`DELETE` should throw an error in case that it fails

red / REP

Red Enhancement Process

BSD 3-Clause "New" or "Revised" License

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`DELETE` should throw an error in case that it fails #99

Open Oldes opened 3 years ago

Oldes commented 3 years ago

Although I consider as a nice change, that delete %not-existing-file now returns false instead throwing an error, I still believe, that it should throw an error, if the file exists and cannot be deleted (rights, locked..).

https://gitter.im/red/bugs?at=603278b347585464db91e088

Currently:

>> delete %aaaa
== false
>> delete %/
== false

Expected:

>> delete %aaaa
== false
>> delete %/bin/sh
** Access error: cannot delete: %/bin/sh

The error could also contain a reason, but I'm not sure if it's necessary.

hiiamboris commented 3 years ago

It would indeed be great if error shown a message from the OS. In the console we usually know what's happening but in a GUI program it's simply not nice to show dumb "no can't do" errors. With extra info, programmer will be able to deliver this info to the user.

It's a bigger design question though, what I/O operations should provide more verbosity in errors.

Oldes commented 3 years ago

Possible scenario where the change would be useful:

SCRIPT does some long processing (like compilation), where result is written into FILE
if the FILE is open by another process, SCRIPT fails to save result to this FILE, and the compilation time is wasted
so we may want to first try to delete the FILE before SCRIPT does its job,
but as there is false when FILE is locked and also when does not exists (which is ok), we must do additional check, if file exists.