Code quality: fix implicit null deprecations

.devcontainer/devcontainer.json

@@ -15,7 +15,14 @@
         "mehedidracula.php-namespace-resolver"
       ],
       "settings": {
-        "php.validate.executablePath": "/usr/local/bin/php"
+        "php.validate.executablePath": "/usr/local/bin/php",
+        "terminal.integrated.defaultProfile.linux": "bash",
+        "terminal.integrated.profiles.linux": {
+          "bash": {
+            "path": "/bin/bash",
+            "args": ["-l"]
+          }
+        }
       }
     }
   },

.github/workflows/phpstan-baseline.yml

@@ -0,0 +1,41 @@
+name: PHPStan Baseline Check
+
+on:
+  pull_request:
+    branches: [ main, master ]
+    paths:
+      - 'src/**/*.php'
+
+jobs:
+  phpstan:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        php-version: ['8.4']
+      fail-fast: false
+
+    steps:
+    - uses: actions/checkout@v5
+
+    - name: Setup PHP
+      uses: shivammathur/setup-php@v2
+      with:
+        php-version: ${{ matrix.php-version }}
+        extensions: dom, json, libxml
+        coverage: xdebug
+
+    - name: Cache Composer packages
+      id: composer-cache
+      uses: actions/cache@v4
+      with:
+        path: vendor
+        key: ${{ runner.os }}-php-${{ matrix.php-version }}-${{ hashFiles('**/composer.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-php-${{ matrix.php-version }}-
+
+    - name: Install dependencies
+      run: composer install --prefer-dist --no-progress
+
+    - name: Run PHPStan with baseline
+      run: vendor/bin/phpstan analyse --error-format=github

docs/codecontributions.md

@@ -0,0 +1,63 @@
+# Code Quality
+
+This project uses PHPStan for static analysis and Rector for automated code refactoring to maintain high code quality standards.
+
+## PHPStan - Static Analysis
+
+PHPStan analyzes the code for potential issues and type safety problems. The configuration is stored in `phpstan.neon.dist`.
+
+### Generate a new baseline
+When introducing PHPStan to legacy code or after major refactoring, you can create a baseline to suppress existing errors:
+```bash
+vendor/bin/phpstan analyse --generate-baseline
+```
+
+### Run analysis
+To analyze the codebase and find issues:
+```bash
+vendor/bin/phpstan analyse
+```
+
+### Configuration
+- Configuration file: `phpstan.neon.dist`
+- Current analysis level: 5
+- Baseline file: `phpstan-baseline.neon` (suppresses known issues)
+
+## Rector - Automated Refactoring
+
+Rector automatically modernizes PHP code and applies coding standards. The configuration is stored in `rector.php`.
+
+### Preview changes (recommended first step)
+Run a dry-run to see what changes Rector would make without actually modifying files:
+```bash
+vendor/bin/rector process --dry-run
+```
+
+### Apply changes
+Apply the refactoring rules to actually modify the code:
+```bash
+vendor/bin/rector process
+```
+
+### Debug mode
+To see detailed information about what Rector is doing:
+```bash
+vendor/bin/rector process --dry-run --debug
+```
+
+### Finding new rules
+To discover additional Rector rules for your project, visit: https://getrector.com/find-rule
+
+## Workflow
+
+1. **Before making changes**: Run `vendor/bin/phpstan analyse` to check current code quality
+2. **Use Rector for improvements**: Run `vendor/bin/rector process --dry-run` to preview automated fixes
+3. **Apply safe changes**: Run `vendor/bin/rector process` to apply the changes
+4. **Verify with tests**: Run `make test` to ensure changes don't break functionality
+5. **Final analysis**: Run `vendor/bin/phpstan analyse` to confirm improvements
+
+## CI/CD Integration
+
+Both PHPStan and Rector are integrated into the CI pipeline to ensure:
+- No new PHPStan errors are introduced (beyond the baseline)
+- Code follows modern PHP practices through Rector

mkdocs.yml

@@ -1,3 +1,7 @@
 site_name: feed-io Documentation
 theme:
   name: material
+
+nav:
+  - Home: index.md
+  - Code Quality: codecontributions.md

phpstan-baseline.neon

@@ -0,0 +1,49 @@
+parameters:
+	ignoreErrors:
+		-
+			message: '#^Call to an undefined method FeedIo\\Feed\\ItemInterface\:\:setHostInContent\(\)\.$#'
+			identifier: method.notFound
+			count: 1
+			path: src/FeedIo/Feed.php
+
+		-
+			message: '#^Call to an undefined method FeedIo\\Feed\\ItemInterface\:\:setLinkForAnalysis\(\)\.$#'
+			identifier: method.notFound
+			count: 1
+			path: src/FeedIo/Parser/XmlParser.php
+
+		-
+			message: '#^Deprecated in PHP 8\.0\: Required parameter \$url follows optional parameter \$modifiedSince\.$#'
+			identifier: parameter.requiredAfterOptional
+			count: 1
+			path: src/FeedIo/Reader/Result.php
+
+		-
+			message: '#^Deprecated in PHP 8\.1\: Required parameter \$response follows optional parameter \$modifiedSince\.$#'
+			identifier: parameter.requiredAfterOptional
+			count: 1
+			path: src/FeedIo/Reader/Result.php
+
+		-
+			message: '#^Offset float on list in isset\(\) does not exist\.$#'
+			identifier: isset.offset
+			count: 1
+			path: src/FeedIo/Reader/Result/UpdateStats.php
+
+		-
+			message: '#^Call to an undefined method FeedIo\\Feed\\NodeInterface\:\:getHostFromLink\(\)\.$#'
+			identifier: method.notFound
+			count: 1
+			path: src/FeedIo/Rule/Atom/Link.php
+
+		-
+			message: '#^Call to an undefined method FeedIo\\Feed\\NodeInterface\:\:getHostFromLink\(\)\.$#'
+			identifier: method.notFound
+			count: 1
+			path: src/FeedIo/Rule/Link.php
+
+		-
+			message: '#^PHPDoc tag @var with type FeedIo\\Reader\\FixerAbstract is not subtype of native type FeedIo\\Reader\\Fixer\\HttpLastModified\|FeedIo\\Reader\\Fixer\\PublicId\.$#'
+			identifier: varTag.nativeType
+			count: 1
+			path: src/FeedIo/Specification.php

phpstan.neon.dist

@@ -1,3 +1,6 @@
+includes:
+	- phpstan-baseline.neon
+
 parameters:
     errorFormat: table
     level: 5

src/FeedIo/Adapter/ClientInterface.php

@@ -21,5 +21,5 @@ interface ClientInterface
      * @throws \FeedIo\Adapter\ServerErrorException
      * @return \FeedIo\Adapter\ResponseInterface
      */
-    public function getResponse(string $url, DateTime $modifiedSince = null): ResponseInterface;
+    public function getResponse(string $url, ?DateTime $modifiedSince = null): ResponseInterface;
 }

src/FeedIo/Adapter/FileSystem/Client.php

@@ -20,7 +20,7 @@ class Client implements ClientInterface
      * @return \FeedIo\Adapter\ResponseInterface
      *@throws \FeedIo\Adapter\NotFoundException
      */
-    public function getResponse(string $path, DateTime $modifiedSince = null): ResponseInterface
+    public function getResponse(string $path, ?DateTime $modifiedSince = null): ResponseInterface
     {
         if (file_exists($path)) {
             return new Response(

src/FeedIo/Adapter/Http/Client.php

@@ -25,7 +25,7 @@ public function __construct(private readonly PsrClientInterface $client)
      * @return ResponseInterface
      * @throws ClientExceptionInterface
      */
-    public function getResponse(string $url, DateTime $modifiedSince = null): ResponseInterface
+    public function getResponse(string $url, ?DateTime $modifiedSince = null): ResponseInterface
     {
         if ($modifiedSince) {
             $headResponse = $this->request('HEAD', $url, $modifiedSince);
@@ -44,7 +44,7 @@ public function getResponse(string $url, DateTime $modifiedSince = null): Respon
      * @return ResponseInterface
      * @throws ClientExceptionInterface
      */
-    protected function request(string $method, string $url, DateTime $modifiedSince = null): ResponseInterface
+    protected function request(string $method, string $url, ?DateTime $modifiedSince = null): ResponseInterface
     {
         $headers = [];
 

src/FeedIo/Adapter/NullClient.php

@@ -16,7 +16,7 @@ class NullClient implements ClientInterface
      * @param  DateTime|null                         $modifiedSince
      * @return \FeedIo\Adapter\ResponseInterface
      */
-    public function getResponse(string $url, DateTime $modifiedSince = null): ResponseInterface
+    public function getResponse(string $url, ?DateTime $modifiedSince = null): ResponseInterface
     {
         return new NullResponse();
     }

src/FeedIo/Explorer.php

@@ -36,7 +36,7 @@ public function discover(string $url): array
         return $feeds;
     }
 
-    protected function extractFeeds(string $html, string $url = null): array    
+    protected function extractFeeds(string $html, ?string $url = null): array    
     {
         $dom = new DOMDocument();
         $dom->loadHTML($html);

src/FeedIo/Feed.php

@@ -49,7 +49,7 @@ public function getUrl(): ?string
      * @param string|null $url
      * @return FeedInterface
      */
-    public function setUrl(string $url = null): FeedInterface
+    public function setUrl(?string $url = null): FeedInterface
     {
         $this->url = $url;
 
@@ -64,7 +64,7 @@ public function getDescription(): ?string
         return $this->description;
     }
 
-    public function setDescription(string $description = null): FeedInterface
+    public function setDescription(?string $description = null): FeedInterface
     {
         $this->description = $description;
 
@@ -76,7 +76,7 @@ public function getLanguage(): ?string
         return $this->language;
     }
 
-    public function setLanguage(string $language = null): FeedInterface
+    public function setLanguage(?string $language = null): FeedInterface
     {
         $this->language = $language;
 
@@ -88,7 +88,7 @@ public function getLogo(): ?string
         return $this->logo;
     }
 
-    public function setLogo(string $logo = null): FeedInterface
+    public function setLogo(?string $logo = null): FeedInterface
     {
         $this->logo = $logo;
 

src/FeedIo/Feed/Item.php

@@ -70,7 +70,7 @@ public function getSummary(): ?string
      * @param string|null $summary
      * @return ItemInterface
      */
-    public function setSummary(string $summary = null): ItemInterface
+    public function setSummary(?string $summary = null): ItemInterface
     {
         $this->summary = $summary;
 
@@ -90,7 +90,7 @@ public function getContent(): ?string
      * @param string|null $content
      * @return ItemInterface
      */
-    public function setContent(string $content = null): ItemInterface
+    public function setContent(?string $content = null): ItemInterface
     {
         $this->content = $content;
 

src/FeedIo/Feed/Item/Author.php

@@ -26,7 +26,7 @@ public function getName(): ?string
      * @param string|null $name
      * @return AuthorInterface
      */
-    public function setName(string $name = null): AuthorInterface
+    public function setName(?string $name = null): AuthorInterface
     {
         $this->name = $name;
 
@@ -45,7 +45,7 @@ public function getUri(): ?string
      * @param string|null $uri
      * @return AuthorInterface
      */
-    public function setUri(string $uri = null): AuthorInterface
+    public function setUri(?string $uri = null): AuthorInterface
     {
         $this->uri = $uri;
 
@@ -64,7 +64,7 @@ public function getEmail(): ?string
      * @param string|null $email
      * @return AuthorInterface
      */
-    public function setEmail(string $email = null): AuthorInterface
+    public function setEmail(?string $email = null): AuthorInterface
     {
         $this->email = $email;
 

src/FeedIo/Feed/Item/AuthorInterface.php

@@ -19,7 +19,7 @@ public function getName(): ?string;
      * @param  string $name
      * @return AuthorInterface
      */
-    public function setName(string $name = null): AuthorInterface;
+    public function setName(?string $name = null): AuthorInterface;
 
     /**
      * @return string
@@ -30,7 +30,7 @@ public function getUri(): ?string;
      * @param  string $uri
      * @return AuthorInterface
      */
-    public function setUri(string $uri = null): AuthorInterface;
+    public function setUri(?string $uri = null): AuthorInterface;
 
     /**
      * @return string
@@ -41,5 +41,5 @@ public function getEmail(): ?string;
      * @param  string $email
      * @return AuthorInterface
      */
-    public function setEmail(string $email = null): AuthorInterface;
+    public function setEmail(?string $email = null): AuthorInterface;
 }

src/FeedIo/Feed/ItemInterface.php

@@ -62,7 +62,7 @@ public function getSummary(): ?string;
      * @param string|null $summary
      * @return ItemInterface
      */
-    public function setSummary(string $summary = null): ItemInterface;
+    public function setSummary(?string $summary = null): ItemInterface;
 
     /**
      * Returns the item's content. Valid for JSONFeed and Atom formats only
@@ -75,5 +75,5 @@ public function getContent(): ?string;
      * @param string|null $content
      * @return ItemInterface
      */
-    public function setContent(string $content = null): ItemInterface;
+    public function setContent(?string $content = null): ItemInterface;
 }