Checking the file checksum on export or import may fail due to sanitizers
The calculated file checksums of the exported
sys_file records in a TYPO3 export dump - made via
EXT:impexp - may not match the actual checksum of the exported file, since the checksum is calculated before the file is copied to the export folder, and the checksum may change during this copying process. The copy process is done by
GeneralUtility::upload_copy_move , which applies arbitrary sanitizers (e.g. SVG sanitizer) under the hood. One solution would be to recalculate the checksum after the file is copied.
The same applies for the import: During import the sanitizers may change the file content and make the final checksum test fail. It has to be checked, if this test should rather raise a notice than an error on failure, or if the test can be modified to still ensure validity.