When navigating in the commits view to a line that is out of view (e.g. by
pressing , or . to scroll by page, or < or > to scroll to the top or bottom),
the commit graph was not correctly highlighted. Fix this by rerendering the
viewport in this case.
It determines the yellow/red status by getting the merge-base between the
current branch and its upstream; while we're rebasing, the current branch is
HEAD, so it tried to get the merge-base between HEAD and HEAD{u}, which doesn't
work. Fix this by passing the name of the checked-out branch separately.
Previously, when pressing right-arrow when the cursor is already in the last
hunk, it would jump back to the beginning of that hunk. This can be confusing if
the hunk is long, maybe the start of the hunk is already scrolled off the top of
the window, and then pressing right-arrow actually scrolls *backwards*, which is
counter-intuitive. It's better to do nothing in this case.
Same for left-arrow when the cursor is already in the first hunk, although here
the problem is not so severe (unless diff context was increased by a huge
amount, and the start of the first hunk is scrolled off the bottom of the
window).
Previously, the current line was only moved as much as necessary so that it's in
view again. This had the problem that when jumping downwards from hunk to hunk
with the right-arrow key, only the first line of the new hunk was shown at the
bottom of the window. I prefer to put the selected line in the middle of the
view in this case, so that I can see more of the newly selected hunk.
This has the consequence that when scrolling through the view line by line using
down-arrow, the view jumps by half a screen whenever I reach the bottom. I can
see how some users might be opposed to this change, but I happen to like it too,
because it allows me to see more context of what's ahead.
This also fixes a bug where after the rebase each commit in the commits view had a tick against it because we hadn't
refreshed the view since the base commit was no longer marked
There's a bug in LineNumberOfLine, but the existing test coverage doesn't catch
it, as the only test case for this was one where oldStart and newStart were the
same for all hunks. Add a test case where newStart is different for one of the
hunks; this demonstrates a bug, where all expected results from index 12 on are
off by one.
