middleware"
+  name    = "rpkgs-router-test"
+  content = file("${path.module}/edge/rpkgs-router.ts")
+}
+
+resource "bunnynet_compute_script_variable" "rpkgs_router_test_union_slots" {
+  script        = bunnynet_compute_script.rpkgs_router_test.id
+  name          = "UNION_SLOTS"
+  default_value = join(",", local.rpkgs_slots)
+  required      = false
+}
+
+# Without this the staging zone rewrites to PUBLIC_CDN_ORIGIN, so its redirects
+# land on production and the test silently measures the wrong system.
+resource "bunnynet_compute_script_variable" "rpkgs_router_test_extra_hosts" {
+  script        = bunnynet_compute_script.rpkgs_router_test.id
+  name          = "EXTRA_PUBLIC_HOSTS"
+  default_value = local.rpkgs_test_hostname
+  required      = false
+}
+
+resource "bunnynet_compute_script_variable" "rpkgs_router_test_known_minors" {
+  script        = bunnynet_compute_script.rpkgs_router_test.id
+  name          = "KNOWN_MINORS"
+  default_value = join(",", local.rpkgs_supported_minors)
+  required      = false
+}
+
+resource "bunnynet_pullzone" "cran_rpkgs_test" {
+  name = "cran-rpkgs-test"
+
+  cache_errors = false
+
+  cache_expiration_time = 31919000
+  websockets_enabled    = false
+  errorpage_whitelabel  = true
+
+  origin {
+    type              = "OriginUrl"
+    url               = "https://devxy-rpkgs-binaries.s3.eu-central-003.backblazeb2.com"
+    middleware_script = bunnynet_compute_script.rpkgs_router_test.id
+  }
+
+  routing {
+    filters = [
+      "scripting",
+    ]
+  }
+
+  s3_auth_enabled = true
+  s3_auth_key     = var.B2_S3_ACCESS_KEY
+  s3_auth_secret  = var.B2_S3_SECRET_KEY
+  s3_auth_region  = "eu-central-003"
+
+  cache_enabled              = true
+  request_coalescing_enabled = true
+  block_post_requests        = true
+
+  cache_vary_headers = ["User-Agent"]
+
+  # Staging carries only synthetic verification traffic, so the production
+  # ceilings would be pure headroom.
+  limit_requests    = 500
+  limit_connections = 100
+
+  safehop_enabled      = true
+  add_canonical_header = true
+  cache_stale          = ["offline", "updating"]
+  block_ips            = var.cdn_block_ips
+
+  # 1 TB
+  limit_bandwidth = 1000000000000
+
+  block_root_path = true
+}
+
+
+# Alliance SwissPass historically used a separate, manually configured pull
+# zone. Adopt it so both public repositories use the same B2 origin, middleware
+# release and cache behavior.
+import {
+  to = bunnynet_pullzone.cran_allianceswisspass
+  id = "3265648"
+}
+
+resource "bunnynet_pullzone" "cran_allianceswisspass" {
+  name = "cran-allianceswisspass"
+
+  cache_errors          = false
+  cache_expiration_time = 31919000
+  websockets_enabled    = false
+  errorpage_whitelabel  = true
+
+  origin {
+    type              = "OriginUrl"
+    url               = "https://devxy-rpkgs-binaries.s3.eu-central-003.backblazeb2.com"
+    middleware_script = bunnynet_compute_script.rpkgs_router.id
+  }
+
+  routing {
+    filters = [
+      "scripting",
+    ]
+  }
+
+  s3_auth_enabled = true
+  s3_auth_key     = var.B2_S3_ACCESS_KEY
+  s3_auth_secret  = var.B2_S3_SECRET_KEY
+  s3_auth_region  = "eu-central-003"
+
+  cache_enabled              = true
+  request_coalescing_enabled = true
+  block_post_requests        = true
+  cache_vary_headers         = ["User-Agent"]
+
+  limit_requests    = 5000
+  limit_connections = 1000
+
+  safehop_enabled      = true
+  add_canonical_header = true
+  cache_stale          = ["offline", "updating"]
+  block_ips            = var.cdn_block_ips
+
+  # 50 TB
+  limit_bandwidth = 50000000000000
+
+  block_root_path = true
+}
+
+resource "bunnynet_pullzone_hostname" "cran_allianceswisspass" {
+  pullzone    = bunnynet_pullzone.cran_allianceswisspass.id
+  name        = "cran.allianceswisspass.devxy.io"
+  force_ssl   = true
+  tls_enabled = true
+}
+
 # resource "bunnynet_storage_zone" "devxy-r-binaries" {
 #   name      = "devxy-r-binaries-storage"
 #   region    = "DE"

edge/rpkgs-router.test.ts

@@ -17,7 +17,12 @@ const UNION_SLOTS = 'amd64/alpine324';
 
 const UA_R45_MUSL = 'R (4.5.3 x86_64-pc-linux-musl x86_64 linux-musl)';
 const UA_R46_MUSL = 'R (4.6.0 x86_64-pc-linux-musl x86_64 linux-musl)';
+const UA_R43_MUSL = 'R (4.3.3 x86_64-pc-linux-musl x86_64 linux-musl)';
+const UA_R47_MUSL = 'R (4.7.0 x86_64-pc-linux-musl x86_64 linux-musl)';
 const UA_R45_ALPINE = 'R/4.5.3 R (4.5.3 x86_64-pc-linux-musl x86_64 linux-musl) Alpine Linux 3.24';
+const UA_R45_RESOLUTE = 'R/4.5.3 (Ubuntu 26.04) (aarch64-unknown-linux-gnu aarch64 linux-gnu)';
+const UA_R45_FUTURE_UBUNTU =
+  'R/4.5.3 (Ubuntu 28.04; codename=dynamic-dugong) (aarch64-unknown-linux-gnu aarch64 linux-gnu)';
 const UA_R45_DARWIN = 'R (4.5.1 aarch64-apple-darwin20 aarch64 darwin20)';
 const UA_CURL = 'curl/8.0.1';
 
@@ -93,6 +98,33 @@ Deno.test('rpkgs-router', async (t) => {
       assertEquals(res.location, `https://cran.rpkgs.com${SLOT}/4.6/PACKAGES.gz`);
     });
 
+    // We publish binaries only for the supported window. An excluded minor has
+    // no slot we can serve safely, so it goes to CRAN for sources rather than
+    // to a 404 or to binaries built under another minor.
+    await t.step('sends an excluded R minor to CRAN for the index', async () => {
+      const res = await probe(`${SLOT}/PACKAGES.gz`, UA_R43_MUSL);
+      assertEquals(res.location, 'https://cran.r-project.org/src/contrib/PACKAGES.gz');
+    });
+
+    await t.step('sends a future R minor to CRAN too', async () => {
+      const res = await probe(`${SLOT}/PACKAGES.gz`, UA_R47_MUSL);
+      assertEquals(res.location, 'https://cran.r-project.org/src/contrib/PACKAGES.gz');
+    });
+
+    // The index and the tarballs R resolves against it have to come from the
+    // same place. Serving one from CRAN and the other from here would hand R a
+    // binary where it expects a source tarball.
+    await t.step('sends an excluded minor to CRAN for tarballs as well', async () => {
+      const res = await probe(`${SLOT}/foo_1.0.tar.gz`, UA_R43_MUSL);
+      assertEquals(res.location, 'https://cran.r-project.org/src/contrib/foo_1.0.tar.gz');
+    });
+
+    await t.step('leaves an excluded minor alone on a slot outside UNION_SLOTS', async () => {
+      const res = await probe(`${OTHER_SLOT}/PACKAGES.gz`, UA_R43_MUSL);
+      assertEquals(res.location, null);
+      assertEquals(res.status, 200);
+    });
+
     await t.step('routes PACKAGES and PACKAGES.rds too', async () => {
       for (const file of ['PACKAGES', 'PACKAGES.rds']) {
         const res = await probe(`${SLOT}/${file}`, UA_R45_MUSL);
@@ -117,6 +149,13 @@ Deno.test('rpkgs-router', async (t) => {
       assertEquals(res.status, 200);
     });
 
+    await t.step('serves an archived binary when it exists', async () => {
+      const path = `${SLOT}/Archive/xml2/xml2_1.5.2.tar.gz`;
+      const res = await probe(path, UA_R45_MUSL);
+      assertEquals(res.status, 200);
+      assertEquals(res.location, null);
+    });
+
     await t.step('does not redirect a path already under a minor', async () => {
       const res = await probe(`${SLOT}/4.5/PACKAGES.gz`, UA_R45_MUSL);
       assertEquals(res.location, null);
@@ -134,6 +173,16 @@ Deno.test('rpkgs-router', async (t) => {
       assertEquals(res.location, `https://cran.rpkgs.com${SLOT}/4.5/PACKAGES.gz`);
     });
 
+    await t.step('resolves Ubuntu 26.04 to the resolute slot', async () => {
+      const res = await probe('/src/contrib/PACKAGES.gz', UA_R45_RESOLUTE);
+      assertEquals(res.location, 'https://cran.rpkgs.com/arm64/resolute/latest/src/contrib/PACKAGES.gz');
+    });
+
+    await t.step('resolves a future Ubuntu release from its codename', async () => {
+      const res = await probe('/src/contrib/PACKAGES.gz', UA_R45_FUTURE_UBUNTU);
+      assertEquals(res.location, 'https://cran.rpkgs.com/arm64/dynamic-dugong/latest/src/contrib/PACKAGES.gz');
+    });
+
     await t.step('sends an unidentifiable distro to CRAN', async () => {
       const res = await probe('/src/contrib/PACKAGES.gz', UA_R45_MUSL);
       assertEquals(res.location, 'https://cran.r-project.org/src/contrib/PACKAGES.gz');

edge/rpkgs-router.ts

@@ -27,6 +27,17 @@ import * as BunnySDK from 'https://esm.sh/@bunny.net/edgescript-sdk@0.12';
 
 const PUBLIC_CDN_ORIGIN = 'https://cran.rpkgs.com';
 const CRAN_ORIGIN = 'https://cran.r-project.org';
+const PUBLIC_CDN_HOSTS = new Set([
+  'cran.rpkgs.com',
+  'cran.allianceswisspass.devxy.io',
+  // Staging hostnames, so the identical script can run on a test pull zone and
+  // redirect within itself. Without this a test zone rewrites to
+  // PUBLIC_CDN_ORIGIN, quietly exercising production instead of itself.
+  ...(Deno.env.get('EXTRA_PUBLIC_HOSTS') ?? '')
+    .split(',')
+    .map((host) => host.trim())
+    .filter((host) => host.length > 0),
+]);
 
 /** Slots ("<arch>/<os>", comma separated) whose per-minor index is a union. */
 const UNION_SLOTS = new Set(
@@ -36,6 +47,21 @@ const UNION_SLOTS = new Set(
     .filter((slot) => slot.length > 0),
 );
 
+/**
+ * R minors for which a per-minor index is actually published.
+ *
+ * contribPath() has no way to probe the origin, so a minor that is not
+ * published here must fall back to the flat index. Routing an unlisted minor
+ * would send that client to a 404 and it would see no packages at all - a
+ * silent, total failure rather than a degraded one.
+ */
+const KNOWN_MINORS = new Set(
+  (Deno.env.get('KNOWN_MINORS') ?? '4.4,4.5,4.6')
+    .split(',')
+    .map((minor) => minor.trim())
+    .filter((minor) => minor.length > 0),
+);
+
 /** `/<arch>/<os>/latest/src/contrib[/<rest>]` */
 const SLOT_PATH_REGEX = /^\/(amd64|arm64)\/([a-z0-9._-]+)\/latest\/src\/contrib\/?(.*)$/;
 
@@ -47,13 +73,19 @@ const INDEX_FILE_REGEX = /^PACKAGES(\.gz|\.rds)?$/;
 
 const SRC_CONTRIB_REGEX = /^\/src\/contrib\/(.+)$/;
 
+/** A binary archive URL whose upstream source counterpart CRAN can serve. */
+const ARCHIVE_TARBALL_REGEX =
+  /^\/(?:amd64|arm64)\/[a-z0-9._-]+\/latest\/src\/contrib\/Archive\/([^/]+)\/([^/]+\.tar\.gz)$/;
+
 const MACOS_BIN_REGEX =
   /^\/bin\/macosx\/(big-sur-arm64|big-sur-x86_64|monterey-arm64|monterey-x86_64)\/contrib\/([0-9.]+)\/(.+)$/;
 
 const RHEL_REGEX = /(almalinux|rocky)[^\d]*(\d+)/i;
 
 const UBUNTU_REGEX = /Ubuntu ([\d.]+)/i;
+const UBUNTU_CODENAME_REGEX = /Ubuntu [\d.]+;\s*codename=([a-z][a-z0-9-]*)/i;
 const UBUNTU_CODENAMES: Record<string, string> = {
+  '26.04': 'resolute',
   '24.04': 'noble',
   '22.04': 'jammy',
 };
@@ -85,6 +117,22 @@ function redirectTo(location: string, status = 302): Response {
   });
 }
 
+function publicCdnOrigin(url: URL): string {
+  return PUBLIC_CDN_HOSTS.has(url.hostname) ? url.origin : PUBLIC_CDN_ORIGIN;
+}
+
+/**
+ * True when the client reports an R minor that we deliberately do not serve.
+ *
+ * A client that reports no minor at all is not "unsupported": non-R fetchers
+ * (mirror scripts, image builds) must keep getting the flat slot. Only a
+ * known-and-excluded minor falls through to CRAN.
+ */
+function isExcludedMinor(userAgent: string): boolean {
+  const rMinor = extractRMinor(userAgent);
+  return rMinor !== null && !KNOWN_MINORS.has(rMinor);
+}
+
 function extractRMinor(userAgent: string): string | null {
   for (const regex of R_MINOR_REGEXES) {
     const match = userAgent.match(regex);
@@ -127,6 +175,11 @@ function parseSlot(userAgent: string): string | null {
 
   const ubuntu = userAgent.match(UBUNTU_REGEX);
   if (ubuntu) {
+    const codenameMatch = userAgent.match(UBUNTU_CODENAME_REGEX);
+    if (codenameMatch) {
+      return `${arch}/${codenameMatch[1].toLowerCase()}`;
+    }
+
     const codename = UBUNTU_CODENAMES[ubuntu[1]];
     if (codename) {
       return `${arch}/${codename}`;
@@ -161,8 +214,8 @@ function parseMacUserAgent(userAgent: string): { os: string; arch: string; rver:
  * The contrib path a request should be served from, relative to the slot.
  *
  * Returns the per-minor path for an index file when the slot is known to carry
- * a union index and the client's R minor is known; otherwise the flat path,
- * which is what every client sees today.
+ * a union index and the client's R minor is one we publish; otherwise the flat
+ * path, which is what every client sees today.
  */
 function contribPath(slot: string, rest: string, userAgent: string): string {
   const flat = rest ? `/${slot}/latest/src/contrib/${rest}` : `/${slot}/latest/src/contrib`;
@@ -172,7 +225,7 @@ function contribPath(slot: string, rest: string, userAgent: string): string {
   }
 
   const rMinor = extractRMinor(userAgent);
-  return rMinor ? `/${slot}/latest/src/contrib/${rMinor}/${rest}` : flat;
+  return rMinor && KNOWN_MINORS.has(rMinor) ? `/${slot}/latest/src/contrib/${rMinor}/${rest}` : flat;
 }
 
 BunnySDK.net.http
@@ -181,15 +234,14 @@ BunnySDK.net.http
     const url = new URL(ctx.request.url);
     const path = normalizePathname(url.pathname);
     const userAgent = ctx.request.headers.get('User-Agent') || '';
+    const publicOrigin = publicCdnOrigin(url);
 
     // macOS clients are served from CRAN's own binary tree.
     const srcContrib = path.match(SRC_CONTRIB_REGEX);
     if (srcContrib && /darwin/.test(userAgent)) {
       const mac = parseMacUserAgent(userAgent);
       if (mac) {
-        return Promise.resolve(
-          redirectTo(`${PUBLIC_CDN_ORIGIN}/bin/macosx/${mac.os}/contrib/${mac.rver}/${srcContrib[1]}`),
-        );
+        return Promise.resolve(redirectTo(`${publicOrigin}/bin/macosx/${mac.os}/contrib/${mac.rver}/${srcContrib[1]}`));
       }
     }
 
@@ -209,11 +261,21 @@ BunnySDK.net.http
         return Promise.resolve(ctx.request);
       }
 
+      // An R minor outside the supported window has no binaries we can safely
+      // serve, so the whole interaction goes to CRAN: the index and the
+      // tarballs R will resolve against it. Serving the index from CRAN but
+      // tarballs from here would hand R a binary where it expects a source
+      // tarball, which fails in a far more confusing way than not being
+      // served at all.
+      if (UNION_SLOTS.has(slot) && isExcludedMinor(userAgent)) {
+        return Promise.resolve(redirectTo(`${CRAN_ORIGIN}/src/contrib/${rest}`));
+      }
+
       const target = contribPath(slot, rest, userAgent);
       if (target === path) {
         return Promise.resolve(ctx.request);
       }
-      return Promise.resolve(redirectTo(`${PUBLIC_CDN_ORIGIN}${target}`));
+      return Promise.resolve(redirectTo(`${publicOrigin}${target}`));
     }
 
     // The bare `https://cran.rpkgs.com` form, resolved from the User-Agent.
@@ -223,13 +285,32 @@ BunnySDK.net.http
         return Promise.resolve(redirectTo(`${CRAN_ORIGIN}${path}`));
       }
 
+      if (UNION_SLOTS.has(slot) && isExcludedMinor(userAgent)) {
+        return Promise.resolve(redirectTo(`${CRAN_ORIGIN}${path}`));
+      }
+
       const rest = srcContrib ? srcContrib[1] : '';
-      return Promise.resolve(redirectTo(`${PUBLIC_CDN_ORIGIN}${contribPath(slot, rest, userAgent)}`));
+      return Promise.resolve(redirectTo(`${publicOrigin}${contribPath(slot, rest, userAgent)}`));
     }
 
     return Promise.resolve(ctx.request);
   })
-  .onOriginResponse((ctx) => {
+  .onOriginResponse(async (ctx) => {
+    const path = normalizePathname(new URL(ctx.request.url).pathname);
+    const archive = path.match(ARCHIVE_TARBALL_REGEX);
+
+    // Binary archives can be incomplete when an older build never succeeded.
+    // Preserve renv/remotes version restores by falling back to CRAN's source
+    // package only for an absent archived tarball. A requested version can be
+    // either archived upstream or still current, so probe the archive first.
+    // Other 404s remain visible.
+    if (ctx.response.status === 404 && archive) {
+      const archiveUrl = `${CRAN_ORIGIN}/src/contrib/Archive/${archive[1]}/${archive[2]}`;
+      const archiveResponse = await fetch(archiveUrl, { method: 'HEAD' });
+      const sourceUrl = archiveResponse.ok ? archiveUrl : `${CRAN_ORIGIN}/src/contrib/${archive[2]}`;
+      return redirectTo(sourceUrl);
+    }
+
     ctx.response.headers.append('X-Via', 'MyMiddleware');
     return Promise.resolve(ctx.response);
   });

local/patches/RcppParallel/force-bundled-tbb.patch

@@ -40,15 +40,11 @@ index 6f6a745..e407986 100644
     if (is.null(name))
        return(tbbRoot)
  
-@@ -58,7 +58,7 @@ tbbCxxFlags <- function() {
-    flags <- c("-DRCPP_PARALLEL_USE_TBB=1")
- 
+@@ -58,3 +58,3 @@ tbbCxxFlags <- function() {
     # if TBB_INC is set, apply those library paths
 -   tbbInc <- Sys.getenv("TBB_INC", unset = TBB_INC)
 +   tbbInc <- bincraftGetenv("TBB_INC", unset = TBB_INC)
     if (!file.exists(tbbInc)) {
-       tbbInc <- system.file("include", package = "RcppParallel")
-    }
 @@ -117,7 +117,7 @@ tbbLdFlags <- function() {
     }
  

local/patches/registry.json

@@ -1,7 +1,7 @@
 [
   {
     "package": "RcppParallel",
-    "versions": ">=6.0.0",
+    "versions": "6.2.1",
     "platforms": ["*"],
     "env": {},
     "configure_args": [],

local/rebuild-missing-helpers.R

@@ -0,0 +1,87 @@
+# Pure helpers for local/rebuild-missing.R, kept separate so local/tests can
+# source them without executing a rebuild.
+
+# Interleaved slice of the rebuild list.
+#
+# The list is alphabetical and build cost clusters by name (Rcpp*, Bioc*,
+# rstan*), so contiguous thirds would be badly unbalanced. Interleaving also
+# makes each shard's progress counter representative of the slot as a whole.
+shard_slice <- function(pkgs, split_into, split_index) {
+  split_into <- as.integer(split_into)
+  split_index <- as.integer(split_index)
+  if (is.na(split_into) || is.na(split_index)) {
+    stop("shard_slice(): split_into and split_index must be integers")
+  }
+  if (split_into < 1L || split_index < 1L || split_index > split_into) {
+    stop(sprintf(
+      "shard_slice(): need 1 <= split_index <= split_into, got %s of %s",
+      split_index,
+      split_into
+    ))
+  }
+  # seq() errors on a descending range, which is what an empty list or a shard
+  # index past the end would produce.
+  if (length(pkgs) < split_index) {
+    return(pkgs[0L])
+  }
+  pkgs[seq.int(split_index, length(pkgs), by = split_into)]
+}
+
+# Packages that still need building, decided from the bucket rather than from
+# remembered progress.
+#
+# This is bincraft's `check_s3_root_package()` evaluated in bulk: an object
+# whose ETag equals CRAN's published MD5sum is byte-identical to CRAN's source,
+# so the build that was supposed to replace it has not happened yet.
+#
+# `etag_by_file`  named by `<pkg>_<ver>.tar.gz`, values are unquoted ETags
+# `cran_version`  named by package
+# `cran_md5`      named by `<pkg>_<ver>`
+#
+# Unknown always means "already a binary", never "rebuild it", so an unreadable
+# CRAN index or a multipart ETag can never mass-schedule work.
+outstanding_packages <- function(pkgs, etag_by_file, cran_version, cran_md5) {
+  if (length(pkgs) == 0L) {
+    return(pkgs)
+  }
+
+  # An empty table indexes to zero length rather than to NA, which would
+  # recycle the whole result away and silently report "nothing to build".
+  lookup <- function(table, key) {
+    if (length(table) == 0L) {
+      return(rep(NA_character_, length(key)))
+    }
+    unname(as.character(table[key]))
+  }
+
+  version <- lookup(cran_version, pkgs)
+  file <- sprintf("%s_%s.tar.gz", pkgs, version)
+  etag <- lookup(etag_by_file, file)
+  md5 <- lookup(cran_md5, paste(pkgs, version, sep = "_"))
+
+  # No CRAN version means the package cannot be resolved to a tarball at all;
+  # leave it in and let bincraft report why.
+  unresolved <- is.na(version)
+  # No object at the key: never built, so it is outstanding by definition.
+  absent <- !unresolved & is.na(etag)
+  # A multipart upload carries a compound ETag rather than an MD5.
+  unknown <- !is.na(etag) & grepl("-", etag, fixed = TRUE)
+
+  is_source <- !unresolved &
+    !is.na(etag) &
+    !unknown &
+    !is.na(md5) &
+    etag == md5
+
+  pkgs[unresolved | absent | is_source]
+}
+
+parse_rebuild_args <- function(args) {
+  pos <- args[!startsWith(args, "--")]
+  budget <- as.numeric(pos[3L])
+  list(
+    split_into = as.integer(pos[1L]),
+    split_index = as.integer(pos[2L]),
+    budget_hours = if (is.na(budget)) 20 else budget
+  )
+}

local/rebuild-missing.R

@@ -0,0 +1,194 @@
+### Rebuild one shard of a slot's missing-binary list.
+#
+# Usage: Rscript local/rebuild-missing.R <split_into> <split_index> [budget_hours]
+#
+# The list itself comes from local/fetch-rebuild-packages-from-issue.R, which
+# writes $REBUILD_PKG_LIST (default /tmp/rebuild_pkgs.txt).
+#
+# Two properties matter here and are the reason this is a script rather than an
+# `R -q -e` argument in the pipeline:
+#
+#   * it is restartable. The outstanding set is re-derived from the bucket on
+#     every start, so a shard that died resumes where it stopped without any
+#     progress file, and without replaying thousands of per-package HEADs.
+#   * it terminates. A wall-clock budget stops the loop cleanly instead of the
+#     run having to be killed, which is what previously skipped the re-index and
+#     CDN purge and left rebuilt binaries hidden behind stale edge copies.
+
+options(error = function() {
+  cat("ERROR:", geterrmessage(), "\n", file = stdout())
+  traceback(2)
+  q(status = 1)
+})
+
+library(bincraft, quietly = TRUE)
+
+source(file.path("local", "rebuild-missing-helpers.R"))
+
+args <- parse_rebuild_args(commandArgs(trailingOnly = TRUE))
+if (is.na(args$split_into) || is.na(args$split_index)) {
+  stop("usage: rebuild-missing.R <split_into> <split_index> [budget_hours]")
+}
+
+list_file <- Sys.getenv("REBUILD_PKG_LIST", "/tmp/rebuild_pkgs.txt")
+pkgs <- if (file.exists(list_file)) readLines(list_file) else character(0)
+pkgs <- pkgs[nzchar(pkgs)]
+if (length(pkgs) == 0L) {
+  cat("Nothing to rebuild\n")
+  q("no")
+}
+
+excluded <- jsonlite::fromJSON("local/excluded-packages.json")[["package"]]
+pkgs <- setdiff(pkgs, excluded)
+
+mine <- shard_slice(pkgs, args$split_into, args$split_index)
+cat(sprintf(
+  "Shard %s/%s: %s of %s listed packages\n",
+  args$split_index,
+  args$split_into,
+  length(mine),
+  length(pkgs)
+))
+
+### Resume: ask the bucket what is still outstanding
+
+codename <- bincraft::set_codename(NULL)
+local_machine <- Sys.info()[["machine"]]
+arch <- if (grepl("arm64|aarch64", local_machine)) "arm64" else "amd64"
+slot_dir <- sprintf(
+  "devxy-rpkgs-binaries/%s/%s/latest/src/contrib",
+  arch,
+  codename
+)
+
+s3fs::s3_file_system(
+  aws_access_key_id = Sys.getenv("B2_S3_ACCESS_KEY"),
+  aws_secret_access_key = Sys.getenv("B2_S3_SECRET_KEY"),
+  endpoint = "https://s3.eu-central-003.backblazeb2.com",
+  region_name = "eu-central-003",
+  refresh = TRUE
+)
+
+# One paginated listing instead of a HEAD per package. Not recursed: the
+# rebuild passes no `is_r_minor_sensitive`, so it only ever targets the flat
+# path, and the resume filter matches that scope deliberately.
+info <- tryCatch(s3fs::s3_dir_info(slot_dir), error = function(e) NULL)
+etag_by_file <- if (is.null(info) || nrow(info) == 0L) {
+  cat(sprintf(
+    "WARNING: could not list %s; building the whole shard\n",
+    slot_dir
+  ))
+  stats::setNames(character(), character())
+} else {
+  stats::setNames(
+    gsub('^"|"$', "", as.character(info$etag)),
+    basename(as.character(info$uri))
+  )
+}
+
+cran <- tryCatch(
+  {
+    con <- gzcon(url(
+      "https://cloud.r-project.org/src/contrib/PACKAGES.gz",
+      open = "rb"
+    ))
+    on.exit(close(con), add = TRUE)
+    read.dcf(con, fields = c("Package", "Version", "MD5sum"))
+  },
+  error = function(e) {
+    cat(sprintf(
+      "WARNING: could not read CRAN's index (%s)\n",
+      conditionMessage(e)
+    ))
+    NULL
+  }
+)
+cran_version <- stats::setNames(character(), character())
+cran_md5 <- stats::setNames(character(), character())
+if (!is.null(cran)) {
+  cran_version <- stats::setNames(
+    as.character(cran[, "Version"]),
+    as.character(cran[, "Package"])
+  )
+  keep <- !is.na(cran[, "MD5sum"])
+  cran_md5 <- stats::setNames(
+    as.character(cran[keep, "MD5sum"]),
+    paste(cran[keep, "Package"], cran[keep, "Version"], sep = "_")
+  )
+}
+
+before <- length(mine)
+mine <- outstanding_packages(mine, etag_by_file, cran_version, cran_md5)
+cat(sprintf(
+  "Resume: %s of %s already carry a binary; %s outstanding\n",
+  before - length(mine),
+  before,
+  length(mine)
+))
+
+if (length(mine) == 0L) {
+  cat("Nothing outstanding for this shard\n")
+  q("no")
+}
+
+### Build
+
+options(
+  crayon.enabled = TRUE,
+  Ncpus = as.integer(Sys.getenv("NCPUS", "2")),
+  future.globals.onReference = NULL
+)
+
+started <- Sys.time()
+n <- length(mine)
+completed <- 0L
+for (i in seq_along(mine)) {
+  elapsed <- as.numeric(difftime(Sys.time(), started, units = "hours"))
+  if (elapsed > args$budget_hours) {
+    cat(sprintf(
+      "Budget of %sh reached after %d/%d packages; stopping cleanly. The next run resumes from the bucket.\n",
+      args$budget_hours,
+      completed,
+      n
+    ))
+    break
+  }
+
+  x <- mine[i]
+  cat(sprintf("[%d/%d] %s\n", i, n, x))
+  tryCatch(
+    bincraft::build_binary_package(
+      x,
+      tag_limit = 1L,
+      patches = "local/patches",
+      s3_endpoint = "https://s3.eu-central-003.backblazeb2.com",
+      s3_region = "eu-central-003",
+      s3_bucket = "devxy-rpkgs-binaries",
+      s3_access_key_id = Sys.getenv("B2_S3_ACCESS_KEY"),
+      s3_secret_access_key = Sys.getenv("B2_S3_SECRET_KEY"),
+      metadata_db_host = "r-binaries.devxy.io",
+      metadata_db_name = "build_metadata",
+      metadata_db_table = "single_builds",
+      metadata_db_user = "rpkgs",
+      metadata_db_password = Sys.getenv("PGPASS"),
+      metadata_db_sslmode = "require",
+      metadata_db_port = 15432,
+      archive = TRUE,
+      upload = TRUE,
+      store_build_metadata = TRUE
+    ),
+    error = function(e) {
+      cat(sprintf("ERROR building %s - %s\n", x, conditionMessage(e)))
+    }
+  )
+  completed <- completed + 1L
+}
+
+cat(sprintf(
+  "Shard %s/%s finished: %d/%d packages processed in %.1fh\n",
+  args$split_index,
+  args$split_into,
+  completed,
+  n,
+  as.numeric(difftime(Sys.time(), started, units = "hours"))
+))

local/tests/test-rebuild-missing.R

@@ -0,0 +1,94 @@
+source(file.path("..", "rebuild-missing-helpers.R"))
+
+test_that("shard_slice partitions the list without gaps or overlap", {
+  pkgs <- letters[1:10]
+  parts <- lapply(1:3, function(i) shard_slice(pkgs, 3, i))
+
+  expect_identical(parts[[1]], c("a", "d", "g", "j"))
+  expect_identical(parts[[2]], c("b", "e", "h"))
+  expect_identical(parts[[3]], c("c", "f", "i"))
+
+  expect_identical(sort(unlist(parts)), sort(pkgs))
+  expect_identical(anyDuplicated(unlist(parts)), 0L)
+})
+
+test_that("shard_slice is deterministic and survives short lists", {
+  expect_identical(
+    shard_slice(letters[1:10], 3, 2),
+    shard_slice(letters[1:10], 3, 2)
+  )
+  expect_identical(shard_slice(character(0), 3, 1), character(0))
+  # more shards than packages: the tail shards get nothing rather than erroring
+  expect_identical(shard_slice(c("a"), 3, 1), "a")
+  expect_identical(shard_slice(c("a"), 3, 2), character(0))
+})
+
+test_that("shard_slice rejects an out-of-range index", {
+  expect_error(shard_slice(letters, 3, 4), "split_index")
+  expect_error(shard_slice(letters, 3, 0), "split_index")
+})
+
+test_that("outstanding_packages keeps source fallbacks and drops real binaries", {
+  cran_version <- c(httr = "1.4.8", R6 = "2.6.1", curl = "7.1.0")
+  cran_md5 <- c(
+    httr_1.4.8 = "8756015b94a9cff6f410ca4de8557f12",
+    R6_2.6.1 = "f01b1787f12797c29194d63c9afd5d70",
+    curl_7.1.0 = "8af2ccbf5d85dc18866f45f1f26f348d"
+  )
+  etag <- c(
+    # byte-identical to CRAN: the build never happened
+    "httr_1.4.8.tar.gz" = "8756015b94a9cff6f410ca4de8557f12",
+    # a real binary was published
+    "R6_2.6.1.tar.gz" = "9d6087ee9adda3f0a3b8067cfc652c05"
+    # curl has no object at all
+  )
+
+  out <- outstanding_packages(
+    c("httr", "R6", "curl"),
+    etag,
+    cran_version,
+    cran_md5
+  )
+  expect_identical(out, c("httr", "curl"))
+})
+
+test_that("outstanding_packages treats unknowns as already built", {
+  cran_version <- c(a = "1.0", b = "1.0")
+  cran_md5 <- c(a_1.0 = "aaaa")
+
+  # a multipart ETag carries no MD5, and `b` is missing from CRAN's index:
+  # neither may schedule a rebuild
+  etag <- c("a_1.0.tar.gz" = "abc-3", "b_1.0.tar.gz" = "bbbb")
+
+  expect_identical(
+    outstanding_packages(c("a", "b"), etag, cran_version, cran_md5),
+    character(0)
+  )
+})
+
+test_that("outstanding_packages keeps a package CRAN has no version for", {
+  out <- outstanding_packages(
+    "ghost",
+    c(),
+    c(other = "1.0"),
+    c(other_1.0 = "aaaa")
+  )
+  expect_identical(out, "ghost")
+})
+
+test_that("outstanding_packages handles an empty list", {
+  expect_identical(
+    outstanding_packages(character(0), c(), c(), c()),
+    character(0)
+  )
+})
+
+test_that("parse_rebuild_args defaults the budget", {
+  a <- parse_rebuild_args(c("3", "2"))
+  expect_identical(a$split_into, 3L)
+  expect_identical(a$split_index, 2L)
+  expect_identical(a$budget_hours, 20)
+
+  b <- parse_rebuild_args(c("3", "2", "1.5"))
+  expect_identical(b$budget_hours, 1.5)
+})

local/uvr-install.sh

@@ -84,9 +84,20 @@ trap 'rm -rf "$project_dir"' EXIT
 cd "$project_dir"
 
 "$uvr_bin" init --here --r-version "$r_full"
-# --no-install: resolve and lock only. The install happens in the sync below,
-# which is the only command that honours --library.
-"$uvr_bin" add --no-install "$@"
+# --no-install resolves and locks only; retry because concurrent shards can
+# expose short-lived DNS or CRAN-index failures and uvr rolls the manifest back
+# cleanly after an unsuccessful resolution.
+add_attempt=1
+while ! "$uvr_bin" add --no-install "$@"; do
+  if [ "$add_attempt" -ge 4 ]; then
+    echo "error: uvr add failed after ${add_attempt} attempts" >&2
+    exit 1
+  fi
+  add_delay=$((add_attempt * 10))
+  echo "warning: uvr add attempt ${add_attempt} failed; retrying in ${add_delay}s" >&2
+  sleep "$add_delay"
+  add_attempt=$((add_attempt + 1))
+done
 
 # TEMPORARY (drop once the images ship a uvr above v0.4.5): the sync below runs
 # `apt-get install` for every resolved system dependency without refreshing the

provider.tf

@@ -2,7 +2,7 @@ terraform {
   required_providers {
     bunnynet = {
       source = "registry.terraform.io/BunnyWay/bunnynet"
-      version = "~> 0.17"
+      version = "~> 0.18"
     }
   }
 }

scripts/purge_cdn_zone.sh

@@ -18,35 +18,70 @@
 # objects were replaced. The cost is a cold cache for everything else, which is
 # why this is not used by the daily update path.
 #
-# All hostnames on the zone (cran.devxy.io, cran.allianceswisspass.devxy.io,
-# cran.rpkgs.com) share pull zone 3857050, so one purge covers all of them.
+# The public hostnames currently use separate pull zones, so callers must pass
+# every zone that serves the repository. A zone can be identified by its
+# numeric ID or by one of its hostnames; hostname lookup avoids persisting IDs
+# that change when a zone is recreated.
 #
 # Usage:
-#   purge_cdn_zone.sh <BUNNYNET_API_KEY> <pull_zone_id>
+#   purge_cdn_zone.sh <BUNNYNET_API_KEY> <pull_zone> [<pull_zone>...]
 #
 set -euo pipefail
 
 if (($# < 2)); then
-  echo "usage: $0 <api_key> <pull_zone_id>" >&2
+  echo "usage: $0 <api_key> <pull_zone> [<pull_zone>...]" >&2
   exit 2
 fi
 
 api_key="$1"
-zone_id="$2"
+shift
 
-echo "Purging BunnyCDN pull zone ${zone_id}"
+resolve_zone_id() {
+  local zone="$1"
+  local response_file
+  local zone_id
 
-status=$(
-  curl -sS -o /tmp/purge_zone_response.txt -w '%{http_code}' -X POST \
+  if [[ "${zone}" =~ ^[0-9]+$ ]]; then
+    echo "${zone}"
+    return
+  fi
+
+  response_file=$(mktemp)
+  curl -sS -o "${response_file}" \
     -H "AccessKey: ${api_key}" \
-    -H "Content-Length: 0" \
-    "https://api.bunny.net/pullzone/${zone_id}/purgeCache"
-)
+    "https://api.bunny.net/pullzone"
+  zone_id=$(
+    jq -r --arg hostname "${zone}" \
+      '(.Items // .)[] | select(any(.Hostnames[]?; .Value == $hostname)) | .Id' \
+      "${response_file}"
+  )
+  rm -f "${response_file}"
 
-if [[ "${status}" != "200" && "${status}" != "204" ]]; then
-  echo "Purge of pull zone ${zone_id} failed with HTTP ${status}:" >&2
-  cat /tmp/purge_zone_response.txt >&2
-  exit 1
-fi
+  if [[ -z "${zone_id}" ]]; then
+    echo "Could not find BunnyCDN pull zone for hostname ${zone}" >&2
+    exit 1
+  fi
 
-echo "Purged pull zone ${zone_id} (HTTP ${status})"
+  echo "${zone_id}"
+}
+
+for zone in "$@"; do
+  zone_id=$(resolve_zone_id "${zone}")
+  echo "Purging BunnyCDN pull zone ${zone_id}"
+
+  response_file="/tmp/purge_zone_response_${zone_id}.txt"
+  status=$(
+    curl -sS -o "${response_file}" -w '%{http_code}' -X POST \
+      -H "AccessKey: ${api_key}" \
+      -H "Content-Length: 0" \
+      "https://api.bunny.net/pullzone/${zone_id}/purgeCache"
+  )
+
+  if [[ "${status}" != "200" && "${status}" != "204" ]]; then
+    echo "Purge of pull zone ${zone_id} failed with HTTP ${status}:" >&2
+    cat "${response_file}" >&2
+    exit 1
+  fi
+
+  echo "Purged pull zone ${zone_id} (HTTP ${status})"
+done

scripts/verify-r-minor-routing.sh

@@ -0,0 +1,309 @@
+#!/usr/bin/env bash
+#
+# Verify per-R-minor index routing for cran.rpkgs.com across every published
+# <arch>/<os> slot.
+#
+# The edge router (edge/rpkgs-router.ts) rewrites PACKAGES* requests to
+# `contrib/<x.y>/` when the slot is listed in UNION_SLOTS and the client's
+# User-Agent carries an R minor. Two properties have to hold before a slot may
+# be added to UNION_SLOTS:
+#
+#   1. the per-minor index is a UNION of the per-minor and flat slots, so
+#      routing to it hides nothing the flat index carries; and
+#   2. every R minor a client might report resolves to an index that exists,
+#      because contribPath() does not check existence and has no fallback.
+#
+# Modes:
+#   (default)  Resolve routing decisions without depending on UNION_SLOTS being
+#              set. Safe to run before enabling: it reads the per-minor indexes
+#              directly and reproduces the router's target path.
+#   --live     Additionally drive the real CDN with R User-Agents and assert the
+#              bytes served match the expected index. Only meaningful once the
+#              slot is in UNION_SLOTS.
+#
+# Usage:
+#   scripts/verify-r-minor-routing.sh
+#   scripts/verify-r-minor-routing.sh --live
+#   MINORS="4.4 4.5" SAMPLE=10 scripts/verify-r-minor-routing.sh
+#
+# Exits non-zero if any check fails.
+
+set -uo pipefail
+
+BASE=${BASE:-https://cran.rpkgs.com}
+ARCHES=${ARCHES:-"amd64 arm64"}
+DISTROS=${DISTROS:-"resolute noble jammy rhel8 rhel9 rhel10 alpine323 alpine324"}
+# The supported window: the current R minor plus the two previous, matching
+# build-env-images' R_VERSION_LATEST/PREV1/PREV2 and cdn.tf's
+# local.rpkgs_supported_minors. Each of these must have a published index.
+MINORS=${MINORS:-"4.4 4.5 4.6"}
+# Minors we deliberately do not serve. These must have NO published index and,
+# once routing is live, must be sent to CRAN for sources rather than 404ing or
+# being handed binaries built under another minor.
+EXCLUDED_MINORS=${EXCLUDED_MINORS:-"4.3"}
+# How many Path: targets to HEAD-check per slot/minor. 0 disables.
+SAMPLE=${SAMPLE:-5}
+# Largest package-count shortfall a non-primary minor may have against the best
+# minor on the same slot before coverage counts as uneven. A slot built under
+# one R minor carries fewer per-minor binaries for the others; until that gap
+# closes, "full coverage for ABI-sensitive packages" is not a claim we can make.
+PARITY_TOLERANCE=${PARITY_TOLERANCE:-25}
+LIVE=0
+
+for arg in "$@"; do
+  case "$arg" in
+    --live) LIVE=1 ;;
+    -h | --help)
+      sed -n '2,32p' "$0"
+      exit 0
+      ;;
+    *)
+      echo "unknown argument: $arg" >&2
+      exit 2
+      ;;
+  esac
+done
+
+WORK=$(mktemp -d)
+trap 'rm -rf "$WORK"' EXIT
+
+PASS=0
+FAIL=0
+FAILURES=""
+
+ok() {
+  PASS=$((PASS + 1))
+  printf '  ok    %s\n' "$1"
+}
+
+bad() {
+  FAIL=$((FAIL + 1))
+  FAILURES="${FAILURES}\n  - $1"
+  printf '  FAIL  %s\n' "$1"
+}
+
+# Fetch a URL into a file, echoing the HTTP status. Cached per URL.
+fetch() {
+  local url=$1 dest=$2 ua=${3:-}
+  if [ -s "$dest" ]; then
+    cat "$dest.status"
+    return 0
+  fi
+  local status
+  if [ -n "$ua" ]; then
+    status=$(curl -sS -A "$ua" -o "$dest" -w '%{http_code}' --max-time 120 "$url" 2>/dev/null)
+  else
+    status=$(curl -sS -o "$dest" -w '%{http_code}' --max-time 120 "$url" 2>/dev/null)
+  fi
+  echo "$status" > "$dest.status"
+  echo "$status"
+}
+
+head_status() {
+  curl -sS -o /dev/null -w '%{http_code}' -I --max-time 60 "$1" 2>/dev/null
+}
+
+# Package names from a gzipped PACKAGES index, sorted.
+pkg_names() {
+  gunzip -c "$1" 2>/dev/null | awk '/^Package:/ {print $2}' | sort -u
+}
+
+# "<Package> <Path>" pairs for entries that carry a Path: field.
+path_entries() {
+  gunzip -c "$1" 2>/dev/null | awk '
+    /^Package:/ { pkg = $2; ver = ""; path = "" }
+    /^Version:/ { ver = $2 }
+    /^Path:/    { path = $2 }
+    /^$/        { if (pkg != "" && path != "") print pkg, ver, path; pkg = "" }
+    END         { if (pkg != "" && path != "") print pkg, ver, path }
+  '
+}
+
+# An R User-Agent of the shape R actually sends.
+r_user_agent() {
+  printf 'R/%s.0 (Ubuntu 24.04; codename=noble) (x86_64-pc-linux-gnu x86_64 linux-gnu)' "$1"
+}
+
+echo "verify-r-minor-routing: $BASE"
+echo "  slots:  $(echo "$ARCHES" | wc -w) arch x $(echo "$DISTROS" | wc -w) os"
+echo "  minors: $MINORS  (excluded: $EXCLUDED_MINORS)"
+echo "  live:   $LIVE"
+echo
+
+for arch in $ARCHES; do
+  for distro in $DISTROS; do
+    slot="$arch/$distro"
+    echo "$slot"
+
+    flat_url="$BASE/$slot/latest/src/contrib/PACKAGES.gz"
+    flat_file="$WORK/${arch}-${distro}-flat.gz"
+    flat_status=$(fetch "$flat_url" "$flat_file")
+
+    if [ "$flat_status" != "200" ]; then
+      bad "$slot flat index unreachable (HTTP $flat_status)"
+      continue
+    fi
+
+    pkg_names "$flat_file" > "$flat_file.names"
+    flat_count=$(wc -l < "$flat_file.names")
+    if [ "$flat_count" -lt 1000 ]; then
+      bad "$slot flat index has only $flat_count packages"
+      continue
+    fi
+    ok "$slot flat index: $flat_count packages"
+
+    for minor in $MINORS; do
+      minor_url="$BASE/$slot/latest/src/contrib/$minor/PACKAGES.gz"
+      minor_file="$WORK/${arch}-${distro}-${minor}.gz"
+      minor_status=$(fetch "$minor_url" "$minor_file")
+
+      # A minor the router would route to must exist, or clients on that R
+      # version get a 404 and see no packages at all.
+      if [ "$minor_status" != "200" ]; then
+        bad "$slot R $minor index missing (HTTP $minor_status) - routing would 404 for R $minor clients"
+        continue
+      fi
+
+      pkg_names "$minor_file" > "$minor_file.names"
+      minor_count=$(wc -l < "$minor_file.names")
+
+      # Union property: nothing the flat index carries may be missing here.
+      missing=$(comm -23 "$flat_file.names" "$minor_file.names" | head -5)
+      missing_count=$(comm -23 "$flat_file.names" "$minor_file.names" | wc -l)
+      if [ "$missing_count" -ne 0 ]; then
+        bad "$slot R $minor index is not a union: $missing_count flat packages absent (e.g. $(echo "$missing" | tr '\n' ' '))"
+      else
+        ok "$slot R $minor index: $minor_count packages, union holds"
+      fi
+
+      # Path: entries steer to per-minor binaries; they must resolve.
+      if [ "$SAMPLE" -gt 0 ]; then
+        path_entries "$minor_file" > "$minor_file.paths"
+        total_paths=$(wc -l < "$minor_file.paths")
+        broken=0
+        checked=0
+        while read -r pkg ver path; do
+          [ -z "${pkg:-}" ] && continue
+          tarball="$BASE/$slot/latest/src/contrib/$path/${pkg}_${ver}.tar.gz"
+          status=$(head_status "$tarball")
+          checked=$((checked + 1))
+          if [ "$status" != "200" ]; then
+            broken=$((broken + 1))
+            [ "$broken" -le 2 ] && printf '        broken target: %s (HTTP %s)\n' "$tarball" "$status"
+          fi
+        done < <(shuf -n "$SAMPLE" "$minor_file.paths" 2>/dev/null || head -n "$SAMPLE" "$minor_file.paths")
+
+        if [ "$broken" -ne 0 ]; then
+          bad "$slot R $minor: $broken/$checked sampled Path: targets do not resolve (of $total_paths total)"
+        elif [ "$checked" -gt 0 ]; then
+          ok "$slot R $minor: $checked/$checked sampled Path: targets resolve (of $total_paths total)"
+        fi
+      fi
+
+      # Live routing: what a real R client on this minor actually receives.
+      if [ "$LIVE" -eq 1 ]; then
+        ua=$(r_user_agent "$minor")
+        live_file="$WORK/${arch}-${distro}-${minor}-live.gz"
+        live_status=$(fetch "$flat_url" "$live_file" "$ua")
+        if [ "$live_status" != "200" ]; then
+          bad "$slot R $minor live request failed (HTTP $live_status)"
+        elif cmp -s "$live_file" "$minor_file"; then
+          ok "$slot R $minor live request served the per-minor index"
+        elif cmp -s "$live_file" "$flat_file"; then
+          bad "$slot R $minor live request served the FLAT index - slot not in UNION_SLOTS?"
+        else
+          bad "$slot R $minor live request served neither the per-minor nor the flat index"
+        fi
+      fi
+    done
+
+    # Coverage parity across minors. The union property only guarantees no
+    # client loses packages relative to the flat index; it says nothing about a
+    # 4.4 client seeing fewer packages than a 4.5 client on the same slot.
+    best=0
+    for minor in $MINORS; do
+      f="$WORK/${arch}-${distro}-${minor}.gz.names"
+      [ -s "$f" ] || continue
+      c=$(wc -l < "$f")
+      [ "$c" -gt "$best" ] && best=$c
+    done
+    if [ "$best" -gt 0 ]; then
+      uneven=""
+      for minor in $MINORS; do
+        f="$WORK/${arch}-${distro}-${minor}.gz.names"
+        [ -s "$f" ] || continue
+        c=$(wc -l < "$f")
+        gap=$((best - c))
+        [ "$gap" -gt "$PARITY_TOLERANCE" ] && uneven="$uneven R$minor:-$gap"
+      done
+      if [ -n "$uneven" ]; then
+        bad "$slot coverage uneven across minors (vs best $best):$uneven"
+      else
+        ok "$slot coverage parity across minors (best $best, all within $PARITY_TOLERANCE)"
+      fi
+    fi
+
+    # Excluded minors: no published index, and under --live a redirect to CRAN.
+    for minor in $EXCLUDED_MINORS; do
+      ex_url="$BASE/$slot/latest/src/contrib/$minor/PACKAGES.gz"
+      ex_status=$(curl -sS -o /dev/null -w '%{http_code}' --max-time 60 "$ex_url" 2>/dev/null)
+      if [ "$ex_status" = "200" ]; then
+        bad "$slot R $minor is excluded but an index is published - the two lists disagree"
+      else
+        ok "$slot R $minor correctly has no published index"
+      fi
+
+      if [ "$LIVE" -eq 1 ]; then
+        loc=$(curl -sS -o /dev/null -w '%{redirect_url}' -A "$(r_user_agent "$minor")" \
+          --max-time 60 "$flat_url" 2>/dev/null)
+        case "$loc" in
+          https://cran.r-project.org/*)
+            ok "$slot R $minor is sent to CRAN ($loc)"
+            ;;
+          "")
+            bad "$slot R $minor was served directly instead of being sent to CRAN"
+            ;;
+          *)
+            bad "$slot R $minor redirected somewhere unexpected: $loc"
+            ;;
+        esac
+      fi
+    done
+
+    # A client whose User-Agent carries no R version must keep getting the flat
+    # index, never a per-minor one.
+    if [ "$LIVE" -eq 1 ]; then
+      plain_file="$WORK/${arch}-${distro}-plain.gz"
+      plain_status=$(fetch "$flat_url" "$plain_file" "curl/8.0.0")
+      if [ "$plain_status" != "200" ]; then
+        bad "$slot non-R User-Agent request failed (HTTP $plain_status)"
+      elif cmp -s "$plain_file" "$flat_file"; then
+        ok "$slot non-R User-Agent still served the flat index"
+      else
+        bad "$slot non-R User-Agent was routed away from the flat index"
+      fi
+
+      # Tarball requests must never be rewritten into a per-minor directory:
+      # flat-slot packages do not live there.
+      sample_pkg=$(gunzip -c "$flat_file" | awk '/^Package:/ {p=$2} /^Version:/ {print p, $2; exit}')
+      if [ -n "$sample_pkg" ]; then
+        # shellcheck disable=SC2086 # deliberate split into $1 (package) and $2 (version)
+        set -- $sample_pkg
+        tb="$BASE/$slot/latest/src/contrib/${1}_${2}.tar.gz"
+        tb_status=$(curl -sS -o /dev/null -w '%{http_code}' -A "$(r_user_agent 4.5)" --max-time 60 "$tb" 2>/dev/null)
+        if [ "$tb_status" = "200" ]; then
+          ok "$slot tarball request under an R User-Agent still resolves"
+        else
+          bad "$slot tarball ${1}_${2}.tar.gz broke under an R User-Agent (HTTP $tb_status)"
+        fi
+      fi
+    fi
+  done
+done
+
+echo
+echo "passed: $PASS   failed: $FAIL"
+if [ "$FAIL" -ne 0 ]; then
+  printf 'failures:%b\n' "$FAILURES"
+  exit 1
+fi