Feat #1239: Add support to goto hunk locations from commit view

[txemaotero]

This PR addresses the feature requested on issue #1239

What was implemented?

Two new functionalities on the CommitView buffer. Placing the cursor on a line inside a hunk:

• Pressing <cr>: Jump file at that specific location in the corresponding commit, i.e., if the cursor is at a line added or at a context line, jump to the commit being viewed. If it is on a deleted line, jump to the parent commit. The view of the commit is done in an hidden read-only buffer and pressing q exits it and put you back on the CommitView.
• Pressing a (the default for the new map OpenFileInWorktree) tries to open the file the hunk belongs to but in its current state (current worktree).

Inspiration and design decisions

The <cr> behavior mimics what magit does (see magit-diff-visit-file). Basically, it opens the view of the file in the current CommitView window.

I didn't find an equivalent for the other feature on magit so I took some decisions when opening the file in the current worktree:

• If there is any window managed by the user (not a Neogit handled one), the buffer is opened there.
• If not, open a new tab.

Initially I opted to implement a more destructive approach, i.e., opening the file closes neogit. However, I realized that you can also open a CommitView while rebasing and you don't want to quit neogit in that location. That was the main motivation to change the approach and be more conservative.

Why a by default and not <s-cr> as mentioned in the issue? Mainly because <s-cr> is a problematic map in some shells/environments. I haven't a strong position about a so any suggestion is welcome (note that it shouldn't collide with other mappings, e.g., we cannot use c).

Some implementation notes

Some general notes for the review:

• I found the Hunk class declaration missed some members so I added them in a separate commit
• I've added some documentation for the neogit_commit_buffer section
• Isolated utilities in a new file jump.lua
• Add a test spec for one of the key new utility

Note: I run the test locally and I've got a failure:

Randomized with seed 39550
 0/469 |>                                                                                                                                                                                                                 |  ETA: ??:??:??

  1) Remote Popup prune_branches with a remote configured can launch remote config popup
     Failure/Error: expect(nvim.screen.last).to start_with("Pruned remote origin")
       expected "                                                                                " to start with "Pruned remote origin"
     # ./spec/popups/remote_popup_spec.rb:145:in `block (5 levels) in <top (required)>'
     # ./spec/support/helpers.rb:17:in `block in await'
     # ./spec/support/helpers.rb:16:in `await'
     # ./spec/popups/remote_popup_spec.rb:144:in `block (4 levels) in <top (required)>'
     # ./spec/spec_helper.rb:59:in `block (3 levels) in <top (required)>'
     # ./spec/spec_helper.rb:58:in `block (2 levels) in <top (required)>'
     # ./spec/spec_helper.rb:50:in `block (5 levels) in <top (required)>'
     # ./spec/spec_helper.rb:47:in `chdir'
     # ./spec/spec_helper.rb:47:in `block (4 levels) in <top (required)>'
     # ./spec/spec_helper.rb:44:in `block (3 levels) in <top (required)>'
     # ./spec/spec_helper.rb:43:in `block (2 levels) in <top (required)>'

 469/469 |===================================================================================================== 100 =====================================================================================================>| Time: 00:04:16

However, the same failure is reproducible on the master branch so, not related with the changes.

[CKolkey]

I think this is really great! Thank you for taking the time to work on this. I'll test-drive this over the week to see if any issues arise, but I don't really have anything I'd want changed (besides linting stuff). Really good stuff.

[txemaotero]

Thank you! I've pushed the fixes for the linting errors (I knew I was missing something 😅 )

I feel quite confortable now navigating the code so I don't discard contributing again with more fixes, features, documentation or whatever. I really like this plugin and I think this is good a way of expressing my gratitude 😄

[CKolkey]

Anything you want to contribute will be appreciated :D As you can see from the commit graph, I haven't had time for this project in about a year, and I don't foresee that changing any time soon. Let me know if you have any questions, and I'll be happy to assist as much as I can.

[txemaotero]

Hey @CKolkey , I'm really sorry 🙏 but there was a bug introduced by this PR. I catch it some minutes ago using the feature branch at work. Then I saw you already merged 😓 I've opened a new PR to fix it. Take a look and I recommend to merge ASAP because it can be really annoying.

[CKolkey]

No worries, thanks for catching and fixing it so quickly :)