docs(rebuild): record the matrix size against the Crow permutation cap

feat(rebuild): shard the weekly rebuild and make each shard resumable
Split every OS/arch row of weekly-rebuild-missing into three shards and move the build loop out of the inline R one-liner into local/rebuild-missing.R. A shard re-derives its outstanding set from the bucket on every start: an object whose ETag equals CRAN's published MD5sum is still a source fallback and needs building. That is bincraft's check_s3_root_package() evaluated in bulk, so a restart resumes rather than replaying thousands of per-package HEADs, and it stays correct when a sibling shard or a process-updates run finishes work in the meantime. No progress file, no volume, no database cursor. Give each shard a 20h wall-clock budget so it exits cleanly instead of having to be killed. A kill matches neither success nor failure, which is how pipeline 10910 skipped its CDN purge and left ~4600 rebuilt binaries behind stale edge copies. Move re-indexing and the purge into weekly-rebuild-reindex.yaml, which depends on the rebuild and runs on success or failure. Three shards writing one slot's PACKAGES concurrently would race: update_PACKAGES lists the live bucket, so an early lister that uploads last publishes an index missing its siblings' work.
2026-08-12 09:18:48 +00:00 · 2026-08-12 08:27:45 +00:00 · 2026-08-12 08:17:49 +00:00
6 changed files with 1011 additions and 36 deletions
--- a/.crow/weekly-rebuild-missing.yaml
+++ b/.crow/weekly-rebuild-missing.yaml
@ -1,12 +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).
+#             its matching matrix rows (via the per-row `cron:` name filter),
 #             which is now all three shards of that slot.
 #   - 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.
 # Arch placement is handled by the group label (rpkgs-amd64, rpkgs-arm64).
 #
 # 9 OS versions x 2 arches x 3 shards = 54 rows. Crow counts the *declared*
 # matrix against CROW_MAX_MATRIX_SIZE before any `when:` gate is applied, so a
 # single-slot manual run expands all 54 too. The server default is 50 and was
 # raised for this; `crow lint` does not check the limit, so adding an OS
 # version here is only caught when a pipeline is triggered.
 #
 # 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
@ -53,74 +68,326 @@ 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 +420,12 @@ 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 +435,7 @@ 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
+      - $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
      # 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
    backend_options:
      docker:
        resources:
@ -183,25 +445,3 @@ 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]
--- a/.crow/weekly-rebuild-reindex.yaml
+++ b/.crow/weekly-rebuild-reindex.yaml
@ -0,0 +1,193 @@
 # 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' for every os/arch, 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:$$REPO_RO_TOKEN@git.devxy.io/devxy/build-cran-binaries.git .
      - mkdir -p /mnt/cache/R-pkgs
      - rm -rf /mnt/cache/R-pkgs/00LOCK-*
      - /opt/R/$R_VERSION/bin/Rscript local/install-bincraft.R
      # The codename is detected from the image's /etc/os-release.
      - /opt/R/$R_VERSION/bin/R -q -e 'library(bincraft); upload_package_index(s3_endpoint = "https://s3.eu-central-003.backblazeb2.com", s3_region = "eu-central-003", s3_bucket = "devxy-rpkgs-binaries", s3_access_key_id = Sys.getenv("B2_S3_ACCESS_KEY"), s3_secret_access_key = Sys.getenv("B2_S3_SECRET_KEY"))'
      - |
        for RBIN in /opt/R/[0-9]*/bin/R; do
          RMINOR=$(basename "$(dirname "$(dirname "$RBIN")")" | cut -d. -f1-2)
          /opt/R/$R_VERSION/bin/R -q -e "library(bincraft); upload_package_index(r_minor = '$RMINOR', s3_endpoint = 'https://s3.eu-central-003.backblazeb2.com', s3_region = 'eu-central-003', s3_bucket = 'devxy-rpkgs-binaries', s3_access_key_id = Sys.getenv('B2_S3_ACCESS_KEY'), s3_secret_access_key = Sys.getenv('B2_S3_SECRET_KEY'))" || true
        done
  - name: Purge CDN cache
    image: reg.devxy.io/docker.io/library/alpine:3.24
    environment:
      OTEL_R_TRACES_EXPORTER: none
      OTEL_R_LOGS_EXPORTER: none
      OTEL_R_METRICS_EXPORTER: none
      BUNNYNET_API_KEY:
        from_secret: BUNNYNET_API_KEY
      REPO_RO_TOKEN:
        from_secret: REPO_RO_TOKEN
      # All hostnames on the zone share this id, so one purge covers
      # cran.devxy.io, cran.allianceswisspass.devxy.io and cran.rpkgs.com.
      BUNNY_PULLZONE: '3857050'
    commands:
      - apk add --no-cache -q bash curl git
      - git clone -q https://pat-s:$$REPO_RO_TOKEN@git.devxy.io/devxy/build-cran-binaries.git .
      - bash scripts/purge_cdn_zone.sh "$BUNNYNET_API_KEY" "$BUNNY_PULLZONE"
    # 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]
--- a/local/rebuild-missing-helpers.R
+++ b/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
  )
 }
--- a/local/rebuild-missing.R
+++ b/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"))
 ))
--- a/local/tests/test-rebuild-missing.R
+++ b/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)
 })
--- a/specs/2026-08-12-shard-weekly-rebuild-design.md
+++ b/specs/2026-08-12-shard-weekly-rebuild-design.md
@ -0,0 +1,167 @@
 # Design: Sharding and resuming the weekly rebuild
 Date: 2026-08-12
 Status: Approved (pending spec review)
 ## Problem
 `weekly-rebuild-missing` runs one job per `<os>-<arch>` and walks that slot's rebuild list serially in a single `R -q -e` invocation (`.crow/weekly-rebuild-missing.yaml:165`).
 Until 2026-08-09 that was cheap, because every source fallback was skipped as "already built" and the list was effectively empty.
 Since bincraft #105/#106/#107 and build-cran-binaries #159 the gate works, and the lists are now large.
 Share of records whose object is byte-identical to CRAN's source, measured against `cran.r-project.org` MD5s on 2026-08-12:
 | slot               | records | source-served |        share |
 | ------------------ | ------: | ------------: | -----------: |
 | `amd64/resolute`   |  24 212 |        15 023 |        62.1% |
 | `arm64/resolute`   |  24 291 |        13 670 |        56.3% |
 | `arm64/alpine324`  |  24 328 |         9 514 |        39.2% |
 | `amd64/alpine324`  |  24 343 |         8 917 |        36.7% |
 | `arm64/rhel10`     |  24 695 |         5 384 |        21.9% |
 | `amd64/rhel10`     |  24 881 |         4 712 |        19.2% |
 | 12 remaining slots | ~24 700 |  850 to 2 130 | 3.5% to 8.7% |
 A single serial job cannot absorb that.
 Pipeline 10910 (`weekly_rebuild_missing:alpine-324-amd64`) started on 2026-08-09, ran for roughly two days, reached `[8692/23885] cholera`, and was killed there.
 Two distinct failures follow from that shape.
 **No parallelism.** The work is embarrassingly parallel across packages, but one job does all of it.
 **No resumability, and no clean stopping point.** The loop has no terminating condition other than exhausting the list, so the only way to stop it is a kill.
 A restarted run re-reads the same list and walks it from the first entry.
 It skips completed packages via `check_s3_root_package()`, but that costs a CRAN version resolution and an S3 `HEAD` per package, thousands of times, before it reaches new work.
 Worse, a kill is not a pipeline failure: the `Purge CDN cache` step is guarded by `when: status: [success, failure]` (`.crow/weekly-rebuild-missing.yaml:206-207`), and on 10910 it produced no output at all.
 So the ~4 600 binaries that run did publish stayed hidden behind stale edge copies.
 ## Goal
 Turn each slot's rebuild into bounded, parallel, restartable units, without introducing state that can disagree with the bucket.
 ## Design
 ### 1. Shard the matrix three ways
 Each of the 18 `OS`/`ARCH` rows in `.crow/weekly-rebuild-missing.yaml` gains `SPLIT_INTO: 3` and `SPLIT_INDEX: 1|2|3`, giving 54 rows.
 This mirrors `.crow/build-all-versions.yaml:57-98`, which already shards its matrix four ways per arch.
 Routing needs no change.
 The cron filter `cron: weekly-rebuild-missing-${OS}-${ARCH}` and the manual `evaluate: weekly_rebuild_missing == "${OS}-${ARCH}"` both match all three shards of a slot.
 Placement stays on the `rpkgs-${ARCH}` group label, so shards queue against available capacity rather than oversubscribing it.
 ### 2. Extract the loop into `local/rebuild-missing.R`
 The build is currently a single ~1 500-character `R -q -e` argument.
 Shard arithmetic and resume logic do not belong in a YAML string, and none of it is testable there.
 The loop moves to `local/rebuild-missing.R`, invoked as `Rscript local/rebuild-missing.R $SPLIT_INTO $SPLIT_INDEX`, mirroring `local/build-all.R`.
 Its body is unchanged in substance: read `/tmp/rebuild_pkgs.txt`, subtract `local/excluded-packages.json`, loop with `tryCatch` around `bincraft::build_binary_package()`.
 The slice is **interleaved**, not contiguous:
 ```r
 # the list is alphabetical and build cost clusters by name (Rcpp*, Bioc*,
 # rstan*), so contiguous thirds would be badly unbalanced
 mine <- pkgs[seq(split_index, length(pkgs), by = split_into)]
 ```
 `local/build-all.R:64` uses contiguous chunks via `cut()`.
 That is fine there because its list is every CRAN package and version, so the chunks average out.
 Here the list is a filtered backlog in which expensive families sit adjacent, so interleaving is the better default.
 Interleaving also makes each shard's `[i/n]` progress representative of the slot as a whole.
 ### 3. Resume by re-deriving state from the bucket
 Before the loop, the shard performs one `s3fs::s3_dir_info()` on `devxy-rpkgs-binaries/<arch>/<codename>/latest/src/contrib` and reads the `etag` column.
 It fetches CRAN's `PACKAGES` once for the latest version and published `MD5sum` of every package.
 A package is still outstanding if and only if the object at `<pkg>_<version>.tar.gz` has an ETag equal to CRAN's `MD5sum` for that version, which is the definition `check_s3_root_package()` already applies one package at a time.
 ```r
 # one paginated listing instead of ~2900 sequential HEAD requests per shard
 info <- s3fs::s3_dir_info(slot_dir)
 etag <- setNames(gsub('^"|"$', "", info$etag), basename(info$uri))
 key <- sprintf("%s_%s.tar.gz", mine, cran_version[mine])
 # keep a package when no object exists yet, or when the object is still
 # byte-identical to CRAN's source; drop it once a real binary is published
 mine <- mine[is.na(etag[key]) | etag[key] == cran_md5[key]]
 ```
 This is the whole resume mechanism.
 There is no progress file, no volume, and no database cursor.
 A restarted shard recomputes ground truth and continues where it stopped, and it is correct even when a sibling shard, a `process-updates` cron, or a manual `just rebuild` completed something in the meantime.
 Three properties make this the right source of truth:
 - **It is what the build itself checks.** Any other store can disagree with the bucket; this one cannot.
 - **It is agent-independent.** `.crow/weekly-rebuild-missing.yaml` mounts no `volumes:`, unlike `.crow/build-all-versions.yaml:132-133`, so `/mnt/cache` is per-job and cannot carry progress anyway.
 - **It costs one listing.** `cranlike`'s `s3` fork already does exactly this call against this bucket at ~24 000 objects, so the approach is proven at the required scale.
 It must read ETags rather than the slot index's `Built` field, which is how `local/packages-to-build.R:104-130` answers the same question.
 Under this design the index is not rewritten until the dependent re-index pipeline runs (section 5), so mid-run it cannot reflect the current run's progress.
 Packages that genuinely fail to build re-publish their CRAN source, so they stay outstanding and would be retried on every restart.
 That is already handled upstream: `bincraft::filter_packages_with_errors()` (`R/build_binaries.R:1018`, `:1143`) drops anything with `error_occurred = TRUE`, and `store_build_metadata = TRUE` is passed on every call.
 No additional poison-pill filter is needed here.
 Only the flat `src/contrib` path is considered.
 The rebuild call passes no `is_r_minor_sensitive`, so it defaults to `FALSE` and only ever targets the flat path; the resume filter matches that scope deliberately.
 ### 4. Give each shard a wall-clock budget
 `local/rebuild-missing.R` takes a budget, defaulting to 20 hours, and breaks out of the loop once it is exceeded:
 ```r
 # exit cleanly rather than being killed, so the dependent re-index still runs
 if (difftime(Sys.time(), started, units = "hours") > budget_hours) {
  cat(sprintf("Budget of %sh reached after %d/%d packages; stopping cleanly\n", budget_hours, i, n))
  break
 }
 ```
 It exits 0 and reports how much of the slice it covered.
 Every run then has a terminating condition, the re-index and purge always fire, and the remainder is picked up by the next run with no bookkeeping, because section 3 recomputes the outstanding set from scratch.
 ### 5. Move the re-index and purge into `.crow/weekly-rebuild-reindex.yaml`
 Three shards per slot means three concurrent `upload_package_index()` calls on the same S3 prefix.
 `cranlike::update_PACKAGES()` lists the live bucket, so an early lister that uploads last publishes an index missing its siblings' work.
 The re-index steps (`.crow/weekly-rebuild-missing.yaml:171-176`) and the purge step (`:187-207`) therefore leave that file entirely.
 The new file carries:
 ```yaml
 depends_on:
  - weekly-rebuild-missing
 runs_on: [success, failure]
 ```
 `runs_on: [success, failure]` validates as a workflow-level key under `crow lint`, so a failing shard no longer withholds the re-index.
 The file uses the same 18-row matrix and the same `when:` gating as `weekly-rebuild-missing`, so it only re-indexes slots that actually ran.
 Each row re-indexes the flat slot and every per-minor slot.
 `scripts/purge_cdn_zone.sh` runs once on a single row, because all hostnames share pull zone `3857050` and 18 identical zone purges would be waste.
 ## Failure behaviour
 | case                       | today                               | after                                                 |
 | -------------------------- | ----------------------------------- | ----------------------------------------------------- |
 | one package errors         | `tryCatch` logs, loop continues     | unchanged                                             |
 | a shard fails outright     | purge runs, re-index does not       | re-index and purge run via `runs_on`                  |
 | a shard exceeds its budget | cannot happen, runs until killed    | exits 0, re-index and purge run                       |
 | a shard is killed          | nothing runs                        | still nothing; trigger the re-index pipeline alone    |
 | a shard restarts           | re-walks the list, HEAD per package | one listing, resumes at the first outstanding package |
 The known cost of `depends_on` being file-level rather than row-level: on the weekly cron no slot is re-indexed until the slowest of all 54 jobs finishes.
 The 20-hour budget bounds that at roughly one day.
 ## Out of scope
 - `build-all-versions` still cannot rebuild source fallbacks, because `local/build-all.R:113-122` drops every version with any `single_builds` row for the platform and arch, which is precisely the source-fallback set. That is a separate change.
 - Bunny Perma-Cache eviction. `scripts/purge_cdn_zone.sh` purges the regular edge cache only; see the note in `CLAUDE.md` and issue history.
 - The audit that produces the rebuild list is unchanged.
 ## Verification
 - `crow lint .crow/` passes for both pipeline files.
 - `local/rebuild-missing.R` gets unit coverage in `local/tests/` for the two pure pieces: the interleaved slice (disjoint, covering, deterministic) and the outstanding-set filter (source-served ETag kept, binary ETag dropped, absent object kept).
 - A single-slot manual run of `alpine-324-amd64` shard 1 confirms the listing shortcut against the live bucket, and that the reported outstanding count is close to the 8 917 measured above divided by three.
 - Restarting that shard mid-run confirms it resumes rather than replaying, by comparing the outstanding count it reports on the second start.