Add phpstan and psalm for static analysis

Author: colinodell

.gitattributes

@@ -5,5 +5,7 @@
 /.gitattributes       export-ignore
 /.github              export-ignore
 /.gitignore           export-ignore
+/phpstan.neon.dist    export-ignore
 /phpunit.xml.dist     export-ignore
+/psalm.xml.dist       export-ignore
 /tests                export-ignore

.github/workflows/tests.yml

@@ -41,3 +41,39 @@ jobs:
 
             - run: vendor/bin/phpunit --coverage-text
               if: ${{ matrix.coverage }}
+
+    phpstan:
+        name: PHPStan
+        runs-on: ubuntu-latest
+
+        steps:
+            - uses: actions/checkout@v2
+
+            - uses: shivammathur/setup-php@v2
+              with:
+                  php-version: 7.1
+                  extensions: curl
+                  coverage: none
+                  tools: composer:v2
+
+            - run: composer update --no-progress
+
+            - run: vendor/bin/phpstan analyse --no-progress
+
+    psalm:
+        name: Psalm
+        runs-on: ubuntu-latest
+
+        steps:
+            - uses: actions/checkout@v2
+
+            - uses: shivammathur/setup-php@v2
+              with:
+                  php-version: 7.1
+                  extensions: curl
+                  coverage: none
+                  tools: composer:v2
+
+            - run: composer update --no-progress
+
+            - run: vendor/bin/psalm --no-progress --output-format=github

.gitignore

@@ -1,4 +1,6 @@
 .phpunit.result.cache
 composer.lock
+phpstan.neon
 phpunit.xml
+psalm.xml
 vendor

composer.json

@@ -26,7 +26,9 @@
         "php": "^7.1 || ^8.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^7.5 || ^8.5 || ^9.3"
+        "phpstan/phpstan": "^0.12.42",
+        "phpunit/phpunit": "^7.5 || ^8.5 || ^9.3",
+        "vimeo/psalm": "^3.14"
     },
     "autoload": {
         "psr-4": {

phpstan.neon.dist

@@ -0,0 +1,4 @@
+parameters:
+  level: max
+  paths:
+    - src

psalm.xml.dist

@@ -0,0 +1,16 @@
+<?xml version="1.0"?>
+<psalm
+    totallyTyped="false"
+    errorLevel="3"
+    resolveFromConfigFile="true"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+>
+    <projectFiles>
+        <directory name="src" />
+        <ignoreFiles>
+            <directory name="vendor" />
+        </ignoreFiles>
+    </projectFiles>
+</psalm>