From 5e811d88537f34581836b53c64c67f62709f48c7 Mon Sep 17 00:00:00 2001
From: Ewerton Scaboro da Silva <ewertons@microsoft.com>
Date: Tue, 29 Sep 2026 15:08:34 +0000
Subject: [PATCH 1/2] [CI] Delete the Actions caches of closed pull requests

A closed pull request's caches serve nothing but count against the
10 GB quota until unused for 7 days. ci-c-yocto saves ~450 MB of sstate
per run that built something, so they could evict main's entry.

- On close: delete that pull request's caches (same-repository only;
  a fork's token is read-only).
- Nightly and manual sweep: delete the caches of every closed pull
  request. Covers forks, entries saved after close, and older pull
  requests. Manual runs can dry-run.
---
 .github/workflows/cleanup-pr-caches.yml | 78 +++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 .github/workflows/cleanup-pr-caches.yml

diff --git a/.github/workflows/cleanup-pr-caches.yml b/.github/workflows/cleanup-pr-caches.yml
new file mode 100644
index 000000000..a5c36916d
--- /dev/null
+++ b/.github/workflows/cleanup-pr-caches.yml
@@ -0,0 +1,78 @@
+# Copyright (c) Microsoft. All rights reserved.
+# Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+# Deletes the Actions caches of closed pull requests.
+#
+# A pull request's caches (ref refs/pull/<n>/merge) serve only that pull
+# request, yet count against the repository's 10 GB cache quota until they go
+# unused for 7 days. ci-c-yocto saves a ~450 MB sstate entry per run that built
+# something, so closed pull requests could push main's entry out.
+#
+# - On close: deletes that pull request's caches. Same-repository pull requests
+#   only: a fork's token is read-only.
+# - Nightly (and manual): deletes the caches of every closed pull request. Covers
+#   forks, entries saved by a run still going when the pull request closed, and
+#   pull requests closed before this workflow existed.
+
+name: cleanup-pr-caches
+
+on:
+  pull_request:
+    types: [ closed ]
+  schedule:
+    - cron: '30 2 * * *'
+  workflow_dispatch:
+    inputs:
+      dry-run:
+        description: List what would be deleted, delete nothing.
+        type: boolean
+        default: false
+
+permissions: {}
+
+jobs:
+  on-close:
+    name: delete this pull request's caches
+    if: github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository
+    runs-on: ubuntu-24.04
+    timeout-minutes: 5
+    permissions:
+      actions: write
+    steps:
+      - name: Delete caches of refs/pull/${{ github.event.pull_request.number }}/merge
+        env:
+          GH_TOKEN: ${{ github.token }}
+          GH_REPO: ${{ github.repository }}
+          REF: refs/pull/${{ github.event.pull_request.number }}/merge
+        run: |
+          gh cache list --ref "$REF" --limit 1000
+          gh cache delete --all --ref "$REF" --succeed-on-no-caches
+
+  sweep:
+    name: delete caches of closed pull requests
+    if: github.event_name != 'pull_request'
+    runs-on: ubuntu-24.04
+    timeout-minutes: 15
+    permissions:
+      actions: write
+      pull-requests: read
+    steps:
+      - name: Delete caches of closed pull requests
+        env:
+          GH_TOKEN: ${{ github.token }}
+          GH_REPO: ${{ github.repository }}
+          DRY_RUN: ${{ inputs.dry-run || false }}
+        run: |
+          set -euo pipefail
+          prs="$(gh cache list --limit 10000 --json ref --jq '.[].ref' \
+                   | sed -n 's|^refs/pull/\([0-9][0-9]*\)/merge$|\1|p' | sort -un)"
+          for pr in $prs; do
+            state="$(gh pr view "$pr" --json state --jq .state)"
+            echo "#$pr: $state"
+            [ "$state" = OPEN ] && continue
+            if [ "$DRY_RUN" = true ]; then
+              gh cache list --ref "refs/pull/$pr/merge" --limit 1000
+            else
+              gh cache delete --all --ref "refs/pull/$pr/merge" --succeed-on-no-caches
+            fi
+          done

From a9d25a9a60ed0a9d4518d28fb4f1bd5fc5e7e0a2 Mon Sep 17 00:00:00 2001
From: Ewerton Scaboro da Silva <ewertons@microsoft.com>
Date: Sat, 10 Oct 2026 07:00:12 +0000
Subject: [PATCH 2/2] [CI] cleanup-pr-caches: list caches as JSON

gh cache list --json returns an empty array with exit status 0 when a
ref has no caches, whatever the gh version.
---
 .github/workflows/cleanup-pr-caches.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/cleanup-pr-caches.yml b/.github/workflows/cleanup-pr-caches.yml
index a5c36916d..3539060fa 100644
--- a/.github/workflows/cleanup-pr-caches.yml
+++ b/.github/workflows/cleanup-pr-caches.yml
@@ -45,7 +45,7 @@ jobs:
           GH_REPO: ${{ github.repository }}
           REF: refs/pull/${{ github.event.pull_request.number }}/merge
         run: |
-          gh cache list --ref "$REF" --limit 1000
+          gh cache list --ref "$REF" --limit 1000 --json id,key,sizeInBytes --jq '.[] | "\(.id) \(.key) \(.sizeInBytes)"'
           gh cache delete --all --ref "$REF" --succeed-on-no-caches
 
   sweep:
@@ -71,7 +71,7 @@ jobs:
             echo "#$pr: $state"
             [ "$state" = OPEN ] && continue
             if [ "$DRY_RUN" = true ]; then
-              gh cache list --ref "refs/pull/$pr/merge" --limit 1000
+              gh cache list --ref "refs/pull/$pr/merge" --limit 1000 --json id,key,sizeInBytes --jq '.[] | "\(.id) \(.key) \(.sizeInBytes)"'
             else
               gh cache delete --all --ref "refs/pull/$pr/merge" --succeed-on-no-caches
             fi