Compare version vs. OC_VersionCanBeUpgradedFrom before making irreversible changes

[deborahgu]

Steps to reproduce

1. Start with any Owncloud version that's document as being migrateable in the migration document, but is not in the current release's current version.php file's VersionCanBeUpgradedFrom.
2. Run migration either using the automatic migration tool or the steps in the migration document
3. Realize the documents weren't accurate and cry noisily into your beer because you now need to restore your database and all of your files. (Or alternately manually edit version.php, which I did because I verified it was safe to go from 10.0.8. But I shouldn't have.)

Expected behaviour

When the migration tool starts, it should access the version.php file and check if this will be a permissible upgrade path before it clobbers the database or the local /var/www/owncloud directory.

Actual behaviour

When the migration tool starts, it migrates the database and the local /var/www/owncloud directory. Then, at the end, it checks to see if this is permitted and throws an error if it wasn't. This forces users to have to recover the database dump and the files from a backup directory, and restart a fairly complex process.

[MorrisJobke]

cc @jospoortvliet - ref #9493

[nextcloud-bot]

Hey, this issue has been closed because the label stale is set and there were no updates for 14 days. Feel free to reopen this issue if you deem it appropriate.

(This is an automated comment from GitMate.io.)

[deborahgu]

This is still a valid bug.

[ChristophWurst]

I'm closing this ticket because it hasn't received any updates in a long time. If this is still relevant, feel free to re-open or file a new ticket. If you do so make sure to fill out the issue template. I can't tell what version of Nextcloud you're referring to based on the information you provided.

Thank you.