Run macOS on main only, and release only what main proved

.github/workflows/ci.yml

@@ -14,18 +14,40 @@ on:
 permissions:
   contents: read # jobs that publish raise their own permissions
 
+# macOS runners are severely constrained: macOS runs only on a push to main, plus the osx-arm64 AOT pack on a release
+# (macOS AOT only compiles on macOS). A release runs no checks of its own beyond packing and the AOT smoke test:
+# main-green requires main's run on the released commit to have passed.
 jobs:
+  # A release ships a commit main has already proven: wait for main's push run of ci.yml on the released commit and stop
+  # unless it passed. Every job that runs on a release needs this one, directly or through another.
+  main-green:
+    if: github.event_name == 'release'
+    name: main is green
+    runs-on: ubuntu-latest
+    timeout-minutes: 70
+    permissions:
+      actions: read # read main's ci.yml runs
+    steps:
+      - uses: nullean/.github/actions/require-green-main@f9eb30d28e48b3f6b8ff1f4e7dae1d2b7b2d544b # v1.6.0
+
   # On pull requests, only linux-x64 runs, to prove AOT still links without burning the full matrix
-  # on packages nobody sees. All five run on push, where the packages are actually uploaded.
+  # on packages nobody sees. All five run on a push to main and on a release, where the packages are actually
+  # uploaded; osx-arm64 is the one macOS job a release runs. workflow_dispatch runs the four that need no macOS.
   aot-pack:
+    needs: main-green
+    # main-green is skipped on everything but a release, which would skip this job too without a status function.
+    if: ${{ !cancelled() && (github.event_name != 'release' || needs.main-green.result == 'success') }}
     runs-on: ${{ matrix.runner }}
     name: AOT pack (${{ matrix.rid }})
     strategy:
       fail-fast: false
       matrix:
-        include: ${{ fromJSON(github.event_name == 'pull_request'
-          && '[{"rid":"linux-x64","runner":"ubuntu-latest"}]'
-          || '[{"rid":"linux-x64","runner":"ubuntu-latest"},{"rid":"linux-arm64","runner":"ubuntu-24.04-arm"},{"rid":"win-x64","runner":"windows-latest"},{"rid":"win-arm64","runner":"windows-11-arm"},{"rid":"osx-arm64","runner":"macos-latest"}]') }}
+        include: ${{ fromJSON(
+          (github.event_name == 'pull_request'
+            && '[{"rid":"linux-x64","runner":"ubuntu-latest"}]')
+          || ((github.event_name == 'push' || github.event_name == 'release')
+            && '[{"rid":"linux-x64","runner":"ubuntu-latest"},{"rid":"linux-arm64","runner":"ubuntu-24.04-arm"},{"rid":"win-x64","runner":"windows-latest"},{"rid":"win-arm64","runner":"windows-11-arm"},{"rid":"osx-arm64","runner":"macos-latest"}]')
+          || '[{"rid":"linux-x64","runner":"ubuntu-latest"},{"rid":"linux-arm64","runner":"ubuntu-24.04-arm"},{"rid":"win-x64","runner":"windows-latest"},{"rid":"win-arm64","runner":"windows-11-arm"}]') }}
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
@@ -75,7 +97,10 @@ jobs:
 
   build:
     runs-on: ubuntu-latest
-    needs: aot-pack
+    needs: [main-green, aot-pack]
+    if: >-
+      ${{ !cancelled() && needs.aot-pack.result == 'success'
+        && (github.event_name != 'release' || needs.main-green.result == 'success') }}
     permissions:
       contents: write   # append the public API changes to the release notes
       packages: write   # push to GitHub Packages and ghcr.io
@@ -113,9 +138,10 @@ jobs:
     - run: ./build.sh generateapichanges -s
       name: "Inspect public API changes"
 
-    # the tools are restored by the steps above
+    # the tools are restored by the steps above. Not on a release: main's run on this commit checked it.
     - run: dotnet curb check .
       name: Check formatting (curb)
+      if: github.event_name != 'release'
 
     - name: publish to github package repository
       if: github.event_name == 'push' && startswith(github.ref, 'refs/heads')
@@ -181,6 +207,6 @@ jobs:
         gh release edit "$TAG" --repo "$GITHUB_REPOSITORY" --notes-file "$RUNNER_TEMP/notes.md"
 
   zizmor:
-    uses: nullean/.github/.github/workflows/zizmor.yml@d850ce6eee9efa9f81b410d15fcd480409518d19 # v1.5.0
+    uses: nullean/.github/.github/workflows/zizmor.yml@e21d5f59405aa7078e51825cd4c407191e28562f # v1.6.1
     permissions:
       contents: read

.github/workflows/create-major-tag.yml

@@ -15,7 +15,19 @@ concurrency:
   cancel-in-progress: false
 
 jobs:
+  # A release moves the major tag only for a commit main has already proven: wait for main's push run of ci.yml on the
+  # released commit and stop unless it passed.
+  main-green:
+    name: main is green
+    runs-on: ubuntu-latest
+    timeout-minutes: 70
+    permissions:
+      actions: read # read main's ci.yml runs
+    steps:
+      - uses: nullean/.github/actions/require-green-main@f9eb30d28e48b3f6b8ff1f4e7dae1d2b7b2d544b # v1.6.0
+
   create-major-tag:
+    needs: main-green
     permissions:
       contents: write
     runs-on: ubuntu-latest

AGENTS.md

@@ -36,8 +36,10 @@ build targets directly; CI calls it step by step, including `publishcontainers`,
 ## Releasing
 
 release-drafter keeps a draft release up to date from the labels of merged pull requests. **Publishing the draft**
-releases: it creates the tag, and `ci.yml` runs on it to build every RID's native-AOT package, push
-`ghcr.io/nullean/release-notes` (tagged `latest` and the version) and push the packages to nuget.org. `mise run release`
+releases: it creates the tag, and `ci.yml` runs on it. Its `main-green` job first waits for main's push run of `ci.yml` on
+the released commit and fails unless it passed (macOS runs only on pushes to main, plus the osx-arm64 AOT pack on a
+release); then it builds every RID's native-AOT package, pushes
+`ghcr.io/nullean/release-notes` (tagged `latest` and the version) and pushes the packages to nuget.org. `mise run release`
 shows the draft. The [releasing](.claude/skills/releasing/SKILL.md) and
 [breaking-changes](.claude/skills/breaking-changes/SKILL.md) skills have the details. Every pull request carries exactly
 one release label. This repository's own releases do not run the tool: release-drafter writes their notes.