oliverdavies.uk/content/node.7064860b-42de-47c3-b5ac-3560d941fe0f.yml

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title:
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      <p>Today, whilst working on <a href="/daily/2024/02/19/introducing-versa">Versa</a>, I was experimenting with different PHPStan levels.</p>

      <p>Level 1 is the least strict level, and applies the fewest rules and returns the fewest results.</p>

      <p>As you increase the level, the stricter PHPStan is.</p>

      <h2 id="levelling-up-to-9">Levelling up to 9</h2>

      <p>Here is the code to get the values of the <code>--extra-args</code> and <code>--working-dir</code> options:</p>

      <pre><code class="language-php">$extraArgs = $input-&gt;getOption('extra-args');
      $workingDir = $input-&gt;getOption('working-dir');
      </code></pre>

      <p>This passed PHPStan level 8, but these are the errors I get when running level 9:</p>

      <pre><code class="language-plain">------ ------------------------------------------------------------------------------------------------------- Line   versa
      ------ ------------------------------------------------------------------------------------------------------- 61     Parameter $extraArgs of static method App\Process\Process::create() expects string|null, mixed given.
       62     Parameter $workingDir of static method App\Process\Process::create() expects string, mixed given.
       72     Parameter $extraArgs of static method App\Process\Process::create() expects string|null, mixed given.
       73     Parameter $workingDir of static method App\Process\Process::create() expects string, mixed given.
       84     Parameter $extraArgs of static method App\Process\Process::create() expects string|null, mixed given.
       85     Parameter $workingDir of static method App\Process\Process::create() expects string, mixed given.
       94     Parameter $extraArgs of static method App\Process\Process::create() expects string|null, mixed given.
       95     Parameter $workingDir of static method App\Process\Process::create() expects string, mixed given.
       104    Parameter $extraArgs of static method App\Process\Process::create() expects string|null, mixed given.
       105    Parameter $workingDir of static method App\Process\Process::create() expects string, mixed given.
       119    Parameter $extraArgs of static method App\Process\Process::create() expects string|null, mixed given.
       120    Parameter $workingDir of static method App\Process\Process::create() expects string, mixed given.
      ------ ------------------------------------------------------------------------------------------------------- [ERROR] Found 12 errors
      </code></pre>

      <p>The issue is that <code>$input-&gt;getOption()</code> from Symfony's <code>InputInterface</code> returns <code>mixed</code> - even though it always returns <code>null</code> or a string.</p>

      <p>If I did <code>--working-dir 2</code>, it would return the string <code>"2"</code>.</p>

      <p>An empty string throws an error, and an empty value (if there are no extra arguments) returns <code>null</code>.</p>

      <p>So, I know <code>$workingDir</code> will always be a string and <code>$extraArgs</code> will either a string or <code>null</code>.</p>

      <h2 id="passing-level-8">Passing level 8</h2>

      <p>To pass level 8, PHPStan needs to be sure the variables are what I think they are.</p>

      <p>Here's the code I can use to get it to pass:</p>

      <pre><code class="language-php">$extraArgs = $input-&gt;getOption('extra-args');
      $workingDir = $input-&gt;getOption('working-dir');
      assert(is_string($extraArgs) || is_null($extraArgs));
      assert(is_string($workingDir));
      </code></pre>

      <p>By using <code>assert()</code> and throwing an Exception if the condition fails, PHPStan is now happy with the code and my code passes level 9.</p>

      <h2 id="here%27s-the-thing">Here's the thing</h2>

      <p>Although the extra code gets PHPStan to pass, it it worth it?</p>

      <p>Is this extra code adding value? Does it make the code more readable or is it likely to prevent a bug?</p>

      <p>In this case, I know the value will always be the type I expect.</p>

      <p>I can work around this using a baseline or annotations for PHPStan to ignore these lines, <strong>or is level 8 good enough for this project</strong>?</p>

      <p>Similar to 100% test coverage, is aiming for the highest PHPStan level an objective to be met, or is enough value being added added by the lower level?</p>

      <p>Which level is right for you and this codebase?</p>

              
    format: full_html
    processed: |
      <p>Today, whilst working on <a href="/daily/2024/02/19/introducing-versa">Versa</a>, I was experimenting with different PHPStan levels.</p>

      <p>Level 1 is the least strict level, and applies the fewest rules and returns the fewest results.</p>

      <p>As you increase the level, the stricter PHPStan is.</p>

      <h2 id="levelling-up-to-9">Levelling up to 9</h2>

      <p>Here is the code to get the values of the <code>--extra-args</code> and <code>--working-dir</code> options:</p>

      <pre><code class="language-php">$extraArgs = $input-&gt;getOption('extra-args');
      $workingDir = $input-&gt;getOption('working-dir');
      </code></pre>

      <p>This passed PHPStan level 8, but these are the errors I get when running level 9:</p>

      <pre><code class="language-plain">------ ------------------------------------------------------------------------------------------------------- Line   versa
      ------ ------------------------------------------------------------------------------------------------------- 61     Parameter $extraArgs of static method App\Process\Process::create() expects string|null, mixed given.
       62     Parameter $workingDir of static method App\Process\Process::create() expects string, mixed given.
       72     Parameter $extraArgs of static method App\Process\Process::create() expects string|null, mixed given.
       73     Parameter $workingDir of static method App\Process\Process::create() expects string, mixed given.
       84     Parameter $extraArgs of static method App\Process\Process::create() expects string|null, mixed given.
       85     Parameter $workingDir of static method App\Process\Process::create() expects string, mixed given.
       94     Parameter $extraArgs of static method App\Process\Process::create() expects string|null, mixed given.
       95     Parameter $workingDir of static method App\Process\Process::create() expects string, mixed given.
       104    Parameter $extraArgs of static method App\Process\Process::create() expects string|null, mixed given.
       105    Parameter $workingDir of static method App\Process\Process::create() expects string, mixed given.
       119    Parameter $extraArgs of static method App\Process\Process::create() expects string|null, mixed given.
       120    Parameter $workingDir of static method App\Process\Process::create() expects string, mixed given.
      ------ ------------------------------------------------------------------------------------------------------- [ERROR] Found 12 errors
      </code></pre>

      <p>The issue is that <code>$input-&gt;getOption()</code> from Symfony's <code>InputInterface</code> returns <code>mixed</code> - even though it always returns <code>null</code> or a string.</p>

      <p>If I did <code>--working-dir 2</code>, it would return the string <code>"2"</code>.</p>

      <p>An empty string throws an error, and an empty value (if there are no extra arguments) returns <code>null</code>.</p>

      <p>So, I know <code>$workingDir</code> will always be a string and <code>$extraArgs</code> will either a string or <code>null</code>.</p>

      <h2 id="passing-level-8">Passing level 8</h2>

      <p>To pass level 8, PHPStan needs to be sure the variables are what I think they are.</p>

      <p>Here's the code I can use to get it to pass:</p>

      <pre><code class="language-php">$extraArgs = $input-&gt;getOption('extra-args');
      $workingDir = $input-&gt;getOption('working-dir');
      assert(is_string($extraArgs) || is_null($extraArgs));
      assert(is_string($workingDir));
      </code></pre>

      <p>By using <code>assert()</code> and throwing an Exception if the condition fails, PHPStan is now happy with the code and my code passes level 9.</p>

      <h2 id="here%27s-the-thing">Here's the thing</h2>

      <p>Although the extra code gets PHPStan to pass, it it worth it?</p>

      <p>Is this extra code adding value? Does it make the code more readable or is it likely to prevent a bug?</p>

      <p>In this case, I know the value will always be the type I expect.</p>

      <p>I can work around this using a baseline or annotations for PHPStan to ignore these lines, <strong>or is level 8 good enough for this project</strong>?</p>

      <p>Similar to 100% test coverage, is aiming for the highest PHPStan level an objective to be met, or is enough value being added added by the lower level?</p>

      <p>Which level is right for you and this codebase?</p>

              
    summary: null
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