Localizations do not have same master

[MatteoPiovanelli]

I noticed this behaviour, that in light of the recent discussions on localization #7352 we may want to change. I am writing it here in case we actually want to change this behaviour.
This is the scenario:

• In a tenant enable 3+ cultures. In my example I have en-US, it-IT, fr-FR, de-DE.
• Pick an en-US content item (I use the "Welcome to Orchard!" page) that I'll call enItem. Call its ID enID.
• From enItem, create a new translation to the it-IT culture. Call the content item itItem, and its ID itID. In the localization records, you will see that the MasterContentItemId for itItem is enID.
• From itItem, create a new translation to the fr-FR culture. Call the content item frItem, and its ID frID. In the localization records, you will see that the MasterContentItemID for frItem is itID.

The behaviour I would have expected was to have the MasterContentItemID for frItem to be enID, since that is the master for itItem.
As things stand, I could then create an en-US localization of frItem, because the localization part ignores the fact that itItem is already the translation of enItem.
On top of that, If I were to delete itItem I would lose all relations between enItem and frItem (I realize that the record would still be in the LocaliationPartRecord table).

I would suggest that the MasterContentItem is the same for all ContentItems in a translation set.

[sebastienros]

This totally looks wrong. I think it would be logical to always use the same master id, but maybe it's by design,.
Let's ask @Jetski5822 what he thinks.