Post History

We've just released a new feature that allows for redaction of revision histories.

This feature was originally developed by @Taeir for use in his [university's private instance](https://meta.codidact.com/posts/287601) in order to redact cases where students would post exam answers. After some discussion, where we decided that this would be helpful for the public network as well, it's now been released to the communities on our network, after some further development work to ensure that it was good to go on a public instance. (Thank you, Taeir!)

### How does it work?

When you go to edit a post, you now have the option to check the "redact" button:

![Checkbox to select "redact": Redact original content by hiding the previous versions from history?](https://meta.codidact.com/uploads/qwvy25mvolpdjabhknuujzjncbpm)

When ticked, this option hides the details of previous entries in the revision history. This applies the edit and the redaction in **two separate history events**. This means that you don't have to worry about editing to remove the PII and _then_ editing to redact; just edit once and tick the "redact" box.

All events in the revision history before the "history hidden" event will have their details hidden. The hidden revisions are then only visible to administrators, the redacting user, and the author of the post (not moderators at the moment). In order to preserve attribution and abide by the terms of the various licenses in use on the network, each revision item will still be publicly attributed to the user who made the revision, but the specific details of the revision are hidden.

![A "history hidden" revision event as revision #4, showing the version of the post after redaction and the message "Detailed history before this event is hidden because of a redaction." Previous revisions, including two edits and the original post, are hidden with the message "The detailed changes of this event are hidden because of a redaction.", but still show the author of each revision and what action was taken.](https://meta.codidact.com/uploads/c5vvm3uhdd2dv3kfxtjfg4vjky4r)

### When should this tool be used?

This feature should ideally be used sparingly and only in cases where it's necessary. Currently, this feature is available to everyone in order to ensure prompt action in cases where it's needed, but please ensure that it's only used for cases of PII leaks and not unrelated scenarios. We don't currently have a way to "unredact" a post, although this should be available when we implement rollbacks (currently in development). If in doubt, raise a moderator flag; they can evaluate the situation and / or escalate it to the Codidact Team as needed.