ci: Add actionlint and zizmor workflow linting

.github/dependabot.yml

@@ -4,8 +4,12 @@ updates:
     directory: /
     schedule:
       interval: weekly
+    cooldown:
+      default-days: 7
 
   - package-ecosystem: maven
     directory: /
     schedule:
       interval: weekly
+    cooldown:
+      default-days: 7

.github/workflows/build-any-branch.yml

@@ -12,6 +12,8 @@ on:
       - '**/*.adoc'
       - '**/*.md'
 
+permissions: {}
+
 env:
   MAVEN_COMMAND: ./mvnw
   MAVEN_CLI_COMMON: "-e -B"
@@ -25,12 +27,28 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 15
     permissions:
-      contents: write
+      contents: read
     steps:
       - uses: actions/checkout@v7
+        with:
+          persist-credentials: false
       - uses: ./.github/actions/jdk-setup
       - name: Build and verify
         run: ${{ env.MAVEN_COMMAND }} ${{ env.MAVEN_CLI_COMMON }} clean verify
+
+  # Isolated from the build job so its write-scoped token is never present
+  # while a build of pull-request code runs. Only fires for pushes to main.
+  submit-dependencies:
+    needs: build
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          persist-credentials: false
+      - uses: ./.github/actions/jdk-setup
       - name: Submit dependencies to GitHub
-        if: github.actor != 'dependabot[bot]'
-        uses: advanced-security/maven-dependency-submission-action@v5
+        uses: advanced-security/maven-dependency-submission-action@a64327a7329c9939cf675e458452febe1894a70c # v6.0.1

.github/workflows/deploy-snapshot.yml

@@ -1,6 +1,11 @@
 name: Deploy Snapshot
 
 on:
+  # zizmor: ignore[dangerous-triggers]
+  # workflow_run is used safely: the job's `if` requires a successful "Build any
+  # branch" run from this repository (head_repository guard, so a fork branch
+  # named `main` cannot reach it) on `main` (branches filter), and it checks out
+  # exactly that run's commit (head_sha) — never fork-controlled code.
   workflow_run:
     workflows: ["Build any branch"]
     types: [completed]
@@ -19,7 +24,9 @@ concurrency:
 
 jobs:
   deploy-snapshot:
-    if: github.event.workflow_run.conclusion == 'success'
+    if: >-
+      github.event.workflow_run.conclusion == 'success' &&
+      github.event.workflow_run.head_repository.full_name == github.repository
     runs-on: ubuntu-latest
     timeout-minutes: 20
     steps:
@@ -36,7 +43,7 @@ jobs:
 
       - name: Get project version
         id: ver
-        run: echo "version=$(${{ env.MAVEN_COMMAND }} help:evaluate -Dexpression=project.version -q -DforceStdout)" >> $GITHUB_OUTPUT
+        run: echo "version=$(${{ env.MAVEN_COMMAND }} help:evaluate -Dexpression=project.version -q -DforceStdout)" >> "$GITHUB_OUTPUT"
 
       - name: Deploy snapshot to Maven Central
         if: endsWith(steps.ver.outputs.version, '-SNAPSHOT')
@@ -47,4 +54,6 @@ jobs:
 
       - name: Skip (not a snapshot version)
         if: "!endsWith(steps.ver.outputs.version, '-SNAPSHOT')"
-        run: echo "Version ${{ steps.ver.outputs.version }} is a release version — skipping snapshot deploy"
+        env:
+          VERSION: ${{ steps.ver.outputs.version }}
+        run: echo "Version ${VERSION} is a release version — skipping snapshot deploy"

.github/workflows/lint-workflows.yml

@@ -0,0 +1,54 @@
+name: Lint workflows
+
+on:
+  pull_request:
+    paths:
+      - '.github/**'
+  push:
+    branches: [main]
+    paths:
+      - '.github/**'
+  schedule:
+    - cron: '0 6 * * 1'  # Mondays 06:00 UTC — surface newly added lint rules and freshly deprecated actions
+  workflow_dispatch:
+
+permissions: {}
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  actionlint:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      contents: read
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          persist-credentials: false
+      - name: Run actionlint
+        uses: raven-actions/actionlint@3d39aea434753780c3b3d4a1a31c854b4dbf49d7 # v2.2.0
+        with:
+          version: 1.7.12  # pin the tool; the action otherwise resolves 'latest' at run time
+
+  zizmor:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      contents: read
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          persist-credentials: false
+      - name: Run zizmor
+        env:
+          GH_TOKEN: ${{ github.token }}
+        # Pinned tool, run directly (not via zizmor-action) so --strict-collection
+        # can fail the job on a malformed collected file — dependabot.yml, an
+        # action.yml — instead of warning and skipping it. pipx is preinstalled
+        # on ubuntu-latest.
+        run: >-
+          pipx run zizmor==1.30.1 --strict-collection --format github
+          --persona regular --collect all -- .github/

.github/workflows/publish-docs.yml

@@ -8,15 +8,17 @@ on:
       - 'src/site/**'
       - '**/*.adoc'
       - '**/*.md'
+  # zizmor: ignore[dangerous-triggers]
+  # workflow_run is used safely: for that event the build-site job requires a
+  # successful "Build any branch" run from this repository (head_repository
+  # guard) on `main` (branches filter), and checks out the default branch — never
+  # a triggering ref, so never fork-controlled code.
   workflow_run:
     workflows: ["Build any branch"]
     types: [completed]
     branches: [main]
 
-permissions:
-  contents: read
-  pages: write
-  id-token: write
+permissions: {}
 
 concurrency:
   group: pages
@@ -28,16 +30,23 @@ env:
 
 jobs:
   build-site:
-    if: github.event_name != 'workflow_run' || github.event.workflow_run.conclusion == 'success'
+    if: >-
+      github.event_name != 'workflow_run' ||
+      (github.event.workflow_run.conclusion == 'success' &&
+       github.event.workflow_run.head_repository.full_name == github.repository)
     runs-on: ubuntu-latest
     timeout-minutes: 20
+    permissions:
+      contents: read
     steps:
       - uses: actions/checkout@v7
+        with:
+          persist-credentials: false
       - uses: ./.github/actions/jdk-setup
       - name: Build project
         run: ${{ env.MAVEN_COMMAND }} ${{ env.MAVEN_CLI_COMMON }} install -DskipTests
       - name: Generate Maven site
-        run: ${{ env.MAVEN_COMMAND }} ${{ env.MAVEN_CLI_COMMON }} site -Dproject.build.outputTimestamp=$(date -u +%Y-%m-%dT%H:%M:%SZ)
+        run: ${{ env.MAVEN_COMMAND }} ${{ env.MAVEN_CLI_COMMON }} site -Dproject.build.outputTimestamp="$(date -u +%Y-%m-%dT%H:%M:%SZ)"
       - name: Upload Pages artifact
         if: >-
           github.event_name == 'workflow_dispatch' ||
@@ -55,6 +64,9 @@ jobs:
       github.event_name == 'workflow_run'
     runs-on: ubuntu-latest
     timeout-minutes: 10
+    permissions:
+      pages: write
+      id-token: write
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}

.github/zizmor.yml

@@ -0,0 +1,22 @@
+# zizmor configuration — see .github/workflows/lint-workflows.yml.
+# https://docs.zizmor.sh/configuration/
+rules:
+  unpinned-uses:
+    config:
+      # Symbolic (tag) refs are acceptable for actions published by GitHub's
+      # own organizations; anything else must be pinned to a full commit SHA.
+      policies:
+        "actions/*": ref-pin
+        "github/*": ref-pin
+        "dependabot/*": ref-pin
+        "*": hash-pin
+
+  self-repository:
+    ignore:
+      # The `$/...` self-repository syntax is only a few weeks old (GitHub,
+      # Jul 2026). The workspace-relative `./...` form is used deliberately
+      # until that syntax has settled; revisit and switch over later.
+      - build-any-branch.yml
+      - deploy-snapshot.yml
+      - publish-docs.yml
+      - release.yml