Static analysis & Travis updates (#1861)

* Add phpstan static analysis to travis config
* Add phpstan configuration
* Add PHP 7.4 to travis CI
* Config changes
* Add changelog
* Update contributing guidelines

.changes/nextrelease/static_analysis.json

@@ -0,0 +1,7 @@
+[
+  {
+    "type": "enhancement",
+    "category": "",
+    "description": "Added static code analysis using PHPStan to Travis CI configuration."
+  }
+]

.travis.yml

@@ -9,6 +9,7 @@ php:
   - 7.1
   - 7.2
   - 7.3
+  - 7.4
   - hhvm
   - nightly
 env:
@@ -19,23 +20,56 @@ matrix:
   allow_failures:
     - php: hhvm
     - php: nightly
+    - php: 7.4
   fast_finish: true
 
 sudo: false
 
 install:
+  # Setup environment variables for testing
   - export AWS_ACCESS_KEY_ID=foo
   - export AWS_SECRET_ACCESS_KEY=bar
   - export AWS_CSM_ENABLED=false
-  - 'if [ $(phpenv version-name) == "5.5" ]; then rm ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/xdebug.ini; fi'
-  - 'if [ $(phpenv version-name) != "hhvm" ] && [ $(phpenv version-name) != "nightly" ]; then echo "xdebug.overload_var_dump = 0" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini; fi'
-  - 'if { [ $(phpenv version-name) == "7.2" ] || [ $(phpenv version-name) == "7.3" ]; } && [ -v COMPOSER_OPTS ]; then composer require --dev phpunit/phpunit "^5.7.11"; fi'
+
+  # Build job specific tweaks
+  - >
+    if [ $(phpenv version-name) == "5.5" ]; then
+      rm ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/xdebug.ini
+    fi
+
+  - >
+    if [ $(phpenv version-name) != "hhvm" ] && [ $(phpenv version-name) != "nightly" ]; then
+      echo "xdebug.overload_var_dump = 0" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
+    fi
+
+  - >
+    if { [ $(phpenv version-name) == "7.2" ] || [ $(phpenv version-name) == "7.3" ]; } && [ -v COMPOSER_OPTS ]; then
+      composer require --dev phpunit/phpunit "^5.7.11"
+    fi
+
+  # Resolve dependencies
   - composer --version
   - travis_retry composer update $COMPOSER_OPTS --no-interaction --prefer-source
 
 script:
+  # Unit tests
   - make test
+
+  # Static analysis
+  - >
+    test_versions=("7.1" "7.2" "7.3" "7.4");
+    if [[ " ${test_versions[@]} " =~ " $(phpenv version-name) " ]] && [ -z $COMPOSER_OPTS ]; then
+      composer require --dev nette/neon "^3.0"
+      composer require --dev phpstan/phpstan
+      vendor/bin/phpstan analyse src
+    fi
+
+  # Package generation
   - if [ -z "$COMPOSER_OPTS" ]; then make package; fi
 
 after_success:
-  - 'if [ $(phpenv version-name) == "7.1" ]; then bash <(curl -s https://codecov.io/bash); fi'
+  # Code coverage report
+  - >
+    if [ $(phpenv version-name) == "7.1" ]; then
+      bash <(curl -s https://codecov.io/bash)
+    fi

CONTRIBUTING.md

@@ -14,6 +14,11 @@ your [issues][] or [pull requests][pull-requests] through GitHub.
    The [PHP CS Fixer][cs-fixer] tool can be helpful for formatting your code.
 1. We maintain a high percentage of code coverage in our unit tests. If you make
    changes to the code, please add, update, and/or remove tests as appropriate.
+1. Static code analysis with [PHPStan][phpstan] is automatically run on the `src` 
+   directory for submitted pull requests. If there is a case that needs to be
+   ignored by static analysis, please update the `ignoreErrors` section in the
+   `phpstan.neon` config file in your PR, and point out why this case warrants
+   ignoring.
 1. We may choose not to accept pull requests that change files in the `src/data`
    directory, since we generate these files based on our internal knowledge of
    the AWS services. Please check in with us ahead of time if you find a mistake
@@ -73,6 +78,7 @@ category field should exist with the value set to an empty string `""`.
 [cla]: https://github.com/aws/aws-cla/blob/master/amazon-single-contribution-license.txt
 [php-fig]: http://php-fig.org
 [cs-fixer]: http://cs.sensiolabs.org/
+[phpstan]: https://github.com/phpstan/phpstan
 [sphinx]: http://sphinx-doc.org/
 [restructuredtext]: http://sphinx-doc.org/rest.html
 [docs-readme]: https://github.com/aws/aws-sdk-php/blob/master/docs/README.md

phpstan.neon

@@ -0,0 +1,22 @@
+parameters:
+
+  level: 0
+
+  excludes_analyse:
+    # Guzzle V5 classes & interfaces changed in V6
+    - %rootDir%/../../../src/Handler/GuzzleV5/*
+
+  ignoreErrors:
+    # Intentional
+    - '#Aws\\Api\\Parser\\Crc32ValidatingParser::__construct\(\) does not call parent constructor from Aws\\Api\\Parser\\AbstractParser\.#'
+    - '#Aws\\S3\\(RetryableMalformedResponse|GetBucketLocation|AmbiguousSuccess)Parser::__construct\(\) does not call parent constructor from Aws\\Api\\Parser\\AbstractParser\.#'
+
+    # HashContext definition sometimes not found by static analysis
+    - '#Property Aws\\PhpHash::\$context has unknown class HashContext as its type\.#'
+    - '#Property Aws\\Api\\Parser\\DecodingEventStreamIterator::\$hashContext has unknown class HashContext as its type\.#'
+    - '#Return typehint of method Aws\\PhpHash::getContext\(\) has invalid type HashContext\.#'
+
+    # Guzzle V5 classes & interfaces changed in V6
+    - '#Call to an undefined static method GuzzleHttp\\Client::getDefaultUserAgent\(\)\.#'
+
+  reportUnmatchedIgnoredErrors: false