Tools: Add and configure PHPStan static analysis

.gitignore

@@ -42,6 +42,7 @@ junit.xml
 .wp-env.override.json
 playwright.config.override.ts
 phpcs.xml
+phpstan.neon
 phpunit.xml
 phpunit-watcher.yml
 .tool-versions

composer.json

@@ -22,7 +22,8 @@
 		},
 		"allow-plugins": {
 			"dealerdirect/phpcodesniffer-composer-installer": true,
-			"composer/installers": true
+			"composer/installers": true,
+			"phpstan/extension-installer": true
 		},
 		"lock": false
 	},
@@ -32,7 +33,10 @@
 		"sirbrillig/phpcs-variable-analysis": "^2.8",
 		"spatie/phpunit-watcher": "^1.23",
 		"yoast/phpunit-polyfills": "^1.1.0",
-		"gutenberg/gutenberg-coding-standards": "@dev"
+		"gutenberg/gutenberg-coding-standards": "@dev",
+		"phpstan/extension-installer": "^1.4",
+		"phpstan/phpstan": "^1.12",
+		"szepeviktor/phpstan-wordpress": "^1.3"
 	},
 	"repositories": [
 		{
@@ -47,6 +51,7 @@
 		"composer/installers": "^1.0 || ^2.0"
 	},
 	"scripts": {
+		"analyse": "phpstan analyse -v",
 		"format": "phpcbf --standard=phpcs.xml.dist --report-summary --report-source",
 		"lint": "phpcs --standard=phpcs.xml.dist",
 		"test": "phpunit",

docs/contributors/folder-structure.md

@@ -19,6 +19,7 @@ The following snippet explains how the Gutenberg repository is structured omitti
     ├── .markdownlintignore
     ├── .npmpackagejsonlintrc.json
     ├── phpcs.xml.dist
+    ├── phpstan.neon.dist
     │   Dot files and config files used to configure the various linting tools
     │   used in the repository (PHP, JS, styles...).
     │
@@ -141,5 +142,8 @@ The following snippet explains how the Gutenberg repository is structured omitti
     ├── tools/eslint
     │   Configuration files for the ESLint linter.
     │
+    ├── tools/phpstan
+    │   Configuration files for the PHPStan analysis.
+    │
     ├── tools/webpack
     │   Configuration files for the webpack build.

phpstan.neon.dist

@@ -0,0 +1,34 @@
+# PHPStan configuration for Gutenberg
+#
+# To overload this configuration, copy this file to phpstan.neon and adjust as needed.
+#
+# https://phpstan.org/config-reference
+
+includes:
+  # The WordPress Core configuration file includes the base configuration for the WordPress codebase.
+  - tools/phpstan/base.neon
+  # The baseline file includes preexisting errors in the codebase that should be ignored.
+  # https://phpstan.org/user-guide/baseline
+  - tools/phpstan/baseline/level-0.php
+  - tools/phpstan/baseline/level-1.php
+  - tools/phpstan/baseline/level-2.php
+  - tools/phpstan/baseline/level-3.php
+  - tools/phpstan/baseline/level-4.php
+  - tools/phpstan/baseline/level-5.php
+  - tools/phpstan/baseline/level-6.php
+  - tools/phpstan/baseline/level-7.php
+
+parameters:
+  level: 7
+
+  treatPhpDocTypesAsCertain: false
+
+  ignoreErrors:
+    # @TODO: need to discover these symbols.
+    - '#Function gutenberg_.* not found.#'
+
+    # Level 6:
+
+    # WPCS syntax for iterable types is not supported:
+    -
+      identifier: missingType.iterableValue

tools/phpstan/base.neon

@@ -0,0 +1,26 @@
+# Base PHPStan configuration for Gutenberg
+#
+# This is kept separate from the main PHPStan configuration file to allow for easy overloading while baseline errors are being fixed.
+#
+# https://phpstan.org/config-reference
+
+parameters:
+  # What directories and files should be scanned.
+  paths:
+    - ../../gutenberg.php
+    - ../../post-content.php
+    - ../../lib
+  bootstrapFiles:
+    - bootstrap.php
+    - ../../gutenberg.php
+  scanFiles:
+    - ../../gutenberg.php
+    - ../../post-content.php
+  scanDirectories:
+    - ../../lib
+    - ../../packages
+  excludePaths:
+    analyse:
+      # Exclude files maintained in WordPress Core and backported to Gutenberg.
+      - ../../lib/compat/wordpress-*/html-api/*
+      - ../../packages/block-serialization-spec-parser/parser

tools/phpstan/baseline/level-0.php

@@ -0,0 +1,65 @@
+<?php declare(strict_types = 1);
+
+$ignoreErrors = [];
+$ignoreErrors[] = [
+	// identifier: arguments.count
+	'message' => '#^Callback expects 1 parameter, \\$accepted_args is set to 2\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/block-supports/block-style-variations.php',
+];
+$ignoreErrors[] = [
+	// identifier: return.missing
+	'message' => '#^Function gutenberg_tinycolor_string_to_rgb\\(\\) should return array but return statement is missing\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/block-supports/duotone.php',
+];
+$ignoreErrors[] = [
+	// identifier: return.missing
+	'message' => '#^Method WP_Duotone_Gutenberg\\:\\:get_selector\\(\\) should return string but return statement is missing\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/class-wp-duotone-gutenberg.php',
+];
+$ignoreErrors[] = [
+	// identifier: return.missing
+	'message' => '#^Method WP_Theme_JSON_Gutenberg\\:\\:should_override_preset\\(\\) should return bool but return statement is missing\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/class-wp-theme-json-gutenberg.php',
+];
+$ignoreErrors[] = [
+	// identifier: phpDoc.parseError
+	'message' => '#^One or more @param tags has an invalid name or invalid syntax\\.$#',
+	'count' => 4,
+	'path' => __DIR__ . '/../../../lib/class-wp-theme-json-resolver-gutenberg.php',
+];
+$ignoreErrors[] = [
+	// identifier: class.notFound
+	'message' => '#^Call to static method get_stores\\(\\) on an unknown class WP_Style_Engine_CSS_Rules_Store_Gutenberg\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/client-assets.php',
+];
+$ignoreErrors[] = [
+	// identifier: new.static
+	'message' => '#^Unsafe usage of new static\\(\\)\\.$#',
+	'count' => 2,
+	'path' => __DIR__ . '/../../../lib/compat/wordpress-6.6/class-gutenberg-token-map-6-6.php',
+];
+$ignoreErrors[] = [
+	// identifier: return.missing
+	'message' => '#^Method Gutenberg_REST_Templates_Controller_6_7\\:\\:get_wp_templates_author_text_field\\(\\) should return string but return statement is missing\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/compat/wordpress-6.7/class-gutenberg-rest-templates-controller-6-7.php',
+];
+$ignoreErrors[] = [
+	// identifier: arguments.count
+	'message' => '#^Callback expects 1 parameter, \\$accepted_args is set to 2\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/experimental/kses-allowed-html.php',
+];
+$ignoreErrors[] = [
+	// identifier: arguments.count
+	'message' => '#^Callback expects 1 parameter, \\$accepted_args is set to 2\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/rest-api.php',
+];
+
+return ['parameters' => ['ignoreErrors' => $ignoreErrors]];

tools/phpstan/baseline/level-1.php

@@ -0,0 +1,59 @@
+<?php declare(strict_types = 1);
+
+$ignoreErrors = [];
+$ignoreErrors[] = [
+	// identifier: arguments.count
+	'message' => '#^Function remove_filter invoked with 4 parameters, 2\\-3 required\\.$#',
+	'count' => 4,
+	'path' => __DIR__ . '/../../../lib/block-supports/elements.php',
+];
+$ignoreErrors[] = [
+	// identifier: arguments.count
+	'message' => '#^Function remove_filter invoked with 4 parameters, 2\\-3 required\\.$#',
+	'count' => 3,
+	'path' => __DIR__ . '/../../../lib/block-supports/layout.php',
+];
+$ignoreErrors[] = [
+	// identifier: arguments.count
+	'message' => '#^Function remove_filter invoked with 4 parameters, 2\\-3 required\\.$#',
+	'count' => 2,
+	'path' => __DIR__ . '/../../../lib/block-supports/settings.php',
+];
+$ignoreErrors[] = [
+	// identifier: variable.undefined
+	'message' => '#^Variable \\$filter_id might not be defined\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/class-wp-duotone-gutenberg.php',
+];
+$ignoreErrors[] = [
+	// identifier: isset.variable
+	'message' => '#^Variable \\$area in isset\\(\\) always exists and is not nullable\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/compat/wordpress-6.6/block-template-utils.php',
+];
+$ignoreErrors[] = [
+	// identifier: arguments.count
+	'message' => '#^Class WP_Webfonts constructor invoked with 1 parameter, 0 required\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/experimental/font-face/bc-layer/webfonts-deprecations.php',
+];
+$ignoreErrors[] = [
+	// identifier: arguments.count
+	'message' => '#^Function gutenberg_url invoked with 2 parameters, 1 required\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/experimental/posts/load.php',
+];
+$ignoreErrors[] = [
+	// identifier: variable.undefined
+	'message' => '#^Variable \\$cache_key might not be defined\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/global-styles-and-settings.php',
+];
+$ignoreErrors[] = [
+	// identifier: variable.undefined
+	'message' => '#^Variable \\$cached might not be defined\\.$#',
+	'count' => 1,
+	'path' => __DIR__ . '/../../../lib/global-styles-and-settings.php',
+];
+
+return ['parameters' => ['ignoreErrors' => $ignoreErrors]];