FileFetchTask ignores write failures and deletes the source file with remove_source

[njoubert-cleverage]

Description

FileFetchTask silently ignores write failures on the destination storage, which can lose data:

• the error thrown by writeStream() is caught and discarded: no log, no exception, the process succeeds;
• the task still outputs the file name, as if the copy had succeeded;
• with remove_source: true, the source file is deleted although it was never copied.

Reproduction

local.storage.fetch_failure is a local storage in which demo_fetch_write_failure.txt is a directory, so the write fails:

clever_age_process:
    configurations:
        demo.flysystem.fetch_write_failure:
            tasks:
                content:
                    service: '@CleverAge\ProcessBundle\Task\ConstantOutputTask'
                    options:
                        output: 'Some important data'
                    outputs: [write_source]
                write_source:
                    service: '@CleverAge\ProcessBundle\Task\File\FileWriterTask'
                    options:
                        filename: '%local.storage.dir%/demo_fetch_write_failure.txt'
                    outputs: [block_destination]
                block_destination:
                    service: '@CleverAge\ProcessBundle\Task\File\FileWriterTask'
                    options:
                        filename: '%kernel.project_dir%/var/storage/fetch_failure/demo_fetch_write_failure.txt/blocker'
                    outputs: [filename]
                filename:
                    service: '@CleverAge\ProcessBundle\Task\ConstantOutputTask'
                    options:
                        output: 'demo_fetch_write_failure.txt'
                    outputs: [fetch]
                fetch:
                    service: '@CleverAge\FlysystemProcessBundle\Task\FileFetchTask'
                    options:
                        source_filesystem: 'local.storage'
                        destination_filesystem: 'local.storage.fetch_failure'
                        remove_source: true
                    outputs: [debug]
                debug:
                    service: '@CleverAge\ProcessBundle\Task\Debug\DebugTask'

$ bin/console cleverage:process:execute demo.flysystem.fetch_write_failure
"demo_fetch_write_failure.txt"
Process 'demo.flysystem.fetch_write_failure' executed successfully
$ ls var/storage/local/demo_fetch_write_failure.txt
ls: cannot access 'var/storage/local/demo_fetch_write_failure.txt': No such file or directory

Expected: the task fails with the write error (the error_strategy applies) and the source file is kept.

Tested on main (5e8488f), cleverage/process-bundle 5.1, PHP 8.5, Symfony 7.4.

Cause

FileFetchTask::doFileCopy() catches FilesystemException around writeStream(), then deletes the source whatever the result. execute() ignores the value returned by doFileCopy().

[njoubert-cleverage]

Fixed in #36