Allow following file renames in commit history activity

[maniac103]

Fixes #1419

[maniac103]

@Fs00 Please review

[maniac103]

Question: store the setting persistently (similarly to 'wrap lines' in file viewer) or keep default as 'off'?

[Fs00]

This is an interesting feature, although I have a few doubts:

• why would we need an option to enable/disable it? I think it's very easy to miss the existence of the feature if it's disabled by default, and I don't see why a user would want to deliberately ignore older history entries
• I'm not really knowledgeable about RxJava, but what happens if the user rotates the screen while entries belonging to an "older filename" are being displayed? As far as I can see, the RenameFollowData will be lost upon fragment recreation.

Have you considered implementing this functionality with an action at the end of the list that opens the history of the previous filename (if there is one), similarly to what the GitHub web UI does? I think it could spare us dealing with paged lists and their known issues.

[maniac103]

why would we need an option to enable/disable it? I think it's very easy to miss the existence of the feature if it's disabled by default, and I don't see why a user would want to deliberately ignore older history entries

It's not the default behavior for git log either, but needs to be explicitly enabled (git log --follow) there as well.

I'm not really knowledgeable about RxJava, but what happens if the user rotates the screen while entries belonging to an "older filename" are being displayed? As far as I can see, the RenameFollowData will be lost upon fragment recreation.

That's probably right, need to check this. Could likely put it into the saved state.

Have you considered implementing this functionality with an action at the end of the list that opens the history of the previous filename (if there is one), similarly to what the GitHub web UI does?

No, but I consider the current solution more suited because

• it's in line with git log
• the GH UI solution will get 'interesting' with both the fragment and adapter setup (we'd need to insert a dummy item into the list, but how to do that with the paging setup?)