Add infrastructure for checking Poetry configuration files

Tasks and a GitHub Actions workflow are added to maintain and check for problems in the Poetry Python dependency
management's configuration files.

The tasks provide the following operations:

- Check for invalid data structure of pyproject.toml
- Check for out of sync poetry.lock file

These tasks are ran by the GitHub Actions workflow on any push or pull request that modifies relevant files, and
periodically to check for breakage caused by external changes.

.github/workflows/check-poetry-task.yml

@@ -0,0 +1,116 @@
+name: Check Poetry
+
+on:
+  create:
+  push:
+    paths:
+      - ".github/workflows/check-poetry-task.ya?ml"
+      - "**/poetry.lock"
+      - "**/pyproject.toml"
+      - "Taskfile.ya?ml"
+  pull_request:
+    paths:
+      - ".github/workflows/check-poetry-task.ya?ml"
+      - "**/poetry.lock"
+      - "**/pyproject.toml"
+      - "Taskfile.ya?ml"
+  schedule:
+    # Run periodically to catch breakage caused by external changes.
+    - cron: "0 11 * * THU"
+  workflow_dispatch:
+  repository_dispatch:
+
+jobs:
+  run-determination:
+    runs-on: ubuntu-latest
+    permissions: {}
+    outputs:
+      result: ${{ steps.determination.outputs.result }}
+    steps:
+      - name: Determine if the rest of the workflow should run
+        id: determination
+        run: |
+          RELEASE_BRANCH_REGEX="refs/heads/[0-9]+.[0-9]+.x"
+          # The `create` event trigger doesn't support `branches` filters, so it's necessary to use Bash instead.
+          if [[
+            "${{ github.event_name }}" != "create" ||
+            "${{ github.ref }}" =~ $RELEASE_BRANCH_REGEX
+          ]]; then
+            # Run the other jobs.
+            RESULT="true"
+          else
+            # There is no need to run the other jobs.
+            RESULT="false"
+          fi
+
+          echo "result=$RESULT" >> $GITHUB_OUTPUT
+
+  validate:
+    needs: run-determination
+    if: needs.run-determination.outputs.result == 'true'
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install Python
+        uses: actions/setup-python@v4
+        with:
+          python-version-file: pyproject.toml
+
+      - name: Install Poetry
+        run: |
+          pipx install \
+            --python "$(which python)" \
+            poetry
+
+      - name: Install Task
+        uses: arduino/setup-task@v1
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          version: 3.x
+
+      - name: Validate pyproject.toml
+        run: task poetry:validate
+
+  check-sync:
+    needs: run-determination
+    if: needs.run-determination.outputs.result == 'true'
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install Python
+        uses: actions/setup-python@v4
+        with:
+          python-version-file: pyproject.toml
+
+      - name: Install Poetry
+        run: |
+          pipx install \
+            --python "$(which python)" \
+            poetry
+
+      - name: Install Task
+        uses: arduino/setup-task@v1
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          version: 3.x
+
+      - name: Sync lockfile
+        run: task poetry:sync
+
+      - name: Check if lockfile was out of sync
+        run: |
+          git \
+            diff \
+              --color \
+              --exit-code \
+              package-lock.json

Taskfile.yml

@@ -21,6 +21,7 @@ tasks:
       - task: general:check-formatting
       - task: general:check-spelling
       - task: npm:validate
+      - task: poetry:validate
 
   fix:
     desc: Make automated corrections to the project's files
@@ -31,6 +32,7 @@ tasks:
       - task: go:format
       - task: go:lint
       - task: go:tidy
+      - task: poetry:sync
 
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-general-formatting-task/Taskfile.yml
   general:check-formatting:
@@ -180,6 +182,22 @@ tasks:
     cmds:
       - poetry install --no-root
 
+  poetry:validate:
+    desc: Validate pyproject.toml
+    cmds:
+      - |
+        poetry \
+          check \
+            --lock
+
+  poetry:sync:
+    desc: Sync poetry.lock
+    cmds:
+      - |
+        poetry \
+          lock \
+            --no-update
+
   # Make a temporary file named according to the passed TEMPLATE variable and print the path passed to stdout
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/windows-task/Taskfile.yml
   utility:mktemp-file: