What reason it persistently analyzes the vendor dir ?

[atlance]

command: vendor/bin/psalm -c psalm.xml --debug-by-line

psalm.xml:

 ...
    <fileExtensions>
        <extension name=".php" />
    </fileExtensions>
    <projectFiles>
        <directory name="src" />
        <ignoreFiles>
            <directory name="vendor" />
            <directory name="tests" />
            <directory name="var/cache" />
        </ignoreFiles>
    </projectFiles>

    <ignoreExceptions>
        <class name="vendor"/>
        <class name="var/cache"/>
    </ignoreExceptions>
 ...

Result:

Getting /app/vendor/doctrine/orm/lib/Doctrine/ORM/Mapping/Driver/AttributeReader.php
Analyzing /app/vendor/doctrine/orm/lib/Doctrine/ORM/Mapping/Driver/AttributeReader.php
/app/vendor/vimeo/psalm/src/Psalm/Internal/Type/SimpleAssertionReconciler.php:1647
/app/vendor/vimeo/psalm/src/Psalm/Internal/Type/SimpleAssertionReconciler.php:1649
Parsing /app/vendor/doctrine/orm/lib/Doctrine/ORM/Mapping/Driver/AttributeReader.php

...

/app/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/Expression/AssertionFinder.php:3440
/app/vendor/friendsofphp/php-cs-fixer/src/Fixer/PhpUnit/PhpUnitConstructFixer.php:108
Uncaught Exception: InvalidArgumentException Could not get class storage for class-string-map
Emitted in /app/vendor/vimeo/psalm/src/Psalm/Internal/Provider/ClassLikeStorageProvider.php:46
Stack trace in the forked worker:
#0 /app/vendor/vimeo/psalm/src/Psalm/Internal/TypeVisitor/TypeChecker.php(364): Psalm\Internal\Provider\ClassLikeStorageProvider->get('class-string-ma...')

All third party package errors in my terminal ... =(

[orklah]

Psalm needs to scan, and sometimes analyse vendors because code in there will have an impact on your own code. For that Psalm need to be able to at least include and parse vendor files.

Here's more details on that: #7289 (comment)