From df80020eecdfd7f9456d4d6311967ba4e3267bb5 Mon Sep 17 00:00:00 2001
From: Dusten Hubbard <dusten@utexas.edu>
Date: Mon, 24 Aug 2026 17:45:22 -0500
Subject: [PATCH] chore(ci): add dependabot config and auto-merge for routine
 bumps

Groups updates into one weekly pull request per ecosystem instead of one per package, and lets patch and minor bumps merge once CI passes. Major bumps get a comment and wait for a maintainer.
---
 .github/dependabot.yml                | 29 ++++++++++++++++++++
 .github/workflows/dependabot-auto.yml | 38 +++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)
 create mode 100644 .github/dependabot.yml
 create mode 100644 .github/workflows/dependabot-auto.yml

diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 000000000..dc156ce8a
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,29 @@
+# Dependency updates.
+#
+# Grouped on purpose: one pull request per ecosystem per week, rather than one
+# per package. A single package's CVE list can otherwise open dozens of pull
+# requests in a morning. Security updates still arrive immediately, outside
+# this schedule, because Dependabot handles those separately.
+version: 2
+updates:
+  - package-ecosystem: "pip"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+    open-pull-requests-limit: 5
+    groups:
+      routine:
+        update-types: ["patch", "minor"]
+    commit-message:
+      prefix: "chore(deps)"
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+    groups:
+      routine:
+        update-types: ["patch", "minor", "major"]
+    commit-message:
+      prefix: "ci(deps)"
diff --git a/.github/workflows/dependabot-auto.yml b/.github/workflows/dependabot-auto.yml
new file mode 100644
index 000000000..0ea2b6e64
--- /dev/null
+++ b/.github/workflows/dependabot-auto.yml
@@ -0,0 +1,38 @@
+# Routine dependency pull requests merge on their own once CI passes.
+#
+# Scope, stated plainly: a pull request opened by Dependabot whose update type
+# is patch or minor merges without a human reading it, after every required
+# check has passed. CI is the evidence for those merges. Major bumps get a
+# comment and wait for a maintainer.
+name: dependabot-auto
+
+on: pull_request_target
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  auto:
+    if: github.actor == 'dependabot[bot]'
+    runs-on: ubuntu-latest
+    steps:
+      - name: read the update type
+        id: meta
+        uses: dependabot/fetch-metadata@v2
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: enable auto-merge for patch and minor
+        if: contains(fromJSON('["version-update:semver-patch","version-update:semver-minor"]'), steps.meta.outputs.update-type)
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: gh pr merge --auto --squash "${{ github.event.pull_request.html_url }}"
+
+      - name: leave a major bump for a maintainer
+        if: steps.meta.outputs.update-type == 'version-update:semver-major'
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          gh pr comment "${{ github.event.pull_request.html_url }}" \
+            --body "Major version bump, so this one waits for a maintainer."