Add CI workflow to check Markdown files for problems

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

@@ -0,0 +1,66 @@
+# Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/check-markdown-task.md
+name: Check Markdown
+
+# See: https://docs.github.com/en/actions/reference/events-that-trigger-workflows
+on:
+  push:
+    paths:
+      - ".github/workflows/check-markdown-task.ya?ml"
+      - ".markdown-link-check.json"
+      - "Taskfile.ya?ml"
+      - "**/.markdownlint*"
+      - "**.mdx?"
+      - "**.mkdn"
+      - "**.mdown"
+      - "**.markdown"
+  pull_request:
+    paths:
+      - ".github/workflows/check-markdown-task.ya?ml"
+      - ".markdown-link-check.json"
+      - "Taskfile.ya?ml"
+      - "**/.markdownlint*"
+      - "**.mdx?"
+      - "**.mkdn"
+      - "**.mdown"
+      - "**.markdown"
+  schedule:
+    # Run every Tuesday at 8 AM UTC to catch breakage caused by external changes.
+    - cron: "0 8 * * TUE"
+  workflow_dispatch:
+  repository_dispatch:
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Initialize markdownlint-cli problem matcher
+        uses: xt0rted/markdownlint-problem-matcher@v1
+
+      - name: Install Task
+        uses: arduino/setup-task@v1
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          version: 3.x
+
+      - name: Lint
+        run: task markdown:lint
+
+  links:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Install Task
+        uses: arduino/setup-task@v1
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          version: 3.x
+
+      - name: Check links
+        run: task --silent markdown:check-links

.markdown-link-check.json

@@ -0,0 +1,5 @@
+{
+  "retryOn429": true,
+  "retryCount": 3,
+  "aliveStatusCodes": [200, 206]
+}

.markdownlint.yml

@@ -0,0 +1,62 @@
+# Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-markdown/.markdownlint.yml
+# See: https://github.com/DavidAnson/markdownlint/blob/main/doc/Rules.md
+# The code style defined in this file is the official standardized style to be used in all Arduino projects and should
+# not be modified.
+# Note: Rules disabled solely because they are redundant to Prettier are marked with a "Prettier" comment.
+
+default: false
+MD001: false
+MD002: false
+MD003: false # Prettier
+MD004: false # Prettier
+MD005: false # Prettier
+MD006: false # Prettier
+MD007: false # Prettier
+MD008: false # Prettier
+MD009:
+  br_spaces: 0
+  strict: true
+  list_item_empty_lines: false # Prettier
+MD010: false # Prettier
+MD011: true
+MD012: false # Prettier
+MD013: false
+MD014: false
+MD018: true
+MD019: false # Prettier
+MD020: true
+MD021: false # Prettier
+MD022: false # Prettier
+MD023: false # Prettier
+MD024: false
+MD025:
+  level: 1
+  front_matter_title: '^\s*"?title"?\s*[:=]'
+MD026: false
+MD027: false # Prettier
+MD028: false
+MD029:
+  style: one
+MD030:
+  ul_single: 1
+  ol_single: 1
+  ul_multi: 1
+  ol_multi: 1
+MD031: false # Prettier
+MD032: false # Prettier
+MD033: false
+MD034: false
+MD035: false # Prettier
+MD036: false
+MD037: true
+MD038: true
+MD039: true
+MD040: false
+MD041: false
+MD042: true
+MD043: false
+MD044: false
+MD045: true
+MD046:
+  style: fenced
+MD047: false # Prettier

README.md

@@ -3,6 +3,7 @@
 [![Tests Status](https://github.com/arduino/arduino-lint/workflows/Run%20tests/badge.svg)](https://github.com/arduino/arduino-lint/actions?workflow=Run+tests)
 [![Check Go status](https://github.com/arduino/arduino-lint/actions/workflows/check-go-task.yml/badge.svg)](https://github.com/arduino/arduino-lint/actions/workflows/check-go-task.yml)
 [![Nightly Status](https://github.com/arduino/arduino-lint/workflows/Nightly%20build/badge.svg)](https://github.com/arduino/arduino-lint/actions?workflow=Nightly+build)
+[![Check Markdown status](https://github.com/arduino/arduino-lint/actions/workflows/check-markdown-task.yml/badge.svg)](https://github.com/arduino/arduino-lint/actions/workflows/check-markdown-task.yml)
 [![Docs Status](https://github.com/arduino/arduino-lint/workflows/Publish%20documentation/badge.svg)](https://github.com/arduino/arduino-lint/actions?workflow=Publish+documentation)
 [![Codecov](https://codecov.io/gh/arduino/arduino-lint/branch/main/graph/badge.svg?token=nprqPQMbdh)](https://codecov.io/gh/arduino/arduino-lint)
 [![Check Certificates status](https://github.com/arduino/arduino-lint/actions/workflows/check-certificates.yml/badge.svg)](https://github.com/arduino/arduino-lint/actions/workflows/check-certificates.yml)

Taskfile.yml

@@ -110,6 +110,61 @@ tasks:
     cmds:
       - go fmt {{default .DEFAULT_GO_PACKAGES .GO_PACKAGES}}
 
+  # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-markdown-task/Taskfile.yml
+  markdown:lint:
+    desc: Check for problems in Markdown files
+    cmds:
+      - npx markdownlint-cli "**/*.md"
+
+  # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-markdown-task/Taskfile.yml
+  markdown:fix:
+    desc: Automatically correct linting violations in Markdown files where possible
+    cmds:
+      - npx markdownlint-cli --fix "**/*.md"
+
+  # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-markdown-task/Taskfile.yml
+  markdown:check-links:
+    desc: Check for broken links
+    deps:
+      - task: docs:generate
+    cmds:
+      - |
+        if [[ "{{.OS}}" == "Windows_NT" ]]; then
+          # npx --call uses the native shell, which makes it too difficult to use npx for this application on Windows,
+          # so the Windows user is required to have markdown-link-check installed and in PATH.
+          if ! which markdown-link-check &>/dev/null; then
+            echo "markdown-link-check not found or not in PATH. Please install: https://github.com/tcort/markdown-link-check#readme"
+            exit 1
+          fi
+          # Default behavior of the task on Windows is to exit the task when the first broken link causes a non-zero
+          # exit status, but it's better to check all links before exiting.
+          set +o errexit
+          STATUS=0
+          # Using -regex instead of -name to avoid Task's behavior of globbing even when quoted on Windows
+          # The odd method for escaping . in the regex is required for windows compatibility because mvdan.cc/sh gives
+          # \ characters special treatment on Windows in an attempt to support them as path separators.
+          for file in $(find . -regex ".*[.]md"); do
+            markdown-link-check \
+              --quiet \
+              --config "./.markdown-link-check.json" \
+              "$file"
+            STATUS=$(( $STATUS + $? ))
+          done
+          exit $STATUS
+        else
+          npx --package=markdown-link-check --call='
+            STATUS=0
+            for file in $(find . -regex ".*[.]md"); do
+              markdown-link-check \
+                --quiet \
+                --config "./.markdown-link-check.json" \
+                "$file"
+              STATUS=$(( $STATUS + $? ))
+            done
+            exit $STATUS
+          '
+        fi
+
   python:check:
     cmds:
       - task: python:lint
@@ -126,6 +181,11 @@ tasks:
       - poetry install --no-root
       - poetry run black .
 
+  docs:generate:
+    desc: Create all generated documentation content
+    deps:
+      - task: docs:gen
+
   docs:gen:
     desc: Generate command reference
     dir: ./docsgen
@@ -161,7 +221,9 @@ tasks:
     desc: Lint and check formatting of documentation files
     cmds:
       - task: docs:check-formatting
-      - task: docs:check-links
+      - task: markdown:lint
+      - task: markdown:fix
+      - task: markdown:check-links
 
   docs:lint:
     desc: Lint documentation files
@@ -192,18 +254,6 @@ tasks:
           exit 1
         fi
 
-  docs:check-links:
-    desc: Check for dead links in documentation
-    cmds:
-      - |
-        npx --package markdown-link-check --call '
-        STATUS=0
-        for file in $(find -name "*.md"); do
-          markdown-link-check --quiet "$file"
-          STATUS=$(( $STATUS + $? ))
-        done
-        exit $STATUS'
-
   docs:check-formatting:
     desc: Check formatting of documentation files
     cmds: