MDEV-38546: Automatically label new unlabeled pull requests

 with foundation/corporation/external contribution

The MariaDB server repository uses certain pull request labels as queue markers
 for incoming pull requests as follows:
- External Contribution: for all external contributions
- MariaDB Corporation: for employees of the MariaDB corporation
- MariaDB Foundation: for the employees of the MariaDB foundation

Right now, when a new pull request is filed, these tags need to be applied
manually.
However a large % of these manual assignments can be automated by checking
if the author is in https://github.com/orgs/MariaDB/teams/staff
or in https://github.com/orgs/MariaDB/teams/developers.

If they are in staff "MariaDB Foundation" is assigned.

if they are not in staff, but are in developers, "MariaDB Corporation" is assigned.

If they are in neither staff nor developers, "External Contribution" is assigned.

A github workflow is created to do the assignments. It is being triggered
every day at 2AM. Or it can be triggered manually.

This is stage1 of the fix: it is read only and only *prints* the changes needed

Author: gkodinov

.github/workflows/label_recent_prs.yaml

@@ -0,0 +1,85 @@
+name: Label recent pull requests
+
+on:
+  schedule:
+    - cron: "0 2 * * *" # 02:00 UTC daily
+  workflow_dispatch:    # allow manual runs
+
+permissions:
+  contents: read
+  pull-requests: write
+  issues: write
+
+jobs:
+  label-prs:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Auto-label PRs
+        env:
+          REPO: ${{ github.repository }}
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          REPO=MariaDB/server
+          set -euo pipefail
+          nfailed=0
+
+          # List first 200 PRs lacking classification labels as JSON
+          gh pr list \
+            --repo "$REPO" \
+            --search 'is:pr -label:"External Contribution" -label:"MariaDB Foundation" -label:"MariaDB Corporation" -label="Codership"' \
+            --limit 200 \
+            --json number,createdAt,labels,author |
+          jq -c '.[]' |
+          while read -r pr; do
+            pr_number=$(echo "$pr" | jq -r '.number')
+            created_at=$(echo "$pr" | jq -r '.createdAt')
+            label_count=$(echo "$pr" | jq '.labels | length')
+            author=$(echo "$pr" | jq -r '.author.login')
+
+            echo "Evaluating PR #$pr_number by $author"
+
+            # Check if author is in the developers team
+            if gh api \
+              -H "Accept: application/vnd.github+json" \
+              "/orgs/MariaDB/teams/developers/members/$author" \
+              >/dev/null 2>&1; then
+              echo "Author is in developers team"
+              is_developer=1
+            else
+              is_developer=0
+              echo "Author is not in developers team"
+            fi
+            # Check if author is in the staff team
+            if gh api \
+              -H "Accept: application/vnd.github+json" \
+              "/orgs/MariaDB/teams/staff/members/$author" \
+              >/dev/null 2>&1; then
+              echo "Author is in staff team"
+              is_foundation=1
+            else
+              is_foundation=0
+              echo "Author is not in staff team"
+            fi
+
+            if [[ "$is_foundation" -ne 0 ]]; then
+              label="MariaDB Foundation"
+            else
+              if [[ "$is_developer" -ne 0 ]]; then
+                label="MariaDB Corporation"
+              else
+                label="External Contribution"
+              fi
+            fi
+
+          # start soft: read-only first.
+          echo "Should apply label [$label] to PR#[$pr_number] by [$author]"
+
+          #  echo "Applying label $label"
+          #  if gh issue edit "$pr_number" \
+          #    --repo "$REPO" \
+          #    --add-label "$label"; then
+          #    echo "**FAILED applying label [$label] to PR#[$pr_number] by [$author]"
+          #    nfailed=$((nfailed + 1))
+          #  fi
+          done