CI: switch to GitHub Actions - step 1: sniff and lint stage

This commit:
* Adds a GH Actions workflow for the CI checks which were previously run on Travis in the `sniff` and `lint` stages.
    For the badge and workflow display, the name `BasicQA` seems an appropriately descriptive name.
* Removes that part of the `.travis.yml` configuration.
* Removes a duplicate line in the `bin/xml-lint` script used by this workflow.

Notes:
1. In the Travis script, these checks were in two separate stages. I've now combined them into one workflow `job`.
    In GH Actions, the environment has to be setup as part of the workflow. And as the environment needed for these checks is largely the same, combining the checks into one workflow simplifies the script and reduced duplication.
2. Builds will run on all pushes and on pull requests, with the exception of pushes just modifying files which are irrelevant to this workflow.
3. The workflow can be manually (re-)triggered if needs be.
4. Any violations reported by the XML validation against the XSD schema, as well as coming from the PHPCS run, are set up to be shown in-line in the pull request to easily see what line in the pull request causes a build to fail.

Author: jrfnl

.github/workflows/basics.yml

@@ -0,0 +1,62 @@
+name: BasicQA
+
+on:
+  # Run on all pushes and on all pull requests.
+  # Prevent the "push" build from running when there are only irrelevant changes.
+  push:
+    paths-ignore:
+      - '**.md'
+  pull_request:
+  # Allow manually triggering the workflow.
+  workflow_dispatch:
+
+jobs:
+  checkcs:
+    name: 'Basic CS and QA checks'
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Install PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '7.4'
+          coverage: none
+          tools: cs2pr
+
+      - name: 'Lint PHP against parse errors'
+        run: ./bin/php-lint
+
+      - name: Install xmllint
+        run: sudo apt-get install --no-install-recommends -y libxml2-utils
+
+      # Show XML violations inline in the file diff.
+      # @link https://github.com/marketplace/actions/xmllint-problem-matcher
+      - uses: korelstar/xmllint-problem-matcher@v1
+
+      # Validate the composer.json file.
+      # @link https://getcomposer.org/doc/03-cli.md#validate
+      - name: Validate Composer installation
+        run: composer validate --no-check-all --strict
+
+      - name: 'Composer: adjust dependencies'
+        # Using PHPCS `master` as an early detection system for bugs upstream.
+        run: composer require --no-update --no-scripts squizlabs/php_codesniffer:"dev-master"
+
+      # Install dependencies and handle caching in one go.
+      # @link https://github.com/marketplace/actions/install-composer-dependencies
+      - name: Install Composer dependencies
+        uses: "ramsey/composer-install@v1"
+
+      - name: 'Validate XML against schema and check code style'
+        run: ./bin/xml-lint
+
+      # Check the code-style consistency of the PHP files.
+      - name: Check PHP code style
+        continue-on-error: true
+        run: vendor/bin/phpcs --report-full --report-checkstyle=./phpcs-report.xml
+
+      - name: Show PHPCS results in PR
+        run: cs2pr ./phpcs-report.xml

.travis.yml

@@ -21,54 +21,11 @@ php:
   - 7.4
   - "nightly"
 
-# Rather than a `matrix` property, we use build stages. This allows early
-# build failure for basic linting and sniffing issues.
-# @link https://docs.travis-ci.com/user/build-stages/
-
-stages:
-  - lint
-  - sniff
-  - test
-
 jobs:
   allow_failures:
     - php: "nightly"
   include:
-
-    - stage: lint
-      php: 7.4
-      env: PHPCS_BRANCH="dev-master"
-      before_install: phpenv config-rm xdebug.ini || echo 'No xdebug config.'
-      install: skip
-      cache: skip
-      script:
-        # Lint the PHP files against parse errors.
-        - ./bin/php-lint
-
-        # Add PHPCS locally for the XSD.
-        - travis_retry composer require squizlabs/php_codesniffer
-        # Validate the XML files and check the code-style consistency of the XML files.
-        - ./bin/xml-lint
-
-        # Validate the composer.json file.
-        # @link https://getcomposer.org/doc/03-cli.md#validate
-        - composer validate --no-check-all --strict
-      addons:
-        apt:
-          packages:
-            - libxml2-utils
-
-    - stage: sniff
-      php: 7.4
-      env: PHPCS_BRANCH="dev-master"
-      before_install: phpenv config-rm xdebug.ini || echo 'No xdebug config.'
-      install: travis_retry composer install --no-suggest
-      script:
-        # Run PHPCS against VIPCS.
-        - ./bin/phpcs
-
     # Builds which need a different distro or specific PHPCS version.
-    - stage: test
     - php: 8.0
       env: PHPCS_BRANCH="dev-master"
     - php: 8.0
@@ -96,7 +53,7 @@ before_install:
   # On stable PHPCS versions, allow for PHP deprecation notices.
   # Unit tests don't need to fail on those for stable releases where those issues won't get fixed anymore.
   - |
-    if [[ "$TRAVIS_BUILD_STAGE_NAME" != "Sniff" && $PHPCS_BRANCH != "dev-master" ]]; then
+    if [[ $PHPCS_BRANCH != "dev-master" ]]; then
       echo 'error_reporting = E_ALL & ~E_DEPRECATED' >> ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/travis.ini
     fi
 

bin/xml-lint

@@ -9,7 +9,6 @@
 #   ./bin/xml-lint
 
 # Validate the ruleset XML files.
-#xmllint --noout --schema ./vendor/squizlabs/php_codesniffer/phpcs.xsd ./*/ruleset.xml
 xmllint --noout --schema ./vendor/squizlabs/php_codesniffer/phpcs.xsd ./*/ruleset.xml
 
 # Check the code-style consistency of the XML files.