psalm.xml

<?xml version="1.0"?>
<psalm
  autoloader="web/autoload-psalm.php"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns="https://getpsalm.org/schema/config"
  xsi:schemaLocation="https://getpsalm.org/schema/config file:///app/vendor/vimeo/psalm/config.xsd"
  findUnusedCode="false"
  findUnusedBaselineEntry="true"
  findUnusedVariablesAndParams="true"
>

  <projectFiles>
    <directory name="web/modules/custom"/>

    <ignoreFiles allowMissingFiles="true">
      <directory name="vendor"/>
      <directory name="web/core"/>
      <directory name="web/modules/contrib"/>
      <directory name="web/themes/contrib"/>
    </ignoreFiles>
  </projectFiles>

  <fileExtensions>
    <extension name=".php"/>
    <extension name=".module"/>
    <extension name=".inc"/>
    <extension name=".theme"/>
    <extension name=".install"/>
    <extension name=".profile"/>
  </fileExtensions>

  <issueHandlers>
    <!-- level 3 issues - slightly lazy code writing, but provably low false-negatives -->
    <DeprecatedInterface errorLevel="info"/>
    <PropertyNotSetInConstructor errorLevel="info"/>
    <NoInterfaceProperties errorLevel="info"/>
    <MoreSpecificReturnType errorLevel="info"/>
    <LessSpecificReturnStatement errorLevel="info"/>
    <MissingConstructor errorLevel="info"/>

    <!-- Do not take into account errors with Drupal\Tests\UnitTestCase -->
    <!--  https://github.com/vimeo/psalm/issues/841#issuecomment-401668742  -->
    <UndefinedClass>
      <errorLevel type="suppress">
        <directory name="web/modules/custom/*/tests" />
      </errorLevel>
    </UndefinedClass>

    <!-- Do not take into account undefined methods in tests (results from the above) -->
    <UndefinedMethod>
      <errorLevel type="suppress">
        <directory name="web/modules/custom/*/tests" />
      </errorLevel>
    </UndefinedMethod>

    <MissingDependency>
      <errorLevel type="suppress">
        <directory name="web/modules/custom/*/tests" />
      </errorLevel>
    </MissingDependency>

    <!-- Suppress some errors -->
    <!-- @see https://github.com/vimeo/psalm/blob/master/docs/dealing_with_code_issues.md -->

    <!-- Do not take into account errors with Drupal\Tests\UnitTestCase -->
    <!--    <UndefinedClass>-->
    <!--      <errorLevel type="suppress">-->
    <!--        <directory name="web/modules/custom/*/tests" />-->
    <!--      </errorLevel>-->
    <!--    </UndefinedClass>-->

    <!-- Do not take into account undefined methods in tests (results from the above) -->
    <!--    <UndefinedMethod>-->
    <!--      <errorLevel type="suppress">-->
    <!--        <directory name="web/modules/custom/*/tests" />-->
    <!--      </errorLevel>-->
    <!--    </UndefinedMethod>-->
  </issueHandlers>

</psalm>