Add "Preserve Settings" configuration safeguards

[calculoso]

Copied from the 1.9.1 thread:

How easy/hard would it be to write a configuration conversion/filter that would prevent bricking when upgrading from a previous firmware and using "Preserve Settings" or when restoring a configuration from a previous firmware/build?

For example: :
- add a "gargoyle version number" file to the configuration

- add a cross-reference table entry for each version that lists configuration files that cannot be directly imported from the last version (or a yes/no for each feature - for example, hosts file reuse - yes, ethers file reuse - yes, wireless configuration - no, etc)
NOTE: This could be on firmware version / build version level, or on module level.

- add logic to the configuration restore and preserve configuration features which looks at the existing firmware version and the configuration to be restored/preserved. This logic would decide what files could be directly re-used without any modification a which could not

- perhaps a dialog could be presented informing the user of the settings that would need to be re-done, and give them an opportunity to cancel it

- extra functionality could be to even convert the files that could not be directly reused into a new usable format? This sounds much harder though...

I'm sure there are lots of configuration files and this may be a big initial step, but at least something like this may prevent the issues that we've seen above.

Thoughts?

[Lantis]

It's a lot of work.
If someone has time to do so, then they are more than welcome to.

I'd much rather people came to the forum and asked first if they were unsure.
If this system is implemented then you are almost making a guarantee that it is safe to preserve. Which it almost always isn't due to the potential for failure even with compatible files.