How does laravel manage to run composer dump-autoload without emptying the classmap mapping relationship?

question

I see laravel"s composer.json file autoload also does not configure the mapping relationship in vendor/autoload_classmap.php . Normally, if there is no configuration, the array that executes the composer dump-autoload file will not be emptied? But after I execute, the mapping relationship is still there. How does laravel not be emptied? is there any configuration?

Mar.04,2021

after executing composer dump-autoload , it will be deleted and then re-established

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b37a78-4ed16.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b37a78-4ed16.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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