Data loss can occur

[bitbrain]

It appears that sometimes it can happen that a bad save would remove all entities (but not categories). Only resetting to a previous version solves this issue at the moment.

Addressed Cases

• custom entity script does not exist or got moved 🐛 fix invalid entity instantiation #74
• custom entity script is not of type PandoraEntity any longer 🐛 fallback to entity instantiation when script is invalid #87
• custom entity script has compilation errors 🐛 fallback to entity instantiation when script is invalid #87
• custom entity script has an invalid constructor 🐛 fallback to entity instantiation when script is invalid #87
• lock Pandora and prevent saving in case entity data cannot be instantiated (see comment) 🐛 avoid saving state when loading error occurs #101
• lock save mechanism and prevent saving until entity data is able to be parsed correctly for saving (see comment) 🐛 avoid saving state when loading error occurs #101

[bitbrain]

This is still happening in 1.0alpha2 - especially when upgrading Pandora and then saving.

[bitbrain]

In case there has been any bug/issue with parsing PandoraEntity, rather than not loading it (current behavior) we should "lock" the save mechanism and only unblock it after the addon has been "reloaded" - that ideally should happen automatically once the error is fixed. We would need to figure out how exactly Godot notifies on compilation errors.

1. attempt to load Pandora
2. in case loading failed for whatever reason, prevent being able to save (and even use the Pandora UI) but instead retry to load
3. once the compilation errors have been addressed and all entities could be loaded correctly, display the Pandora UI

Once data is loaded successfully, someone could go and again break things - in case trying to save an existing entity results in either a null or empty dictionary, do the same approach:

1. disable the save mechanism until the issue is fixed (and notify the user)
2. once the compilation/error is resolved, auto-save